Ok. last night after enjoying the fruits of my labor sorting out the last group of issues, I have yet encountered another.

I got in the car, tried to turn the key, and tried turning the engine, but it would not start. Usually, when i twist the key to the on position, all the gauges do a sanity check, the the all go off.. the oil pressure usually clicks over to half way, battery, etc..

The Oil pressure was at 0. The car just would not start. I was at a convenience store accross the street from my neighborhood so didnt have any tools.

After about 3 minutes, I tried cranking again.. car starts.. I head out to the road to get into the turning lane to go home and the car dies.. first it kind of chugs.. runs rough, then the check gauges light came on, i noticed that the oil presure sensor was at 0.. before that it was bouncing around all over the place.. anyway.. there I was again.. stuck in the turning lane.. gave it 3 minutes.. she cranked back up..

got her in the garage.. and tried simulating the same scenario.. trying like heck to get this no start condition.. car runs good when this is not happening.

If the oil pressure sender goes to 0, will it signal the fuel pump to turn off so it does not damage engine in case of real loss of pressure?

If the oil pressure sender is indeed bad, would it exhibit this behavior of the needle dancing around at idle under load.. in gear?

Also, it seems when I am parked, and I put the transmission into gear.. the volts meter will dip below 12.. when I put it in park,, it goes to 12v.. usually it goes ro 14,, alittle past half way..

If I disconnected the oil sender, would i be able to start my car? Does the oil sender talk to the PCM in any way?

Thanks!!

 

Oil pressure should read zero with the motor not running. It will fluctuate some while idling, but not much. If your needles are bouncing around, could be an alternator problem.

 

could a voltage regulator on a alternator cause this? If the alternator was going.. or at least the regulator, would it casue it to not start? i could turn the motor, but not start..

If I remember correctly, just the oil sensor would bounce around.. not any other gauges...

If there was a fault with the regulator, would it casue my engine to just die?

I do experience hard starts,, even when warm...

thanks

 

There is no interlock between the oil pressure sensor and the fuel pump on an F-Body LT1. "0" oil pressure will not prevent the engine from starting. There is an interlock circuit on the Corvette LT1.

The pressure sensors do go bad, and they leak. There is a single wire that connects to it, so the engine grounds provide the return on the electrical circuit. If the gauge is moving around unreasonably, it could be a faulty sensor, a loose harness wire or a bad engine ground. A bad engine ground would also affect the coolant temp gauge, since the coolant temp sensor in the head is also a 1-wire sensor.

 

Hmmm... ok.

Well the Oil gauge is the only one doing the dancing...

It doesnt dance around while the engine is under load...
It doesnt dance when it is in park..

just when i am at a light.. in gear... or some other scenerio where I am in gear stopped... maybe its youtube time... brb... time to take a test drive.... I will take a video of my dash..

 

The oil pressure will vary with RPM. Small changes in idle should produce small changes in oil pressure.... RPM up/pressure up, RPM down/pressure down. Is your tach indicating significant variations in engine RPM when you are sitting at a light, with it in gear?

 

Yes. When I see the gauge dancing.. While I idle in gear, when the light turns green, the gauge will bounce back to normal and rise and fall with engine rpm...

 

http://www.youtube.com/watch?v=GfQnqm5TwhY

If you view the above video clip, you can see the dancing of the gauge while idleing. There is not much for sound on the video, but if I blip the throttle, it seems to steady out...



Also, just went by Autozone during the testing to have a my battery and alt tested. They said the battery failed with a 363 CCA.. alt passed.

Could a battery that is on its way out be a culprit to the stall and hard starting?

 

replaced the battery.. still same..

It might be me.. but when that oil pressure gauge moved around, it is often while the engine runs alittle rough.. like it is missing out or something.. cant quite put my finger on it,,

I guess i can just replace it.. or put a mechanical gauge on it to see whats up...

I just dont know...

 

also would like to add that i reached back there and unplugged the pigtail, and felt around with my hand.. no oil.. so i do not think its leaking.. then i reconnected the pigtail to make sure it had a good connection... problem remains...

 

My last o/p sensor developed a slight leak at the electrical connector that manifested itself by giving lower than actual readings (idle looked especially low). The leak was not obvious until I removed it and could look it over. You might try replacing the sensor (I used a genuine AC-Delco one).

 

ok,, I will replace the sensor and report back.

Thanks Rob.

 

They have been known to not function properly after so long. I replaced mine at one point and was getting more consistent readings after. I dont think it was that expensive either.

 

Ok. sounds good.. I will be doing a remove / replace ASAP.. will report back.