HELP... Runs fine then crappy then ecu shuts down wtf??????

[makaveli913]

In short the ecu is being forced to shut down n not turn on. I reset it with efi fuse n neg. it turns on. but keeps shuting down on 20min rides.


ok so its done this 5 times now. Its a 92 7mgte. It was rebuilt still under 500 miles. It ran great for about 70 miles (short trips). I took it on a long trip after about 10 or 15 miles i feel the engine slightly jerk in gear kinda feels like its workin a bit harder. i take it out of gear and it doesnt want to idle it goes to 400 to 500 and i have to give it gas to keep it running. Then it shuts off completely no check engine light. the cars still cranks fine. I thought i blew the ecu... i bought one and waited for it to show up. I then messed with the efi fuse and neg on bat. I got the ecu light back on!!!!!!! when i mess with the neg it gives off a good spark. the car fires right up n idles strong n smooth. So now i put 200 miles on it more then it happened again yesterday. I think it could be the harness but i dont know. Can a sensor be going bad causing this??? cps tps maft bad ecu???????????????? short in wiring????

 

[mk3_7m]

Well this an interesting nut case.

I'd start of by the ECU,(provided that it's a stock ecu but your sig says otherwise) Try getting another ecu see if it does the samething. If it does, then it's the ECU. If not move to phase two.

Check your sensors, Try buying or atleast repair all the sensors you know of in the engine that might have an effect to your problem. If that doesn't work move to phase 3

Which is try another wiring loom .

 

[makaveli913]

THANK YOU for you input. It is a 92 7m turbo. The ecu is stock. I replaced once already because a broken connector touched metal and fried up the ecu. I have another one sittin here just in case. I was thinkin it could be cps or maf based on it running shitty after running good. I wanted to see if any else has had this problem with one of those sensors going bad.