Yukon Stalling HELP!

[2001Yukon]

The Yukon has been stalling out for what I thought was a loss of power. Recently found out that the battery was not the right size, so I bought a new Super Start 34/78 EXT tonight.

* Cold Cranking Amps: 800
* Cranking Amps: 940
* Reserve Capacity: 115
* Length: 10-3/4"
* Width: 6-7/8"
* Height: 8"

Took it out around the block after installing the new battery and it stalled. After it stalls it becomes tough to start. I was pretty sure I had narrowed it down to an electrical issue, especially after the load test on the old battery. It still could be an electrical issue... Basically what happens is the trucks acts like it is flooded. It starts to surge and the RPM gauge starts bouncing around.

Here is what I have already done.

* Cleaned the throttle body
* Can of Sea Foam in a full tank of gas
* Changed out air and oil filters
* Filled her with Q TorquePower 4x4 Full Synthetic 5W30 Motor Oil
* New fuel filter
* New battery

No codes are showing up when hooked up to a computer at the auto parts store. The alternator was also checked and everything tested good. Why is this thing stalling out on me? Will taking it to a dealership shop help me troubleshoot the problem?

What is the next thing to check?

 

[matt14]

So, does it crank over slow? Maybe for fuel pump is going out? Connect a fuel pressure guage to the car and have the pressure checked. If its low, then it could be a bad pump

 

[2001Yukon]

I will try to test the fuel pump. Will a dealer test that for free?

The engine turns over just fine on a cold start. Regular warm starts are just fine too.

On a hot start (after stalling) it sounds like it is flooded. So it takes multiple tries to fire it up. Even then the RPM's won't stay high enough for the motor to stay running.

Will try to clean the trottle body again today and use another can of Sea Foam. Are there any step-by-step instructions on how to use Sea Foam? Before I just dumped the whole can in a full tank of gas.

 

[hassoun]

stealerships dont do anything for free. go to the dealer or a mechanic and have them diagnose your truck for a $100. at least you'll know whats going on. then go from there. i prefer checking things myself but its not worth it go buy a pressure gauge for $80 if you can get the whole truck diagnosed for $100 u know what i mean ? it sounds like a fuel pressure issue to me. either a fuel pressure regulator or a fuel pump. or could be even a clogged fuel filter.

 

[2001Yukon]

I am 99% sure it is the alternator. All week I drove the Yukon and no stalls. I was only able to avoid the stall by running few electronics. Then to shut off the electronics as soon as I noticed the RPM's spiking. As soon as I turn on the heated seats, radio, heater, etc. the motor sputters and dies.

Is there anything electronic that it could be other than the alternator? What signs should I look for to confirm the alternator is almost dead? Testing equipment has shown it is good. WTF?

 

[Mac]

When was the last time you change your fan belt?
*(Check the condition of the belt and the tensioner.)*

Having a Glazed, or polish belt could cause it to slip. Not enough friction to grab hold of the pulley and unable to turn the alternator properly.

If it's good then use that 1% to change the alternator.

 

[2001Yukon]

Could the performance of the belt be related to the amount of amps needed. So as amps increases (use of electrical features) the belt fails?

 

[Mac]

Uh...yes!!..

At idle and low rpm, the alternator can't keep up with current load due to Slippage. And only when you rev up everything runs normal.
(In short not enough power cause the alternator is not turning fast enough.)

Also check the tensioner if it's giving proper tension to the belt...

 

[2001Yukon]

Still no luck finding what the real problem is for my Yukon. Filled it up with a higher octane gas and put a 2 cans of Sea Foam in the tank. There must be a cheap way to find the codes that the engine is throwing.

None of the auto parts stores have a computer smart enough to read the code. The auto repair shop wants $90 to diagnose the problem. In the meantime I will just keep tooling with it and try to narrow it down.

I've been thinking it has something to do with the alternator. Although every check of the alternator has been good.

So now I am going to go on the path of upgrades. Spending money on upgrading equipment on the truck might solve the problem. What is the next best upgrade to the truck that might solve the problem?

- - Dual exhaust muffler
- - New plugs and wires
- - Computer chip
- - K&N Cold Air Intake Kit

Which upgrade would any of you guys put on the truck and why? Which one is more likely to address the issue of the stalling issue?

 

[2001Yukon]

Service Engine Light finally came on and stayed long enough to pull the code. It was the EGR Valve that was causing the stall.

Pulled it out and scraped off the carbon build-up. Checked out the owners manual today. It was supposed to be a 60,000 mile maintenance check. Doubt it ever was maintained.

Thanks for all the ideas fellas. I think adding a double dose of Sea Foam to a full tank of high octane gas really cleaned up some carbon. That carbon pushed on through and really clogged up the EGR.

Seriously fellas, if you have never pulled out your EGR and done basic maintenance, you probably should. It is really simple to unplug, unbolt, and scraped out, plus it will save you $150. Will probably upgrade mine when I bolt in a new K&N CAI Kit.