Jrmotorworks

iTrader: (19)

Car is a '94 Trans Am, LT1 to 6.0 swap. L92 heads, LS3 intake, cam, no MAF (will be tuned for SD).... and so on. Using '02 F-body OS.

Attempted the first start yesterday, would "idle" for about 2 seconds then cut off.
Scanner shows timing advance, injector pulse, all that. Doesn't get above 800-900 RPM.

VATS is set to "None" in HPTuners, any codes for security or whatever have been set to "no report". I set the MAF codes to "MIL on first error" and I am seeing that in the DTC, so it should be failing over to SD mode so I don't think that's the problem. Everything I've seen points to VATS, but I have that tuned out.

The security light comes on with the key, but goes out while cranking and "running" then comes back on later. Is this correct?

Did a ton of searching here, but what I found was people "going to check with their tuner" to make sure vats was off and didn't report their findings. Or other things that wouldn't apply to my situation.

I'm f-ing lost, frustrated... you get the idea.

If I open the throttle any at all it will not fire. I have 12v at the coils and injectors in ignition key position. waiting for someone to come crank it while I measure voltage during crank and this short run period.

Does anyone have any ideas or where to start at?

Thanks for the help.

-Jeremy

aknovaman

iTrader: (7)

Got o the HPTuners repository and download a stock file for comparison.

If you want to run it in SD, go to engine, engine diagnostics tab, DTC tab and only turn off the SES light and leave the Error mode to zero.
That should get it to run if VATS is dis-abled.

deuce4935

iTrader: (2)

X2 on what Aknovaman said, it sounds like the computer is still looking for the maf sensor as it causes the engine to run and then die out after a few seconds, thats if the maf sensor is good. Do you have the maf connected at all? If the maf connector IS plugged in and the maf ISN'T disabled in the computer, then it could very well be a faulty maf sensor also. Try disconnecting the maf plug and see what happens.

1BAD_LS1 Tunes

iTrader: (8)

make sure ALL your grounds are good!

ones from the block to the body AND the most common (the ones on the back of the heads)!

the450r

iTrader: (1)

the VATS wire in the diagram shows its controlled by pulling to ground signal inside the BCM could you just ground that VATS wire near the PCM to allow it to run?

crainholio

iTrader: (2)

I think the one you're referring to is the Starter Enable Relay, which closes to allow starter solenoid trigger voltage to pass from the ignition switch to the starter solenoid.

His is cranking fine so that one's not likely the issue.

OP: what is your fuel pressure while it's idling?

Jrmotorworks

iTrader: (19)

Thanks for all the replies guys... I'll try to answer all the questions in one shot here:

I am not running a MAF, I actually don't even have one to hook up for reference unfortunately... I set the MAF codes to "MIL on first error" and DO see the DTC for this. That's good news right?

I'll go back and check the grounds. I know I'm getting continuity from my grounding point on the back of the head to my grounding point on the body. I have 4 gauge wire from the head to the body, 4 gauge from the block to the battery and from the body back to body at the same point as the ground from the head. Never hurts to double check though.

Fuel pressure is a stong 55-60 the entire time, before crank, during crank, during this "idle" period, and after. I have the fuel pump running on a different circuit than the crontrols from the PCM so I know the PCM isn't killing it. I hooked a noid light up to one of the injectors, can see a bright pulse for a few seconds then dims quickly as the engine dies. I'm in the process of wiring a relay (fused) directly to the battery to eliminate a potential bad power source (using the LT1 injector feed).

I'll post up my log file from HPTuners if that interests anyone.

I'll check all of what was stated before and see if anything makes a difference. Something just isn't right.

Thanks for all the help so far, very much appreciated!

the450r

iTrader: (1)

i was thinking of the fuel enable wire but if he has the fuel pump control from the pcm by passed i would think it would run. my experience with vats when u dont have the special key signal to the bcm it primes the pump, cranks, runs, and dies after the prime supply is gone.

Jrmotorworks

iTrader: (19)

See, I've heard different answers on this one. I've heard VATS would cut the signal to injectors but leave the pump run, and I've heard it will just cut the pump. If it just cuts the pump then I know I have a different problem, but if it does in fact cut signal to the injectors than this could still be my problem.

Don't you love conflicting answers?

What you're saying makes sense and could be a different issue of mine. I'll add it to my list of things to check.

Thanks

Jrmotorworks

iTrader: (19)

Update:
I think I ruled out the VATS situation. I found the VATS signal in the "Status Bit" section, it's showing as pass at all times. Don't think that's my problem.

So onto other areas... here is what I've found:

added some parameters to my scanner...
I'm seeing "cam signal hi to lo" and "cam signal lo to hi" which are either always the same or "hi to lo" is 1 more than "lo to hi"... not sure if that's normal.
I'm seeing Crank Sensor current Cyl.... once in a wile I see it say "0". Need to look into this to see if that's right or not, i'm assuming no....

The other point of concern is the MAP is staying flat at 21 kPa the entire time, no fluctuatoin at all. You would think something would make some movement.

I found one ground on a pin to the PCM that wasn't connected, fixed that and no change. I changed the ground on the left head (bigger wire) and it seemed to help slightly. I'm seeing 900+ rpm now. Grounded a plug to the body and getting good blue spark. NO voltage drop on coils or injectors (power side) regardless of key position.

My other concern is when I hooked a noid light up to an injector. It gets one bright pulse, then the rest are much less bright. However, that could coincide with the initial "prime pulse", then as there is less demand from the PCM the light is dimmer.

Sorry for so much information. Seems like I figure one thing out and uncover other something else that I wonder about.

But hey, we know it's not the VATS :-)

Thanks again everyone.

Jrmotorworks

iTrader: (19)

In some more digging through the numbers, I found this:

Here is the firing sequence that HPT is loging (current cylinder firing). By sequence, I mean each time I try to start it, fires and stops running.
Each time it rests on cyl 8. So each sequence starts on 8 and ends on 8.

#1:
8-1-3-7-5-8

#2
8-7-3-6-5-3-2-3-8

#3
8-5-3-1-0-7-5-8

#4
8-1-2-3-2-1-6-0-8

#5
8-1-2-7-2-4-5-8

#6
8-5-0-4-1-2-7-2-8

#7
8-4-1-0-3-8

That doesn't look right to me at all.

Or can I not go by this parameter?

Jrmotorworks

iTrader: (19)

Another update... Might have found part of the problem.
Contrary to some information that I've found on here, the LS3 MAP sensor is apparently not compatible with the 02 Camaro OS. it reads differently than the standard LS1 MAP, and unless you switch to 2 Bar SD in HPTuners you cannot edit the paramerts to make it work correctly. This is what I've discovered today anyway...

So, I'll be putting on my LS1 MAP, rewiring that and giving it a go.

Those of you that can't see my log, my MAP is reading about 21 kPa at key on, not the 102 or so that it should be seeing. So I'm going to start there and see what comes of that.