ecm B fuse blowing

ecm B fuse blowing

Postby jgrosho [OP] » October 14th 2009, 4:12am

I am getting a little frustrated because of the inconsistant nature that I am stranded by the side of the road. This is my second awd safari. the first Is a 93 with 250K on it and my main driver is a 2000 awd with 170K. Bought in 2003 with 60K on it off ebay. So I am very committed to the breed. I am inconsistanly blowing the ecm B fuse in the fuse box under the hood, (thank god for AAA.) I replaced the $300 fuel pump 1.5 years ago and about 3 months ago this problem started. So looking at the wiring diagram, I concluded the most likely cause was a another defective fuel pump. ( after replacing the relay). It usually happens on a 1/2 tank or less of gas. so I replace the fuel pump again (part under warrantee) Alls good for 3 weeks. and 1700+ miles. today, wifey takes grandma to doctor and it dies on interstate. She thinks its out of gas cause the gauge is on zero. but when the fuse blows, the gas gauge does goes dead. as does the fuel pump. So I rescue them and trade cars. put another fuse in and drive away.. on way home, the fuse blows 2 more time's in 5 miles. I stop and put 10 bucks in the tank. stop at hardware store and buy more fuses and drive 10 more miles with no problem.

Looking at wiring diagram, the ecm b fuse also connects to the VCM. wich I can only guess is the ECM for the engine control. I got my wiring diagram off autozones web site, it is high quality but not factory. can anyone help me with this.. my thanks in advance as I need my workhorse van. It has a new trans and 4 new Michelins, so you know my commitment. :confused:
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Re: ecm B fuse blowing

Postby ASTROJOE LT1 » October 14th 2009, 4:25am

Welcome to AstroSafari.com, Glad to have you here. I will have to give your problem some thought. One of our other members will probably get back to you before I do but it sounds like a short somewhere in that circuit
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Re: ecm B fuse blowing

Postby webcat » October 14th 2009, 4:47am

Can you upload your schematic so we can analize it
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Re: ecm B fuse blowing

Postby astro355 » October 15th 2009, 7:18am

I owned a 91 safari that did the exact same thing. Turns out when the fuel pump was going bad, it was drawing more amps and would pop the fuse. A new fuel pump fixed the problem.

What brand name fuel pump did you have installed in the van?

What size fuse are you using for the ecm b?

Did you check the ground connection under the van for the fuel pump wiring?
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Re: ecm B fuse blowing

Postby jgrosho [OP] » October 15th 2009, 4:54pm

20 amp fuse
airtex fuel pump assembly ( 2nd one installed sept.09 )
when the fuse blows.. It is instantly and will blow another instantly. wait 15 minutes and usually will not blow fuse.
that may last 5 minutes or 30 days. I suspect the vcm (ecm?) and when I find it, i will knock it around(tap on it) to see if I can get it too blow fuse.

I inspected all the wiring and grounds of the van when I had the tank out to replace the pump assemble. Pulled all of it out of the sheathing and inspected every wire. Nothing was broken or rubbed. Did the same thing on the fuse box end.. pulled fuse box under hood and inspected every wire as far as I could go. I have changed out the fuel pump relay as well. I would post a wiring diagram, but haven't been able how to up- load a GIF image file
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Re: ecm B fuse blowing

Postby $uperJoe » October 15th 2009, 5:14pm

airtex is not the preferred brand of fuel pump on this site. many will let you know that delco or delphi is best but at double the cost or more i realize sometimes there are reasons to go with a different brand. you say it happens when the fuel is low. the fuel in the tank sloshing around is what cools the pump. if the fuel is low it will not be able to and thus the pump will heat up. when electronic things heat up they use more power. this may be your "short". keep an eye on the fuel guage and see if you can keep it half tank or more all the time. then notice when the fuse pops where the fuel is at. i will be interested to see the outcome.
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Re: ecm B fuse blowing

Postby webcat » October 15th 2009, 6:45pm

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Re: ecm B fuse blowing

Postby astro355 » October 15th 2009, 11:26pm

The ecm is not the problem here. Replacing it, beating it, kicking it, even singing softly to it will make no difference.
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Re: ecm B fuse blowing

Postby grandamle91 » October 17th 2009, 3:21pm

If it only does it when it gets down to half of a tank, it would sound like the sender to me, i had a problem kinda like it with my grand am
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Re: ecm B fuse blowing

Postby $uperJoe » October 17th 2009, 5:09pm

astro355 wrote:The ecm is not the problem here. Replacing it, beating it, kicking it, even singing softly to it will make no difference.

:rofl: la lal alalaa lalaaa cooo cooo ca choooo doo da doo :whistle:
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Re: ecm B fuse blowing

Postby dazzleaj » July 7th 2010, 5:04pm

Any body ever actually solve this?

I just bought this van 3 weeks ago. 93000 miles and has been given required maintenance. Three days ago the "service engine soon" light came on but I didn't check the codes. Actually had the reader in the car (yes, I know :banghead: ).

It just blew the fuse and a spare (105F on the thermometer) and I had it towed. They put a new fuse in it this morning and it is running like a champ for them. The gas tank was 3/4 full. I had driven 5 miles and left it idling with the AC on to ship a package. Was away about 10 min. When I returned the van was not running, AC (front and back) blowers were still on, gas gauge was dead and when I tried to read the codes the reader could not find the computer (fuse blown).

I actually just got rid of 2 Fords that served me well for a couple decades to "upgrade"! I have never been left on the side of the road for lack of maintenance or ignorance. This has me scared! Too much like a Gremlin!
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Re: ecm B fuse blowing

Postby dazzleaj » June 1st 2012, 12:23am

Found problem, melting wire harness to fuel pump. Sucker almost melted through the plastic gas tank!!! Made my own harness from 14 gauge wire and junkyard connectors, changed out the fuel pump (connections melted on top also) and good to go. Total cost less than $300. Used the recommended pump, not the cheep easy to get one.
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