Having an issue getting my swap to run. 2003 DBW LQ4/ T56 vats has been removed, rear 02’s are gone as well as egr, and evap. Have 55-60psi at the rail. It was running the ther day for 15-20 min trying to cycle through for a DBW relearn, shut it down for an hour came back and now the most I can get out of it is a quick fire idle for a few seconds then it shuts down. Will do this as many times as I crank the key. This is as far as I have gotten. Not throwing any codes. Does anyone have any ideas? I’m lost.
I had the guy that did the tune verify it. Also probably would have never ran for extended periods of time if it was vats. Does anyone have HPTuners I could use to verify nothing is wrong with the tune?
Oil pressure or oil level sensor? Unplug the MAF? Since it ran fine for a bit, maybe a loose wire or failed sensor. Otherwise, it does sound like VATS.
I dont believe it is VATS but I am willing to try just about anything at this point. I get nothing different going around and unplugging sensors one by one. Where am I wiring a resistor in? Do i have a way to test without having the key from the donor vehicle? This motor is now into a 1997 Chevy Silverado so Im not sure that I can pick up a resistance reading at the key cylinder.
Set a lofty goal back in May to use this as the getaway vehicle at my wedding this saturday, but as with most swaps things just didnt go as planned. Figuring this out is just about the last step to having it on the road.
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I should add it never “ran fine” by any means. It idled around 400-500 rpm with map sensor unplugged and had a max rev of 1400rpm, wouldnt run with map hooked up. Replaced MAP, got nothing. Then grounded out c1-32&34 to get rid of the Park/Neutral rev limiter and now it wont idle at all. lol.
Is it possible for VATS to not delete/come back after initially firing and idling?
What are the possibilities of clogged injectors keeping it from firing? Motor sat for 2 years in my shop. We ran it in the donor vehicle before we pulled it.
Checked injectors with with a noid light and they are never going out when the motor dies. Leads me to believe it’s not a Vats issue? Would a cam or crank sensor cause anything like this?
If the VATS is tuned out then it won’t come back unless you go back in the tune and turn it on.
Possibly a wiring issue, especially since you have fuel at the rail, since it ran for 20 mins and now died. Wire may have come loose somewhere.
Is it possible that old rusty sediment got stirred up in the tank and clogged the pickup/pump? Maybe pull the fuel rail off the manifold and crank it to make sure injectors are spraying.
I don’t think the injectors are getting a strong enough pulse to fire past the initial crank. Any noid light test videos I saw held a steady flashing light the same brightness, I’m getting one bright flash then dimmer flashes after that.
Vats will shut down in 1-2 sec. I love that everyone blames vats. Let’s start with. Is this a bone stick engine no cam, no injectors? Is this a maf car? Is the maf hooked up? Are the plugs fouled? Are the cam/crank sensors fully seated? Is the pcm setup for an auto. It could have the wrong parameters.
Bone stock engine. Maf makes no difference plugged or unplugged. New spark plugs initially and have changed them again since diagnosing these problems. Cam sensor was never out, crank sensor was out at one point not sure if it’s seated correctly or not. Pcm was set up for manual trans. All I have is the tuners word on that though.
Willing to to pay someone $$ beer food to come hook up hptuners and see where we can get with that.
@BadnewsMike wish i would’ve seen this!! Thanks for the offer though. Turned out to be a bad MAF. Must have damaged it during removal/install. Would not run with it unplugged because it had not done the DBW relearn and it starts off with a ~500rpm idle.