Electrical Gremlins

91blazins10

91blazins10

Active member
Re: Electrical Gremlins

So this happened whenever you just switched to code59, it sounds like maybe the tune is just off a little, and when it warms up its just going to bad spot in the tune.
 
turbodig

turbodig

Active member
Re: Electrical Gremlins

Aeroking said:
right now the problem isnt the temp sensor not working. The whole truck will not run. We can start it and the wideband will fluctuate for a few seconds. Then the truck slowly fades lean until it pegs the gauge at 20:1 and the truck stalls. The ALDL port does not register and will not connect to DM or TPrt. I've tried richening the tune through an emulator, but it did no good. And with the ALDL not functioning i cannot determine if the tuning changes are taking place.
Click to expand...

I'm betting no.

With no ALDL, the ECM is generally in backup mode - ie, dead ECM or MEMCAL.
I assume you've swapped ECMs? (swapped the bad one into your truck?)

Strange that you get codes out of it, but no ALDL.

An ECM will 'work' with very little hooked up at all.. Power and ground, basically.
What's the voltage at the ECM?

The Voltage chart in the sy suppliment is useful for this... go from pin-to-pin with a voltmeter and check to see that each pin is within the range.
 
Aeroking

Aeroking

e.i.
Re: Electrical Gremlins

to answer a few questions. The "good running" chip was a Code59 tuned chip, and we pulled it to replace it with a revised tune. I tried replacing the revise chip with the original, and no change.

We have tried multiple ECMs, 3 to be exact, and all 3 function correctly in my truck. We have tried 2 chip adapters (again both work fine in my truck). We've tried 3 different memcals, even pulled the adapter out and ran straight stock memcal. I've also tried the Ostrich emulator and same problem. I think i might've already posted this but, with the emulator on it. I chased the lean AFR with a higher and higher VE until i maxxed the F29x table, and the truck still leaned out. Again, without the ALDL, i dont know if those VE changed were registering in the ECM.

So basically by dropping the ECM 8 inches to the floor, send the truck from running great to its current limp state. So i'm 99% sure its a broken wire.
 
Aeroking

Aeroking

e.i.
Re: Electrical Gremlins

Update:

ALDL problems i had before was due to a faulty cable. I brought a couple other ALDL cables today, and got it scanning.

This morning we tested the pink/black wire running power from the fuse block to the ECM. The wire came out at 500-600ohms of resistance. So i temporarily hotwired the ECM. Got over 12V at the ECM pin. Started the truck up and it idled fine. Unfortunately i forgot to plugin the coolant temperature sensor. The idiot light came on and the AFR leaned out. I started bumping the wiring harness to check for broken wires and the truck shutoff. So i know that the ECM hotwire helped the cause. But there is still a wire in the ECM harness that kills the motor when twisted.

When we tried to restart the truck, it keeps popping ECM1 fuses. Currently the O2 sensor, EGR, and boost solenoid connectors are disconnected. So i checked and none of them are grounding out. But it keeps blowing the ECM1 fuse.

So in short. Hotwiring the ECM helped. Still have a broken wire in the harness causing the truck to shutoff. And now we're popping ECM1 fuse when we try to crank the engine. (which kills the ESC and injectors)
 
sly dvl

sly dvl

Ya, it's got a Turbo
Re: Electrical Gremlins

I'd suspect a shorted injector, or a shorted/grounded wire in the injector harness. Should be easy enough to check; unplug the inj. harness and give it a crank. If the fuse doesn't blow then you know the fault lies in the inj. circuit. Ohm your injectors...
 
Gnocide

Gnocide

turbo game burt reynolds
Re: Electrical Gremlins

thanks for the continued input guys and please keep it coming
 
Throws

Throws

Active member
Re: Electrical Gremlins

No to drag up an oooooold thread, but what was the eventual resolution on this?

-P
 
Gnocide

Gnocide

turbo game burt reynolds
Re: Electrical Gremlins

we rewired one of the cpu harnesses with new comb clips and correct pigtail wires from caspers electronics

it just went away - so prolly broken wire in that clip- which one?
-right now all is good and driving
but it does need a wiring guy severely to make electronics reliable,
 
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