My 1996 Blazer 4.3 4wd has an electrical problem that I can't solve. The Blazer will just die while driving down the road and won't start. It doesn't sputter, it just dies like you turned the key off. It cranks fine but it's like it just doesn't get gas. When this happened a couple of weeks ago I changed the fuel filter but it still wouldn't start. After sitting there for a day it started right up and ran great until today it just died again driving down a rough country road. I've towed it home again but don't know where to start looking. The thing that has me puzzled is that the dome light comes on when this happens. It's on with the vehicle off and the key out, it won't turn off unless you turn the key on. I had to pull the fuse to get the dome light off so it wouldn't drain my battery. I've had 2 new fuel pumps in the last year and a half and can hear the pump kick on so I don't think the pump is the problem. They dome light situation makes me think it's some kind of electrical problem Any help as to where to start looking will be greatly appreciated, I'm at my wits end.

 

Sounds almost like the ignition switch is failing, but the fuel pump could also be the source of the issue.

 

Would the ignition switch cause the dome light to come on and stay on? That's what had me puzzled. The vehicle is not getting gas it seems but cranks fine.

 

Ok, an update on my Blazer problem. It appears that it very well could be a fuel pump problem. I can hear the pump come on part of the time and sometimes not. It will start fine occasionally and then other times just crank and not start, just like it's not getting any fuel. Here's my question: I've had 2 fuel pumps put on the the last year and a half. What could be causing them to go out like this. This is not a cheap fix and I'm really tired of replacing fuel pumps every six months or so. Has anybody else posted with a problem like this? Is there something in the fuel tank that could be causing this problem?

 

What brand of pumps did you install..? Many of the aftermarket pumps are garbage.

 

It was a local mechanic that did the work before so there's no telling what kind he put on. I'm going to take the time to do this one myself with a help of a mechanically inclined friend. What brand of fuel pump do you recommend? Also since I've never replaced a fuel pump before do you know of a link that will help with any info on problems that I might expect to run into on the job?
By the way this is a great forum, it's helped we with several problems, both with diagnostics and technical information.
Thanks for your help.

 

the same thing happened to my dads 97 chevy truck it turned out that the ground strap wasnt gettin a good ground so double check that its on the top side of the frame if i remember right.

 

Thanks for that info, I'll check the ground strap. Could this be a problem with the fuel pump relay? If that's a possibility how do I check it? What is the purpose of the relay? If I remember right it's located in the glove box, the one on the drivers side. This might be a dumb question since I'm not a mechanic, about all I know is what I've read on here.

 

A follow question up before I go out and buy another fuel pump. I did a pressure test and it jumped to 60 when turning the key to on and then immediately dropped to 50, after less than 5 minutes it bled down to 40. Started it maintained a running pressure of 50. I've read on here that it should hold 58 to 60. Does this indicated a fuel pump problem or is there other things that I should check before I buy a pump? Also what brand of pump would you recommend? Thanks for all your help.

 

Yes 58 -60 psi is what you want. Factory spec on a 96 is 58 psi. However I had a pump go bad that had been doing 53- 55 psi and running fine but having intermittent trouble starting. It might start right up or it might take 2-12 cranks before it would start. It got progressivly worse over many months until it would not start at all. The pressure was then 33 psi. I put a new pump in and it has started and ran perfectly ever since. But the pressure is now 47 psi. It should not even start ay 47 psi
The relay is in the glove box on a 96. I think it is the one on the left if I remember right. All 3 relays in there are the same type so you can swap them around if you want. They would not all be bad at the same time.

If you can hear the pump run the relay should be ok. There should be a red test wire in front of the master cylinder. Connecting this wire to a 12 volt source with a 10 amp fuse will make the pump run by by-passing the relay.

If you pull the pump inspect the connector carefully. They are famous for getting corroded. Most pumps now come with a different style connector. Do not rely on the crimp on connectors they come with. Do it right and get some non-insulated crimp connectors at the hardware store or Radio Shack. They look like small steel tubes. Crimp and then solder the connections and use heat shrink tubing. Then wrap with electrical tape and secure the tape with a ty-wrap or 2 so the tape can't come off later. Use a dab of di-electric grease on the terminals of the plug.

Are you sure the fuel filter in not clogged?

When you turn the key on the pump will only run for a few seconds unless the engine starts.