Ls runs like it has 2 step.
Ls runs like it has 2 step. Needing some help here. 04 escalade LQ9 was shot, had a LQ4 sitting in the shop that ran, stock bottom end, fresh 706 heads, no port work, btr trunion kit and 660 springs. Custom grind comp 235/242 .610 lift. 2007 style intake that was port match to the heads, 42lb Delphi injectors, and long tubes. It will not run for ****, have to hold it half trottle to get it to start, won't idle, won't go over 3k sounds like I have a 2 step on it, and smells like raw fuel. Took computer out had a reputable guy put a base tune on it so I could finish up all my exhaust and what not. Still won't run, idled for a second then was right back to the way it was. I'm at a loss here, is the injectors too big, would there be an issue running the newer intake? I've read people using the intake with no issues. I have no vacuum leaks, everything is hooked up like factory. It is not throwing any engine codes at all.
This happened to me once when I raised the engine too high and mashed the MAP sensor on the underside of the hood. The sensor cracked, but you couldn't see it easily. The engine ran like you described, until I finally found the crack and replaced the sensor.
TECH Fanatic
Joined: Jan 2009
Posts: 1,063
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From: Bostwick, GA.
Have you gone over the inj harness for correct routing?
All grounds on their respective locations?
As mentioned in post 2, injs leaking?
Were injectors allowed to sit in the new engine for an extended time period?
Fuel pressure is?
All grounds on their respective locations?
As mentioned in post 2, injs leaking?
Were injectors allowed to sit in the new engine for an extended time period?
Fuel pressure is?
Any vacuum leaks? Timing could be off a little as well. I had issues with my tune. I had sent my engine specs to a tuner to get everything unlocked and a base tune. It stalled at lights all the time, was hard to start and would pop while accelerating. It was best to have it Dyno tuned with an AFR gauge so that you can tell how its running.
