Cleaning 944 Engine Grounds

In my never ending quest to get my temperature gauge to work properly on the Porsche 944, I have decided to embark on cleaning the Engine grounds.  After doing some extensive internet research, it seems that the grounds can get corroded and cause all kinds of electrical gremlins.  After replacing the thermostat, the temperature sender, and messing with the wiring and such, I am willing to try and get this to work.

Cleaning the grounds is really not that hard of a task if you know where the grounds are located.  I cleaned two of them in this article.  I cleaned the one closest to the battery, and the one that is located on the engine block.  If this is caused by a bad ground, those two should suffice to get a good reading on that gauge.

Both of these lines are connected directly to the negative terminal on the battery, finding the one that is close is really easy, just trace the line and see it connected to the firewall.

Two Lines Off the Negative Battery Terminal, You are cleaning the Other Ends Of These!

I believe that this is a 12mm nut that needs to be removed.  Remove the bolt and take a look at the connector.  You want to clean the end of the connector with a wire brush until it is completely shiny.  You will want to do the same to the attachment point on the firewall. 

Ground Closest To The Battery.
Make It Shiny!

When you are done, you can reconnect the ground cable using the bolt that you previously removed.

The next grounding point is a little trickier to get to.  You can trace the line that comes off the battery cable and goes through the firewall.  You will see it snake around the back of the motor and come to rest close to the top of the bell housing.

That Line Runs To The Ground, Just follow it through the firewall.

I found it much easier to remove the items that were in the way than to try and get a socket into that tight spot.  You can try and do that, but this is probably easier.

Remove the bracket that is holding the electrical connectors in place above the coolant lines.  You do not need to take the bolt all the way out, just loosen it and the bracket will slide out. 

Now, take a flat head screwdriver and loosen the hose clamp is attached to the EVAP system. 

Slide the hose off the nipple to make some room for yourself.

You Can See I Already Have the Nut Off

You should now have an easy shot straight down to the electrical connector and the Engine ground.  Remove the nut that is holding it in place and inspect for corrosion.  I had two connectors here, the one that was on the bottom, was corroded and needed a good cleaning.  The main connector was ok, but was on top of the corroded one.  When putting this back together, I swapped the corroded one (which was no longer corroded) and the main so that the main was a direct connection to the block.

That was the Wire on the bottom, before cleaning.

You will also want to clean the connection to the block.  I found this pretty difficult to do but ended up using a circular bristle brush to clean it.  I did not come out the best but it seems to have worked. 

Re-assemble all the connections and go start it up.  I noticed right away that the car was getting a better ground connection.  It started quicker and seemed to be less finicky.  Unfortunately, my gauge is still not functioning properly.  Either way, I’m glad I did it and believe it is worth doing if you own one of these cars.

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