Marauder loses oil pressure

[Seneca]

Has this happend to anyone else? I was out for an afternoon ride.. on my way home.. car was running tops..I stop at a traffic light.. light turns push down a lil just for fun.. trani, dont kick in, :( Look down at the shift lever only to see that my oil level takes a plunge :confused: engine light comes on.. kills the engine.. checks under car for oil.. then checks oil levels .. hard to do when it's hot i know.. everything seems fine.. waits 5 minutes restarts.. everything seems fine drives home.. calls dealer.. the car goes in tomorrow.. :help: anyone else have anything like this happen?

[LincMercLover]

Something may be messed up in the oil pressure sending unit. The MM's oil gauge isn't a real one, so it reads that either you have pressure, or you don't. If a faulty signal was sent that you don't, then it probably threw the check engine light and killed the engine. No major worries buddy.

[WolfeBros]

You will not get a check engine light for low oil pressure on this car. This sounds like the engine stalled first for whatever reason I am not sure. And then he noticed no pressure and engine light as a result of the stall.

[martyo]

I agree with Wolfe!

[RF Overlord]

Sam, I know you (and others) have installed the "real" oil pressure sender and gauge, but is it possible the ECM actually DOES monitor this line? As long the ECM gets a voltage that is higher than the minimum threshold (6 lbs, I believe), everything is fine...it doesn't care what the voltage actually IS, as long as it's higher than "X", so it works just as well with the real sender?

That would be a nice safety feature if it's so...maybe someone with the service manual can confirm or deny this?

If the above hypothesis is true, an intermittent sender would cause exactly what happened to MD666...

[mdmarauder]

I would say it stalled. I have had my MM stumble and almost stall pulling away from a light once.

[MAD-3R]

MarauderMD666,
Do you happen to know if you have a 300A or a 300B, and the the aproxemat build date? And before you got to the light had you had your foot in it, ie High speed run.

[WolfeBros]

Originally posted by RF Overlord
Sam, I know you (and others) have installed the "real" oil pressure sender and gauge, but is it possible the ECM actually DOES monitor this line?

I can tell you that I have actually started and driven around in my car with the OEM sending unit UNPLUGGED. I did this on purpose to see if the ECM does monitor the oil pressure. It does not.

I am convinced that this guy just stalled his car.

[LincMercLover]

Just because you unplug the gauge doesn't account for the sending unit itself. The gauge is merely something to look at the sending unit with. At least this is how this all comes together in my head...

[Blue Marauder]

WolfeBros said he unpluged the SENDING UNIT, not the gauge. I interpret this as meaning that he disconnected the wire at the sender which would take it out of the system completely.

[WolfeBros]

^^^ What Blue Marauder said ^^^

LML........I unplugged the sending unit at the sending unit. Probably drove around town 1/2 the day. No lights, no warnings.

Fomoco would not shut down a running engine because of low oil pressure anyway. Too many different scenerios where dangerous things could happen and legal action could take place.

Guys I don't make this stuff up. If I don't know something for sure I do not post about it. Speculation is not good 411.

[RF Overlord]

That's good enough for me.

[LincMercLover]

Okie dokie somkie! :up:

[SergntMac]

Originally posted by WolfeBros
Speculation is not good 411.

I agree, Wolfe, 100 percent. We should not jump to any conclusions, but let's keep an eye on things oil system related, and report what we see, eh?

I must add that until your post, I too believed that the car would shut down on a low oil pressure signal and save the motor. With all the other "monitoring" and engine protection features we have, that protection made sense to me. Thanks for clearing this up, I have neither a warning light or a pressure gauge working for me...Time for a full set of custom gauges from egauge.com yes?

[RF Overlord]

Originally posted by SergntMac
Time for a full set of custom gauges from eguage.com yes?

Sarge: if you put any more doo-dads on your car, it's gonna turn into a UFO...



:banana2: :rock:

[WolfeBros]

It is amazing to me too Sarge that there is not a low pressure oil light or even a check engine light for a low oil condition.

What is interesting is that these cars will tolerate and even compensate a little for overheating and yet you still will get a warning light. Doesn't make much sense to me that oil is not important enough for a light ??

Lose oil pressure and all you will get is funny noises until it quits.

I am a gauge and instrumentation guy. Always have been. I enjoy watching the working autometer gauge that I put in. You can tell when you have reached operating temperature by watching it, and even engine speed to a degree. At temperature the gauge will go from 25 psi at idle to over 75 lbs at highway speed.

And your right about monitoring oil related subject matter for this car. (I am watching the outcome of our fellow brothers car too) I am keeping all my receipts and a computer log of all service on this one. I may even go as far as taking the occasional oil sample and dating it when I change oil from now on.

[frdwrnch]

Check my post on "potential problem" in the Garage forum. A wiring problem in this area or on the left head can cause this symptom. I now have a photo on that thread.