Finally got a chance to pull the fuel rail and injectors and found no problems with the O-rings.

I'm *ing done.

The mechanic I found is fairly familiar with VQ's, he did a GTM supercharger install a few weeks ago. He will be making a house call on Tuesday to troubleshoot including a compression and leakdown test although I am reasonably certain there won't be issues there.

This car ran strong with a proper tune at over 300 whp on nitrous right up until it was parked last fall. There is no way the combined 5 minutes of drive time since the turbo install has created major internal issues. The answer to the problem is something that was installed over the winter is either faulty or was installed improperly. The tune is not to blame for 3 cylinders running lean so there is either a fuel delivery issue which can only be the injectors or their harness because the fuel pressure is good or there is an air leak into those three cylinders only. Given the condition of the lower gasket and the complete lack of noise when leak testing the answer should be fuel.

I am out of skill and patience. I will post the answer when someone with more of both finds the issue.

Thank you all for the help.

 

It is easy to check the harness with an ohm meter, that would only take about 2 minutes. Injectors can also be checked with an ohm meter, and should show a low resistance when measuring the two posts, since it is simply a coil of wire. It is also possible to connect each injector to 12v and ground (polarity does not matter here) and see if they are clicking/firing. This would eliminate the injector right away.

Is it possible that when you put the injector harness on that the two banks were swapped, as in bank one connector went to bank two? Not sure if the car would even run...it may, but it would be rough since the injector firing would be way off.


How did the plugs look when you pulled them off? All about the same? If so, it would indicate that fueling may be fine.

 

I have an ohm meter but I am an electronic retard so how would I go about testing the harness? I understand how to do the injectors and will try that tonight and post the results.

I thought that might be the case too but the harness was on correctly. Bank 1 on the left (from the front of the car).

The plugs from the strong cylinders are black and wet. I'm guessing that is from dumping fuel to compensate for the lean cylinders. The "dead" cylinders plugs are light brown. They seem to have browned out some of the white flecks from the last drive where I went WOT. I'm guessing that is from lower temps sitting at idle but not really sure.

 

looking at plugs after the car has been sitting at idle for a while is useless, unless there was catastrophic failure.

so when you drive the car, what are you feeling? does it just not run smooth? Are you still not getting any boost and the stutter?

 

With the misfire/dead/lean cylinders I haven't tried to drive it again. Just been troubleshooting/fixing and starting it in the garage.

Vince sent me a new tune last night noting that my idle is fairly high compared to target and my MAF voltage is high. I won't be able to try it until I get the injectors and harness tested tonight and have everything reassembled but it will not fix 3 cylinders that aren't firing.

 

Well, it sounds like all cylinder are getting fuel at least. As for testing continuity:

http://www.ladyada.net/learn/multimeter/continuity.html

It is much faster to google than to explain. I don't think there will be a problem here though, however it is always good to confirm.

 

Some incorrect logic, here. If they are lean, doesn't that mean they are short on fuel? Why would they be black?
WOT on a base tune?!? That's a nada good thing.
Hope you find what it is and you didn't completely bugger it.

 

3 cylinders are essentially dead and 3 are running well.The cylinders that are running strong are black and wet from over-fueling to compensate for the lean cylinders. On bank 1 there is 2 bad cylinders and the one good one cannot supply enough fuel to bring down the overall AFR on that bank. On bank 2 there are 2 good cylinders and they can compensate enough to bring the overall bank 2 AFR down to normal.

Just so everyone doesn't continue thinking I'm nuts, here is the email Vince sent me with the base map where he directly tells me to be careful but get into WOT. From everything I have researchedon him I saw no reason to distrust his instructions.

Hey Shaun, attached is VER1 of your ROM. Set your fuel pressure with the vacuum line off at 45 psi. Get it fired up and send me some datalogs of idle, slow acceleration and (be careful with this one) get into WOT but only let it boost about halfway. We will see how everything is rolling in before we do a full pull. Also if you want to send me the zetronix logs as i would like to see anther wideband and boost logs that would be great. let me know how you makle out.

Thanks, Vince

 

Checked out the injectors - all clicked with power applied and all showed 012 or 013 on the multimeter continuity test. Results of injector harness test below.


The FSM shows this connection from injector-harness pin:
1-6
2-4
3-2
4-3
5-1
6-7

Here is what I found on my harness:
1-7
2-1
3-3
4-2
5-4
6-6

This would create a problem because the ECM is sending a signal to the wrong injectors, correct?

The ground pin (8) showed continuity on each injector plug so no ground issues. I noted that 2 of the injector clips had the ground connected with the black wire and 4 with red but as I understand from Sasha the polarity doesn't matter. The multimeter reading was 000 for each connection. I also tested every pin on each injector clip connection to make sure there was no other connections happening.

I'm hoping to hear this is the cause of the problems but I am expecting someone will educate me on why it isn't and I can go back to looking for a cliff.

 

here is an easy way to test. put your stock injector harness back in with the stock injectors. Not sure if you have a stock tune you can load but even a not stock tune the car would probably still start up. ask vince for a stock tune and see if that fixes the issue. If it starts and runs with stock injectors and injector harness then the wiring is the issue.

 

Sounds like the harness is good, injectors are fine and you had the pig tails connected to the wrong banks/injectors? This is why I was asking if the harness was flipped.

And the wire colors don't matter; it is a voltage energizing a coil, creating an electromagnet so current direction (polarity) is irrelevant. I have soldered 5 sets of pigtails to the OEM injector harness the same way prior to this one.

 

I sold my stock injectors and I traded Sasha my stock harness for a harness he had already put new clips on so I can't try that.

Sasha, the harness was connected to the proper injectors. They are numbered and were connected based on those numbers. What I'm saying is the pins on the injector harness aren't connected to the correct injector clips if I compare them to the FSM wiring diagram.

I'm going to look at every year of FSM and see if the pin outs ever changed on this harness. Do you have another harness you can test and see which pins go to which injector clips?

 

Remember the part where I said I am an electrical retard? I am going to go out on a limb and say I read the pins off the plug backwards, so what I thought was pin 1 is actually pin 4, 2 is 3, etc...

When you make that small logic adjustment there is nothing wrong with the connections on the harness.

So.... I'm back to waiting for the mechanic.

 

Ok, well, that settles that then. So nothing wrong with the fueling... I still don't like the -15hg at idle, and it may be the root of the problem.

 

just from reading over your thread i guess i can chime in a bit. -15 in of vacum is completely off from what its supposed to be. normally its around -20 to -21 stock with or without a turbo kit or charger. the next thing i wanna bring up is the simple fact that you had nitrous on it. nitrous hits alot harder and isnt progressive like a turbo would be so the load that is going on top of the piston is way more violent then your traditional turbo kit would be. did you ever do a compression check or leak down?

 

Thanks for the input. We will be doing a compression and leakdown test on Tuesday when I have a mechanic making a house call.

I am starting to think there must be some major internal damage but it should sound horrible and it really just sounds like a miss.

 

I think you'll find a lot more answers in the compression and leak down tests. Just a hunch.

Random question, but have you changed fuel and fuel filter etc. after letting is sit so long? I didn't see that in there anywhere, but I may have skimmed over it.

 

I didn't change the fuel or the filter. Thinking the injectors got dirty and clogged?

 

Zero idea... but as long as you're looking for stuff to check, it's another thing to add to the list.

How old is the gas?

 

bad gas will have problems but it wouldn't be the source of the low vac.