RJB

Does anyone else feel that these cars are possessed sometimes???

Let me describe my problem and then what I have done thus far to fix it. Hopefully someone can help me with what to do next.

My oil gauge seems to have a mind of its own. When I start the car, the pressure goes above the 5 and stays there until the engine oil heats up. This is normal. It then goes down to around the 4 when I am driving. Again, normal. However, when I start to slow down, or especially when I push in the clutch and come to a stop, the needle pegs above 5 and then settles down to the 2 to 3 number. It continues to peg and drop as if there is something electrical wrong. I do not get the feeling that the pressure fluctuates that wildly because it happens too fast and when it settles down, periodically, it has a proper reading. The oil light is not on, but it does work. The thing that is driving me crazy is that the needle keeps dancing up and down.

Here is what I have done. I have pulled out the gauge assembly, cleaned the football plugs for the gauge, cleaned the connectors, and replaced all of the bulbs. I have not removed the flexible circuit board to check for bad solder joints because I was concerned about damage. I have cleaned the grounds under the dash.

I have measured the current from the negative battery terminal to the block and there is no current flowing. Also measured the voltage between the negative battery and the block, which was zero. Therefore, I do not suspect a ground problem to the block.

I have cleaned the terminals to the oil sender. They were dirty, but they are sparkling clean now. I have not replaced the oil sender yet.

So, now my question. What suggestions does anyone have for my next steps? Do I pull the gauge assembly again and dig deeper for bad solder joints? Does anyone have a test procedure to see if the sender is bad? Is there another ground that I need to find and check? This thing is driving me crazy!

Thanks for reading this long message and any help that you can provide.

M758

Well,
The gauge is doing exaclty what I would expect. Except for the rapid fluctuations a lower pressue.

Does the gauge only jump a low pressure? If so then it maybe related to the pressure on the sender rather than an electrical problem. I know it ain't cheap (otherwise you would have done it by now) , but you could replace the sender and see if it happens again.

Maybe you could talk to your parts guy and see if you could return it if it does not cure the problem?


M758

Peter swallow

Rodney,

My Guage was doing exactly the same thing. I was on the verge of replacing the oil pressure sending unit when it miraculously stopped! I had gotten under the motor and cleaned the connectors on the sender. Otherwise, I tightened a ground wire which attaches near the center of the steering rack (replacing the rubber bushing which surrounds the metal fluid line at the same). The dancing stopped. The problem is that I did so many small things - cleaning and tightening, that I can't be sure what actually fixed that problem. I was also having a problem with flickering of my brake,brake sensor and oilwarning lights. This also stopped......Like you said - SPOOKY!

Good Luck

84 944
Blk on Blk

RJB

Peter,

Thanks for the tips and help. Last night, I cleaned the sender connections, took the dash apart and resoldered the connections on the back of the gauges, cleaned the ground from the negative battery side to the frame, cleaned the ground under the dashboard near the steering wheel, cleaned the ground inside the engine compartment on the driver's side, and finally cleaned the ground behind the driver side light. It's still dancing!

Can you provide me a bit more information on the ground near the steering rack? I don't think I have found that one yet and would like to try that next - but then on to the sender! Cleaning all of the grounds did make my voltage gauge read the proper voltage.

As you said, changing so many things at once makes it difficult to determine what actually fixes something. When I find it, I will post what I finally did. Again, thanks!

Peter swallow

Wow, it sounds like you just about cleaned and checked all of the possible fault points!

As far as that one ground that I mentioned is concerned, I will try to describe its location a little better but I have to tell you that I'm not certain what all of the surrounding structures are. Anyway... After you've taken off the aluminium shield under the engine, look just to the driver's side of the midline along the steering rack. On my car there is a metal line running between the two front wheels (this is what I cannot identify for the life of me - it must be a power steering or brake line ?!) I don't remember if it goes all the way to the wheels or not. Around this line there is a clamp who's purpose appears to be to stabilize the line itself. There is a rubber bushing which surrounds the line at the clamping point. My bushing had dry-rotted to oblivion so the metal line was loose within the clamp allowing them to come in direct contact with one another. I manufactured another using a rubber hose and placed it around the line, inside the clamp and retightened. One end of the ground wire is attached to the tightening bolt on the back side of the clamp, while the other end is screwed to the cross member. The wire itself is about 20-25 cm long.
I hope this helps! Let me know how it turns out.

RJB

Well, it seems that my odyssey is over. After cleaning all of the ground points, connectors, and gauges that I could find, I finally replaced the oil sender. That fixed the problem and now the gauge works like it was supposed to. I am so happy.

A couple of side benefits. Cleaning all of the grounds fixed an idle problem where the idle would be pulled very low when I pushed in the clutch when the A/C was on, the voltage gauge reads properly, and the lights on the dash are even brighter than when I replaced the bulbs and covered the light tunnels.

Thanks for the suggestions.