Larry Pletcher

I own an '86 Corvette that just came back from the Chevy garage. I drove it maybe 35 miles since I got it back. When I got into the garage it would not idle. An Auto Xray diagnostic system gave a "Governor failure". When I got out of the car I saw a pool of oil under the car - lost a quart according to the dipstick. I am pretty sure the oil pressure ending unit is where the leak is. Drain cap and oil filter are OK.

Is the governor failure and the oil leak related? Does the governor shut down when there is a serious oil leak or oil pressure loss? I hate to start the engine up just to read oil pressure. Thanks for any advice.
Regards,
Larry Pletcher

383vett

The only governor on a C4 is in the transmission. Check the oil level and start it up too check the pressure. No other way to test pressure.

Cliff Harris

There is no connection between the governor and the ECM, so it has no way to report a governor failure. Apparently the Auto Xray is referring to something else...

You said it just came back from the Chevy garage. Was work done there? If so, what? If something was worked on then the odds near 100% that the oil leak is related to whatever was done.

Larry Pletcher

Thank you for your advice.
When I had the car in, it wouldn't idle well and stalled often if I let it get under 900 rpm. Quoting from the work order," found o2 sensors out of range and a burnoff sensor failing, replaced burnoff sensor and relearned o2 sensors."

My gut says that these things probably didn't cause the leak. The oil filter and drain plug show no signs of leaking, so the oil sending unit seemed like the only thing left.

The bulk of the oil lost was after I got the car into the garage, and was running the diagnostics. I hope that there was enough oil pressure to cause no damage then. Today I'll top off the oil and see if I get oil pressure. I have a couple of reliable guys within a 1.5 miles that could help with changing the oil sending unit - if that's the source of the leak.
Regards,
Larry Pletcher

Larry Pletcher

383vette,
Today I took your advice. I topped off the oil; I did check again and found I was 1 qt low. I planned to start the car and look at the oil pressure. I discovered that last night I had left the ignition key ON! Just wasn't my day. Out came the charger.

After the battery was up to 12.49v, I decided to try it. Engine started and ran, pressure varied, but read 60-70 lbs above 1200 rpm. So, I don't think I hurt the engine. I ran diagnostics again and got three errors:

sensor is high
transmission shift fault
9 EAS electrical fault

I have an auto engineering firm close by that I will ask to change the oil pressure sending unit and get the car on their computer system. (Precision Technologies does work for GM, Briggs, and others. I became acquainted with them when they helped out high school's engineering class with their entry in the Shell Eco Marathon in Houston.

Regards,
Pletch

-js-

Pletch the information your telling us is from the autoxray scan tool is not what's expected for a 1986 corvette.
Which autoxray scanner do you have??

Larry Pletcher

It's called EZ Link Automotive Diagnostic System
On the back it says Auto X ray SN# 3039914

In the manual they use the term EZ-Link Scanner. I don't know if this is enough to identify the unit. Is it possible that it is not configured correctly? This an older model. I probably bought it maybe 2002 or 2003. It has been rarely used and probably not used since 2005.

Regards,
Pletch

-js-

Ez link is the software package that came with the scanner.
I would think the model number is on it some where.
Autoxray is still in business and has a web site.
If you can't identify maybe take a picture and share it here.

Cliff Harris

Can you pull the error codes with the paperclip method and let us know what they are?

http://forums.corvetteforum.com/1574918379-post18.html
http://corvettephotographs.com/c4vettes/codes.htm

What they mean:

http://forums.corvetteforum.com/1576116036-post35.html

Larry Pletcher

Cliff,
The links were very helpful. I got one error code: code#34 - Mass Airflow Sensor Low.

I saw high oil pressures (60-75) and felt safe moving the car. It is now at Precision Technologies. When I know more I'll report back.

Thank you all for your advice
Regards,
Pletch

Cliff Harris

Error code 34 could be caused by a bad connection (corroded contact in a connector) or a wire that is pinched and shorted to ground.

Larry Pletcher

I got the car back today. The oil leak was the oil pressure sensor. The also sprayed some cleaner on the Mass Airflow sensor. We'll see how that works. It did idle well.

Regards,
Pletch