As the title states,
I have a need. Have time on my hands to do this. My car has been down for many years. I want to get it on the road again. The good Lord knows I had fun in it until the primary fuel injector failed in one housing. 2K mile motor that just won`t spray fuel on the rear rotor. I don`t see any other way to get the little bastid out other than to pull the entire motor again. Gave up on the project after it took me 3 months to finish putting a rebuilt engine in my car. I will say this. There was one awesome member named `Blue on this site. `Blue, you stuck with me and encouraged me through my entire project. All of the BEST to you and your family! I hope that you are OK. You know who you are. DJseven was also a TREMENDOUS help for me also! Thank You for EVERYTHING!

Been a long time since I was on this forum. Haven`t forgotten about all of the GREAT folks that are here. Wished I could have met up with them and bought them a beer. Seems like there was also a user named Dale I spoke to once or twice. He tried to offer help too.A fine gentleman.

I don`t have an e-mail address right now so IM me through this site.

All of the BEST to the group and their families!

 

Welcome back and sorry about your troubles. The factory injectors in these cars are pretty reliable so its pretty odd to have an injector just not fire. You don't have to pull the entire motor to get to it, that's for sure. You can obtain a noid light that plugs into the injector connector to see if its even sending the signal to fire but you still have to removed the UIM to get to it which is a bit of work especially if you still have the rats nest. Is the car stock? How do you know the injector isn't firing in general? I would hate for you to pull the manifold and dig into this to find out it was another issue that was more easily solved.

 

Howdy!

While it isn't the most fun thing on Earth, you can remove the injectors with the engine in. As stated, I would be 100% sure that's the case before going forward. Quite possible that it's the wiring to the injector and not the injector itself.

What I would do -

- Put in new leading plugs and start the car. Try and run the car for a minute or two. If it's super obvious it's only on one rotor, shut it down.
- Pull the plugs, you should get some carbon deposits on a plug that is firing. If the plug has no carbon but is wet with fuel you have no spark. If it's bone dry and no carbon you have no fuel.

No spark, move forward on that. No fuel, here we go.

- If you have one rotor running, you have enough fuel pressure to make the car go. Should be good on fuel pump and fuel pressure.
- Get a Noid light as stated, pull the upper intake manifold and unplug both primary injectors and install the noid lights. Have someone crank the car while looking at the lights, you should see them blink as the ECU tries to fire them. If both are blinking you have good wiring, if only 1 is blinking you have a wiring issue.
- Injectors have 1 wire that is 12v always. The other wire goes to the ECU and it "taps" it to ground every time the injector fires.
- If the connectors are bad and crap, you can get new ones. Cut out the old ones and splice in the new ones. Polarity doesn't matter.

If the wiring is good, I'd pull the primary and secondary rails as a unit.
- Remove upper intake manifold
- Remove coil packs
- Use a 1/4" drive 10mm socket with long extensions and maybe a universal to remove the 3 bolts that hold the air control valve on.
- With long reach tools and some good lighting and patience you can unbolt the 2 fuel rails and remove both as an assembly.

Once they are out, hit each injector with 12v and ground using wire with alligator clips. If you hook an injector to 12v and ground it should click and you should see the tip move in. No click = bad or stuck injector. Sometimes spraying PB-Blaster on the tip and hitting it with 12v/gnd a few times will get the injector moving again. Sometimes they just get stuck from sitting. If you have them cleaned, ALWAYS do this, they frequently stick after cleaning due to the leftover cleaner in the injector.

I THINK you can still buy the injectors new from Mazda.

Dale

 

Car is stock and trying to get to that harness buried under everything is a nightmare on my street! LOL! Pulled the plugs and the front chamber is blowing fuel vapor when cranking but the rear is not. Loud hiss coming from both housings.
Driving the car is an absolute dream! When it ran..............................

 

Hello Mr. Dale!
Nice to speak with you!
Have fuel mist coming out of only the front rotor housing on cranking. ( Plugs removed )
When the motor was out, I sent the injectors off to be cleaned and spray tested. Car ran great for 2K miles but then one day, I came home on one running rotor. That was no fun. Both rotors definitely have spark. Rear has no fuel mist but hisses like no tomorrow. It definitely is a fuel issue it would appear. Those primary injectors are a real mudsucker to get to.

 

as robust as the stock injectors are, we have ran into quite a few that simply stopped working or were stuck open. sending many off to be cleaned and not all can be re-used. in our experience, its not uncommon for a stock injector to give up.

getting to the rails in factory configuration is an awful job. even with our combined 647 years of experience it still takes about an hour or 2 to get them extracted and then another hour or 2 to put it all back. any less experience than that and you may want to hand the job to someone familiar with the car or just take your absolute sweet time with it and mark everything. there's no easy way with this and honestly motor in or out, it doesn't make the job any more or less difficult.

as was mentioned, you absolutely will want to be 100% sure its an injector before going in because you will have to live with it if you're wrong lol. your test with seeing mist coming out one side but not the other is a pretty good indication and for me, it would be sufficient to warrant chasing an injector.

 

At this point I just flat don't recommend cleaning stock injectors. I have seen MANY cases with them locking up or having problems eventually..

I think it makes sense on a newer car but if you have 30+ year old parts they just don't like it.

Remember, you have only a handful of bolts that connects the whole rat's nest and rails to the engine. Follow my instructions above. Worst case you can remove the 2 12mm bolts that holds the vacuum rack to the top. of the engine and get some more wiggle room.

Long needle nose pliers, long hose pliers, long extensions - those are all the order of the day. It's doable.

Dale

 

You may get lucky and be able to reach the top of the injector with a long screwdriver or something and tap the head while somebody cranks the engine. I have unstuck injectors like that in the past on JDM motors we've received. If it does start working then run some good injector cleaner like 44k or do a 3m fuel treatment on it ($$$ because you have to buy the tool.) Not saying it will work or that is the issue but its worth a shot over starting to rip everything apart. You still need to see if you are getting signal to that injector as well.

 

Good to see/have you back Nat.
My only experience with FD injectors was with the engine out. So I have very little advice on doing it in the car. I’m with boostin13b though. I think before trying pull them though, I might check for power/signal at the connector. I remember the leads on mine at 90k were pretty crispy and I bought new pigtails from one of the vendors. Not sure I’d call it luck, but maybe it’s just a continuity issue and pulling them not necessary…under the circumstances that might be a win.

 

Awful job it was to pull everything to put the new motor in.
I have a bad feeling that the problem may be a corroded connector pin inside the pintel to the rear fuel injector. ( If it isn`t the actual injector itself ) If I am going to dive into this thing, I want to cover all of my bases.
I appreciate your comments.
Anyone know, if that is what it is, where I can find one?

 

My fuel tank is 3/4 full.
What do you think about what the fuel is like now?
Probably varnish after 7 or more years of sitting?
I also wonder what high test ethanol fuel has done to my fuel lines.
I agree with you & other posters about checking for signal. No signal. No result for a working housing.

 

Hello young man.
Been awhile!
I thought you might see this post and respond. ( Fishermans cast........zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz..... ....sploink ) Click. Click. Click. LOL!
GLAD that you are still around! Good folks are difficult to come by and far & few in between.

Thank you for your help in getting my car back on the road. You tried and inspired me to keep going. It was a big job.

Now if I can only do it again. I lost a hard drive with all of my RX-7 data on it. I need a print of the vacuum hose connections. I also need suggestions from you or others as to how to reduce the boost pressure after using a high flow exhaust system. I need to get the boost down to 10 PSI. The twins love the new Hi-flow exhaust system and seem to want to go to 12 or 13 PSI when given the opportunity. This is on the factory computer. I know that that is a no-no. Before the seals break, I want to fix this. Heard too many horror stories of excessive boost pressure on the factory computer. Every time I saw the boost gauge encroaching near those levels, I let off the gas.
I am thinking of machining a constrictor to put between the down pipe and exhaust. Either that, or I will have to drill out the little plastic wastegate control fitting in the vacuum hose. I just don`t know what size opening I would need.

Oh, hate to say this. The car has sat so long in the garage, white mold is showing up on the interior. Any suggestions as to what may take it off? I am thinking Armor-All. Don`t know what would work best.

Jim, Like I said before, was good to hear from you.

After 101K miles on the car, I want to see another 100K. Remains to be seen. From Boston.......It`s more than a feeling! I still remember that first day out of the garage and going down the road.

 

I think step 1 is going to be figuring out wiring or bad injector. Get that solved then move forward.

I do have a feeling it will be the injector, but I would make 100% sure before moving forward. I've got everything posted here you need to make that determination.

Vacuum diagram -
https://www.rx7club.com/3rd-generati...-turbo-749702/

Save a copy of the image on a USB drive and take it to Kinko's or a copy shop. Have them print it in color on 11x17 paper. and laminate it. Should cost only a few bucks and you'll have a great reference that will last forever.

If the gas is that old in the tank I'd give it a good smell. If it stinks, drain the tank and get some fresh gas in there. There is a drain on the bottom of the tank.

Get the car running first then we'll move to boost creep

Dale

 

Yeah, get the car using both rotors first, and boost creep is relatively simple to cure. For those using a mid-pipe, as simple as adding a cat back in…even a hi-flow cat.

It may have been mentioned already, but a cell phone camera can really be your friend going under the manifold. Take your time with all the vac hose routing. If you haven’t already, I might even order up a set of those viton check-valves from DC since you’re in there anyway.
Should be a (iirc) a 14mm drain plug on the gas tank. That’ll be a messy job for outside. Not sure, but you might be able to use it in your lawn mower…for the next three years.
Keep us posted. Again, good to see you back on the board.

 

Dale,
THAT is EXACTLY what I lost!!!!
THANK YOU!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
You are AWESOME!!!!!!!!!

 

Thanks folks for the help.
Someone e-mail me an aspirin before this quest is over.

 

Forgot to mention. Running a Hi-Flow Cat.

 

I might even order up a set of those viton check-valves from DC since you’re in there anyway
Which parts are you referring too?
I replaced all of the problematic vacuum control valves in the engine compartment. Even brand new, some didn`t work right. Hand to forehead. Shakes head at Mazda. Thank God for information on the web.
Lost that information too on my dead hard drive. Sheesh.

Again, good to see you back on the board.
Good to be back among friends.

 

I would definitely drain the tank and get rid of that fuel. I would not doubt if there is some "gel" in the fuel system due to that old fuel. That could also be the cause of your injector issue on that rotor. I see it all the time with carbs and in injectors gelling up on the boats and small engines down here just from sitting for much less time. I would feel all the fuel lines and see if they feel soft but the lines themselves seem to hold up well, its the Gel that forms that causes the problems that I've had to deal with. When you get it running, run a can of fuel system cleaner in high concentration then replace the fuel filter. That stuff tends to dislodge the gel and the filter should help catch everything from that point back to the pump and sock. I'm going to be pulling my UIM and restoring my fuel system soon and I will be replacing everything under the manifold (including the lines) because its 30 years old and might as well do it right one time rather than have to address it again in the near future, then I should be good for another 30 years.