Has anybody had an issue like this before? If I accelerate, even with the pedal on the floor, it climbs to 1500 rpm, then drops and tries to die. Me, along with three other gearheads are pretty much baffled.

 

Year, trans type, mileage, any major modifications???????

This is the kind of info you have to put in a "Signature" to help people answer your questions.

Have you scanned it for codes? Have you checked the fuel pressure? Have you checked for a plugged catalytic converter?

 

Sorry, it's a 1995 M6, 60k miles, all stock, and I've owned it for just over a week. I don't have a scanner yet, but I'm getting one tomorrow. It threw a code once, but it was gone after I shut it off. Fuel pressure is fine, but how do I check for a clogged cat?

 

Interested to see what codes you might have stored. You can take the car to a mechanic and have the cat tested. Did it do it when you test drove the car? How exactly did you check the fuel pressure and what were the results? Very low miles for that old of a car and sometimes sitting is the worst thing for them. Have you checked everything like the air filter and plugs and wires?

 

What values did you get when you tested the fuel pump pressure, and concluded it was "fine"?

As far as a scanner, your 95 has an OBD-I PCM and a 16-pin OBD-II "style" ALDL connector. Scanning requires an OBD-I scanner with a 12-pin to 16-pin adapter, or you need to use jumper wires. Once the SES light turns on, the code is stored, and remains there even if the SES light goes out or you shut the engine down. There are also codes that don't turn on the SES light.

 

I bought this car last Friday, the 16th. It drove beautifully for the test drive, on the way home, and to work that night. Then the next day, it crapped out on me. This is because for the winter of 2010, some squirrels got into the guy's garage and made their way into the engine compartment. After gnawing through some wires, they were kicked out. The owner sautered and taped up all the wires, and they haven't had an issue since. what we discovered last week was that the ignition coil wire was also chewed on, and it was sometimes arcing to the block. So we did all the plugs and wires, changed the oil, topped of the transmission fluid, it got a new air filter, and is now on its third fuel filter. When I got it back Thursday night, it drove great on the way home, to school on Friday, and to work that night. Then when I went to go home, the symptoms started.

I checked the fuel pressure with a guage after the first set of issues, last night, and today. Each time, when the pump primed it went up to 37-38 and held well, goes up into the low forties while driving, and never dropped below 40 at WOT. The only difference is that I can't test WOT very much now because it wants to die right away. However, as I accelerate, it does still climb.

There's also this weird growling noise coming from what seems like the air intake before the MAF when I rev the engine.

I don't know if this is related, but when I drove home after the second set of symptoms started, it was dripping some oil. There are drips up my driveway and a pretty decent-sized blotch under where it stayed overnight. The oil was running down the fuel filter, but really does not appear to be coming from the filter. Now, it's pretty much stopped. Oil levels and pressure remained normal the entire time.

I also don't know why I forgot this before, but we tested the MAF with a multimeter, and it started at around 4 v, and upon revving the engine, the voltage dropped.

We're so confused I just have no idea where to go next. This sucks.

 

The MAF sensor puts out a variable frequency, riding on the low voltage reference. You would have to use a frequency meter to check the MAF sensor output.

If you have oil on the FUEL filter, it could only be getting slung off the pinion shaft seal on the differential. There is no other source of "oil" near the fuel filter. Or did you mean the oil leak is near the OIL filter?

 

Put 1 at TDC and pull the cap off the distributor.

 

Yeah, that is what I meant. Sorry, it was late when I typed that.

Speedygonzalez - I'm not sure what you mean. Can you elaborate?

 

put number 1 cylinder at top dead center

take off the distributor cap.

 

It could be related to your work. Maybe something came loose like a plug wire or you burnt one of them and that would explain why it took a couple days. You should double check your work and when this happened to me, it was the same symptoms. Happens all the time!

 

Speedy - Sorry, but I'm still confused. What would that do?

 

I just checked all the wires, and nothing was wrong. It has started to leak a lot of oil again, but I still can't tell where it's coming from. There was a lot underneath the drivers side of the block, a bit lower than where the plugs are. There was also some behind the engine on some type of circular thing that was about 6-8 inches in diameter. Sorry for the poor descriptions, but it's really hard to tell what everything is with a small mirror.

 

Update - No codes, and the only thing funny the scanner showed was a knock and the oxy's were picking up a lot of oxygen in the car.

Symptoms so far are:

• Limited rpm range up to 1500-2200
• MAF voltage drops when engine is revved
• MAP supply line is reading 14 ohms
• Intermittent oil leak
• Odd low growling noise coming from engine compartment upon revving
• No codes
• Knock sensor going off and delaying ignition
• O2 sensors reading a lot of oxygen in exhaust

That's all I can think of right now. Any more ideas?

 

The MAF output signal is variable frequency, riding on the voltage. It's the frequency that matters, not the voltage.

What do you mean by the MAP supply line is reading 14 ohms? MAP reference voltage is 5.0V and the signal ranges from 1.5V (35kPa at idle) to 4.9V (100kPa at WOT, or when registering barometric pressure).

How did you determine "O2 sensors reading a lot of oxygen in exhaust "? Was the system in closed loop? Were the O2 sensor voltages cycling rapidly back and forth between 0xx - 9xx millivolts like they are supposed to? If they were stuck below 200mV, indicating a very lean mixture, they would set a code.

What kind of "knock"? From a knock retard reading, or aknock count reading?