GloriaRedStang

Do you think cleaning grounds would resolve a cold no start condition. If so, which grounds should I focus on?

I thought I resolved my problem with a new DME relay and by checking S & R sensors, but the problem is back. I haven't driven my car in a month!

choinga

I doubt it would completely solve a no start, but anything is possible.

That said, I just went through a whole ground cleaning/replacing process. Added the supplemental ground from the drivers side ground to the front of the engine and replaced the factory negative cable from the battery to the bellhousing area. VERY noticeable improvements.

For those of you with MAF's or thinking about putting in a MAF, going through the ground exercise is a MUST...those things are so sensitive to voltage that any irregularties caused by bad ground will royally screw things up...including your AFR readings on a wideband, which will make you run in circles like a cat chasing it's tail. Not fun.

It's very easy to do - takes an hour or so with a socket wrench and a dremel tool. I bought a nice battery cable replacement kit + supplemental ground from Robby on this forum. rkc951 AT yahoo DOT com. Get yours too...

83944

After I have a great cup of espresso coffee I have grounds left over - any of you blokes want some??

phil823

i would be interested if your talking about the ground wires! or what are you talking about?

83944

Sorry phil823 - just couldn't resist injecting a bit of humor and spark up the debate into this topic. I will chain the humor dog.
The only earthing point on my '89 S2 I have cleaned is the battery negative terminal and the earth to the body. This car has been in Oz for all its life and so never exposed to snow/salt. My SC on the other hand is a RHD British import and possibly exposed to the salty roads over there. Most evident is the corrosion on the alloy taillight assemblies and earthing points. Some restorative wiring was required to get the indicator lights working proberly.

The S2 & SC in action.

http://www.youtube.com/watch?v=yOk5gwZAimE

http://www.youtube.com/watch?v=91B-fLUaOfk

Cheers to all.

WizPorsche944

Where exactly is the ground for the temp gauge ?

phil823

LOL im stupid....i posted that at a busy long night at work....and my shift was just over 1/2 done ....

i was thinking WAY to litteral!

sTyleR

What exactly must be done to clean the grounds?

Randy_J

cleaning the grounds is easy - all except that bell housing ground and don't drop the nut in the open clutch inspection hole in the bellhousing (great design...)

here's a schematic with all the grounds. well worth the effort and using sandpaper and a little dielectric grease when reassembling helps keep things working when you put it all back together.
Attached Images
944 ground pts.jpg (25.9 KB, 133 views)

YoungerThan944

Soooo guess what just happened...

Is it still safe for me to drive my car or do I have to get the bolt out?

Also, what size of bolt is it?

Randy_J

OK, sorry to hear that

#1 - DON'T drive the car! The bolt could get caught up and do all sorts of nasty things that will be $$$$$

#2 - IIRC it should be a 10mm bolt (or was it a 10mm nut - I can't recall)

#3 - you might be able to use a magnetic retrieval tool - basically a strong magnet on the end of a long coiled spring and reach down into the bell housing through that top inspection hole, or maybe if you are lucky and it fell to the bottom of the bell housing, go from the side inspection hole on the DS and use the magnet to get it out.

Worst case is you have to basically go through the 12-17 hrs procedure to remove the tranny, torque tube, bell housing etc as if you were doing a clutch change.

Just noticed you are in Vancouver - if you really get stuck, call SCAN Automotive in North Van and ask the guys if there is an easy way to retrieve that bolt

YoungerThan944

Thanks for the quick reply, it confirmed my worst fears haha

It was a 10mm bolt (i was taking off the smaller of the two grounds right next to each other), I guess i'll find out length and thread count when I find it.

I'll pick up/borrow one of those magnet things tomorrow and hope for the best! Time for a beer.

Randy_J

the magnetic tool is pretty cheap - should be able to get one for $5 from CDN Tire, Lordco, etc. The spring rod is about 50-60cm long. The 10mm bolt is about 15mm long, so it's short, but will do a lot of damage in that bellhousing! Good luck, and yes, time for a ..

peanut

yes good grounds are really crucial to the good starting and running of any car with Bosch engine management system.
The most important are the fuel pump ground at the rear valance and the two under the bonnet which ground the ECU and DME and those two are on the top chassis rail just forward of the relay/fusebox on later cars and the battery on earlier cars .
Also the engine to chassis strap between the firewall and cam cover. (Don't drop the nuts /bolts into the clutch housing ! ahem )

looking at the diag provided by Randy they are GP 1,GP ll & GP lll

Randy_J

Here's a factory diagram with all the grounding points. Most are easy to access, so a great Saturday DIY project that yields big results.

I upgraded to the IceShark wiring harness a few years ago when they were available and the HUGE ground straps and alternator cables which made a very big difference - and with cleaning the grounds, I have no problems with 100W E-Code headlights (IceShark harness relays carry the current load for the HL), 100W Euro driving lights (on relays), OEM fogs, amp, subwoofer, etc.