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98 Blazer stalls when i put on brakes


stevebritches@yaho
07-29-2008, 11:50 AM
So about a month ago my fuel pump went out.. no buzz from pump and would not start. So i got on ebay got a new pump and put it on. It started up(old pump would not start the engine) it ran fine for about a week then started stalling when i would come to a stop. It will start back up after it dies and i can drive it to the next stop. So i sent that pump back and they sent me another new pump....well the 2nd new pump did the same thing and now the gas gage stays on empty and is not working. I put a new fuel filter on when i changed the 2nd pump...I am stumped

stevebritches@yaho
07-29-2008, 01:17 PM
i did take it to a guy who did a fuel pressure test and said it seemed ok he tells me a tune up is the fix but it was fine before all the fuel pump problems started and has been in for a tune up in the past 2 years, seems like a tune up will help but not fix my problem and does not explain the gas gauge and the cruise control stop working as well

dewaynep
07-30-2008, 08:10 AM
To start troubleshooting you will want to get a fuel pressure guage and hook it up and tape it to you windsheild. Drive around and watch the fuel pressure. If it drops and then stalls, you have a clue where to look next, if it stalls but the pressure is still good you will have to look at other things (ignition, crank sensor, etc..). The fuel guage problem is probably a bad ground or connection on the tank. The entire problem may be a bad connection at the tank since you've had it out twice now and that allows for many errors.

MT-2500
07-30-2008, 10:12 AM
As said it may be a electrical or ground problem.
Check all grounds and power to pump.
Was the pump plugin rewired replaced or rewires good with solder connections when replaced?
The only fuel pump that is much good is the ac-delco/delphi oem type pump.

Guide lines for checking pump and fuel pressure.The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold or hot and fuel pressure testing guide lines.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

MT

godzeye
11-21-2008, 08:17 AM
I am having the same problem with my 97 only I did NOT change a fuel pump. It was tuned up about 6 mos ago. The blazer also stalled with me putting on my headlights on..A friend suggested the headlight switch. After disconnecting the switch and starting I applied the braked and the daytime running lights went out..I can't even get the switch out... any info would be appreciated! Oh yea this all was after installing a new alternator because the voltage was spiking when tested. Is this just a bad short in a bad place? Ignition switch? thank you all in advance!!

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