Paul Bakker

Hi.
Just drove my car for about 10km. When I arrived and drove very slowly (<3Km/h) looking for a parking spot the engine suddenly stalls.
I saw the light "low engine oil" come up (or maybe low pressure, I'm not sure).
I was in the middle of the road so I had to start the car again and drove to the nearest place to park my car. During this 200 meter drive the car stalls 2 times again but not with the presure light come on....

I checked the oil level but my dipstick is very hard to see if the level is under minimal. I think it is so I'll top it off in a minute to max.

Question: Is it normal for the car to stall if oil pressure/level is too low ?
Is this a safety feature to prevent damage to the car ?

What kind of oil should I use ? I'll check the manual in a minute but what do you use ?
Thanks.
Paul

Shark Attack

A year woudl help AT or 5 speed?

Leon Speed

Paul, was the message on the digi dash accompanied by a picture of an oil can or oil resevoir with dip stick? The first one means low oil pressure, the second one low oil level. If the second one: fill up with oil and see how she does. If the first one, might be a bigger problem. These cars use a lot of oil so I am guessing you just need to add oil. Might be best to use whatever was used before. If that's not known, 10W40 is an all year good start point. Some people (like me) use 0W40, some people use higher viscosity. There are a lot of threads about this here and in the end you choose what you think is best. There is no consensus on what oil to use, just that lower viscosity is good for colder climates and higher for warmer climates. The user manual has a chart, refer to that one.

Paul Bakker

It's a 1990 S4 AT 173000km.

I have a very small oil leakage so it is possible the level is at refill level.
Car has had recent maintanace with several oil leakages repaired. Since then driven several hundreds of km's without any problems.

Last trip was a 500km trip to Germany and because of no speed limit drove it at top speed 257km/h.

Hope this additional info helps.

Thanks.

Alan

More like the other way around... the car is stalling and as it does the low rpm at the oil pump causes a low oil presssure that just registers a warning before the car fully stalls...

I'd say be sure it wasn't a level issue (fill) and see if it happens again.

Low oil pressure shouldn't cause a stall at least not initially (do it for long enough and it will just sieze). Monitor the pressure guage at hot idle - whats it doing....

There are 3 warnings - the illuminated gauge segment at the bottom of the pressure gauge. (low prssure switch) and on digi dash cars - an OIL PRESSURE INSUFFICIENT text warning and (not sure of the warning wording exactly) OIL LEVEL LOW.

Which did you see?

Alan

Paul Bakker

Update:

I drove my car (S4 '90) to the fuel station to get a bottle of 5W40.
Arriving at the pump (a 750m drive) I noticed the engine was seeking stalling.
I mean the computer was trying to let the motor rev a 750 RPM but it was constantly
seeking "balance". I noticed the oilpressure was going up/down between 2 and 3 bar.
This all was when the car was almost to a stop so at low RPM.
Engine was hot (normal operating temp).
I filled her up with gasoline and bought myself a bottle of 5W40.
I added 0,5 litre just to be sure there was enough oil in the engine.
When driving back home I noticed nothing special. Engine runs smoothly.
In my parking lot I let the engine running just to see what happened.
After a minute or so the engine suddlenly stoppend (without stalling) and the pod said "check engine oil level" with and dipstick symbol.
I started the engine again and everything looked good. Nothing special. I reved the engine and the pressure the goes to 5 bar.
Then after again a minute or so the engine suddenly began to seek balance again (stalling).
Oilpressure went between 2 and 3 bar up and down. Revs around 750 RPM but one can hear the engine is not in balance.
It sound a bit if a cylinder isn't fireing. I tried to put a bit more gasoline in the cylinders but when the pedal is neutral again the stalling begins immidiatly.
When reving hard several times the problem also stays but I never saw the low oil warning again.
When I put the engine off and start it again the problem stays away for a couple of minutes and then it begins again.
I don't know yet if this problem als appears when driving the motorway, tommorow I'll check.

Maybe a co-incedence but I now have also a brake light waringlight come on. Did'nt have that problem.... It goes away after I hit the brakepedal.

I've read the computer is notorious for giving up one day due to a faulty kit inside the computer.
Because of the random warning lights comming on I thought maybe the computer is due to fail.

What do you think ?

Thanks.
Paul

Landseer

Paul, what is the status of these things: cleaning of key ground points, inspection of top of coils for corrosion after removing coil wire from them, cleaning of little + wire on battery, flex plate tension release? Not keying-in on your oil pressure as much as the runnability.

taffelman

If I understand you right, you knew you had a oil leak and you knew the oil level was somewhere below the minium on the dipstick but not exactly how low it was. The computer showed you one of the oil error messages and the oil pressure was around 2 bar when idling hot. Then you added 0,5 liter oil (0,13 US gallons) and the error message on the computer went away for a little while.

Looking at this "isolated" tells me your computer works as it should, you had way too little oil in the engine and the computer told you so, then you added 0.5 liter but I think you added too little, and the error message came back because there still wasn't enough oil in the engine. I'd suggest to add oil until it levels out at the maximum on the dipstick.

As for the 2-3 bar oil pressure, this is normal when idling a hot engine, but it should quickly raise to 5 bars when you rev the engine. If you start it cold it should be around 5 bars at idle.

The brake light is supposed to come on if you start the car without touching the brake pedal, then the first time you hit the brake pedal it goes away, this is normal and how it should work.

So as far as I can understand your car works as it should except for the bad idling and engine dying. If this is directly related to the low oil level is another question. I don't know the answer to that, but others might help you here. Just keep in mind that bad idle and engine dying can have a lot of other causes that might not be related to the oil level at all.

Bill Ball

Your oil presure at idle hot (2-3 bar) is great. The brake warning light is supposed to be on when you start the car until you tap the pedal.

While your stalling and idle speed hunting may be a problem with the fuel injection brain, as you have heard about, it could be due to other causes. It would be worthwhile to remove the carpet pieces that cover the CE panel in the front passenger footwell. This will expose a clear plastic relay box mounted next to ignition and fuel injection brains (larger metal boxes next to the CE panel). Inside that clear plastic box you will see two LEDs, red and green. They should never light up if things are OK. If one of those lights up next time the car goes into the stalling mode, that's a clue that there is most likely a problem in the ignition system or a malfunction in this monitoring relay system. Your description sounds similar to what I would expect when this monitoring relay trips. However, this system is not mounted in cars which do not have catalytic converters from the factory. Yours has converters, right?

James Bailey

As Bill stated most likely a running on 4 cylinders issue but possibly an idle stabilizer sticking or the very worst it may be crankshaft thrust bearing failure in the early stages. The engine may be seizing ! It is time to check out more carefully BEFORE driving it much at all. You could destroy the engine and need to replace it. What is needed is to check the crankshaft endplay , how far it can move front to back.

Paul Bakker

Bottom line of the story is that the car only has problems with idle.
For 60-90 seconds after starting the engine -> no problems.

During a trip I feel the car is operating normally. I don't think there's a meganical problem at all. Car picks up as it should be. All 8 cylinders are working. No white smoke from exhaust.

I'm no mechanic but it looks like it's an electrical problem. Something with a sensor (in catalyc convertor maybe ?) giving a wrong readout causing the computer to seek a solution for the (false) input.

Did 3 tests during last ride:

1- Start engine -> no problem -> drive directly -> next stop -> idle problem.

2- Idle problem -> drive car normal trip -> next stop -> still idle problem.

3- Idle problem -> stop engine -> start engine -> Idle problem gone ->wait 1 minute without driving -> engine gets problem with idle

Problems began after a (hand)wash of the car but that is of no interest (I presume ).

Any idea's with this latest info ?

Thanks.
Paul

Landseer

Condition of grounds and 14 pin connector? Last cleaning?

JHowell37

If I had a S4 with an automatic transmission and it was stalling while hot, I'd check the flexplate.

Calgary Ole

Check the oil in the morning before starting and you should be able to see the level on the dipstick. Make sure it is between the lines.
In my limited exp. it is not normal to stall at low speed. When did you last release the flex plate and check end play? I do not think at this point you need to worry about TBF but make sure your oil is at the correct level first.

I mark the amount of release with a Sharpie on the plate.

I stole this idea from a Rennlister because I thought it was a great idea.(not sure which post but thanks to whomever it was)

James Bailey

Mark Anderson of 928 International who knows a bit about 928s , was chasing a hot stall issue on his son's 1991 S-4 , it too seemed like an electrical issue / idle stabilizer , car ran and drove just fine.....He later discovered that the hot stall issue (which is why the prior owner sold the car) was in fact thrust bearing failure. Now Mark did buy the car cheap and had good used engines ... like you said YOU are no mechanic but you might want to find one !