kevin2012

My 91 S4 runs well yesterday until I had it parked in a public car park. The car starts fine and strong but dies in about 5 second. Had swapped the 53 relay from the fan blower/horn to the ignition/fuel pump/LH-Jetronic control unit relays but no change.

Tried to unplug the MAF, the car won't start at all.

Also, the engine oil level is dropping, after several starts the engine oil level dropped to min and the engine oil level warning is on. I am not going to start it anymore. Not quite bad smoke from the muffler.

Is the engine gasket blown ? where does the oil go? (No oil on the ground or anywhere that I can see, it must be an internal.)

Thanks for helping out in advance.

ilikebig928butts

Could be a couple of things that looks like one big fustercluck...

1) If you don't see oil anywhere, it could just be the oil sensor. They do go bad.
2) If it starts and then dies, could just be loose or gone vacuum hose.

Good luck.

OTR18WHEELER

This makes me think of a certain scene from Ferris Buelers Day Off,
When you say the oil level drops, are you referring to the gage, or actually checking the dip stick?
Also you state that it starts, but dies.
Also, you said you HAD the car parked?
Sounds to me like someone had a joy ride and busted the block, all the oil was gone several blocks away.
...your engine is seizing up.

kevin2012

Thanks for the reply. I checked the oil level from the dip stick. when the car started to have this problem, I had checked the oil level immediately from the dip stick and it was close to max. after several attempts to start, the oil level had dropped to min and the warning light on.

No trace of oil leak anywhere externally, so this must be an internal leak. Possible?
Please forgive my poor English, I actually meant that I parked the car in a public car park myself.

Cheers.

OTR18WHEELER

Ok, now your description leads me to think that perhaps the oil passages in the top of the engine are possibly blocked, not allowing proper flow back to the oil pump., but I dont understand how this could happen while parked.
Sorry, I can't be of any real help here.

Mrmerlin

OK so let the car sit for an hour then check the oil,
has the level returned?
maybe it was low to start with and cranking it pumped the oil from the pan into the engine.
What is the weight of oil you are using it should be 20W50.
From the info it also sounds like the fuel pump is going bad.

have the computers ever been rebuilt?
Has an intake refresh ever been done?

kevin2012

Yes, I did waited for 5 hrs but still the same. I have not done any intake refresh job and I am using 10w60 synthetic oil.
Computer never rebuilt but the fuel pump and filter were changed in 2013 or about 7000km ago with Roger's parts so I doubt about the failure from fuel pump.
I had changed all vacuum lines last year and there should be no major vacuum leak.

Now the car was towed to the repair shop so I am waiting for their findings. Waiting for the bad news to come.
Cheers

kevin2012

My mechanic had pulled all the spark plugs and there were no trace of any engine oil. No trace of oil anywhere under the engine as well.The plugs are just showing that the engine is running very rich so he suspects the mass air flow sensor. My mechanic was able to start the car with the help of pressing the gas pedal but it runs roughly.
Yes, a faulty MAF can explain the start and die problem but how about the missing engine oil? I am sure that I was seeing the engine oil level dropped but really don't know where did it go?
I am ordering a rebuilt unit now. Is that possible that the intake vacuum was too strong and it sucked the oil into the intake?
Cheers

Mrmerlin

lets not worry about the dropping oil level till you get the engine running,
its quite possible you misread the dipstick.

I had that happen just the other day,on a BMW bike,
an owner pulled the stick and couldnt see the level so he added another quart.

When I got to the engine it was so full of oil,
the level would not have been where you would have expected to see it ,
plus some fuel had drained out of the tank into the crankcase due to leaking petcocks,
but thats another story

The Deputy

So, the first time you checked the oil was after it wouldn't start...if so...it may have read higher on the stick, because you were turning the engine over and oil was splashing around in there. Possibly, it was low to begin with.

I believe you have one issue to contend with...and that sounds like a relay or bad connection somewhere.

Good luck,

Brian.

kevin2012

Thanks for your encouragement. I also hope that this is just a problem of relay or electrical connection only. But with my 3 years of 928 ownership experience, it never been easy on this car.
Actually, it is my habit to check the oil level every one or two weeks so I know roughly about the oil level in my car. even I have some minor leak around the cam covers and on the coolant bridge as usual but it just don't add up the nearly 1.5 liter engine oil(from the max mark to min on the dip stick)
A rebuilt MAF unit is on the way from Roger but I think that the problem is far beyond the MAF.
Cheers.

kevin2012

Maybe a compression test is a good thing to do.
Cheers.

kevin2012

Update, thanks for Roger that I recieved the rebuilt MAF sensor in only 2 days. Plug it in and it runs never better. It runs smoothly and even exhaust sounds better too.

As for the missing oil, I am not worry too much as the engine compression test result was very good.
Thanks for all of your great helps.
Cheers

The Deputy

Good news!

ilikebig928butts

For the oil level thing, again, replace the oil pressure sender.
http://members.rennlist.com/v1uhoh/oilp.htm