Leaky Injectors Advice - Rebuild or New?
 

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?

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.

What, can no one chime in on this?

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.

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?

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/

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.

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/

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

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...

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

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...

pics
 

Here some aftermath shots...

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.

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

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.

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?

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

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.

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.

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

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

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...

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

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).

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.