Rune

Hi, my friend has a hot rod project with C5 LS1, and trans
wiring harness from street and performance and PCM from same company.
VATS turned off.

Car will fire up, but die after a split second, if we use starting fluid it will run ?

We monitor with Ease scanner and injectors shut down, ie pulse width is 0.64 ms


Ease scanner also shows negative "delivered torque" ????? when idling ???

Any hint to what can cause PCM to shut down injectors, leading to positive starting of this engine setup will be rewarded with usd 200

I can pay with PAYPAL


TIA
Rune

MyLS1Hauls

iTrader: (2)

Sounds like it could be VATS related. I know it will do that with an improper key chip. You're sure its been completely disabled? I'd give street and performance a call.

Rune

Yes, we have called them , they have no good idea what it could be.
First we tried to use an old 1998 PCM and reprogram with LS1edit, disabled VATS, but still would not start.
Bought a new PCM from S&P programmed to this harness.
Engine refuse to run.......

There must be another thing that prevents PCM from commanding correct injector pulse width ??????????????

A negative "delivered torque" shuold give us a clue ?

ataylors

iTrader: (2)

loss of crank sensor maybe?

SmokingWS6

iTrader: (1)

what year is the wiring harness for? 98 pcm's are completly different than 99+ You might try finding a 99 or newer stock pcm and try again.

Rune

we will look into that, as for wiring harness and PCM not beeing compatible, we bought it as a set from S&P, so i would assume it is ok ?

thanks for your input

Team ZR-1

Not giving enough info, does the car have a BCM ?
If so was the PCM to BCM relearn done, if not it will not start well at all.
Also was the CASE CKS relearn done befre the problem started ?

Rune

No BCM present
kit was wiring harness + PCM
We did not do any CASE CKS, i thought engine had to be running to perform this ?

John , you take this job, then go check your email :-)

Team ZR-1

Check your PM here for I replied this AM.

jimmyblue

iTrader: (11)

In my F-body schematics it shows the fuel pump relay
being controlled by the PCM, but there are two "fellow
travelers" - the BCM sends a "fuel enable control" as
short-to-ground on C2 pin 30, Dk Blue (Helm book does
not say which of the two connectors) and there is also
a fuel level sensor signal that routes through the dash
cluster and comes into the PCM on C2 pin 54. The fuel
pump relay output is C2 pin 9, +12 output to run.

So this all may be different in the C5 case, but it looks to
me like if you lost the BCM you may need to ground the
fuel pump enable pin (maybe the PCM runs pump itself
for start, but drops it without enable in run position?