01 5.3 won't stay running

[mgfan58]

My Tahoe will ocassionally fail to continue running after starting. It barely starts and then dies. You can try if 50 times and no luck. Leave it for 20 or 30 minutes, try it again, and it will start perfectly. Doesn't matter how much gas is in the tank either.

Any help would be appreciated.

mgfan59

 

[radkon]

Throwing any codes?

Sounds like the old school vapor lock which newer FI vehicles are immune to.

 

[DarkTahoe00]

Is your fuel gauge working correct?

 

[mgfan58]

How do I check for the codes, besides taking it to Autozone? The fule gauge seems to be fine and it will do this if it is full of gas or almost empty. Gauge goes below empty and we have never run out of gas so I have to assume it is fairly accurate.

We had a 96 Suburban that would sometimes take several times to start and it was the fuel pump. I've thinking this might be the same problem. I'll take it to Autozone later to get the codes read.

Chris

 

[DarkTahoe00]

Yea thats what i was gonna say that it sounds like your fuel pump. Well hope everything pans out for ya, post back lets know if that was your problem.

 

[ware8083]

I would bet on the fuel pump. I find they only last for close to 120,000 miles. and I dont believe it will throw a code on it. Just check your fuel pressure with just turning your key to on position and let pump primp and report your findings.

 

[mgfan58]

So where's the best place to buy a new fuel pump from?

mgfan58
Chris

 

[mgfan58]

Fuel Pump only or Pump assembly?

Okay, I've been reading about a check valve that goes bad in these fuel pumps. If you change the pump onlu will this replace the check valve or do you need to replace the entire assembly. Going to do it this week so I really need some help.

No codes thrown and it hasn't failed again so I can't give any fuel pressure readings. I have my gauge ready for a failure but you know it never will when I'm prepared.

mgfan58

 

[Sepiroth]

WAIT!!!!!!.

Before you go changing out the fule pump, which will come with a new bypass valve, check your feul pressure and volume. If you dont know how, youre going to need to have this performed by a shop professional.

If all is within spec, your problem is most likely not fuel but air. Now these engine have been know to have intake gasket leaks and the symtoms you describe are similar to the intake gaskets leaking. You can do a few things without the engine running. Check all hose connections going to the throttle body. This includes the air intake, mass air flow sensor, air intake to throttle body.

Now if there is someway the engine will start, even if you have to work the throttle to get it and keep it running, have another person try to keep the truck running while you use a can of carb cleaner and spray it around the bolts that attach the intake to the heads. If you notice a change in idle, your intake gaskets are bad.

 

[mgfan58]

Thanks for the information. When it has one of it's "I don't want to start" fit's there's nothing you can do to get it running. No ampunt of throttle manipulation does anything. You just have to sit and wait. Sometimes 10 minutes and sometimes longer. It just tries to start and then quits.
I have decided to take it to a shop, that I trust completely, and let them look at it. I'm not ready to just start throwing parts at it yet.

mgfan58

 

[oneradride]

Does your security light ever come on when you are driving for no reason?

 

[mgfan58]

All the freaking time! Does that have something to do with it?

Chris

 

[oneradride]

Lol, I had a feeling……… (only because mine does the same thing & the symptoms are related) This is what works for me.
Save up about 5000.00 and then…. I’m kidding, blow some compressed air in the ignition switch. That’s it!


I don’t know all the specifics but this is a vague overview….these trucks have what I think is called a passlock security system in them. There is something in or around the key tumbler that senses when your key is in close proximity (I.E. in the ignition switch) and this allows your truck to start. Your truck is 8 years old now and you have jammed a fair share of pocket lint, dirt, and god only knows what else in there during those 8 years. You won’t believe all the sh!t the comes out of there.


For me, this fixes the security light coming on AND the occasional no start. Where the truck will fire and run for about 1 second and die. It takes exactly 15 minutes for the damn thing to re-set and I’m off to work.

Good Luck!

 

[mgfan58]

My Wife said "God Bless You" and I agree. I can't beleive it will be that simple but I'll do it tomorrow afternoon and hopefully it will work out.

I told her the $5000 part first and she started getting a look like whe was going to hurl so I moved on with the real story. Thanks a ton. I'll let everyone know if this works out for us.

I wonder if this has anything to do with the Dark Gray exterior? My wife's Tahoe is the same color as yours but not near as nice looking. She likes to back into stuff and side swipe the garage. Good thing she's not a fighter pilot. She's might have a tendency to have mid-air collisions. ha-ha

Thanks again, Chris and Julie

Chris

 

[oneradride]

Chris,
How did you end up on this? After 6 months my freaking security light came back on yesterday, then last night I had the notorious no start for 15 minutes. I knew it would start again shortly because it always does, but that has to be one of the most aggravating feelings. To know there is nothing ‘really’ wrong with your truck and some damn computer thing (paslock2) is telling it not to run.
I tore off the clam shell this morning and removed the 2 wire connectors that go into the ignition cylinder. Then I douched almost an entire can of electrical parts spray cleaner in there, through the various holes and where the key goes in. Last time I did this just with compressed air and it worked great for 6 months. Hopefully this will clear it up again for a while. I have a bad temper and I would hate to blow up my truck over this :susel:

 

[mgfan58]

Still happening! Help!!!!!!!!!!!!!

Well, mine only lasted about 4 days. Security light came back on today. I'm thinking about a new ignition switch or if the sensor can be replaced independantly I'll do that. Was there anything you could actually see to clean or did you just "Hose it Out"? I may give that a try as well.

I don't think it's worth blowing up the truck but it could be very bad in an emergency situation. My wife is now driving my Jeep Grand Cherokee until I figure it and get it fixed.

Thanks for keeping in touch on this as I'm not convinced that you and I are the only GMT-800 (Tahoe/Yukon/Escalade) owners that have this problem. My employer is the current model GMT-900 supplier for weatherstrips. When I go back to work on Tuesday I may have some folks that can help us out. If it's a warranty issue they will have records and fixes. If not they can probably still help me. I'll just have to find the correct person to discuss it with.

Chris

 

[oneradride]

Thanks, let me know if you come up with anything.
There is a hole in the top of the cylinder and I used the little tube attachment to blow the cleaner in there. The first few seconds where black then it cleared up…… we’ll see
And trust me we are not the only ones…..Different vehicles but all passlock 2 – I could not believe all the sh!t I found on this today. Some have gone to the dealer had the ignition changed out only to have the same problem the next week… I’m am 100% confident the security light and the no start are related but no where have I found a valid fix.
This And this And this And this and this and this it’s crazy and there are several others, but they are all folks just bitching like we are, no real good advice.

 

[mgfan58]

Read one of the threads and it mentioned that the sensor reads the depth of the key. Could an old, worn out, key create the same problem? Just a thought. I don't drive the Tahoe with my keys very often but I've never had the problem. Every time it's happened it was with my wifes key.

Going to look for wear on the key and see how they compare. I'm also going to clean out the sensor hoel per your suggestion. Thanks for letting me know we're not the only one's.

Chris

 

[oneradride]

I'll be.. I hadn't read that far.... interesting.... Might have to start using the other key for a while.

GM's Passlock system does not use a transponder key. The actual transponder is in the ignitions lock and tumblers. When the key is inserted it sends a magnetic pulse to the pcm. If the pulse is correct it then allows the bcm send the message to the fuel system. The keys only have to be cut to the correct factory depth. In my opinion its a stupid way of having a transponder system, but beats having to pay a fortune for a key.

 

[mgfan58]

I'm going to clean mine first. If that doesn't do it, I'll change keys. It is a pretty wierd system but not the stupidest I've seen in the auto industry. I've worked in the OEM Sealing Systems industry since 1992 and I've seen some really wild stuff, and a ton of waste. I see why they're in so much trouble. They spend millions to fix things that the average consumer couldn't care less about and let the big stuff slip through.

Went to the Ford test track, back around 96 or 97, and their was a Bad to the Bone Mustang sitting there on 4 flat tires. Went to look at it and it was an SVO mule of some sort. Had a supercharger on it and all kinds of custom parts. It was a white car bu was so dirty that it was hard to tell. Asked the Security Gaurd about it and he said it had sat there for years. He laughed and said "Some Engineer probably just forgot about it, happens all the time". They had vehicles from every manufacturer, including R/H drive from Europe and Japan. Saw a Honda, R/H Drive, CRV 2 years before it hit the states.