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TypeFD 03-17-08 03:31 PM

Leaky Injectors Advice - Rebuild or New?
 
2 Attachment(s)
Right, so I was doing my oil change this weekend (93 Touring, 76k mi on the clock) when I sensed a slight scent of fuel coming from under UIM. After removing a little bit of this, taking off a little bit of that, and breaking the other, I ended up at ground zero - the primary injector rail soaked with fuel. Tripped the f/p, and immediately both primary injectors got saturated with fuel. There was fuel even inside the connectors, when I took those off! Everything else looks clean though, even the FPD, which is what I thought it was for sure. So at this point I'm not sure if the injectors stuck closed, or voltage not getting to them (yet to test that) so they're just sitting there drowning in fuel but wanted to run this by and see if I can get feedback from those knowledgeable on the subject matter of as this part of the vehicle has yet to peak my interest, until now.

At this point, all I need to know is the following:
- Any advice on what could be causing this issue?
- If these OEM injectors need cleaning and balancing - is it worth doing that or better to get new ones at this time?
- if replacing new, does it make sense to upgrade in size now, than deal with it in the future when I'm ready to overhaul the entire fuel sys or should I wait and do it all in one time?

This is a bit of unfamiliar territory for me with the exception of replacing F/P and FPD on my previous FD. I don't mind doing the work now but I really don't want to have to revisit this site in the future if I don't have to. This was supposed to be only an oil change, now my FD is grounded for a week!

Thanks in advance for your help!

P.S. While I'm doing this, I might as well replace FPD (OEM?) and do the hose job. Anything else anyone can think of they wish they did when they were dealing with their injectors?

TypeFD 03-17-08 03:40 PM

The car ran fine btw before all this mess. The fuel economy was too low for my liking but other than that, idle and under load no noticeable issues.

TypeFD 03-18-08 08:56 AM

What, can no one chime in on this?

Mahjik 03-18-08 10:44 AM

You need to do a test like this:

https://www.rx7club.com/showpost.php...&postcount=255

This will let you see if you have an issue with the primary injectors for sure. Most places are typically able to repair the injectors when they are serviced.

TypeFD 03-18-08 11:19 AM

Thanks man. I did inspect the rest of the system to verify no leaks anywhere else. It's definitely at the primaries, I let it sit and get dried up and when I tripped the F/P again, I observed the area around the primaries become really saturated with fuel.

Not sure what could've failed like this, I didn't do any recent work in that part of the vehicle and there weren't anything drastic happening. It's like it just started for no obvious reason. Not sure what could go like that except maybe injectors fouled up, but both of them at the same time?

I'll do the test that you did to at least see if they're spraying. If the injectors are fouled out, where can I take them. I'm assuming I will probably also need to get the o-rings, diffusers, and FDP while I'm at it - best place to go?

Mahjik 03-18-08 11:28 AM

If you are getting a leak there, it's most likely the upper o-ring on the injectors. If those fail, you'll get the fuel squirting up like that.

As far as parts for servicing the fuel system, Malloy Mazda will give you the best OEM prices. For injector servicing:

http://www.witchhunter.com/

TypeFD 03-18-08 12:24 PM

Yeah, just did some more digging. It appears that compromised o-rings would be the cause of such issues. So some o-rings would be in order. Does witchhunter still sell viton o-rings or best to get the nitrile ones from Malloy?

Thanks for helping out.

Mahjik 03-18-08 12:33 PM

If you send your injectors out for cleaning (and if you don't know when the last time they have been cleaned, you should take this opportunity to do so), they will provide new o-rings.

Having said that, myself and others have had issues with the o-rings supplied by RC Engineering. I'm not saying they did a horrible job, but their o-rings leaked for me, and a local friend of mine. I had another set cleaned by WitchHunder and I used their o-rings without an issue.

Here is also a post on refreshening the fuel system:

https://www.rx7club.com/3rd-gen-archives-73/injector-removal-reconditioning-replacement-232603/

TypeFD 03-18-08 12:45 PM

Yeah, I was going to just do the o-rings and get some other stuff (diffusers, FDP, etc) but it does make sense to pull them all out and have them cleaned now. I'm going to give witchhunter a shot, will pull primaries/secondaries and send them out. While at it, get the rest of the parts in - shite! so much for a simple oil change! ;)

FWIW: I'll post an update here for others.

Thanks again for the info, certainly helps when diving into the unknown ;)

Regards

TypeFD 03-21-08 04:23 PM

Quick update:

Injectors sent out for cleaning...

- New hose kit with some couples (2.75"IDx3L) ordered from Hose Techniques
- Placed an order with Ray over at Malloy, what a guy - fast, efficient, and courteous. Ended up getting insulators (under the injectors), FPD, diffusers and DTC solenoid (yeah, I broke it).

BTW, Ray mentioned that if diffusers look good and clean with no cracks or anything like that then they may be reused. So I'm going to pull them this weekend (still in the motor) and give 'em a visual inspection anyway.

Good Friday everyone...

Mahjik 03-21-08 04:26 PM


Originally Posted by TypeFD (Post 8004542)
BTW, Ray mentioned that if diffusers look good and clean with no cracks or anything like that then they may be reused. So I'm going to pull them this weekend (still in the motor) and give 'em a visual inspection anyway.

Yep, its rare you 'need' to replace the diffusers (or air bleed sockets). The rubber parts are more of a concern to replace. ;)

TypeFD 03-31-08 05:19 PM

Alright!!! What a fun weekend that was... or rather just Saturday... Let see... here's a recap:

Got the injectors back on Thursday, same day one of the new solenoids to replace the one I broke (trying to take the hose off) came in, also silicone hoses and bunch of other stuff from Ray over at Malloy Mazda like the primary/secondary insulators, FPD, and diffusers... Decided to replace those anyway while I was down there.

So it started all coming back apart Thursday night - 2 hours of making love to my fd which included primarily all the fuel rail work: cleaning, reassembly, hookup, testing, etc... Secondary diffusers went it, insulators on top, then inserted injectors/rail. Primary diffusers went in, then I placed the insulators on the fuel rail and put the whole thing... wanted to make sure nothing got torn or split so did it nice and easy. Once everything was hooked up, bridged F/P and GND at the Diagnostics box and everything seemed cool, no leaking whatsoever. Not sure about the smell though 'cause by that time I had so much shit going between the Carb cleaner, WD40, and degreaser that I probably was as high as a friggin' kite.

Anyway, Friday night, 2 more hours starting to remove all vac hoses... The trick here was to REMOVE ALL solenoids from the rack before attempting to remove hoses. You will need to cut the hoses while for each solenoid and then gently remove the solenoid. Do not attempt to slide any of the hoses off while the solenoid is still on. So, once I isolated each solenoid, I saturated the connection with lots of WD40 and let it soak for 15 min or so... then gently working it back and forth it gave way. There were couple of ones really caked on there... I had to use a pick to splice it while it was on the solenoid and slide it off then. In the end... no broken solenoids at all! That was a gratifying experience.

Resumed on Sat morning for another 10 hours... which completed the job. All the hoses were replaced with silicone ones from Hose Techniques, ended up cleaning and painting the UIM and the elbow, got everything back together and was done about 8pm... decided to go ahead and give it a try and click... click... click... battery dead.

Recharge...

Try again...

Won't start, but it was turning over this time though... Gave it a few more tries... still wouldn't start and the battery was starting to drain. Jumped it. Tried again. Noticed that exhaust was reeking of Carb cleaner which is what I used to clean out the UIM, TB, and the elbow. So figured just needed to purge all that shit out... so kept cranking for 2-3 minutes until it started catching on... Then finally it started... and died... then started again... then died again. Couple of more times like that and I was able to finally start it up and keep it running! Hell yeah, that was awesome, I would've been pissed if I had to tear back into it because I forgot to connect or misconnected something.

Took it for a ride, nice and smooth... boosting 12-8-10psi STRONG... I actually felt my secondary kick in and wholly shit I missed that ALOT!!! It idles nice and smooth (had to adjust the ICV as it was idling too high) so I'm pretty happy at this point.

Couple of follow up items...

Initially, that Sat and Sun... it would start right up when cranking. Today, Monday, I've been driving it around town, etc and it took a bit of cranking for it to start up... not sure if it's the heat soak or plug wires but may look into that to see what's going on.

Another thing... there still a little bit of fuel smell right above the injectors. I was hoping that whatever residue was left over from previous fuel leak/spill was gone or has evaporated but may be not. The smell is quite faint and you can't smell it in the cabin when you turn the fan/air on, but if I stick the nose right up to the UIM I can definitely smell fuel vapor. So, will watch that for the next week see how it goes, if it doesn't go away then I might have to tear back into it - could either be one of the injectors (still) or some hose/valve. All the injectors have brand new o-rings and insulators... I took extra care to make sure that I didn't mix up the bolts on primary and secondary rails so that everything went back to where it all came from... Will keep my fingers crossed.

I'll post some pics in a sec...

TypeFD 03-31-08 05:36 PM

pics
 
4 Attachment(s)
Here some aftermath shots...

TypeFD 04-03-08 10:17 AM

Crap... well, I've got some follow up comments to make...

The /cranking/ observation... seems to be more related to electrical than anything else. Starts right up in the morning when it's cooler and the car's been sitting for a while. Cranks a bit longer during the day when fully warmed up and it's hot out (I'm in FL). Just replaced spark plugs, so could be wires, grounding, etc. Not really a priority right now. Eventually will throw new wires in there and do the grounding mod (which has been on my agenda for months) and will see how that goes.

Here is a part that really pisses me off, there is still fuel smell by the injectors. It's not residue or anything left over, it's something that keeps manifesting itself every time I take a drive. It's faint, but definitely noticeable. Right under the vacuum chamber... shite, so I guess I'm going to take her apart this weekend again. Fek! I thought I was done. Will post follow up later.

TypeFD 05-18-08 09:18 PM

UPDATE...

The most noticeable difference is the fuel economy, I can get about 300mi on a tank in city (un-spirited) driving. Car runs smoother, acceleration is more consistent, and no plumes of smoke under heavy boost.

As for the faint smell, I wasn't able to reproduce it jumping the F/P and GND in Diagnostics, and it eventually went away. I mean there is still a very, very faint odor of what "could" be fuel vapor but at this point, the only time that's even present is after driving, and the motor is hot - makes it unbearable to troubleshoot anything with those conditions.

Like I said, pressurizing the system using the F/P - GND bridge gets no noticeable abnormalities, no fuel, no fuel/vapor odor, nothing. There isn't even a residue around the injectors/rails, it looks just as clean and dry as I had when first put back together.

So I'm going to leave that alone for now. I'm doing some work in the area next weekend which will give me a chance to inspect it again, if I don't find anything then I'll close out the thread.

Cheers

dhays 05-19-08 12:28 AM

First off, nice job on doing all that work. The thought of working on the fuel system and taking apart the rat's nest intimidates the hell out of me. Someday however, I'll need to tackle it.


Originally Posted by TypeFD (Post 8040525)
ended up cleaning and painting the UIM and the elbow, got everything back together and was done about 8pm...

The UIM and elbow look really good. What type of prep and paint did you use on each and how has it held up in the short time that you have had it all running again?

TypeFD 05-19-08 02:49 PM

Hey thanks David,

To answer your question, I used black 1200F ceramic engine paint (Autozone/Napa/PepBoys - all should have it).

The only prep I did was clean the UIM real good, get all the grease, dirt and other debris out, then masked it off and sprayed it with several coats of paint giving about 15min between the first two, then 45min between the rest. I didn't want the coat to be too thick cause it will chip easier if you bang it, so I stopped as soon as I accomplished a nice uniform black layer. Also, I did wet-sand the elbow a little bit to get the surface a little rough for paint to grip. I think I used 400-500grit.

It held up pretty good so far. I've taken the UIM and the elbow off couple of times and didn't notice any scratching, etc... I left the UIM surface porous so even if there was any scratching, it wouldn't show that much. Besides, if there'll be a scratch that'll really bother me, I could always mask it off and touch it up with it still attached, or take it off and hit it with some paint.

I was looking for something that looked good, held up well, and was easy to maintain. I think this was a good solution.

If you're going to do it, just be sure to mask off the locations of the chromed bolts as they'll chip the paint when you put them in.

Cheers

pomanferrari 05-19-08 03:39 PM


Originally Posted by TypeFD (Post 8203835)
UPDATE...



As for the faint smell, I wasn't able to reproduce it jumping the F/P and GND in Diagnostics, and it eventually went away. I mean there is still a very, very faint odor of what "could" be fuel vapor but at this point, the only time that's even present is after driving, and the motor is hot - makes it unbearable to troubleshoot anything with those conditions.

Like I said, pressurizing the system using the F/P - GND bridge gets no noticeable abnormalities, no fuel, no fuel/vapor odor, nothing. There isn't even a residue around the injectors/rails, it looks just as clean and dry as I had when first put back together.


Cheers

My injectors (all 4) had to be replaced at 65K because the heat had damaged the seals on the body so fuel was leaking through the body of each of the 4. New o-rings didn't help because pressurization caused fuel to leak out of the electrical connector.

gracer7-rx7 05-19-08 03:40 PM

You are a brave soul doing that work. :)

Regarding your fuel smell - IIRC, there is a metal check valve that can cause a fuel odor. It is in front of the throttle body to the driver's side of the vac canister.

Since you had everything apart, you may want to check your TPS sensor to make sure it is still in spec - especially if you start getting some odd idle changes or part throttle response. The FAQ has a link to a thread in the Archives by damian.



Other unrelated remarks, consider an aftermarket aluminum AST to replace your stock plastic one (which is prone to splitting open, especially after this many years of heat cycles). Pettit racing has one in FL.

Bleed your brakes. Your brake fluid look very dark.

Consider relocating your battery so you get some more airflow through the rad.

the car and engine bay looks great. Congrats.

TypeFD 05-26-08 10:06 PM


Originally Posted by pomanferrari (Post 8206223)
My injectors (all 4) had to be replaced at 65K because the heat had damaged the seals on the body so fuel was leaking through the body of each of the 4. New o-rings didn't help because pressurization caused fuel to leak out of the electrical connector.

I know this is a bit late but you could've had them rebuilt for pretty cheap. The only sure way to know whether your injectors are gone is to have them flown and tested by a shop that does FI cleaning and servicing. They also replace seals and whatever other parts they can at that time.

New o-rings wouldn't help because the problem is not with sealing, or rather the injector itself is gummed up. This is what was happening to mine, as you can see in the pics, the fuel was not only coming up through the seals but also up in the electrical connector as well.

If you have this happen to you again, just remember to send them up first. It's like $20 for the cleaning, servicing, seals, etc...

Hope this helps.
Cheers

TypeFD 05-26-08 10:27 PM


Originally Posted by gracer7-rx7 (Post 8206226)
You are a brave soul doing that work. :)

Regarding your fuel smell - IIRC, there is a metal check valve that can cause a fuel odor. It is in front of the throttle body to the driver's side of the vac canister.

Since you had everything apart, you may want to check your TPS sensor to make sure it is still in spec - especially if you start getting some odd idle changes or part throttle response. The FAQ has a link to a thread in the Archives by damian.



Other unrelated remarks, consider an aftermarket aluminum AST to replace your stock plastic one (which is prone to splitting open, especially after this many years of heat cycles). Pettit racing has one in FL.

Bleed your brakes. Your brake fluid look very dark.

Consider relocating your battery so you get some more airflow through the rad.

the car and engine bay looks great. Congrats.

Yep, those could be the culprits as well, but the fuel odor was only coming only from the injector area. Couldn't smell anything anywhere else. Did a TPS adjustment a while ago as well, that's a good pointer. That writeup by Damian is a keeper.

Some good observations on the rest of the stuff. I'm actually doing the brakes now, flushing with alcohol to get the old fluid and dirt completely out, and replacing it with silicone for better performance and inhibiting corrosion. Also upgrading to SS brake lines for better response.

The AST and battery I'll do when I replace my OEM rad. Haven't figured out where I'm going to put the battery though, relocating it to the trunk or the passenger compartment bin just don't seem to be the best locations for it. I'll think of something.

BTW, I checked for fuel smell again this weekend and inspected area around it, still dry and clean, with no residue. The faint smell may be lingering but I can't tell anymore. I might be just loosing it ;)

Cheers

TypeFD 11-22-08 09:53 PM

The Sage Continues...
 
Over the last few weeks fuel odor has been getting stronger. After a quick removal of the UIM and flashlight at hand... I have discovered a noticeable fuel leak at the primaries. Jumping the F/P and GND to pressurize and... few minutes later produced a nice little puddle of fule underneath the primary rail.

Gave it a nice careful lookaround and not noticing leaking anywhere else. Seems to be isolated to the primaries.

At this point, I'm thinking it's the seals so I'll have to take the rest of it apart and inspect. I suspect I might have not seated the injectors properly during re-assembly.

To be continued...

rd_turbo 11-23-08 06:09 AM

Sheesh...6 months later....GL with that. I know how annoying that it, not to mention dangerous.

TypeFD 11-30-08 01:11 PM

Alright, so I finally tore at it this weekend. Based on the fuel residue pattern it seems that the leak is coming from the primary injectors... but get this, I can't replicate the fuel leak tripping the F/P and GND connections in the DIAGNOSTICS box. I can hear the pump coming on but no leak! Now I'm not loosing my mind here because I saw the leak last weekend when I took it apart right after my run.

Anyone heard of such intermittent behavior of this problem? Is it because the car has been sitting for a week or is it more related to the level of pressure (which would indicate that it was insufficient in this case to produce the leak).

TypeFD 11-30-08 01:21 PM

Also, at this point I'm thinking the leak here is related to the rubber insulators, or the primary injectors not seated properly...

For now, I'm ruling the injectors out of the equation due to recent cleaning, among with the seals they came with. The insulators are normally dropped into the fuel rail and the injectors go on top of them ensuring a nice, proper fitment and ofcourse, sealing. My suspicion is that the injectors were not seated properly during previous reassembly causing irregularities or a tear in the seal. Overtime the insulators eroded. I haven't had a change to take the old insulators out yet for inspection... will post results as I do.

Mahjik 11-30-08 01:29 PM

Test the fuel system like my link several posts above. If that tests out ok, then check the grommets. I've seen the grommets get pushed down into the injector hole instead of having the rail slide into the place on the primaries.

TypeFD 12-06-08 09:22 AM

Alright, so the last theory is going right out of the window... the insulators are not present where I thought they did, they're seated between the rail and the engine block. Crap.

I still can't track down where it's coming from. I've bridged F/P and GND countless times and I can't replicate the leak. I removed the injectors and bridged the F/P and it's spraying in there with what seems to an ample amount of fuel.

One thing I thought weird... I didn't relieve the fuel pressure when I removed the injector and when I did that, the fuel system was not pressurized - in fact, the injector came out as if I did relieve the fuel pressure. But if anything, the lack of fuel pressure would not contribute to the fuel leak... maybe it's nothing.

I'm going to reassemble everything and see if I can get the fuel leak replicated again with motor running... at this point I'm at a loss. It feels almost as if may be too much fuel is being delivered to the injectors under too much pressure and they're spitting it out through the top and via the connectors.

There is definitely a leak there, I saw the small puddle and there is obvious residue. The hunt continues...

Mahjik 12-06-08 09:34 AM


Originally Posted by TypeFD (Post 8777255)
I removed the injectors and bridged the F/P and it's spraying in there with what seems to an ample amount of fuel.

If you removed the fuel rail, then did the F/P - GND test (like in my link), there should be no fuel coming out of the injectors. The injectors should be off, but the fuel pump pressuring the lines to see if any fuel is leaking anywhere.

TypeFD 12-06-08 09:35 AM


Originally Posted by Mahjik (Post 8760596)
Test the fuel system like my link several posts above. If that tests out ok, then check the grommets. I've seen the grommets get pushed down into the injector hole instead of having the rail slide into the place on the primaries.

Thanks for chiming in mate, I did go over the information you referenced extensively. I was sure to check the o-rings when I pulled the injectors, which looked good and still like-new condition.

I should have taken the picture of this... but I believe the fuel is coming up through the connectors as I found fuel inside the connectors after initially pulling it all off. Then, it was leaking down on the injector and looking like as if the fuel was coming through the o-ring, between the rail and the injector itself.

In any case, I'll try replicating the issue and taking some pics. I can't do jack unless I can get it to leak again right now ;(

Thanks again...

TypeFD 12-06-08 09:38 AM


Originally Posted by Mahjik (Post 8777263)
If you removed the fuel rail, then did the F/P - GND test (like in my link), there should be no fuel coming out of the injectors. The injectors should be off, but the fuel pump pressuring the lines to see if any fuel is leaking anywhere.

Correct... and no leaking was present. I didn't even smell any fuel!

BTW, just so it's clear: in that case, I pulled the injectors out and did the GND-F/P test to see if the fuel was even delivered as I was seeing no leak at that time I was attempting to replicate it - and thought that may be it was a different problem. But the fuel was getting to the injectors so that wasn't the problem.

Mahjik 12-06-08 09:47 AM

Ok, this statement is what's confusing:


Originally Posted by TypeFD (Post 8777255)
I removed the injectors and bridged the F/P and it's spraying in there with what seems to an ample amount of fuel.

At this point, I would recommend just reconditioning your fuel system. New o-rings, grommets, injector cleaning, etc... I posted a link to that earlier in your thread:

https://www.rx7club.com/showthread.php?t=232603

If the parts have been on there for 70k+ miles, it's probably time to have some maintenance done there anyways.

TypeFD 12-06-08 09:49 AM

Whoa whoa whoa dogg, I just got it serviced, the injectors were serviced, new o-rings, grommets, insulators, diffusers, FPD, etc... check out the initial posts (I know, it's a lot of reading).

Mahjik 12-06-08 10:42 AM


Originally Posted by TypeFD (Post 8777282)
Whoa whoa whoa dogg, I just got it serviced, the injectors were serviced, new o-rings, grommets, insulators, diffusers, FPD, etc... check out the initial posts (I know, it's a lot of reading).

How long did you wait before you installed the injectors after the cleaning? Are you using the o-rings from the injector cleaning service or OEM o-rings?

TypeFD 12-06-08 11:30 AM


Originally Posted by Mahjik (Post 8777383)
How long did you wait before you installed the injectors after the cleaning? Are you using the o-rings from the injector cleaning service or OEM o-rings?

Put them in right away, using o-ring that came with the injectors after service. They were green. I believe Auto RnD did the job... there was a group by on the forum they were running a special.

Mahjik 12-06-08 11:48 AM


Originally Posted by TypeFD (Post 8777465)
Put them in right away, using o-ring that came with the injectors after service. They were green. I believe Auto RnD did the job... there was a group by on the forum they were running a special.

I've had issues with non-OEM o-rings. It's possible that your leak requires more load on the system to appear. It's safe to assume that you do have a problem if you have fuel pooling so regardless of when the system was reconditioned. Something either wasn't done properly or you just have bad/damaged injectors.

If it's the injectors, you'll need an injector service company to check/test them. If it's just part of the fuel system, then that's something you can address yourself.

From what I've read, you have two options to go with from here:

1. Purchase OEM o-rings and see if those provide a better seal
2. Send the injectors to an injector company for checking & testing

TypeFD 12-06-08 01:57 PM

I think I've got something!

Now I'm still following this lead but even if that's not the source it's still worth bringing up for whoever tries to troubleshoot similar issues.

Right, so combing over the Workshop Manual I noticed that I'm missing a washer on my Fuel Thermosensor.

Fuel thermosensor is sitting on the secondary rail and when I was getting to put the ACV back on (yeah, the PITA nut underneath) I took the Fuel Thermosensor off for more room to get my hands under the ACV. Well, ofcourse the fuel came out and one thing I noticed is that the "flooding" pattern was very similar, fuel was all over the primaries and then there was a puddle underneath. Even more interesting, there was a puddle of fuel accumulated at the rear of that area... which I was puzzle before who the fuel could've gotten there if it was coming off the injectors since there it's sitting at a higher elevation. Now if it is a Fuel Thermosensor then the fuel could've easily ran down the secondary rail to the rear and dripped there!

Right, so I'm throwing the washer on, soaking up the area with a rag and going to give it a week to make sure the remaining residue is gone.

I'll report back as soon as I have something.

alexdimen 12-06-08 04:57 PM


Originally Posted by TypeFD (Post 8777718)
I think I've got something!

Now I'm still following this lead but even if that's not the source it's still worth bringing up for whoever tries to troubleshoot similar issues.

Right, so combing over the Workshop Manual I noticed that I'm missing a washer on my Fuel Thermosensor.

Fuel thermosensor is sitting on the secondary rail and when I was getting to put the ACV back on (yeah, the PITA nut underneath) I took the Fuel Thermosensor off for more room to get my hands under the ACV. Well, ofcourse the fuel came out and one thing I noticed is that the "flooding" pattern was very similar, fuel was all over the primaries and then there was a puddle underneath. Even more interesting, there was a puddle of fuel accumulated at the rear of that area... which I was puzzle before who the fuel could've gotten there if it was coming off the injectors since there it's sitting at a higher elevation. Now if it is a Fuel Thermosensor then the fuel could've easily ran down the secondary rail to the rear and dripped there!

Right, so I'm throwing the washer on, soaking up the area with a rag and going to give it a week to make sure the remaining residue is gone.

I'll report back as soon as I have something.

My thermosensor threads tore up the o-ring when i removed the sensor from the fuel rail to clean the rail during the rebuild. They are sharp machined brass threads.

Mahjik 12-06-08 05:47 PM

Hopefully that's your problem. However the F/P - GND test is usually able to make that leak if there's a problem with the washer. Good luck!

Sometimes just taking things apart and putting them back a 2nd time fixes the issue (i.e. you didn't do something 'exactly' right the first time but you took more care the 2nd time).

TypeFD 12-07-08 07:44 PM

Well, I've got some good news and some bad news...

Bad news first - after installing a copper washer on the thermosensor I observed no leaking... Unfortunately, I simultaneously observed fuel saturating the primary rail without an apparent source of the leak... again.

Good news - after reassembling everything, getting the motor warmed up... AND... turning the motor off I was finally able to find the source this time. The fuel is coming from the primary injectors - not through the connector, but right from where it sits in the rail - indicative of a bad seal by the existing o-rings.

It was interesting - while the engine was running I saw the area around primaries become evenly saturated with fuel but not strong enough to detect source or even excessive concentration of fuel in any particular area. Only once I turned the motor off, I could instantly see the fuel squirting out of the fuel rail from under the top of the injectors. I also heard a "percolating" sound?! Weird...

I'll call Malloy and order a new set of OEM o-rings for the injectors... Watch for my report next weekend!

Thanks again to all you guys chiming in.

alexdimen 12-07-08 09:03 PM


Originally Posted by TypeFD (Post 8780501)
Well, I've got some good news and some bad news...

Bad news first - after installing a copper washer on the thermosensor I observed no leaking... Unfortunately, I simultaneously observed fuel saturating the primary rail without an apparent source of the leak... again.

Good news - after reassembling everything, getting the motor warmed up... AND... turning the motor off I was finally able to find the source this time. The fuel is coming from the primary injectors - not through the connector, but right from where it sits in the rail - indicative of a bad seal by the existing o-rings.

It was interesting - while the engine was running I saw the area around primaries become evenly saturated with fuel but not strong enough to detect source or even excessive concentration of fuel in any particular area. Only once I turned the motor off, I could instantly see the fuel squirting out of the fuel rail from under the top of the injectors. I also heard a "percolating" sound?! Weird...

I'll call Malloy and order a new set of OEM o-rings for the injectors... Watch for my report next weekend!

Thanks again to all you guys chiming in.

I thought the sensor on the secondary rail was an o-ring seal...

gripp2maxx 12-07-08 09:46 PM

been down this roads with two fd's fun huh..................a+ on your attn detail!!

nguybao 12-07-08 09:57 PM

That's some serious long term troubleshooting! I did my fuel system last month since I was taking everything apart for inspections and maintenance. I sent my injectors to RC Engineering for flow testing and balancing. They replaced the o-rings and I installed new insulators. Haven't had any leaks so far, but when I was seating everything, I used a small mirror and went real slow to check that everything was seating properly.
Some people posted they had problems with RC so I guess I just have to see. I'm using the stock fuel system and sequential twins.

TypeFD 12-12-08 10:15 PM

Shite! Well now I'm pissed... So I spent $50 bucks in getting blasted oem orings from malloy then 4 hours outside putting the shits and today's test drive revealed.... the same damn leak. It's reeking fuel under there and prominent puddle of gas, the only dry areas are actual connectors on the primary injectors. Everything else is soaked.

I have no frakking clue what to do next. Anyone looking to buy an FD?

Okie-RX7 12-14-08 10:34 PM

Is the primary rail damaged, like a small burr or anything that could be damaging the o-rings. I only ask because I am in the middle of the same project myself right now. I had a leaking FPD, and in the process of replacing it, I have also replaced the diffusers and grommets. Installed it all and ran the fuel pump and have a similar leak from the primary injectors, mine appeared to just be slowly leaking from the top of the injector by the rail, not from the connector, so I just ordered new injector o-rings, hopefuly it's only that. Have you coinsidered trying a new primary rail, they can be purchased fairly cheap on ebay, Good luck with it.

TypeFD 12-16-08 03:21 PM

Okie-RX7 - it couldn't be the rail or the insulators as the fuel appears to be on top of the rail. Insulators would lead to a leak underneath the rail.

I carefully inspected the whole area and definitely don't see fuel in the injector connectors either, so it's either leaking somewhere between the injector and rail (sealing) or maybe it's coming out of the very top of the injector, right there through the center. Anyone had an injector leak from that location?

Another theory I've heard was that may be fuel pressure regulator malfunction is causing a high fuel pressure buildup causing injectors to leak... anyone can comment on this?

Thanks again guys.

Mahjik 12-16-08 04:51 PM

Did you do the test I showed in the link earlier by extending the fuel lines to test with the rails exposed?

TypeFD 12-16-08 08:38 PM

Latest Status
 

Originally Posted by Mahjik (Post 8804524)
Did you do the test I showed in the link earlier by extending the fuel lines to test with the rails exposed?

I didn't pull it out like you did. I didn't think that was necessary at the time as I wasn't even able to replicate the leak. I might have to do it if this continues.

STATUS UPDATE:
I was so pissed since my last post that I just left it alone and worked on my bike instead. I took the car to work Monday and Tuesday and today, after work, I decided to take another glance and see how things are looking under the hood.

Long story short I think I'm loosing my friggin' mind.. I can't find the leak anywhere. I tried grounding the F/P, starting the car and warming it up, taking couple of hard runs... I can smell the fuel a little bit still but I can't find any wet residue anywhere. Maybe I'm just getting high on gas...

I'm going to lay off this problem for a week or so and may be watch for the leak, in the meantime, can someone get me some input on a failing pressure regulator? Symptoms? Outcome? etc... Is it possible that my injectors are fine but being subjected to too much pressure?

bond007 03-07-09 08:29 PM


Originally Posted by TypeFD (Post 8804269)
I carefully inspected the whole area and definitely don't see fuel in the injector connectors either, so it's either leaking somewhere between the injector and rail (sealing) or maybe it's coming out of the very top of the injector, right there through the center. Anyone had an injector leak from that location?

Yes. I had a FD I worked on with a fuel smell and it turned out to that the primary injector was leaking out of the top, through the plastic. It was the strangest fuel leak that I had ever seen!

Anyhow, I contacted the various injector service facilities and described the problem and was told that it was not repairable (at the time, this was probably 7-8 years ago, I doubt that this has changed recently, though). The owner bought a new primary injector and that was that.

You can VERY, VERY carefully pressurize the fuel rail without the metal "cap" that holds the injectors in place to look for this leak, provided you hold the injectors down with safety-wire or are willing to hold them in with your hands (fully understand though, the risks, i.e. fuel under pressure, fire hazard etc.). It is not as dangerous as one might think, as you have to "jury rig" top-feed injectors similarly to leak-test them while not mounted to the intake manifold on a FC or Miata. When I removed the cap, the fuel leak was VERY apparent.

Dab the corner of a white paper towel against the suspected leak area and you will easily see minor fuel leaks wicking onto the paper towel (I stole this test methodology from my EMT training, the "halo" test where you do a test for cerebrospinal fluid, to give credit where credit is due).


Originally Posted by TypeFD (Post 8804269)
Another theory I've heard was that may be fuel pressure regulator malfunction is causing a high fuel pressure buildup causing injectors to leak... anyone can comment on this?

Easy-peasy. Run the fuel pump test like before. Take a mity-vac and apply pressure to the FPR, say, 15 PSI or so and that will increase the fuel pressure to the levels seen under boost. This would not accounts for vibration or heat inducing the leak, though. To test the FPR, you need a F/P gauge but I doubt that it is the problem if you can find an external leak.

--Ashraf

GreatShamanGT 08-10-09 01:59 AM

Didn't want to start a new thread, when Witch Hunter sends the injectors back, do they label which ones are which? Like which ones flow xxxx amt? I'm thinking about going through theem to have my injectors cleaned, but I'm a bit worried about signing a sheet with my credit card number, etc on it, lol.

pomanferrari 08-10-09 10:43 AM


Originally Posted by TypeFD (Post 8805169)
I'm going to lay off this problem for a week or so and may be watch for the leak, in the meantime, can someone get me some input on a failing pressure regulator? Symptoms? Outcome? etc... Is it possible that my injectors are fine but being subjected to too much pressure?

Don't mind saying this: told you so ... the injectors are structurally defective ... no rebuild will save them. You'll have to get new injectors.


Make sure you have the insulators between the tip of the injector and the fuel rail. I chased this problem for over 5 years and it turned out that the Mazda dealer monkey didn't install them.


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