Acantor

Hi all, I just finished an engine rebuild, and after some hiccups (leaking fuel rail) I was ready to start the car and break in the cam. The car starts but eventually sputters out and dies. Everything looked good besides a little leak on the connection to the regulator. I tightened the connection down...still not wanting to run. After further inspection, I found that the ground wire from the chassis to the engine was disconnected. Could this be causing the engine not to spark? If so, where does it connect to? Whenever I hit the gas the car dies, so maybe a spark/fuel issue? Oil pressure is great.

Any help or more experienced minds on this will be greatly appreciated.

GPA951s

It connects to the back of the bellhousing

The rough running sounds like a vacuum leak.. you mentioned oil pressure is great, as a word of caution, if the wires are swapped on the oil pressure sender you will have great oil pressure always! ( pegs the gauge) as long as when the car is on idle and the pressure comes down a bit you're good..

Acantor

I replaced all the vacuum tubing so I don't think that it is that. Do you have a picture of the connection? Is it accessible with the intake manifold on?

Acantor

The car does not idle, I am stumped

harveyf

There is a pretty complete set of tests on Clarks Garage.
http://www.clarks-garage.com/
Shop manaul/troubleshooting/engine

It does sound like a vacuum leak. Remember, just about every damn hose in the engine compartment, as well as components like the brake booster, can introduce a vacuum leak. It's all interconnected.
My short list of basics:
Check fuel pressure at the fuel rail. See Clarks
Check that all injectors are firing. See Clarks
Make sure your plug wires are installed correctly. Watch the engine compartment after dark and look for arcing.

Gasngo

Wow it cranked with the ground off. I could be so lucky assuming you have or have not got that taken care of every other ground in the car is doing its business. So super important to get that squared away. With that being said take a few minutes to go over everything and make sure connection are good and clean Etc.

Just a note many moons ago I had a young man working next to me at the MB dealer doing a starter replacement he bolted it back on and forgot the ground. He went to crank it up and it grounded thru the AC control panel. You could smell the smoke in the Int. Be careful!!

Dan Martinic

There's also a warning in the Workshop Manual about leaving the main ground disconnected and destroying the DME. I did that once but thankfully it did not destroy it

Acantor

As far as I know, it was disconnected when I bought it, and it was running. I never removed the bold on the bell housing. I will go though Clark's garage and let y'all know what I come up with.

Gasngo

Pretty interesting but I would be all means get it put back on. Assuming mine is correct theres a bolt going somewhat straight down at the top of the block/bell housing rt bellow the ref/speed sensor connection 13mm head. Unless there a alternate ground somewhere I would be concerned as mentioned above the ground has to go somewhere. You could smoke the harness or DME or what ever. Stay at it and take you time.

Acantor

I think I've found the bolt but it's going to be hard to get back in without removing the hose that goes over top of it. It connects to the rear cool and passage (or that's at least what I think it is), so does that mean if I remove it, will coolant spill? I just want to be sure that I don't get surprised by it.

Gasngo

Heater control valve is what I have and ya its rt there. I managed to push it aside carefully and get it loose to clean the connection. Im dealing something quirky on mine and just making sure I have exhausted all ideas/connection before I take the starter back to the repair. Like I said take your time. There alot of things going on under that hood and hard to see.

Dan Martinic

Coolant will spill into the hole in the bellhousing and onto your clutch assembly

It is very difficult to work in this area--probably why the ground is disconnected in the first place. However, you have to get it on, so get into your best yoga mode and make creative use of all your tools & extensions. Be sure to have your magnet handy. And, cover that bellhousing hole

GPA951s

Just happen to have an engine laying around.. as long as that big wire connects with the block Youre good but here is where the factory puts it


On the stud of the bellhousing is another connection,

Acantor

now I am a little confused. Does the thick wire that comes from the firewall go to the bell housing or the block? Since they are both metal and touching, wouldn't it be the same either way?

Gasngo

I believe it goes to the block and ya whats up with that and you would think with the bell housing bolted to the block it would be or at least in my case. There also another ground there. My car runs fine but the first 2 or 3 cranks the starter spins but does not engage the ring gear then next time it hooks and fires up. I had the starter reworked and retested and still the same thing. I have even run jumper cables direct to the starter and on occasion it would miss but before I pull it off to have it looked at again Ill be going over everything even if I need to run a additional ground. Enough about mine back to you.