ECU fuse keeps blowing while driving

[Lynz9d4]

This is my first post on here and I am not sure if this is the right area to be posting this. I have a 1992 chevy c1500 5.7 V8 my ECU 10A fuse keeps blowing out when my truck goes over 40MPH if I keep it under 40 MPH the engine runs great, transmission shifts great with no issues. I am in the process of pulling out the engine harness to look for any fray or damaged wires. Anyone has an idea what could be causing this issue with my truck?

 

[PlayingWithTBI]

I have a 1992 chevy c1500 5.7 V8 my ECU 10A fuse keeps blowing out when my truck goes over 40MPH if I keep it under 40 MPH the engine runs great, transmission shifts great with no issues.

Do you have an automatic trans like the 4L60E? I'm thinking maybe your Torque Converter Clutch or circuit is shorting out. Does it go into 4th (OD) too? If not, that could be the issue. YMMV

 

[Lynz9d4]

Do you have an automatic trans like the 4L60E? I'm thinking maybe your Torque Converter Clutch or circuit is shorting out. Does it go into 4th (OD) too? If not, that could be the issue. YMMV

I have a 700R4 transmission. It does goes into 4th gear.

 

[Schurkey]

Does the TCC work? I'd expect the TCC to engage somewhere around 40-ish MPH. If that's when the fuse pops, TCC is high on the list of suspects.

 

[Lynz9d4]

Does the TCC work? I'd expect the TCC to engage somewhere around 40-ish MPH. If that's when the fuse pops, TCC is high on the list of suspects.

Yes TCC does work. I'm thinking it's a electrical issue but I could be wrong. I did get the truck to drive over 40 MPH once and soon as I released the throttle engine shuts off and ECU fuse blows out.

 

[Macs Garage]

Check the wiring to the O2 sensors. Mine did something similar any time the roads were damp. Wiring for O2 was touching front drive shaft and wore a hole in the wire insulation.

 

[Lynz9d4]

Found the issue. A few months ago I replaced the TCC connector o ring bc it was leaking and I guess the harness inside the transmission pan got unplugged when I pulled it out the connector. This weekend I dropped the transmission pan and saw the TCC. harness was unplugged I plugged it back in and went for a drive and I didn’t have any issues going over 40 mph and my ECU fuse didn’t blow out.

 

[Lynz9d4]

Thanks for the help

 

[PlayingWithTBI]

harness was unplugged I plugged it back in and went for a drive and I didn’t have any issues going over 40 mph and my ECU fuse didn’t blow out.

Glad you got it fixed and, posted the fix