I have a 1998 Blazer LT with a 1999 used blazer engine that was recently installed into it about 2 weeks ago (the old engine actually went bad on me a month after I bought the Blazer). Original engine had a little more the 90,000 miles on it.

Anyway, I was driving today with 6 people in the Blazerand the AC on (I've used the AC a lot since I bought the Blazer) and myBlazer turned off on me three times within a 30 minute period and the battery light indicator would come on after it turned off. I unfortunately didn't look to see what the battery guage needle was doing before or after it turned off on me.I tried justturning it back on everytime it shut off by turning the key but it would only crank but notstay on. I then got it to stay on by giving it gas while trying to turn the engine onand it eventually didturn on but it was idling & revving in a hesitating way before the idle evened out. I had to keep giving it gas so it wouldn't turn off again until the idle evened out.

I've heard how the fuel pump in the gas tank go bad on these Blazers but am hoping maybe it's more like a battery or altenator problem.

Any advise would be very welcomed. Thank you.

 

It's me again,

I had the same problem today. I turned her on and everything was fine and then about 2 blocks away the Blazer turned off on me at a red light. Then I drove about 2 or 3 miles and it shut off on me again making a left turn and then again about 50 yards away. This is all city driving so I was making quite a few stops on the way to work which is when my 98 Blazer kept shutting off. I had the AC on and notices that my voltage gauge looked good and when I would finally make the Blazer turn on again it would once again rev and idlein a hesitating manner until I would get the idle to even out by continuing to rev the engine in the neutral position.

I'm starting to really think it's going to be my fuel pump but if someone could tell me what the tell tale signs of a bad fuel pump would be I would really appreciate it. I think I also noticed that humming sound was barely there when I tried to restart the engine after it shut off on me which I know is supposed to be the fuel pump hum or buzzing sound these trucks make.

 

Man, I could have sworn that I responded to this earlier today... When it cuts off, does the security light on the dash come on? If it does, then this is mostlikely an ignition switch problem which is common.

As far as the fuel pump goes, well, if the ignition switch was acting up, it will shut off the fuel pump... Typically a dead fuel pump stays dead... Doesn't just come back for round 2...

 

Sorry for the confusion on the other posting on here swartlkk. But to answer your security light question... that would be NO, the security light does not come on when the Blazer turns off on me. The only light on the dash that comes on is the battery light. So I'll assume I have no ignition switch problem. Thanks.

 

Is it typical that it will stall when costing to a stop or does it die when you are under power (accelerating or cruising) as well?

 

could be alternator not charging the battery anymore and using a/c, brake lights, etc is killing power.How many miles on the new engine?

 

The engine does shut off on me usually when I'm coasting to a stop swartlkk. It's ok when I'm in park or stopped at a red light and also when accelarating.

 

It's possible that this is a problem with the EGR valve not closing all the way. But a few things can be done as preventative maintenance that may help this situation.

First of which would be to remove and clean the throttle body. Once the TB is off, you'll want to remove the throttle position sensor, taking note of which side of the pin in the throttle shaft the arm in the sensor goes on. Then remove the IAC valve and clean the pintle on the end of the valve. Then continue on cleaning the rest of the throttle bore, shaft, and butterfly.

Next, remove the EGR valve (have a new gasket in hand first) and clean as much of the inside of the valve as you can. Before you put the valve back on, attempt to start the motor. If it does start, shut it down right away. It'll be quite loud. Doe this a few times to clear out any carbon deposits that may be loose in the EGR supply tube. If you can, tap the EGR supply tube (on the driver's side of the intake manifold running to the rear of the driver's side exhaust manifold) gently along its entire length to loosen any scale that may be built up inside and turn it over a few times to clear it out. Again, do not allow it to run long if you can help it. The engine shouldn't start if the MAF sensor is still plugged in, but if it does, it'll race due to the massive vacuum leak from the missing EGR valve. Using the new gasket, reinstall the EGR valve.

The last thing would be to clean the MAF sensor with MAF specific cleaner. You need to clean any buildup of dirt/debris from the 3 elements in the MAF sensor.

Give those things a try and see what the results are. It really only takes about $10 worth of cleaner and a few hours of time and if nothing else, your vehicle will love you more for the attention.

 

Thanks for the help swartlkk. I took theBlazer to my mechanic and he unfortunately hasn't experienced this problem of mine. I mentioned the EGR valve possibly not closing all the way the way you mentioned in the last post and he mentioned that he checked the Blazer with his diagnostic tool and that it showed no codes or problems and he assured me that if there was a problem with the EGR valve thathis diagnostic tool would've shown something.

To make a long story short my mechanic is about 70% sure its the fuel pump based on how I described the problem to him and he's going to change it out for me and not charge me until I've driven it for a week or so just to make sure that was the problem if it even was the fuel pump. So I guess I'll just have to wait and see.

Thanks

 

Here's what I would do before you replace the pump. Install a fuel pressure gauge such that you can see it with the hood closed. Also install an 'idiot' light on the fuel pump power wire at the fuel pump relay. Then drive it. When it dies, look at the fuel pressure and see if the light is on. If the light is on and the pressure is down, then you've got a pump problem. But if the light goes out while you're driving down the road, there's something amiss electrically. If it dies and neither of these things happen, its something else mechanical.

And I think that sometimes mechanics rely way too heavily on the scantool to tell them exactly what the problem is. Too many times have members on this site had problems with the EGR valve with no codes present. The EGR valve can be cleaned in your driveway. All that is necessary is a 10mm socket and a 12" extension.