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

[Jims86]

Damn interchange is showing that the V2500 could have a 700r4, but the factory info says otherwise.

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See your edit. 4L80E did not come out until 1991. Let me look at the compnine info I have and see what it says, could have been a late year option.

Compnine says no 4 speed auto R or V 2500s. So I get schooled as well!

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They could be calling it the THM-R2,
I have not scene anything over 1/2 ton with a 700r4, but then again, it is possible. just see if it has a TV cable.

 

[HotRodPC]

Welcome Back Jene. So being from the land of fruits and nuts... should we be concerned that you are going crazy? I'd have figured you were crazy already.

So have you had any luck studying the diagram yet on the ECM 1 circuit? As in what all is running off of that circuit?

Chegny might be the guy for this issue and he only comes in 1 or 2 days a week usually unless he's offering continued day to day support for someone. Keep updating as you figure things out and try different things, but hang tight and a light bulb will go off with someone. I fall short of knowledge on the 87 and up squares other then basics and what's backwards compatible from the GMT400 body trucks.

What part of So Cal are you in? I was born in Downey and pretty much lived most of my childhood in Downey and Norwalk.

 

[CWGRL]

I have studied those %#%#@&% diagram so much that I'm dreaming pink/black wires!

It seems my neighbors aren't to happy seeing me work on the truck in front of my house... anyway, I walk out to the truck this morning and there a stupid ticket on it!

Here my girl question of the day ( I'm pretty sure I know the answer already. LMAO)

Can I put a larger amp fuse in the ECM1 just to get the truck running long enough to put it in the driveway without doing any damage?

 

[CWGRL]

Welcome Back Jene. So being from the land of fruits and nuts... should we be concerned that you are going crazy? I'd have figured you were crazy already.

What part of So Cal are you in? I was born in Downey and pretty much lived most of my childhood in Downey and Norwalk.

LMAO!! I am CRAZY, HotRodPC. LOL South Torrance....

 

[Jims86]

get under the hood, and pull the harness away from the intake around the throttle body. gets hot around there! maybe melted through the loom, and got a wire. FYI, the Kickdown relay does run off of the ECM/IGN fuse.
If you put in a bigger fuse, you may toast the ecm. Pull in the harness, and try another fuse, and see what happens. Also, check to see if the injector wires are not touching the air cleaner.

 

[HotRodPC]

I agree with Jim, the bigger fuse might toast the ECM, but honestly, as bad and as quick as your blowing the fuse, I'm thinking a dead short and even a 100 amp or 150 amp fuse if there was such a thing would blow instantly.

 

[HotRodPC]

LMAO!! I am CRAZY, HotRodPC. LOL South Torrance....

Yup, I know where it's at. So you're in an LA Suburb too. So you're a lifer and not going anywhere huh? I left in Dec 90 and other than missing friends and family which FB helps alot with, I"m not the least bit homesick.

 

[MrMarty51]

 

[89Suburban]

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

Anyone know wtf this is?

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Posted from hell

 

[89Suburban]

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greenshot download

 

[MrMarty51]

Anyone know wtf this is?

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Posted from hell

It has diodes in it, I wonder if it is the alternator, but, it does`nt look quite right for that.

 

[89Suburban]

I'm going to pull the 89' harness out of the box and trace that wire and report back....

 

[RetroC10Sport]

Anyone know wtf this is?

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Posted from hell

It has diodes in it, I wonder if it is the alternator, but, it does`nt look quite right for that.

It is the alternator.

 

[Jims86]

Anyone know wtf this is?

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Posted from hell

Thats the alternator.

 

[89Suburban]

Thats the alternator.

For some reason that diagram shows that dotted line going to the ECM 1 fuse. Let me try and get a clearer pic of that...