All of a sudden my truck won't start after 2 years of starting every time the same way very reliably. Have done quite a bit of troubleshooting, now the main symptom is NO WHINE of FUEL PUMP with IGNITION ON (before START.)

These all check out:

• fuel pump works (w/ bypass lead),
• fuel pump relay replaced new
• fuel filter clear
• has plenty gas w/ Heet, new air filter

What would make the fuel pump NOT run for a few seconds when I turn the ignition ON? After cranking a lot without start we think we hear the fuel pump power down, but not at ON before cranking - ?

 

Whats your fuel pressure with the bypass lead on? It could that your fuel pump is dying, its trying to pump but cant build enough pressure for it to start and run. Does the truck start and run if you spray carb cleaner into the Throttle body?
I had the same problem a few weeks ago, it would start with carb cleaner but die once that ran out. I could hear the pump with the bypass lead connected and my pressure would slowly build but it wasnt strong enough for it to run. Replaced the pump and havent had a problem since.

 

I will check this out!

Isn't there another problem of no fuel pump whine at ON, when with test lead (or even at shutdown/OFF) we clearly hear the pump working, whether low pressure or not?

 

Check your ground and connection at the back. Ground might have come loose or rusted away. Ground wire is attached at the top of the cross-member thats directly behind the rear bumper. Next to that is the fuel pump connection. That could cause your pump not to run and thats why you dont hear the pump noise.

 

I wanted to post my success in determining the trivial problem causing my 87 Blazer not to start all of a sudden. I got really great help from this forum and I hope this will help someone else.

Having chased down all the leads here in 2 forum threads (#48533 & #49696) everything checked out (without advanced tools) but I kept hitting absolutely NO GO! A mechanic friend told me about the ECM-B fuse causing this problem on another Blazer he had worked on - which was fine on my truck - but right next to it is the ECM-1 fuse = and that was way blown!

Scouting around here and googling for 'ECM 1 blown fuse' for this model I found this post:
http://wiki.answers.com/Q/ECM1_blowi...991_S10_Blazer

And that was exactly the problem - someone years ago had mashed the rubber connection on the positive lead off one of the throttle body injectors and it had finally worn/melted through shorting out to ground on the air cleaner housing. So I spliced and insulated that back together, replaced the fuse, truck started right up! Total cost (not counting my educational labor!) less than a buck!

So I hope I put enough keywords in this to help someone here find this possible solution directly - all our problems should be so simple to solve!

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