[kirk.toune]

I have a '96 GMC Suburban K2500 4x4 with the 5.7L engine.

Over the last few weeks and months my truck has started to cut off.

This seems to happen mostly when the truck is idling or when I've let off the gas and coasting to a red light. But it also happens when I'm accelerating.

Let me be as specific as I can about the issue. I hate people that are vague, don't you?

The truck is completely stock. I have had the existing battery (NAPA) in the truck for about a year. I have replaced the cap and rotor about 4 years ago. The positive/negative battery cables are original, as far as I can tell. At some point the original owner chopped the positive end and replaced it with the crimp type. There is a cable that is crimped with the positive that appears to run off to the somewhere near the fuse box or what someone has described as the power distribution unit.

I replaced a faulty fuel pump about 2-3 years ago and the fuel filter about 2 years ago.

In the beginning when the truck would shut off and wouldn't immediately fire (it has always turned over), I would remove/replace the fuel pump relay or the starter relay and it would start. I realize now that this probably was inconsequential. Now the sequence that I just described doesn't seem to work and the time between the instance where it shuts off and starts back up is getting longer and longer. This makes it very difficult for my family to feel safe riding with me and really makes the people behind me at red lights mad.

I am a computer network engineer by trade and not a mechanic/technician.

I really think that this issue smacks of an electrical problem. I can hear the fuel pump "prime" when I turn on the key and the vehicle doesn't lope like it is running out of fuel. When the truck won't start there is a noise coming from under the hood that sounds "weak" and when it starts it sounds "strong." The "sound" is coming from the area of the intake.

One more thing. The voltmeter gauge on the dash has for as long as I can remember been on the negative side instead of neutral or on the positive side.

According to Advance Auto Parts the alternator is putting out the correct amount of voltage. They also say that the battery is "fine" even though I suspect otherwise. Why? Because if I drive the truck for any length of time and plug in my battery charger it shows about 75-80% charge. The battery will eventually go to 100% (full) charge, but like I said it always reverts back to 75% afterwards.

I just want my truck to be back to its reliable self. I'm emotionally attached as this truck has seen me through a couple of marriages.

Any assistance you can provide to help me in the right direction would really be appreciated.

Thanks...

Kirk

 

[Toymyster]

Well a fuel filter never hurts!!! Also check your vacuum lines, your problem sounds like a classic case of vacuum leak!! Aside from that, try cleaning your throttle body and your Idle air valve!! I'm assuming of course you have already checked your plugs, wires etc... Hope this helps!!

 

[tbplus10]

The first problem, cutting off, sounds like the Idle Air Control Valve, possibly just dirty and a good top end cleaning may help it out.
Try a can of Sea Foam, follow the directions on the can.

The voltmeter sounds like the gauge may be bad, not uncommon. The best way to test it is to get access to the wire harness, using a multi meter read the system while the truck is running.

Have you tested your battery charger on other batteries? Trust me if Auto Zone could show you your battery has issues they'd be trying to sell you a new battery.

 

[kirk.toune]

Additional information

Hello all.

Here's a little more information.

NAPA replaced the battery that would not seem to hold a charge. I would charge the battery and then drive the truck, come back and put it back on the charger only to see it about 80% charged. This w/o the ac or anything else on. Not even the radio.

Anywho....

I was driving on the Interstate (I4) today and the truck proceeded to cut out on me. I popped the accelerator and the truck came to life. Drove another 10 miles....and the same thing happened again... I popped the accelerator and it sprung to life. Hasn't done it sense.

I know that the IAC was specifically referenced in a few other posts, that I appreciate and will change out this weekend.

Does this make any sense?


Thanks...

 

[kirk.toune]

Engine Cut off Issue Resolved

Hello everyone!

Or should I say everyone that reads this forum thread.

I finally found the resolution to my problem. I stopped by Advance Auto Parts to buy oil and filter for my truck, and my wife car as well as my son's car.

I asked one of the guys there to consider my symptoms. He listened to me and didn't answer right away. He laid out the following scenario.

"You drive your truck....and the engine cuts off, you pop the hood, get out of your truck, lift the hood, go the fuse panel, pop the top on the fuse panel, pull the relay switch..... and then reverse the above and the truck starts. Does that sound about right?" I said "yes except it was taking longer to get the truck started and getting seemingly worse." He said that what he described was the fuel pump relay overheating and opening the fuel pump circuit cutting off fuel.

He said that while he understood that I was willing to spend whatever I needed to to resolve the issue, he suggested that I choose a relatively easy path and purchase a $15 fuel pump relay. I did, replaced the fpr and BOOOOMMM!!! The problem is gone! My wonderful truck is fixed, and my family will now ride with me again.

Thanks to everyone who weighed in on my problem. While I realize that this won't be the fix for eveyone's issue that I read was having a similar problem, I hope that this helps someone.

Happy Trucking!!!!

Kirk

 

[MrShorty]

Glad to hear you got it fixed.