1990 Suburban ECM-1 fuse blows, again & again :-(

[CWGRL]

Either that, or how about a defuctive ECM? Something on board got hot, melted some pins causing a direct dead short. ? ?

I wish it was a bad ECM. But, I completely unplugged the ECM and had it laying on the floor and the fuse still blew.

 

[CWGRL]

During my Pink/Black wire hunting expedition, I found this orange wire with a 30 amp fuse (which is blown).

Back to the diagrams I go.

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[Jims86]

that looks aftermarket.
You have an alarm?

 

[CWGRL]

that looks aftermarket.
You have an alarm?

No alarm...

 

[HotRodPC]

That orange wire with fuse holder certainly does look aftermarket. Maybe an Amp or Auxiliarry Off-Road or Driving Lights etc.

 

[RetroC10Sport]

I've seen those on factory stock trucks. Not sure about Suburbans though.

 

[Jims86]

So, with the ecm, all engine sensores and actuators, alternator, transmission, coil, distributor, all unplugged at the same time....boom?

 

[89Suburban]

1990 Suburban ECM-1 fuse blows, again & again :-(

Take a good look at the injector wires where they enter the throttle body and where the collar is under the air cleaner and see if they have a break in the insulation. Pull the injector harness completely out of the TB and take a good look. Then from there, with everything unplugged, and no fuse installed, I would get a ohm meter, probe one of the injector connectors red or white wires at the terminal (not stab the insulation) and other probe to engine block and see if there is continuity. Do you have an ohm meter?



Posted From Hell

 

[89Suburban]

1990 Suburban ECM-1 fuse blows, again & again :-(

During my Pink/Black wire hunting expedition, I found this orange wire with a 30 amp fuse (which is blown).

Back to the diagrams I go.

You must be registered for see images attach

I have that same thing on mine. I asked about that here not too long ago and never got it figured out what the hell it is for lol.


Posted From Hell

 

[CWGRL]

So, with the ecm, all engine sensores and actuators, alternator, transmission, coil, distributor, all unplugged at the same time....boom?

YES.. and the fuel pump, radio out, no dome lights, etc.

 

[CWGRL]

Take a good look at the injector wires where they enter the throttle body and where the collar is under the air cleaner and see if they have a break in the insulation. Pull the injector harness completely out of the TB and take a good look. Then from there, with everything unplugged, and no fuse installed, I would get a ohm meter, probe one of the injector connectors red or white wires at the terminal (not stab the insulation) and other probe to engine block and see if there is continuity. Do you have an ohm meter?



Posted From Hell

Yes, I do. a few months ago I did do a repair on a few of those wires in that bundle. I have triple checked that repair and it looks fine. I will do it again though.

 

[HotRodPC]

I have that same thing on mine. I asked about that here not too long ago and never got it figured out what the hell it is for lol.


Posted From Hell

Makes me wonder if it's just a Burb thing. Obviously not rear power glass since yours is barn doors. How about maybe Rear Air?

 

[CWGRL]

Makes me wonder if it's just a Burb thing. Obviously not rear power glass since yours is barn doors. How about maybe Rear Air?

Rear air works good... I will add this mystery wire to my list of unknown... LOL

and the hunt continues!

 

[MrMarty51]

 

[89Suburban]

YES.. and the fuel pump, radio out, no dome lights, etc.

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You mean that stuff don't work or it's unhooked?

Here is a pic of my mystery fuse, it has a 3 amp fuse in it, Retro took a high heel to my nuts and said it's for the starter circuit in my build thread.

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So right there is something strange, yours is 30 amp fuse and mine is 3 amp, maybe a clue? I don't recall seeing that in my '89 harness but after I finish up my breakfast here I will go check it out.

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