01 Yukon wont stay broke long enough to fix

Guys I need some help. I can’t figure this one out. 2001 Yukon 5.3 70,000 miles. We have owned it since 2002. You try to crank it up and no start. None at all. Like it is out of gas or has no spark. It has done this about 5 times over the last year. I have seen no pattern to it whatsoever. It is usually after a short trip and rest like a trip to the grocery store. You come out of the store and no start. The bad part is it wont stay broke long enough to find the trouble. It will always start back up after some time???
My first thoughts were fuel pump. I figured it was getting hot and when you cut it off it would not pump until it cools. So I change out the pump and the connectors for the pump. That didn’t fix it. Now I keep a fuel pressure gauge in the truck in case I can get it on there when it won’t start. Well, last night it happened again. We came out of the restaurant and no start. I put the gauge on the fuel rail and it has a good 60 psi. So I start thinking about spark. Could it be the factory security system?? I did notice the security light in the dash on last night. Anyway we were using her keys in the ignition but we unlocked it with mine. So just to try it, I took her keys out and tried mine and IT CRANKS!! Can the keys even have anything to do with it? What about locking it with the remote then unlock with the key? Can any combination of this trigger anything with the factory security system? Does the factory security system have the ability to keep the motor from starting? The security light in the dash seems to have a mind of its own. I don’t know what triggers it but it does come of from time to time.
The truck does have a remote start. Can that play into this? I had it installed using the factory remote. You have to hit the lock button twice for it to crank. I guess it works off the old blow horn to verify lock thing. I don’t think this has anything to do with it but I’m not sure. This is the wife’s ride with the baby seats in it so you can see how this is a problem. Any ideas???

P.S. I know this isn’t a LS1 but I’m not exactly a member of any Yukon forums.


http://i153.photobucket.com/albums/s...IMG_4252_1.jpg

also check for, i cant remember the name of it, but when you wreck there is a switch that gets jarred and shuts down the fuel, find out were it is and first push the button to reset it, and if that dont owrk, replace it. I have heard of alarms causing problems with kill switches before, might wanna get it removed/ and or replaced

Since you have an alarm, get the tune changed to remove VATS and that issue will be gone for good.

The remote start is just a remote start. Not an alarm. I thought VATS would let it run for a few seconds. It wont start at all. Just spin over...Until it decides to crank.Then it fires right up as normal.

is this the same Tahoe with the SEL misfire code?

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Originally Posted by vff_jeff

is this the same Tahoe with the SEL misfire code?

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No. No trouble with that.

there was another guy haveing problems with ruff idle and startup. I am preety sure either he had bad gas or not enough fuel to injectors. preety sure yours is the Vats vehicle anti theft system, or killswitch. do like he said above. But if that doesnt work, let us know. Some of us (me) Have allot of time on our hands. And I have connects in automotive repair and diagnosis.

my mom had the SAME EXACT problem with her 2002 Impala LS. it was all in the security system. there would be nites that she would come in mad and i'd ask what it was and she'd say "the security light was on when i got out of the car tonite, so the dang thing isnt gonna start in the mornin to go to work" It happened to her car more than 5 times in a year though. probly about 10-15 times a month. it was terrible, but there was never anything that we could do to fix it.

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Originally Posted by vff_jeff

also check for, i cant remember the name of it, but when you wreck there is a switch that gets jarred and shuts down the fuel, find out were it is and first push the button to reset it, and if that dont owrk, replace it. I have heard of alarms causing problems with kill switches before, might wanna get it removed/ and or replaced

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I THINK you are talking about an inertia switch. Unless GM has changed in the last couple of years that is still only a f**d feature. Please correct me if I am wrong.
PLEASE forgive me for saying the f word and don't tell my wife if I am wrong.

I dont think it has it, but I still think it is the VATS. call Allen at nelson performance, i think he can fix it with a tune

eBay Motors: VATS Security Bypass Corvette Camaro LS1 LT1 LT5 L98 (item 160183728142 end time Dec-03-07 07:37:07 PST)
lookin arround and found this hope it helps

try leavin the pressure gauge on there for a while to see if it drops? or maybe you've already done that

Any chance that key has a chip in it that has lost it's link with the 'Kon?

A lost association will yield what you're talking about. I only say this b/c you said you switched keys, and it started right up. Has it always happened ONLY when using her keys, or both?

Just another angle to look into.

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Originally Posted by 1BADC10

Any chance that key has a chip in it that has lost it's link with the 'Kon?

A lost association will yield what you're talking about. I only say this b/c you said you switched keys, and it started right up. Has it always happened ONLY when using her keys, or both?

Just another angle to look into.

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thats why i sent him the links for the vats eliminator, it is that.

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Originally Posted by vff_jeff

thats why i sent him the links for the vats eliminator, it is that.

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But why not have the dealership quote a reprogram price... worst they can tell you is it'll cost ya $40 to reprogram (if that's really the issue).

I'd be curious as to how the bypass kit works, and what's the downside to using it. Sounds like this is to eliminate VATS all together. I wouldn't do that to mine, but to each his/her own.

Quote:

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Originally Posted by 1BADC10

Any chance that key has a chip in it that has lost it's link with the 'Kon?

A lost association will yield what you're talking about. I only say this b/c you said you switched keys, and it started right up. Has it always happened ONLY when using her keys, or both?

Just another angle to look into.

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I'm not sure. That isnt something I have paid attention to before now. It may have been a coincidence that it cranked with the other key but I dont think so. I have done some searching and heres what I have found so far:
The main possibilities are: 1. Bad lock cylinder. 2. Bad ignition switch. 3. Bad IPC. 4. Bad ECM. 5. Wiring problem to either of these components.
Im still not sure about the security system. How does this thing work? What triggers it?

I'd honestly try to see if the key is the problem before tearing into any wiring!!

Ok a couple things you should check for when this is happening. 1. Is the security light on when you try to crank it and it wont start. That alone will tell you if it is security!! 2. Try using the other key almost immediately. Don't give it time to reset or whatever it's doing that cases it to start out of nowhere. 3. Have you ever heard of something called identity theft?? It is a little security system that GM was doing for a few folks for free for a while with new purchase and some service vehicles. Anyway, if you have Identity Theft, there will be a little keychain thing on your key ring. IF the battery dies in it, you have to physically press the button on the key chain(The button does not look like a button till you press it and the light lights up on the key chain deally.) 4. Check the wiring of the Keyless start, they could've tapped into a line or cut something else that is now giving this truck an intermitant signal through the wire!!! Especially grounds! 5. Last thing I can think of right now is if you checked or changed you sprkplugs lately??

If your starter circuit is active then you can eliminate the remote start side as they are not wired into the ignition but rather just interrupt the starter circuit. However with GM's Passlock Security System all remote starts need a bypass module to get around this system. Passlock is designed to kill the fuel pump if the "key" isn't inserted into the ignition this differs from VATS because the old system had a resistor value in the key itself, with this all you had to do was bust the ignition switch out and you could still start the car ( and steal it) not much of a security system, with PasslockII it's ( the resistance value) in the ignition switch itself with the key being a part of the value of the switch assembly and there is no fast way around it in a parking lot or side of the road. With out the "key". If you had a security light then your Passlock is triggered and they only are designed to trigger when they don't see the "right" key the system learned with. Your installer had to use a bypass module and this module installed in this same circuit bypassing it when you use the remote start option. Could be related but I doubt this is your problem because you had fuel pressure but its something to be aware of and eliminate off the list. This system cant be accessed with out a GMTec 2 and a Gm TIS puter is need to do the relearn. ... Get your codes downloaded I'm sure it will be a better starting point, whatever happened it coded I'm sure.

P.S. That 86 of your's defines CLEAN! nice job.

OK. got it scanned and it had 2 codes.
1) B2960 Security system data wrong but valid
2) B2961 Key in ignition circuit fault

My buddy is getting with alldata. Anybody had any experience with these?

Vats

After getting with alldata....replace the ignition lock cylinder. Does everyone involved concur?

boingy boingy boingy... LOL

So what ever happened?

We replaced the ignition lock cylinder, GM part # 88965342 and cleared all codes. So far, so good.