Z28MJ

Ok hear is the deal, I have been having weird issues with my car for a while, last summer for a while I had to have an OBD2 scanner plugged in in-order for the engine to run, sometimes my RPM and water temp gauges wont work. now I am having to have the OBD2 scanner plugged in again in order for it to run. last week it was fine and I got it tuned and they did not say there was anything wrong with it but the car is acting up now, i dont know what else it could be.

Z28MJ

bump.

joecar

You have a ground problem... when you plug in your scanner it completes the path to ground allowing you engine to run...

you need to check the various grounds, including the ones on the rear of the driver side head.

salemetro

iTrader: (5)

^^+1

It's been my experience that whenever odd electrical gremlins rear their ugly heads, 99.9% of the time it's a grounding issue. You might also search for a PCM wiring schematic to help you ID the PCM grounding circuit paths more easily.

Z28MJ

Last time I was having this problem we thought it was a ground problem too, so I looked at all the grounds and they looked fine. now that you brought up the fact that it is a ground problem, I was like **** it I will put a wrench on them and make sure they are tight. The ground on the back of the head was an 1/8 turn loose lol. It runs fine now, thanks

salemetro

iTrader: (5)

Weird that just 1/8 turn solved it....but glad it took care of it. My only other suggestion is that since it appears that you found the culprit, you should completely remove the bolt from the back of the head and clean the grounding loops thoroughly.....then bolt it all back up. Corrosion can be a bitch, and cause more issues....even when everything looks clean.

Z28MJ

yeah I was surprised that an 1/8 turn fixed it. ok I will do that. thanks

Emdmechanic

iTrader: (2)

Wasnt so much of it being 1/8 lose . Like someone else said , that 1/8 knocked the corrosion lose between the terminal and head.