Another electrical gremlin

[TexasOutlaw87Cummins]

ECMB fuse keeps blowing. What's in ECM B ? Look for a short underneath my dash but no luck . I'm also having trouble with left tank fuel sending unit could this also be a problem? I think my clutch is hitting a wire and causing the short because it happened today after driving To Walmart. Also with parking brake all the way down the dash lights go out but they don't blow a fuse. So seems like I have a few problems I'm pretty confused with I don't really know where to start if anybody could help me at least get a starting place where I could track at least one of these down and it might follow suit to the other ones any help would be greatly appreciated. Just for the ones That don't know my build I have a 87 crew cab duly that was a TBI that now has a cummins swap thanks

 

[TexasOutlaw87Cummins]

No one ?

 

[MrMarty51]

ECM B is,I`m thinking for the fuel pump or the injectors.
I would start with getting that faulty sending unit sorted out then go from there.

 

[Jims86]

You could have problems with the Hot fuel module, if you left it in there which was tied in with the old fuel pump circuit.
All the 30s with 5.7 and 7.4 had hot fuel modules...a known cause of problems.
Or part of the old fuel pump wiring could be grounding somewhere.

 

[MrMarty51]

You could have problems with the Hot fuel module, if you left it in there which was tied in with the old fuel pump circuit.
All the 30s with 5.7 and 7.4 had hot fuel modules...a known cause of problems.
Or part of the old fuel pump wiring could be grounding somewhere.

What is this "Hot Fuel Module" thing that You speak of ?

 

[TexasOutlaw87Cummins]

You could have problems with the Hot fuel module, if you left it in there which was tied in with the old fuel pump circuit.
All the 30s with 5.7 and 7.4 had hot fuel modules...a known cause of problems.
Or part of the old fuel pump wiring could be grounding somewhere.

All the old stuff in the tanks are gone there new sending units for a 6.2 diesel . So now feul pump or anything . Just the sending unit . The left side works but the engine won't suck from that tank for some reason . Seems like it's getting air or just blockage or something . But the right the engine will suck from all day but I been out there standing on my head to get this sending unit working . So it's pretty $hitty . What's a hot fuel module ? Where is that located ? Yes the truck was a 454 . Well so ECM B doesn't work the fuel sending units ? I don't need that fuse to be clear ? My water temp isn't working now neather ! Just getting these bugs worked out is making me wana pull my
Hair out ! I get one thing fixed its on to the next !!

 

[Jims86]

What is this "Hot Fuel Module" thing that You speak of ?

Allows the fuel pump on heavier duty models prime for 15-20 seconds, compaired to the 1/2 ton 2 second priming.

 

[TexasOutlaw87Cummins]

Where is that located ? Would that be a problem with the sending unit

 

[Jims86]

Where is that located ? Would that be a problem with the sending unit

No, the senders work on resistance.
The ecm B fuse is the fuel pump, and memory circuit for the ecm. Its constant hot. It is an orange small gauge wire, running out the firewall cavity to the oil pressure switch, in turn providing the FP power.
Best recommendation I can make, is to pull the fuse block, and follow the wire to see if you discover any chaffing.
The Hot fuel module is on the side of the steering column, and has A 3 wire plug with pink and black, black and white, and tan and white wires.
properly terminate the pink and black, it is hot in start and run, and is running from the gauge/idle fuse.

 

[89Suburban]

Jim beat me to it, here is some diagrams if it helps.

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image hosting

 

[Jims86]

I love those, but I cant blow them up.

 

[89Suburban]

They won't expand when you click on the bar?

 

[Jims86]

They won't expand when you click on the bar?

Oh...when I clicked before, it sent me to the hosting site.

 

[Jims86]

WhareJoo get those anyways? I like those much better.

 

[89Suburban]

Yah you got to click on the bar at the top of the pic to expand it. Retro hooked me up with a bunch of this stuff. I can spend hours looking at all of it. They are in PDF so every one I post as a pic I have to screen shoot it on my large monitor at work and make a pic out of it.