OT-Question for GM techs
 

We've been having a reoccuring problem with our S-10 Blazer. The fuel pumps keep on burning out. The problem usually shows up as a no start situation. The truck may also die when at a stop, and has cut out (but not died) when being driven. Sometimes, the truck will restart if you wait several hours. The dealer has replaced the pump 3 times now, and the problem is still occuring. My question is; what is causing the pump to fail? This last one had less than a weeks worth of use on it.

Drugs in the Gas Tank:D

OG:cool:

Hey Cord....when i had an s-10 while i was an installer doing alarms and stuff for dealers...one of the head service guys told me to change the fule filters on those trucks like every other oil change.....said they are crap and go out fast! Also told me to keep an eye out on the whole "spider"assembly fuel injection setup under the manifold. told me that those are prone to go out as well....just passing some info along... :)

Yep, the dealer is shot gunning the truck. We just replaced the spider assembly and fuel regulator as it was leaking. They just called me to say that the truck starts just fine, so they can't diagnose the no start condition. They also say that my cap and rotor are bad, which will cost $300 to replace. I asked him if the bad cap & rotor were the cause of the no-start and he wouldn't answer the question. So I answered it for him. Morons.

Cord:

I'm assuming this is an electric pump.

Replace the fuel pump relay (cheap $6-$9 at national auto parts stores). Sometimes the relay sticks causing the simptoms you mentioned. Mechanics seem to have a hard time diagnosing this.

Also consider replacing the fuel pressure regulator.

Third, possibly a vapor lock condition, via the gas tank vent, etc.

Regards,


vtec

first off are they aftermarket pumps that you are using, if so there is your problem, the filter is true esp. if its an older truck. next time you drop the tank flush it to ensure your not resurculating any debris. and replace it with a gm pump.

VTEC-Yea, I'm thinking about that relay too. Might just do it. The problem with the techs is that they can't think anymore. They can bench test all they want but if it tests ok, then it has to be ok. More than once I've ordered the manager to replace something because I know it's bad-despite testing OK

The vapor lock is a good idea too. I'll look into that also. The regulator was replace when we did the spider manifold.

just once-we did the fuel filter already. I really don't know what the condition of the tank is in-but any respecting mechanic should have checked it. Yes, these are GM pumps are they are being waranteed at no cost to us. 3 pumps in 15,000 is a tad bit excessive.

Cord - Can't help you with the solution, but I had to laugh when I read this. When they first changed the body style on the S-10 Blazers, my ex brother-in-law bought one. Within a month he was having the exact same problems as you are.
It would die on the road, the dealer would pick it up, then by the time they got around to working on it, it would start.
After not being able to figure out the problem for a few months, they finally bought the truck back from him.

Cord,first impression is they are doing the old flatrate trick of jacking the box to access the fuel pump for replacement. This makes the pump quick to change but if the tank has a load of crap in the bottom.guess what the new pump gets installed in? Secondly,these are a problematic pump. They are very suseptible to heat damage. Always keep your tank filled at least half way in order for the pump to be submerged in fuel(coolant) and it will prolong the life somewhat.

I ran into similar problems on a Chevy Tahoe. I heard it all.
1. Don't drop below a 1/4 tank to maintain pump cooling.
2. Check you have a good ground, or the pump may be drawing excessive amperage.
3. Other GM cars have had problems with the supply wire harness to the pump being to small a wire gauge, again draws high amperage.

I went through 3 pumps in just over a year. The last one failed slowly while I was towing our boat. I would have bet I had blown a tranny. I started drop gears- drive, then second, then I could only use first. Pulled into a rest stop and it wouldn't restart. I had the truck towed to a tranny shop. The tranny was fine, fuel pump was bad. As I dropped fuel pressure it effect the engine and trans.

I now drive a F250.

like todd said a loose are bad ground will cause a higher than normal amp load, also have had some of the pins in the connector that plugs into the fuel pump get burned from the first fuel pump failure, a bad connection here will cause all kind of problems, with GM though you can get just the connector and pins you do not have to replace the whole wiring harness, good luck

Well, I had the idiots replace the cap and rotor. The kid drove the truck around for me to drive. I got in AND IT WOULDN'T START! They wouldn't drag a tech around to look at it so I know that it will start just fine when the check it in the morning.

Thanks guys for your suggestions. I'll forward them on to the dealer for them to look into. Not that they would listen to me...

When they pull out the fuel pump have them check the connector that goes thru the sending unit. Check for burnt contacts. Clean all grounds. Ran into this a few times.;)

Ing. switch too

Well, the truck wouldn't start, BECAUSE THE FUEL PUMP WAS BURNED OUT! And the tech tried arguing with me that it was because the cap & rotor were bad. Anybody want to get in on a pool for how long this one lasts?

The dealer didn't replace the cap & rotor. They did replace the pump. I ran down the list you guys had given me, and they did check an number of the items. Any other ideas out there?

Fuel pump was burnt out BECAUSE of the cap and rotor??? I would love an explination to that one!!!

Well, you know...stupid customer. :rolleyes:

check your blinker fluid, flux capaciter, and muffler bearings.
I've worked at a # of dealerships and none of them b.s. thier customers I don't know how those shops can stay in buisness.
Cord: hope you get the bugs out.

yea....and dont forget about those glove box metering valve's sticking!!! :P

Cord check your fuel pressure it should hold even when the pump stops running if it drops off you have internal leak some where. presurise the fuel system by running the pump key on engine off and check fuel pressure should be 55 to 60 psi then crimp off the return line and feed at the rubber part of the line underneath then with the system pressurised see if it holds pressure. If the pressure goes down with both clamped off your leak is under the intake possibly craked fuel lines to the spider commonly missed. if it holds with them clamped off your leak is in the tank posibly a fuel dampner which is between the pump and sender I always replace them with a pump because they leak. Also is the pump priming the fuel rail called a 2 second run? I am not figuring in pump and spider because they have been replaced. let me know if you need any more info it's hard to explain here. Are you shure its a fuel problem? check spark coil wires are common also. :)

What year s-10? Sounds electrical to me. How about the fuel pump relay??

maybe playn might be kinda correct,I had a 944 that would start and go to work and run fine,but if it got extremly cool or extremly hot out that ***** wouldnt start for nothin,no fuel pressure,they took the pump out and checked it over and over again,gotta love those car dealers,the dealers answer was that I bought a porcshe and there not suppose to start all the time,so while I was over in daytona that som***** wouldnt run,had it towed to a garage that a freind of mine used to work at and they dug deep into the car and found everthing working fine,started right up,but the guy wasnt stupid and finally found the fuel pump relay had a burnt terminal in it and when it got hot or cold that terminal wouldnt make contact,he soldered that bad boy up(coundnt get any parts on late saturday) and it never did it again....ended up gettin rid of it finally after a dope dealer rented a house across from mine and his customers kept runnin into the rear quarter panels,nothin like gettin up at three in the mornin with some guy a f-up with no insurance......now I own that house to!!!!

I had previously replaced the relay, just on a whim. It hasn't made a difference. I'm thinking that I need to install some sort of test equipment so I can try to track this thing. Maybe jury rig up a pressure gauge and a amp meter.