1990 TT Fuel Injector Issue

[Xemplifi]

1990 Z32 TT with about 88k miles. Justpulled the plenum and replaced all coolant, fuel, and vacuum lines I could get to. Also replaced the plenum and iacv gasket as well as spark plugs and fuel regulator/ dampener. So the problem is the car will fire up but won't stay on longer than 5 secs. It's getting no throttle response from the pedal and the car won't get above 500 rpms. I can hear the fuel pump working and gas is flowing at least past the fuel filter. The TPS is getting correct voltage at open and closed. I feel that the injectors either aren't spraying or aren't getting power. Any help would be nice.

[Jn1306]

loosenthe two screws that hold the tps and rotate clockwise a bit.

[Xemplifi]

loosenthe two screws that hold the tps and rotate clockwise a bit.

Even though the TPS is getting its correct voltage? About .5 volts at closed throttle and 4.83 volts at wode open?

[nissanfreak12]

Tps will cause issues, but if you have it at the right settings, not the issue.

Are you sure you put the fuel regulator in the right spot? Where did you buy the fuel reg and damp? Are you sure the fuel lines are not crossed?

[Xemplifi]

Tps will cause issues, but if you have it at the right settings, not the issue.

Are you sure you put the fuel regulator in the right spot? Where did you buy the fuel reg and damp? Are you sure the fuel lines are not crossed?

I will double check my lines and make sure they're correct, but I bought bout from Courtesynissan.com

[Xemplifi]

How would I be able to test if my injectors are actually spraying?

[nissanfreak12]

Unplug the coil packs and turn the CAS with the car on. Then pull the plug and see if the spark plug is wet.

Another way is put voltage(9 volt battery) to the injector, then pull the plug.

What are the injectors ohming at? And I am sorry I didnt ask this before, which PTU do you have? Is it all black or does it have silver fins?

[evildky]

The fact that it starts up then immediately dies would suggest an iacv issue or a large vac leak.

[Xemplifi]

Unplug the coil packs and turn the CAS with the car on. Then pull the plug and see if the spark plug is wet.

Another way is put voltage(9 volt battery) to the injector, then pull the plug.

What are the injectors ohming at? And I am sorry I didnt ask this before, which PTU do you have? Is it all black or does it have silver fins?

My PTU is black, and I can't get a reading on any of my fuel injectors in ohms with my multimeter. I put both probes on each prong of the injector right? Cause I'm getting no reading
I was gonna test the connector to see if it was at least getting power.

[Xemplifi]

The fact that it starts up then immediately dies would suggest an iacv issue or a large vac leak.

Would a vac leak be enough to make the car not stay on at all? I know it can make the car run like s*** but I haven't heard of it keeping it from running at all.

[nissanfreak12]

My PTU is black, and I can't get a reading on any of my fuel injectors in ohms with my multimeter. I put both probes on each prong of the injector right? Cause I'm getting no reading
I was gonna test the connector to see if it was at least getting power.

You put the red or positive on one prong and the black or negative on the other prong. If you are not getting a reading make sure you have it on ohm's and clean the prongs, scrape it off with a small screwdriver.

[evildky]

The fact that it starts up then immediately dies would suggest an iacv issue or a large vac leak.

Would a vac leak be enough to make the car not stay on at all? I know it can make the car run like s*** but I haven't heard of it keeping it from running at all.

A big enough leak, yes. If enough unmetered air finds its way in the mixture leans out and the car won't keep running. Start up is by default a bit rich, so the fact that it fires and dies immediately makes me think it's either getting not enough air or way too much. A ptu issue will cause dead cylinders,and makes it run crappy and if the whole thing craps it just wont start at all. So either it's an air issue or a voltage issue, has anything electrical changed? unplug and replug all your electrical connectors. Your coil pacts, ptu, injectors, ecu all require cranking voltage and run voltage so a bad ignition switch, relay fuse or wiring issue is also suspect.

[budget300zx]

I also had this problem when i replaced my heads. Mine would stay running if i would give it throttle. It turned out my idle was set too low ~ 400rpm(was a cleaned j30 unit). turn you idle adjustment screw counter clock wise till it stops and go from there.

write up for proper adjustment if this is your issue.
http://www.nicoclub.com/archives/adjust ... level.html

[Xemplifi]

I also had this problem when i replaced my heads. Mine would stay running if i would give it throttle. It turned out my idle was set too low ~ 400rpm(was a cleaned j30 unit). turn you idle adjustment screw counter clock wise till it stops and go from there.

write up for proper adjustment if this is your issue.
http://www.nicoclub.com/archives/adjust ... level.html

Well I'm not getting any throttle response whatsoever. I can give it a shot, but either the engine isn't getting fuel or not enough/too much air. Plus it's hard to look for vac leaks when the engine doesn't stay on.

[evildky]

Also there are a couple of connectors around the back of the plenum that are identical and can be plugged in wrong, thinking it's the O2 and the vtc solenoid, but crossing these plugs might cause non run, not sure.

[Xemplifi]

Also there are a couple of connectors around the back of the plenum that are identical and can be plugged in wrong, thinking it's the O2 and the vtc solenoid, but crossing these plugs might cause non run, not sure.

Ok, I'll double check those too.

[nissanfreak12]

Also there are a couple of connectors around the back of the plenum that are identical and can be plugged in wrong, thinking it's the O2 and the vtc solenoid, but crossing these plugs might cause non run, not sure.

Will not cause a no run issue, besides its the VTC and knock sensor, these are 2 wired. O2 sensor is 3 wired.

Did you have this issue before you pulled the plenum? Are you sure you have the correct plugs on the correct injectors/coil packs? Are all the grounds connected, especially on the back of the plenum? These have been known to fry the PTU if not grounded.

Also recheck the TPS and make sure the plugs are in correctly. The one that goes into the TPS, not the wired one. This is directional and can be turned upside down. It still will run, just be very odd throttle. I only know this because it happened to me.

Have you checked the timing? CAS? The CAS can be removed and slowly turned with the ignition on so you shoul dbe able to hear each injector click.

[Xemplifi]

Also there are a couple of connectors around the back of the plenum that are identical and can be plugged in wrong, thinking it's the O2 and the vtc solenoid, but crossing these plugs might cause non run, not sure.

Will not cause a no run issue, besides its the VTC and knock sensor, these are 2 wired. O2 sensor is 3 wired.

Did you have this issue before you pulled the plenum? Are you sure you have the correct plugs on the correct injectors/coil packs? Are all the grounds connected, especially on the back of the plenum? These have been known to fry the PTU if not grounded.

Also recheck the TPS and make sure the plugs are in correctly. The one that goes into the TPS, not the wired one. This is directional and can be turned upside down. It still will run, just be very odd throttle. I only know this because it happened to me.

Have you checked the timing? CAS? The CAS can be removed and slowly turned with the ignition on so you shoul dbe able to hear each injector click.

I haven't checked my timing, but I already ordered a new cas because I broke the old one trying to get it out so I could check the injectors.

[nissanfreak12]

I would wait on everything until the new CAS comes in. If it broke coming out, chances are it was broke in. Make sure the key is still there and in good shape. That will also cause a ton of issues, like bad timing and what you are describing, if it is not seated correctly. Its a little pricey compare to stock but here is a chromoly steel one vs whatever they use on OEM one.

https://conceptzperformance.com/jwt-300 ... p_4589.php

[Xemplifi]

I would wait on everything until the new CAS comes in. If it broke coming out, chances are it was broke in. Make sure the key is still there and in good shape. That will also cause a ton of issues, like bad timing and what you are describing, if it is not seated correctly. Its a little pricey compare to stock but here is a chromoly steel one vs whatever they use on OEM one.

https://conceptzperformance.com/jwt-300 ... p_4589.php

So the new cas came in today. Plug it into the harness and turned it with the ignition on, I heard no real "clicking" except I got my ear close to injectors and there was definitely only one injector spraying. So I put the cas back on and it still jas the exact same problem, nothing different at all.

[nissanfreak12]

voltUse a long screwdriver touching the injector, even though you should be able to hear it without. If the injectors are not clicking, your injectors are either toast or gummed up. Try a 9volt to see if they click at all before tearing that apart.

[Xemplifi]

voltUse a long screwdriver touching the injector, even though you should be able to hear it without. If the injectors are not clicking, your injectors are either toast or gummed up. Try a 9volt to see if they click at all before tearing that apart.

So if there is no audible clicking or spraying would that suggest the injectors are either clogged or not working? Could it be a connection issue? Because the only ony that I could hear spraying was the only one I could get a resistance reading on. Everything else was an open circuit even after cleaning them. I was already planning on upgrading the newer style pintless injectors and 300 degree fuel rail, but it might have to happen sooner than later now.

[MrFeesLaw]

The fact that it starts up then immediately dies would suggest an iacv issue or a large vac leak.

Would a vac leak be enough to make the car not stay on at all? I know it can make the car run like s*** but I haven't heard of it keeping it from running at all.

The vacuum line to the fuel pressure regulator is extremely important. At idle you should be pulling quite a bit of vacuum and without the vacuum on the regulator it will think the engine is under heavy load and push WAY too much fuel into the engine. Therefore, pressing the throttle would change nothing, since the fuel flow rate is already maxed out and can't go any higher.

I would double-check all vacuum lines and fuel connections. Best to check the easy stuff first, than to start pulling injectors and plugs and find out you didn't plug in a connector or something simple.

[MrFeesLaw]

voltUse a long screwdriver touching the injector, even though you should be able to hear it without. If the injectors are not clicking, your injectors are either toast or gummed up. Try a 9volt to see if they click at all before tearing that apart.

I haven't had my fuel rails apart personally yet, but shouldn't there be a way to point the injector into a bottle or something and give it 9v to see if it sprays? That's how I always check them. Audible clicking is not always a perfect test. 3 of the injectors on my impala make noise, and 3 don't, but they all still pulse fine. Just a matter of how each injector has worn.

Although, I have heard that the older pintle style injectors are not very well suited for ethanol blended fuels, so i suppose that could have caused problems with the injectors.

I would point an injector into a bottle with with fuel flowing to it and see if it sprays just to make sure.

[budget300zx]

IMO i would be leaning towards a massive vacuum leak at this point if the car ran fine before. my suggestion is to do a smoke test for vacum leaks. also here a link to make a cheap smoke tester that you can adapt as needed.

https://www.youtube.com/watch?v=2U5kFib ... tml5=False

[Xemplifi]

IMO i would be leaning towards a massive vacuum leak at this point if the car ran fine before. my suggestion is to do a smoke test for vacum leaks. also here a link to make a cheap smoke tester that you can adapt as needed.

https://www.youtube.com/watch?v=2U5kFib ... tml5=False

Well that's the thing, before I pulled the plenum and did the coolant bypass the car had starting issues similar to what's happening now, there would be frequent times when the car wouldn't have any throttle response, and it was starting to stall while driving all about 2 weeks before the plenum was pulled.

[nissanfreak12]

Our injectors are side feed, so if you keep them in the rail you can spray them in a bottle. I urge against just because fuel is VERY flammable. The way the z's injectors are designed, it will make a click sound, if they don't they are bad. Pintleless are much, much quieter than older style. But will still click, sometimes only audible through a stethoscope, screwdriver, stick or anything that will act as a stethoscope

OP, if you are not getting any readings on the injectors, they are more than likely done for. Yes, old style injectors can fail just that suddenly especially if they sat without any fuel in the system. Like stated, go with the pintleless injectors, you will be much happier.

Vacuum leaks yes and no on these, it would have to be a very large leak, even then it would still run, just like crap. Vac to the FPR is necessary, and without will cause it to push more fuel into the cylinders. Its an easy trick to run a richer condition, but will not cause what is described.

[Xemplifi]

Our injectors are side feed, so if you keep them in the rail you can spray them in a bottle. I urge against just because fuel is VERY flammable. The way the z's injectors are designed, it will make a click sound, if they don't they are bad. Pintleless are much, much quieter than older style. But will still click, sometimes only audible through a stethoscope, screwdriver, stick or anything that will act as a stethoscope

OP, if you are not getting any readings on the injectors, they are more than likely done for. Yes, old style injectors can fail just that suddenly especially if they sat without any fuel in the system. Like stated, go with the pintleless injectors, you will be much happier.

Vacuum leaks yes and no on these, it would have to be a very large leak, even then it would still run, just like crap. Vac to the FPR is necessary, and without will cause it to push more fuel into the cylinders. Its an easy trick to run a richer condition, but will not cause what is described.

Alrigh so, I got my fuel rail off and taped some water bottes under each injector. As I turned the cas only one injector sprayed, so I moved the connector of the one that sprayed to every other one and turned the cas again and I got only one other to spray. The injectors and connectors are really corroded so could I get by if i take them off and clean them and replace the connectors, because I already have those. Thanks guys

[nissanfreak12]

Are you testing the injectors through the connectors? Or are you taking the connectors off and testing the directly on the injector?

If they are corroded on the 2 spades, you definitely need to clean them before you can actually test them. Otherwise you will get a bad reading or no reading. You can clean them with a small flat head screwdriver by scraping them or a small file. Check out the ohms after they are cleaned, you may be surprised. If they still show no reading or do not spray, they are more than likely going to need to be replaced.

[MrFeesLaw]

I would recommend finding a 9v source voltage and jump it along with a ground to each injector. That will tell you for sure if the injector is bad. If they all fire that way, then you know the problem is somewhere else.

As Nissanfreak said, be careful with the fuel.