Rob Utzig

OK, so i had to replace an engine wire harness (the monster that connects to everything) and it isnt working since i finished. I tried to double and triple check every connection, and i am stumped. There is a small ground off the harness at the top back of the engine right off the top right corner (as viewed facing the engine!) - and it isnt grounded. The big ones that attach behind the alternator and behind the radiator into the top of the tranny casing are not grounding! What am i missing?

The computer wont communicate with an OBD scanner and it wont even click at the starter. All the connectors seem to be tight, and it is a brand new harness that was matched to the vin.

Anyone with ideas? A ground for the engine that went bad? Previous issues that fixed something like this? My uncle who is a retired mechanic and myself a long time hobbyist are stumped! (Grant you our experience is mostly cars with minimal electronics) HELP!!

donbrew

The one on the rad support and the one on top of the trans are connected. The rad support is the "main" ground.

You remembered to hook the battery back up?

What was wrong to begin with?

Rob Utzig

i had no signal to several wires throughout the harness. It was losing power as soon as it was warm. we also had a leak at the valve cover and that was fixed. We started testing wires to track down the problem, there were multiple either no signal or intermittent signals suggesting an incomplete break in the wire! All three ground points dont have a solid ground. Tried testing with different meters and nothing connected to the engine seems to provide any ground!

Is there a ground that is not part of the harness than connects the engine/tranny to the body to ground?

donbrew

This might help.

https://www.chevyhhr.net/forums/how-...cations-56504/

firemangeorge

Yep. There is a single seperate ground wire as Don mentioned before. One end is at the radiator core support(left side of car near the AC line) other end at the trans.

Rob Utzig

So the ground was buried looking like it was attached but just sitting there! I connected it and all the power and grounds seemed fine - but nothing at the starter. Computer connects (Huge improvement) but with the engine not running it gives me little relevant data!

Tried a jump - just in case the battery had dwindled. No response!

Do i replace the starter? Is there some other connection i may have missed? Pulling my hair out, and my uncle with 40 years experience is stumped!

firemangeorge

The main power wire to the starter comes straight from the battery. It's always hot. Are you saying there is no power to that cable ? If no power at the starter, time to get out the volt meter or test light and find where the break is.

Rob Utzig

Currently, the battery died and wouldnt even offer a hint of a groan at the starter when we tried jumping it. Battery out for the night to charge up (No garage to leave charger in.) Not sure why battery died, but we are going one step at a time. After charging, any suggestions on where to start?

whopper

As FMG said - "If no power at the starter, time to get out the volt meter or test light and find where the break is." Check the voltage at the starter while attempting to start it.
If power is getting to the starter, you can try jumping the starter solenoid to get it going - but the starter would need replacement.

If it wouldn't start with a jump (assuming it was hooked up correctly with the Neg attached to one of the strut studs on the inner fender), then you obviously still have problems.
Once the battery is charged, give it a try, also monitor the battery voltage when you start or attempt to start it.

donbrew

The large red wire to the starter comes from the battery via the jump point on the fuse box, then goes to the alternator (always HOT). the starter is grounded to the bell housing. The wire to the solenoid comes from the fuse box.

I am thinking a total mis diagnosis. Did you think to check the connectors on the bottom of the fuse box?