Fresh rebuild issues. Timing off by a tooth?

[vannatta20]

got a customers 69 in today and went to fire it up today.
Engine is a rebulit ls1 by local no name shop that does not build ls engines much...
228 228 duration cam with 588 lift and 112 lsa. stock heads ls1 intake and has long tube headers. Open headers for now. No 02s.
At first no fire at all. Turned out all 8 injectos were stuck. Fixed that and tried starting. It finally fired but could not idle below 1400 rpms. Ive tuned quite a bit of cars and knew what the base settings should be. Next I played with idle air flow and that did nothing. I then locked the timing and started raising it. It was at 22-24 degrees. I upped it to 36 degrees and it would finally idle. Sounded crappy but all cylinders are firing. Why will it only idle at 36 degrees to 40 degree...Once it could idle i had to change the idle airflow back to a decent range. This car doesnt want to even fire up with timing in the 20's.

[mattcrp1]

I have never set up an LS cam, I have set many over head cam engines, but would a vacuum help isolate a cam timing issue?

[vannatta20]

looked stable but then again it was hard to get it below 1400 rpms. Once i increased timing to 36 it idled. I dont understand why every other engine I have tuned wants timing in the low 20's and this needs almost double. Something is way off.

[BR3W CITY]

40* and your heading towards bad things. Was there a large built in advance or retard in the cam?

[GMC-YA68]

what do you mean by open headers?? If that O2 sensor is anywhere close to the end of that header it is going to cause all kinds of chaos at idle.

Just re-read, you have no front sensors?

[BR3W CITY]

BTW, I assume its throwing some kind of code right? It should still idle without 02's at all.

What else was done to that motor? Mystery builds make it kinda hard to pinpoint tune related problems, especially not knowing how far from stock we are starting. Were there other valvetrain upgrades done as well? 112 lsa will always idle a bit choppier, so you won't be looking at a 700rpm idle or anything. But you should be able to get it to settle 850-900.

Did you start making changes to VE and PE? If your tuning it, give us some more information. A mystery build and "base settings" isn't much to go off.

[midwest customs]

I tune alot and this was the first start of the engine in the vehicle. Im not worried about getting a perfect idle or anything but I could immediately tell there was a major issue. No 02s are installed. They dont need to be for a test start. No maf either. Its disabled in the tune. Im just testing it until the full exhaust gets installed. We checked cranking psi and it seems low at 148. Similar combos are in the low 200's

[BR3W CITY]

Originally Posted by midwest customs

I tune alot and this was the first start of the engine in the vehicle. Im not worried about getting a perfect idle or anything but I could immediately tell there was a major issue. No 02s are installed. They dont need to be for a test start. No maf either. Its disabled in the tune. Im just testing it until the full exhaust gets installed. We checked cranking psi and it seems low at 148. Similar combos are in the low 200's

Ok so I'm guessing by this post that your the customer being referred to in post #1. Which one of you is actually tuning the truck?

Yall still need to give us some more details on the build. Without knowing anything more, all I can guess is that your bleeding compression off through weak valvesprings and then tuning it to compensate.

Was that compression equal on every cylinder? Was it with the TB open, or closed? Help us help you.