Duffinatur

I think this is my first post here, but everyone who knows says this is where to ask newbie LS1 questions. I usually find an answer by searching through the threads, but this time I'm stuck. If this is in the wrong spot please feel free to move. So here goes:

I've been trying to start my swap LS1 (99') w/ 4L60E.
(76 TA with Painless body harness and LT1Wiring engine harness and PCM flash)

It fired right up the first crank, ran for about a minute b4 I shut it down, but now just cranks and cranks.
- 58 lbs of pressure at the rail
- noid light says I'm getting spark at the injectors, power constant and flashing during cranking
- good grounds - but I'm constantly checking for something I missed
- no gauges/lights set up yet other than fuel pressure and MIL
- plugs are WET, so I stopped cranking her for now - bought new plugs/wires but hesitant to foul them ( I can smell gas from exhaust)
- I have 2 ground wires at the driver side rear head, I've seen somewhere that there should be 3 (FOUND, 3rd was hooked to firewall)
- VATS is disabled - PCM was flashed by LT1wiring/harness reworked also
-

possibilities:
- bad MAF, would this cause a crank-no-start? won't fire with it plugged in or not
- timing chain out of kilter - (but it did run at idle on initial startup)
- crank sensor - was replaced before install
- no DTC's, on scan tool, but there seems to be an issue with o2 reading (possible from too much fuel leaking through.
- I'm going to try disconnecting the battery for 1/2 hour or so to see if it resets anything.

- coils on opposite banks? saw this somewhere but not sure why it would cause an issue
- coils not grounded?

Man, I'm really stumped! Anyone have any ideas?
Duff

My build thread:
http://transamcountry.com/community/...?topic=57079.0

Duffinatur

Got it by jumping the airbox plug (don't know the proper designation)
Could it still be a bad MAF?
Duff

HappySalesman

iTrader: (3)

Hmmm... I guess the best place to start would be the basics...

We can assume that all 8 cylinders didn't lose compression overnight. We know the injectors are receiving signal, do they have enough pressure?

Have you checked for spark at all? I know you said you checked the plugs but have you verified they're firing?

I don't think a MAF would cause a no-start issue. You could try swapping the coils, but I dunno how much that would help.

Duffinatur

Thanks for answering. The plug I jumped was the IAT sensor and it seems to start and run OK when I jump that plug. I ordered a new IAT sensor and will install it in the intake elbow.
I did check each plug (and cleaned each injector during assembly). I was surprised the IAT
would cause so much trouble. I'll probably order a new MAF just to be safe.

HappySalesman

iTrader: (3)

When you say "jumped" what exactly do you mean? Like you're shorting the pins to one another?

Duffinatur

Exactly. just closed the circuit with a jumper wire. I never had an IAT sensor, just the plug hanging off the harness. I must have thrown it away or sold it with the donor car's air box.
Earlier this afternoon I installed the new IAT sensor on the harness and everything seems to be working well.

HappySalesman

iTrader: (3)

Glad to hear it! I read through your thread, looks great!

Duffinatur

Thanks