Hlp 2002 yukon 5.3 starts then stalls

[gse2schmidt]

first post for this vehicle....2002 Yukon 5.3 flexfuel 90K

Had an issue about a month ago. The engine starts then shuts off in about a second. All the gauges work, I can see RPM's while it fires. I can hear the fuel pump start during key on and sounds like its running for a few seconds after it stalls. No security light after the inital light up of security light before key on. Last time the wife tried to start it with the remote(aftermarket clifford professionally installed with passlock or passcode bypass module). Then I played with the remote start on and off, key on and off and all of a sudden it started and ran fine so it's not like a fuel filter clogging or regulator going bad slowly....right?
Anyway a week ago it did it again and all of a sudden it started and ran great until today and now nothing seems to make it better. disconnected the battery, tapped on the relays and checked them for corrosion and even swapped ones with the same serial numbers between the fuel pump and stuff then back again.
So now do I take it to the place that installed the remote start or my mechanic.....seems like I should be able to start it with the key or if that passlock/or passcode bypass module possibly hosing me?????
Seems like if the engine fires the crank/cam sensor must be working.
ignition module?

anybody out there have it happen to them?

 

[DarkTahoe00]

Did it do it before or after the alarm install?

 

[gse2schmidt]

Worked OK

Yeah the alarm was installed last December and no issues.

The first time(month ago) it didn't want to start it was after an electrical storm and the wife was parked near trees and I thought maybe a near strike might have just scrambled the logic of the remote start system and I just did things in the right order to get it going again.

After doing a little surfing on the internet it seems the bypass module for the remote start system is only used during remote start and not during key start.....that someone had a fuel code that kills fuel to the engine after an unauthorized start....hmmm that the engine will start but the signal will kill the fuel right away. Seems to me that if it was either the key switch or the remote start failing the opposite would work.....the wicked web we weave

 

[oneradride]

I know this might sound stupid but it’s cheap and worth a try. It solved several problems for me.

Try blowing some compressed air in the ignition switch. Depending on whether you have an aftermarket starter (not sure how the factory ones work) but the aftermarkets place a small ring around the ignition switch that feeds the correct chip signal to bypass the factory security. After pocket lint, dust, and all kinds of other crap gets shoved into that switch everyday it messes up the ohm transfer.

This also jacks up starting when you are trying with the key one in about 50 times and will cause the security light to come on.....

 

[gse2schmidt]

I sure will give it a try

I'll try some canned air, had an issue with moisture blowing out a computer....took 2 days before it would boot again...moisture behind cpu from using the air compressor without a good dryer.

Yeah I looked up the install manuals and did some surfing and I need to talk to the installer. The clifford remote start module that bypasses the security says that it uses a parallel path one for the remote start and one for the key directly. It seems once the computer detects an unauthorized start it cuts the fuel. Not sure if an authorized start clears it but it says it will retain the code unless you disconnect the battery....oops....I did so I can't find out if the code was triggered.

I had an oldsmobile alero which had the similar key setup and the transponder was actually in the tumbler not in the key like old days. So when the tumbler was replaced after a couple starts the security light would flash. Finally it wouldn't start and the procedure was to key on the car with like the door open....wait for the flash, then key it off wait 10 or 15 mins and do it again. I guess burglars are not going to wait around to steal your car anyway after about a half hour the thing was fixed. Sounds similar to what's happening to me know. You know I would rather have my vehicle stolen then be stuck with an unreliable vehicle at this point

The trucks running OK now and I have to wait for it to fail again so the wife has my car