Hey all! Long time no see. It's been awhile since I've been here. There are some very smart people here and I wanted to share an issue I'm having with my totally stock 2011 2500 Burb with 138k miles. For the last few years, there have been instances where we'd drive over a speed bump too fast, or really rough asphalt, and the RPMs would start to drop and the motor would die in about 5-7 seconds. It feels similar to when a fuel pump gives up while driving.

This issue is starting to happen more and more frequently. Last weekend I was pulling our boat to Havasu and headed north on HIghway 40. There was some construction and we were diverted to the shoulder and we had to drive on the 'grooved asphalt' on the shoulder. The RPM's started to drop, the engine started to shutter, and she died. I nursed it to the side of the road with the boat in tow (kinda scary), put the car in Park, turned off the key. Waited about 10 seconds, and fired it back up and she ran fine two more hours to Lake Havasu.

This is pretty much what happens... it dies, we put it in Park, turn the key Off, wait 10 seconds and restart, and all is fine. There are no error codes thrown, and this happens in any weather, towing or not towing.

Any thoughts or ideas?

Thanks,
Jeff

 

It sounds like a fuel delivery issue. But hard to diagnose when it is intermittent of course. Next time it dies, BEFORE you turn it off, listen to see if you can hear the fuel pump running. That should be running any time the key is in the ON position.

If you don't hear the pump running back in the gas tank, there is a possibility that you have a wiring issue somewhere on the vehicle, which is triggered by vibration.

Here's my example of that...

I had what I thought was a fuel pump failure on my 1996 C1500 years ago, when the truck was only 8 to 10 years old. It was intermittent, and happened when I hit bumps, etc. I finally pulled the bed off to get to the top of the gas tank without dropping it, and what I found when I pulled the pump out was that the wiring harness on the frame that suspends the pump INSIDE the tank had the two wires to the pump touching, and the insulation had frayed over time (from vibration), and the 12V and GND wires were shorting intermittently, killing the pump, and causing the engine to die. Always freaked me out too, that it was happening INSIDE the tank, above the level of the gas, which is an area full of gasoline vapor. I always was thankful my truck didn't blow up. What surprises me is that no fuses ever blew for the condition. The engine would just cut out.

 

@jfmorris Thank you for chiming in. Your description is very similar to what I'm experiencing. I had the Fuel Pump replaced about 3 years ago. And now that I'm thinking about it, I'm now not sure if this issue was happening before I had it replaced. It's too long ago to remember. But maybe it's possible that the wiring was pinched or impacted somehow.

Funny enough... I was pulled my boat to Tahoe 3 years ago and was just outside of Bakersfield, CA on Interstate 5. Lost the fuel pump and had to have the Burb AND the boat towed to the nearest dealership. They fixed the Fuel Pump the next day, but now I'm wondering if they possibly hosed up the wiring somehow.

 

I can't say for sure your issue is the fuel pump - I'm just suggesting that entire cirdcuit is a place to look for faulty intermittent wiring, bad ground, SOMETHING that would interrupt the flow of fuel to the engine. Mine was an odd one for sure, with the wires rubbing on each other inside the gas tank, above the pump.

 

UPDATE / FIXED:

Hey all - I wanted to follow-up here and let you know I'm pretty sure I've solved this. After posting here, I did a lot of research online and learned there are a lot of GM owners that have had this issue. The short story is that the negative battery cable has a way to getting pinched and fraying. The negative line comes off the battery post, and has has two lines: one that grounds to the passenger side of the motor on the front of the head. The other line runs up to the front and attaches to the frame. Huge PITA to get to and you have to take the front bumper off to access it.

And sure enough, mine was pinched and frayed too! I'm been driving for a few months now and haven't had the car stall, or hear the door lock flickering, as I'd go over rough road. Anyway, thought I'd post here and let you know all.



Notice the ground lead routes inside the body mount. Lame.

Rerouted lines outside the body mount point.

Cleaned and tight.


Below is the YT vid that really clued me in this issue. I ended up replacing the positive and negative lines, just to be sure. You'll see it in the first 60 seconds.

 

Wow! That sure was a hard thing to find - especially if you had to pull the front bumper to see it. Glad you finally resolved your issues though.

 

With the key on engine off, wouldn't the fuel pump stop as soon as it pumped up to the regulated pressure or does it keep running and the regulator just bleeds it off? Just curious.

 

No. The Burb would run just fine. Then we'd hit a pot hole or speed bump, and the door locks would cycle. Sometimes, the car would go into a 'limp mode' where the RPMs would drop. Even if I went WOT, the RPMs wouldn't go over 2k and she'd stall in about 7 seconds. The car was doing this for 6 months. I went to three different mechanics (referrals) and nobody could get it to repeat. I'd pick it up and with them not being able to find anything wrong, and then the same thing would happen again in a few days or a week.

Finally I just dedicated an entire evening to going thru vids on YT and reading other Forums. Turns out there is a lot of content on this, and it's apparently pretty common with GM trucks and SUVs. In one evening I narrowed this down to the POS and NEG battery cables and ordered replacements from RockAuto.

Replaced them both and it's been trouble free. The biggest shock to me though is how these 'professional' mechanics, two of which was GM specialists, couldn't figure this out. Do these people never open a laptop and research anything?! Somehow, a software sales rep (me) had to figure this out on his own, and did so in one evening.