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blown ecm bat feed fuse

snoozer

By snoozer
in Ask A GM Technician

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snoozer Enthusiast

snoozer

Posted
Posted

I have a 1989 Chevy Suburban 5.7 1/2 ton and recently I keep having a problem with the ecm bat feed fuse blowing. This problem started about 50 miles after having the heater core replaced, so I don't if something got messed up during the replacement or what.

If I replace the fuse truck will start and run about a dozen times then the fuse blows again.

The last time I replaced the fuse it blew out again within 2 blocks, but luckliy I was close enough to home to coast into driveway. Next day I replaced the fuse and trcuk was hard to start, ended up holding the gas pedal half way down while cranking the starter, then it started, but idled very, very slow, so shut it off restarted and it was running to fat at idle, once again shut off restarted and it ran fine, nice smooth idle.

I have not drove the truck since having the restarting problem. To afraid of getting stranded with it.

 

Talked to repair shop who installed the heater core and they seem to be convinced the fule pump is pulling to many amps and causing the fuse to blow.

Not sure how they came up with this, but I thought I would get some ideas from here before going through this expense.

 

btw I did replace the fuel pump relay shortly after this problem started, but it did not help.

 

Any suggestions on what to look for

Thanks for any help

Mark

  • 4 weeks later...
snoozer Enthusiast

snoozer

Posted
  • Author
Posted

replaced fuel pump and 114 miles later fuse blew again. engine just shut off, replaced fuse and it started right back up, but engine was idling very slow.

 

Any suggestions on where to look for the problem

 

Thanks in advance

mark

454ss Enthusiast

454ss

Posted
Posted

my truck was doing that same thing and i found it to be a wire in the harness behind the engine by the distributor had worn through and was shorting out intermittantly. that truck was a 1997 k3500 with a 454, but your symtoms sound the same.

snoozer Enthusiast

snoozer

Posted
  • Author
Posted
my truck was doing that same thing and i found it to be a wire in the harness behind the engine by the distributor had worn through and was shorting out intermittantly. that truck was a 1997 k3500 with a 454, but your symtoms sound the same.

 

 

 

 

Was it blowing the ecm bat fuse?

454ss Enthusiast

454ss

Posted
Posted

i will have to double check what the fuse was labled for, but yes it was blowing the fuse and wouldnt start until i replaced it.

snoozer Enthusiast

snoozer

Posted
  • Author
Posted
i will have to double check what the fuse was labled for, but yes it was blowing the fuse and wouldnt start until i replaced it.

 

 

 

 

If you get a chance could you please check for me.

Boy don't you just hate electrical problems?

c502cid Enthusiast

c502cid

Posted
Posted

Snoozer it is exactly what 454ss said it is. I had the problem in a 90 V3500 (same body style as your sub). When they replaced the heater core they were probably working in the area around the rear of the motor, passenger side and thats where the short probably is. They didnt cause it, they just brought it to your attention sooner.

 

Do the "wiggle" test in your driveway. Start the Sub up and start wiggling wires towards the back of the engine compartment, closer to the distributor and the back of the passenger side cylinder head. You'll find your short pretty quick.

snoozer Enthusiast

snoozer

Posted
  • Author
Posted

Problem Solved!! Thank you c502cid and 454ss you were right on the money.

Oil soaked, bare wires right were you said to look.

 

Thank you

Thank You

Thank You

 

You guys are the greatest

Your help is much appreciated

 

Did I say Thank You

Mark

c502cid Enthusiast

c502cid

Posted
Posted

No problem. I wish there was the internet when I had my problem many many moons ago. I almost didnt respond to this but I really felt for you! Glad it is fixed.

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