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1988 2.5 ECM wiring by Firezappy
Started on: 04-24-2020 06:32 PM
Replies: 5 (350 views)
Last post by: theogre on 04-25-2020 11:46 AM
Firezappy
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Report this Post04-24-2020 06:32 PM Click Here to See the Profile for FirezappySend a Private Message to FirezappyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hello, I cannot for the life of me get a good connection with my wiring to the ecm. I have at this point soldered some wires directly to the pcb, and still even just to much vibration makes the other wiring lose connection. You so much as touch it and bam, the engine stops because the fuel pump stops. There are two plugs that go into the back of the ecm, I am trying to find out how to replace those. I do not even know what they are called, or a part number. Any tips?
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olejoedad
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Report this Post04-24-2020 11:40 PM Click Here to See the Profile for olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Could you post up a few pics?
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Firezappy
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Report this Post04-25-2020 01:28 AM Click Here to See the Profile for FirezappySend a Private Message to FirezappyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sure, the cables in the circle are the issue. If you so much as touch them it messes with the cars idle, firing, or fuel pump. They are driving me nuts.
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phonedawgz
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Report this Post04-25-2020 05:33 AM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have you pulled the board out of the case and looked for loose components?
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wftb
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Report this Post04-25-2020 08:17 AM Click Here to See the Profile for wftbSend a Private Message to wftbEdit/Delete MessageReply w/QuoteDirect Link to This Post
Put it all back together, remount it properly and make sure all the grounds are attached properly. If that does not help then you need to check continuity from one side of the connector to the other and gently flex each wire till you find a poor connection.

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86 GT built 2.2 ecotec turbo
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theogre
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Report this Post04-25-2020 11:46 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
DIY "fixing" ECM plugs and other things often creates More problems now or down the road in middle of night or on highway in rain far from home.

Those Plugs are likely just fine but ECM is dying causing problems.
Most ECM "Dies" from heat and crack solder joints. Plus Many Old GM ECM units have problems right from the factory because board "paint" swells and can crack chips off the board.
Just Touch the plugs will often make the board to move some and set off crack joints. More so when you remove ECM cover that is part of mounting the board in it and heat sink for driver "chips" "bolted" to the intermediate heat sink on the board.

A GM official test is to tap the ECM w/ fingers and watch motor and MIL. This Tapping along can set off crap joints anywhere on the board and motor instantly dies or has other problems, set bogus codes, etc.

1 typical example w/ this ECM is no "signal" to run fuel injector after running then parked over night. The driver chip (1 of several MOSFETs) has crank joint(s) for heat cycling and cooling down finally "kills" it and won't start.

But This Won't kill the Fuel Pump unless FP wiring has other problems because Oil Pressure Switch will keep that On even w/ FP Relay turns off or dies.

Save the PROM to use w/ new/rebuilt ECM from Cardone etc.
See my Cave, ECM Heat

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