I have had my car at a local mechanics for the past 3 days trying to figure this out. It is a problem that has been going on for about a year. I've called numerous mechanics and all say fuel pump, but when the current mechanic tested it he said it only had a failed reading once (good/bad??).

Here is the issue:

Engine makes the loud revving noise when driving in hot weather or in stop/go traffic for more than 10 or so miles. Come to a stop light and it stalls.

Also when the gas is below 1/4 of a tank the gas gauge goes crazy and then the stalling is more frequent.

These guys now found a mouse nest and thought it was a chewed wire, which of course they can't find. And another one of their mechanics said they didnt' think that was it because there isn't any other "signs" of electrical issues...

The truck starts up immediately when it stalls but it will do it at pretty much every stop after that until I let it cool/rest.

I have had diagnostics done, inspections, etc. NO ONE can figure it out! I've been reading forums, watching YouTube videos. I'm wishing now I would have become a mechanic

PLEASE tell me one of your Blazer guru's has an answer. I LOVE my "Gus" (yes I'm a girl and we name our vehicles ). And besides this he has been an amazingly reliable vehicle!

 

Hello frustrated_chevy_girl,

Lots of help here but you will need to give as much detail/
info on the type of vehicle you are driving.
Year, mileage, kinds of maintenance that have been done.
I am sure somebody will be able to give some advice but you have to give
them some good background on your vehicle. Be as detailed minded as possible.
We all love our Blazers and be patient, help is here.

Mark K

 

There's a clue right there, sounds like an overheating fuel pump. Don't let the fuel get that low because it helps cool the pump and sending unit.

 

OH I forgot all that info! ha! OOPS!

Ok here we go:

2001 V6 4.3 Vortec. 125k miles. I have owned him for 4 years. Right when i purchased him I put a new Mass Air Flow sensor in it. 2 years ago I put a new thermostat in it and did some other minor work to it. We moved from WI to CO 2 years ago and a year ago is when the problems started.

First I started to hear a bubbling noise when I would accelerate. Temp outside didn't matter. No one could figure that out.

Then the Check engine light came on. So a mechanic recommended that we clean the EGR valve. It was pretty bad, so we did and also cleaned the butterfly valve (is that what it is called?). After that check engine light went off and hasn't been on since.

Weather got hotter here and more often it would die again. I work 10 miles from my house and the highway gets CRAZY so its a lot of stop and go. It didn't do it (stall) until last weekend when we were doing errands (100 degree weather) through town and it started dying at the stop lights and it ran that heavy engine noise. Temp gauge stayed at 210 and would only go slightly over.

When it dies I don't think the security light comes on, but I know for a fact the "check gauges" light comes on.

I hope this is enough detail...let me know what else.

I really really appreciate all your help!!!

**recently when the truck stalled this past weekend the fuel was full. I had JUST filled it all the way that morning.

 

HI, IM A 2000 BLAZER OWNER (6 MONTHS) AND I BEEN READING ALOT OF THREADS IN THE FORUM, I THINK THE PROBLEM WITH YOUR TRUCK COULD BE SOLVED JUST BY DOING AND OIL CHANGE WITH THICKER OIL, IF YOU ARE USING 5W-30 OIL TRY 10W-40, MY CHECK GAUGES WAS COMMING ON ON HOT WHETHER MY TRUCK DID NOT DIED BUT I NOTICE THAT WHEN THAT HAPPENED MY OIL PRESSURE WAS LIKE 8PSI, I THINK I READ SOMEWHERE THAT IF YOUR OIL PRESSURE GOES TOO LOW WILL STOP YOUR ENGINE, OR IF THE COMPUTER SENSES LOW OIL PRESSURE YOUR TRUCK WONT START, SOME PEOPLE USE 5W30 OIL ON WINTER AND THEN CHANGE TO A THICKER OIL ON SUMMER, i HOPE THIS HELP YOU.

 

It is true that fuel cools the fuel pump, but the fuel runs THROUGH it. so as long as the pump has fuel to pump, its being cooled.

I would get Gus back from the shop before they start throwing parts at it and spending your money.

Spend about $150 and get a good scanner that will record the live data stream. Basically a brain probe on Gus. When Gus stalls, the scanner will record what is happening in the computer and it may give you a clue as to what is going on.

Yea, I know 150 sounds like alot, but how much has been charged so far and you still have the problem?

I follow what agunez (We are right here, you dont have to yell!) is saying about the oil pressure, the oil sender powers the fuel pump after the truck starts. If pressure drops too low, your fuel pump will shut off. There is a fuel pump relay that sends power to the fuel pump before you start the truck and right after it shuts down. That would explain why it reliably starts after each stalling occasion. SO - Oil pressure may be dropping, or the oil pressure sender my be bad.

After typing this, and thinking the problem through a little more, I would hold off on the data scan. Not sure how long since an oil change or whet weight oil you are using. An oil change wont hurt, give it a try. If its really hot in CO, look in the manual and see how heavy oil GM recommends. I would personally use 15w40 Rotella in my truck. I love that oil.

Give Gus a hug. He will enjoy it!

 

Since we're all guessing here...I guess that there's a ground problem with the fuel pump. Most of the time when I see gauges go crazy it's a bad ground. Is there a way to check and record the fuel pressure while driving?

 

I agree with dobyken on checking the ground for your fuel pump. I'm not sure on your generation of blazer, but on the 1st generation blazers, the ground for the fuel pump and the ground for the sending unit for the fuel gage are one and the same. Now, i have personally experienced the stalling when the fuel is below 1/4 tank. It is TRUE that fuel passes through the pump, but being submerged in fuel is what keeps the motor of the pump cool, just like rriddle3 says. I Think you should change your pump. Oh, your fuel filter too while you're at it.

What part of CO are you from? My daughter and I (and Jimmy) are in CO springs.

 

You guys are being so helpful. I appreciate ALL these responses!
I had an oil change about 200 miles ago, but will try the richer fuel. I'm pretty sure they use 10W30. I'd have to check. But I will get it changed with the richer oil. The oil pressure gauge does move as I accelerate...is that normal? It doesn't go crazy but when Im' stopped its almost at zero and when I drive it moves up.

Maddie's Dad. I am also in the Springs.

So the verdict from the mechanic today is that its a wiring issue?? And/or my mass air flow sensor...I disagree with that one. I told them I need him back at noon! I have you guys now

dobyken i could rent one of the pressure testers and use that for a couple of days to test the fuel pressure.

 

I am a woman too and like you wish i would have become s mechanic try what they say these guys know blazers big time. I love this forum. I do not know if this would contribute to your issue but mine would die alot and it ended up being the ignition moduler also that part made my tranny act like it was going just a thought.