Hey everyone -- This is on my 1986 GT, 2.8, 4-speed.

Just got my injectors back from fuel injector connection (www.fuelinjectorconnection.com). They rebuilt all my injectors, including the cold start injector. I put everything together, car starts but feels funny and idles at about 1500 rpm...after about 3 seconds, it revs up to 2500 rpm for about 1 second, then promptly stalls. Check engine light comes on AS the car is stalling but it will not actually give me a code. This repeats in an infinite loop. If I give the car throttle immediately after starting, i can keep the car running.

Some observations:

1 - exhaust stinks, smells "funny". almost like gunpowder.
2 - i checked ignition with a timing light, all plugs are firing. Dizzy is relatively new (star-pickup style), new cap, rotor, plugs, wires.
3 - I applied 12 volts across all of the injectors, and they all "click".
4 - I cleaned the fuel rail when I had it removed.
5 - after the car stalls, there is *some* fuel pressure in the rail (I unfortunately have not checked pressure, but the car was running very well before I had the injectors rebuilt).
6 - IAC is new.

My question is, WHAT is going on? And a possibly related question - does the cold start injector feed all cylinders or just 5 & 6? (it seems like it should feed all of them, but its location seems to prohibit this)

ANY help is greatly appreciated. Thanks all!!

EDIT/UPDATE: vacuum line running to fuel regulator was unplugged. Now the car will run but feels "rough" - my suspicion is that its running really rich but I have not confirmed this. Fuel pressure holds steady at 45 psi with key primed, ruling out leaking injectors or faulty regulator. All injectors fire with +12 volts across terminals, including cold start. All vacuum lines have been double checked for proper routing. Car stalls immediately when the IAC port is blocked, leading me to believe its not a vacuum leak.

[This message has been edited by masospaghetti (edited 06-21-2010).]

The last time I changed fuel Injectors, I didnt use a little vasoline (or oil) on the o rings and they were all leaking gas on top of the motor (because they were crooked)...you would probubley smell gas or notice that...What else did you do to the motor?Is this a total rebuild?Did you mess with the timeing?Possibley two of your injector connectors are reversed....???

Did you reset the IAC after you put it all back together?

If not, search around, there are a few posts on how to do it. When I had my 2.8 apart, it had a high idle, reset the iac and it was fine.

Stinky smell could be from the cat coz it's running rich. If left too long like this it will kill the cat.

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Dave

www.ltlfrari.com

[This message has been edited by ltlfrari (edited 06-20-2010).]

I have not reset the IAC. Will try that.

Does not seem to be leaking gas around the injectors...I did put some motor oil on the o-rings before reassembling. Ill have to recheck the injector connectors but I think I got them right...

First thing is to get a fuel pressure gauge on it and see what's going on there. Could be pressure regulator is goofy? - Maybe you have vacuum leak(s)? Try putting you finger over the IAC port in the front of the TB while idling - if it continues to idle high, you have a vac leak. If it dies, you have another problem. Got to know what the fuel pressure is doing first.

quote Originally posted by masospaghetti: Hey everyone -- This is on my 1986 GT, 2.8, 4-speed. Just got my injectors back from fuel injector connection (www.fuelinjectorconnection.com). They rebuilt all my injectors, including the cold start injector. I put everything together, car starts but feels funny and idles at about 1500 rpm...after about 3 seconds, it revs up to 2500 rpm for about 1 second, then promptly stalls. Check engine light comes on AS the car is stalling but it will not actually give me a code. This repeats in an infinite loop. If I give the car throttle immediately after starting, i can keep the car running. Some observations: 1 - exhaust stinks, smells "funny". almost like gunpowder. 2 - i checked ignition with a timing light, all plugs are firing. Dizzy is relatively new (star-pickup style), new cap, rotor, plugs, wires. 3 - I applied 12 volts across all of the injectors, and they all "click". 4 - I cleaned the fuel rail when I had it removed. 5 - after the car stalls, there is *some* fuel pressure in the rail (I unfortunately have not checked pressure, but the car was running very well before I had the injectors rebuilt). 6 - IAC is new. My question is, WHAT is going on? And a possibly related question - does the cold start injector feed all cylinders or just 5 & 6? (it seems like it should feed all of them, but its location seems to prohibit this) ANY help is greatly appreciated. Thanks all!!

Did you use oil on the O-rings when you re-installed them?
I'm almost positive that if the check engine light comes on, that it has stored some codes. Check it again just to make sure.

I would guess a vacuum leak. Try creating a home-made stethescope an see if you can hear any hissing from anywhere. Also check for leaking fuel!!!

------------------
Todd,
2008 Jeep Patriot Limited 4x2
2002 Ford Explorer Sport 2dr 4x2
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6
1973 Volkswagen Type-2 Transporter

maybe you forget to plug a vaccum line
check the one for the pcv valve follow the line from the valve cover to the intake
it's the vaccum line I foget to plug me to when I do the same job

Or maybe you crack the EGR tube in the installation

quote Originally posted by 82-T/A [At Work]: Did you use oil on the O-rings when you re-installed them? I'm almost positive that if the check engine light comes on, that it has stored some codes. Check it again just to make sure. I would guess a vacuum leak. Try creating a home-made stethescope an see if you can hear any hissing from anywhere. Also check for leaking fuel!!!

I did oil the o-rings before installing.

quote Try putting you finger over the IAC port in the front of the TB while idling - if it continues to idle high, you have a vac leak. If it dies, you have another problem. Got to know what the fuel pressure is doing first.

good suggestion and I will find a fuel pressure tester.

Thanks for the suggestions!

I get the impression you have a really bad vacuum leak. Since you have to remove the intake plenum to get at the fuel rail, you should concentrate your search around that area.

Ill try covering the IAC port and see how she does.

Can anyone shed light on the cold start injector circuit?

sounds like a vacuum leak....just because I had lots of those...you may have forgot to plug in a vacuum line, there are many, or you could have cracked one.

You did replace the upper intake gasket's and TORQUE them correctly in the right sequence right?
over or undertightening and out of sequence can cause leaks,and you cannot reuse paper type gaskets.
Did you remove the throttle body? same questions.

I would suggest having someone totally unfamiliar with the car look at it.
Just ask them if they see anything unplugged or unhooked or ???
Sometimes you can easily not see the forest if you've been looking at the trees too long,especially on something obvious.

The only variable between running good and running bad looks to be your labor so far.
So double check your work and have someone else give it a once-over.

UPDATE! The fuel pressure regulator "t" fitting was unplugged. Now, the car runs and does not stall, but still does not run properly.

I've come to the conclusion that its running rich but all advice is really appreciated...the car stalls immediately when the IAC port is covered, which tells me there is not a huge vacuum leak. The car has 45 psi of fuel pressure when primed and 35-40 psi when running, and the car runs BETTER when the pressure drops to 35 (it fluctuates). The car holds 45 psi indefinitely with the key primed.

The engine runs rough and feels soggy, in addition to the details above.

quote sounds like a vacuum leak....just because I had lots of those...you may have forgot to plug in a vacuum line, there are many, or you could have cracked one.

What is the best way to check for cracked lines? Just look at them? Visually they seemed OK, and I triple checked the routing.

quote You did replace the upper intake gasket's and TORQUE them correctly in the right sequence right? over or undertightening and out of sequence can cause leaks,and you cannot reuse paper type gaskets. Did you remove the throttle body? same questions.

I did NOT replace my upper gaskets or my TB gasket, as they were replaced a couple months prior. I was not aware these gaskets were completely disposable. If the gaskets were the problem, wouldn't it cause a vacuum leak and lean condition?

quote The only variable between running good and running bad looks to be your labor so far. So double check your work and have someone else give it a once-over.

I know...its frustrating. I've taken the upper plenum off six or seven times now in the past day, checking and rechecking my work, but it seems exceedingly likely the problem is my labor or the injectors themselves.

Thanks all

[This message has been edited by masospaghetti (edited 06-20-2010).]

Now that the engine is running have you timed the engine with a timing light using the correct procedure?

http://www.youtube.com/user...g#p/u/52/3CzDk9wswG4

Are you getting any codes now that the engine is running?

quote I've come to the conclusion that its running rich but all advice is really appreciated...the car stalls immediately when the IAC port is covered, which tells me there is not a huge vacuum leak. The car has 45 psi of fuel pressure when primed and 35-40 psi when running, and the car runs BETTER when the pressure drops to 35 (it fluctuates). The car holds 45 psi indefinitely with the key primed.

The fuel pressure regulator holds the fuel pressure at a constant vs the intake manifold absolute pressure. Also remember vacuum pressure is actually negative pressure. So when the intake has a higher vaccum, the fuel pressure regulator will drop the fuel pressure. When you pop open the throttle, the intake vacuum drops (the absolute manifold pressure rises) and the fuel pressure regulator will increase the fuel pressure. So when you say it runs better when the fuel pressure drops - I'm not sure what your seeing is the chicken or the egg. The dropping fuel pressure is most likely the regulator doing its job and is just an indication of a higher intake vacuum, and your higher intake vacuum is an indication of a better running engine.

[This message has been edited by phonedawgz (edited 06-20-2010).]

To check for a vacuum leak, and this is an old trick, take a can of carb cleaner, and while the car is running, spray it around the mating surfaces of the intake and TB, vacuum lines, etc. If it bogs down when you spray in one area, concentrate your search there. I have found many leaks this way through the years. Some say use starting fluid and the engine revs, but I have always been a little leary of spraying a highly flammable substance around a hot engine, and the carb cleaner gives the same results, just in a different way.

quote Originally posted by phonedawgz: Now that the engine is running have you timed the engine with a timing light using the correct procedure? http://www.youtube.com/user...g#p/u/52/3CzDk9wswG4 Are you getting any codes now that the engine is running? The fuel pressure regulator holds the fuel pressure at a constant vs the intake manifold absolute pressure. Also remember vacuum pressure is actually negative pressure. So when the intake has a higher vaccum, the fuel pressure regulator will drop the fuel pressure. When you pop open the throttle, the intake vacuum drops (the absolute manifold pressure rises) and the fuel pressure regulator will increase the fuel pressure. So when you say it runs better when the fuel pressure drops - I'm not sure what your seeing is the chicken or the egg. The dropping fuel pressure is most likely the regulator doing its job and is just an indication of a higher intake vacuum, and your higher intake vacuum is an indication of a better running engine.

I should back up a bit and note that the car was running GREAT before I had my injectors rebuilt. The only reason I had them rebuilt was because they leaked a little bit, but the car ran really well. But yeah, I did properly set the timing, and I haven't changed it since I swapped the injectors.

Thanks for the bit on the regulator...good info to know.

Also, the car will NOT start with the MAP sensor unplugged, if that is relevant.

quote Originally posted by masospaghetti: UPDATE! The fuel pressure regulator "t" fitting was unplugged. Now, the car runs and does not stall, but still does not run properly.

Yeah, that could cause some problems.

With that fitting unplugged, you had 2 things going on. First of all, the fuel pressure regulator had no vacuum. So it was dumping fuel into the engine like it would at wide open throttle. Second, you had a vacuum leak, due to the unplugged hose. Those two things conspired to cause a runaway idle, and a really rich fuel / air mixture. The ECM's vain attempts to correct for that was probably what caused the engine to stall.

The ECM may be still using the settings that it "learned" while the fitting was unplugged. You can clear the ECM's memory by removing one of the battery cables from the battery for a moment.

On a side note, I've re-used intake manifold and throttle body gaskets before (several times, actually). As long as the gasket isn't damaged in any way, it should be re-usable. I like to spread a thin coat of oil or grease on the gasket with my finger, to help seal it (and keep it from sticking to the manifold next time I remove it). That said, using the proper torque, and proper torquing sequence, is very important, especially if you install your intake gaskets the way I just described.

quote Originally posted by Blacktree: With that fitting unplugged, you had 2 things going on. First of all, the fuel pressure regulator had no vacuum. So it was dumping fuel into the engine like it would at wide open throttle. torquing sequence, is very important, especially if you install your intake gaskets the way I just described.

The reason they vary the fuel pressure with the manifold pressure is so the pressure differential across the injector is constant. Fuel pressure is not increased at WOT. Injector pulse duration is extended. So yeah while the amount of fuel injected would be increased - it would not be "like it would at wide open throttle"'

quote Originally posted by Blacktree: The ECM may be still using the settings that it "learned" while the fitting was unplugged. You can clear the ECM's memory by removing one of the battery cables from the battery for a moment.

Agreed - If you haven't reset the ECM you for surely need to. Make sure it's at least 30 seconds.

[This message has been edited by phonedawgz (edited 06-21-2010).]

quote Originally posted by Blacktree: I get the impression you have a really bad vacuum leak. Since you have to remove the intake plenum to get at the fuel rail, you should concentrate your search around that area.

Thats my suspicion as well. A high idle can indicate a vacuum leak. If the fuel presure was right before you started it should be right after the job was done. As for "rebuilt injectors"; there is no way to rebuild an injector as they are hermetically sealed when they are manufactured. All they do is pressure clean them, (hopefully flow test them) change the little filter screen and put new O rings on them.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by phonedawgz: The reason they vary the fuel pressure with the manifold pressure is so the pressure differential across the injector is constant. Fuel pressure is not increased at WOT. Injector pulse duration is extended. So yeah while the amount of fuel injected would be increased - it would not be "like it would at wide open throttle"'

The point I was trying to make is that with the vacuum line unplugged, the fuel pressure regulator would be running at maximum pressure (like it would at WOT). With the engine at idle, that would cause the engine to run rich.

quote Originally posted by Dennis LaGrua: Thats my suspicion as well. A high idle can indicate a vacuum leak. If the fuel presure was right before you started it should be right after the job was done. As for "rebuilt injectors"; there is no way to rebuild an injector as they are hermetically sealed when they are manufactured. All they do is pressure clean them, (hopefully flow test them) change the little filter screen and put new O rings on them.

Wouldn't a vacuum leak show itself when the IAC port is plugged and the car continues to run? (the car dies immediately when the port is plugged).

quote Originally posted by masospaghetti: Wouldn't a vacuum leak show itself when the IAC port is plugged and the car continues to run? (the car dies immediately when the port is plugged).

Even with the IAC fully closed/disconnected should the car not idle at around 600 rpm per the manual?
If so then not a definitive test unless it idles wayy above 600rpm correct?

Well I don't see a post about idle speed AFTER the fuel pressure regulator T was re-connected. That initial high idle speed back then could have been very well from the ECM being reset and the engine never running long enough to learn the idle.

As of now is the idle speed normal, around normal? way above normal?

Unless it is idleing substantially above normal I see nothing to say vacuum leak other than the roughness/power. Not enough to conclude there is much of a vacuum leak.

Can you give us a rundown of how the engine is running now?

Car idles at about 1500 rpm now but is rough - sounds like it has a big cam in it, but it certainly doesn't...note that this is when the car is cold, as I have not run it long enough to enter closed loop operation.

Exhaust still stinks.

Engine is visibly shaking when idling.

I was thinking either 1) one cylinder is deador 2) running rich. I have not pulled plugs, yet, but all of the cylinders are getting spark as determined with my timing light.

Thanks again for all the help --

[This message has been edited by masospaghetti (edited 06-21-2010).]

Maybe pop one plug wire off at a time and see if the rough idle changes (it should get rougher).. If it does not change on one perticular wire, then that is the cylinder you should concentrate on...

Pull the plugs to see if they are wet or not from running rich. Also have you taken it for a drive yet so the ECM can re-learn?

I replaced all my injectors as well, and at first had a rough idle. It went away once I reset the ECM and drove it around.

Ken~

quote Originally posted by MooCow: Pull the plugs to see if they are wet or not from running rich. Also have you taken it for a drive yet so the ECM can re-learn? I replaced all my injectors as well, and at first had a rough idle. It went away once I reset the ECM and drove it around. Ken~

I just took it out for a drive...car is barely driveable. I'm leaning more towards a dead cylinder by the performance and feel of it, but I've having a really tough time diagnosing this (obviously)

All cylinders have spark (used timing light to verify all plugs are firing)

All cylinders have fuel (all injectors work and fuel pressure is good)

All cylinders have compression, since the car ran great before service (assumption)

I tried listening for a vacuum leak, nothing. Also spraying carb cleaner around sealing surfaces did not yield anything.

Overall, it doesn't make sense.

Would a bad MAP sensor cause these symptoms?

[This message has been edited by masospaghetti (edited 06-21-2010).]

quote Originally posted by masospaghetti: All cylinders have spark (used timing light to verify all plugs are firing)

Just because the timing light sees curent, does not mean the spark plug is firing... Try what I mentioned in my above post...

Check the dist. cap for a crack, even a hair-line crack (which is very hard to notice) will cause your symptoms...

ALDR, I tried pulling plug wires with the engine running. Only thing I noticed was my arm twitching from the shock...couldnt tell any difference, in ANY of them, in how the car ran (its too rough already to tell)

I did pull all the plugs - all had a nice tan electrode, no blackened, no wet. If I had an ignition problem, the plug would show wet or blackened, correct?

In addition, I installed another new set of Napa Belden wires, just to be sure. No difference.

I also just pulled the fuel rail again and checked the injectors themselves - nothing unusual. I can't flow test the injectors but they all flow fuel (I just filled the rail with carb cleaner and applied 12 volts across each one). I am ordering another gasket set so the upper plenum gaskets and TB gasket are new.

I also tried spraying the exhaust manifolds with a water sprayer to see if any of the cylinders were colder (dead) but couldn't tell. The exhaust runners are too short and they all get hot almost immediately.

Any other suggestions? Thanks again for the help...

quote Originally posted by masospaghetti: ALDR, I tried pulling plug wires with the engine running. Only thing I noticed was my arm twitching from the shock...couldnt tell any difference, in ANY of them, in how the car ran (its too rough already to tell) I did pull all the plugs - all had a nice tan electrode, no blackened, no wet. If I had an ignition problem, the plug would show wet or blackened, correct? In addition, I installed another new set of Napa Belden wires, just to be sure. No difference. I also just pulled the fuel rail again and checked the injectors themselves - nothing unusual. I can't flow test the injectors but they all flow fuel (I just filled the rail with carb cleaner and applied 12 volts across each one). I am ordering another gasket set so the upper plenum gaskets and TB gasket are new. I also tried spraying the exhaust manifolds with a water sprayer to see if any of the cylinders were colder (dead) but couldn't tell. The exhaust runners are too short and they all get hot almost immediately. Any other suggestions? Thanks again for the help...

did you swap a plug wire out of sequence? maybe you crossed a wire when you changed them?

quote Originally posted by stickpony: did you swap a plug wire out of sequence? maybe you crossed a wire when you changed them?

I checked and I don't think so, I only removed 3 of the plug wires.

I did just receive my fuel injector flow data; before has flow rates between 122-151 cc, after 155-158 cc. Average increase is about 12 cc. Cold start flow rate is 259 cc.

Would the increase of 12 cc (about 8-9%) cause this problem? Would the computer be too dumb to compensate for this?

[This message has been edited by masospaghetti (edited 06-23-2010).]

I'm still going to go with timing or firing order.

When you are cranking it what does it sound like? Sound normal or? How quickly does it start up? You have to give it throttle to start it right?

Have you tried turning the distributor without loosening the dist hold down bolt to make sure the Distributor didn't get bumped? It is tight right?

Have you tried a 'noid' light on the injectors? Checked BOTH 5 AMP fuses (Fuses 16 and 17) for the fuel injection? If you don't have a noid light you can still check for an injector signal with a multi-meter set to VOLTAGE see if your getting injector pulses on both of the injector sets. Injectors 1,3,5 are wired together and 2,4,6 are wired together. Each set has a seperate fuse. Unplug an injector on the string and put the leads of your meter into the connector. Make sure your Meter is set to VOLTAGE. DON'T use a regular incandesent test light or you most likely will damage your ECM. Make sure the big flat plug up by the thermostat/alternator is fully plugged in.

[This message has been edited by phonedawgz (edited 06-23-2010).]

quote Originally posted by phonedawgz: I'm still going to go with timing or firing order. When you are cranking it what does it sound like? Sound normal or? How quickly does it start up? You have to give it throttle to start it right? Have you tried turning the distributor without loosening the dist hold down bolt to make sure the Distributor didn't get bumped? It is tight right? Have you tried a 'noid' light on the injectors? Checked BOTH 5 AMP fuses (Fuses 16 and 17) for the fuel injection? If you don't have a noid light you can still check for an injector signal with a multi-meter set to VOLTAGE see if your getting injector pulses on both of the injector sets. Injectors 1,3,5 are wired together and 2,4,6 are wired together. Each set has a seperate fuse. Unplug an injector on the string and put the leads of your meter into the connector. Make sure your Meter is set to VOLTAGE. DON'T use a regular incandesent test light or you most likely will damage your ECM. Make sure the big flat plug up by the thermostat/alternator is fully plugged in.

So, I tried using a small incandescent light as a test light before I read the last part of your post. How likely is it that I screwed up my ECM?

I found that using a LED works as a noid light, and both banks AND the cold start all tested positive (light blinked for both banks, stayed solid for the cold start). This was after I tried the incandescent bulb. Note that I unplugged the big flat plug and checked it there, but I also did a continuity check at each injector and found all connections good from the injector plugs to the big flat plug.

The dizzy hasn't moved (its tight) and the wires are in the right order, although offset from the picture you provided.

Also tested my TPS, found it ranged from 0.78 volts to 4.8 volts.

Definitely NOT trying to hijack the thread but I will be following very closely, as I am experiencing virtually identical problems with very similar troubleshooting steps taken to solve my own problem. I am waiting for my injectors to come back from cruzinperformance now. I sent my injectors off to be inspected due to my driveablilty issue and they tested perfect, no issues ...

Hard to believe there are two of us with the same ghost

Cold start stayed solid?

Can you unplug just the cold start injector?

Seems to me it shouldn't stay solid, but I don't know much about it.

If the engine "runs" the same as before you started testing, then I'm sure you didn't kill your ECM.

======

Cold Start Injector link

http://calgaryfieros.com/OS...-start-injector.html

[This message has been edited by phonedawgz (edited 06-23-2010).]

So try running it with each of the fuses pulled.

Try with the cold start injector unplugged

if you haven't put a timing light on it, jumper a-b and see that the mark is where it is supposed to be.

You will need to check the exhaust with an exhaust gas analyzer or scan to determine if the engine is running lean or rich. That should lead you in the right direction. As for the cold start injector, I never really liked using one for starting as its just another valve prone to eventual leakage. If it leaks it will give you the problmes that you report. Smell the exhaust. Does it smell like raw gasoline? Any Black smoke?
When you plugged the harness back into the injectors, any chance that you broke a wire or plugged the harness in wrong?
------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 06-24-2010).]

quote Originally posted by phonedawgz: So try running it with each of the fuses pulled. Try with the cold start injector unplugged if you haven't put a timing light on it, jumper a-b and see that the mark is where it is supposed to be.

Will try all of these things. Thanks for the suggestions.