87 Chevy Pickup 350 EFI "Blown ECM Fuse"

I replaced the battery in my truck last week. In the middle of this process my wife told me she was going into labor with our first child. Paying little attention to the polarity on the battery I hooked the
leads up backwards and things began to smoke. I cooked the alternator as well as the voltage regulator lead off the alternator wiring. I have since replaced the alternator, and the connector for the above said wiring. This motor normally starts with out a hitch. When I tried to start the truck I got nothing, nada, zilch. I checked over the fuses under the dash and found only one that was blown. It is labled "ECM B". When I replace the 10 Amp fuse it instantly pops. I can't recall hearing the fuel pump priming either. I did get the engine to fire by pouring a little gas down the throttle body, but immediatly dies. So at this point I know I am not getting fuel. So what else could possibly be blown and or shorted out at this point?
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Pode, ECM-B is the computer's battery output to the fuel pump. Sounds like you blew the computer. Pull out the computer and replace the fuse. If it doesn't blow, measure the voltage on the socket (same as the orange wire to the fuel pump relay. If the voltage is low, measure the resistance from the ECMB fuse to ground (not sure which side). If it isn't shorted to ground you probably isolated the problem to the computer. If that's the case you may have damaged the computer's PROMs too (hope not) - but just in case, a J-yard replacement w/ chips seems the way to go (AZ has them w/o chips). If it is still shorted w/o the computer, pull the fuel pump relay, and do it again. If it's still shorted (blowing fuses) try pulling the Electronic Spark Module (ESM (a flat black box in the middle of the fire wall with an hand full of wires to it)). Elliott
pode wrote:

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Elliott,
Thanx, I will give it a try. Just curious to why the engine would fire w/ me pouring a little gas into the intake. Does the computer not control the firing of the electronic ignition? On this old of a pick up, is the computer located inside under the dash, or under the hood next to the firewall. I know sounds kinda lame, but the only experience I have with automotive cpu's is on a 94 vortec Blazer. I will also see if I can find a wiring diagram online.
Thanx again,
Daniel
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snipped-for-privacy@ckt.net (pode) wrote:

No. At RPMs under appx. 400, the ignition module is in by-pass.

Passenger side, under the dash.

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Could have taken out the computer. Kids will always cost you money.....
--
Steve Williams


"pode" < snipped-for-privacy@ckt.net> wrote in message
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I thought 87's had carbs.... I have a Haynes manual sitting next to me that is for TBI/CPI/etc. machines, 88-98..... Was 87 a bastard year as well?
~KJ~

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KJ,
My 87 S-10 is TBI. So I guess that's an indication. And Pode labeled this email as an 87 350 with EFI and discusses an ECMB fuse.
Meanwhile We've not heard from Pode. He must be busy with the baby and have alternate transportation (or maybe just had it fixed somewhere).
I was thinking about his fuse-pops and figured that the ornge wire that comes out of the ECMB fuse must have a short on it somewhere. My computer on my truck powers that wire. You may remember me hotting it with the old computer prior to finding out it didn't have a chip. Thus I'm thinking it's possible his computer is ok, but something else on that circuit is not. Maybe the ESC.
Elliott
KJ wrote:

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Yes '87 was a bastard year too.
--
Computer Tips & Tweaks
Builds/Upgrades/Repairs
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yup...
trucks under 8500lbs got TBI motors, 8501lbs+ still got a carb...
Bret

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Re: " From: snipped-for-privacy@ckt.net (pode) I replaced the battery in my truck last week. In the middle of this process my wife told me she was going into labor with our first child. Paying little attention to the polarity on the battery I hooked the leads up backwards and things began to smoke. I cooked the alternator as well as the voltage regulator lead off the alternator wiring. I have since replaced the alternator, and the connector for the above said wiring. This motor normally starts with out a hitch. When I tried to start the truck I got nothing, nada, zilch. I checked over the fuses under the dash and found only one that was blown. It is labled "ECM B". When I replace the 10 Amp fuse it instantly pops. I can't recall hearing the fuel pump priming either. I did get the engine to fire by pouring a little gas down the throttle body, but immediatly dies. So at this point I know I am not getting fuel. So what else could possibly be blown and or shorted out at this point? " --------------------------------------------------------------- Before giving this problem any more thought,go ahead and take the poor woman to the hospital in another vehicle.
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snipped-for-privacy@webtv.net (Brian Orion) wrote in message
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