Nadine

Hiya,


Hope all is doing well unlike myself !

I went on holiday and left my S4 with the airport valet parking people for a week. Came back after 7 days, collected the car. It was only driven 1.2 miles (clocked the odometer!). Got in the and drove back home no problem (40miles).

Jumped in the car this evening to make a short journey and the car felt as if it was slightly misfiring as was shaking at low revs. While at the level crossing, the car stalled in D. I immediately started with no probs and all was fine. It seems to be the car is running low on revs (the rev meter is below 1 at idle).

It wasn't long ago that I changed all the distributor caps and rotors and also a full new set of ignition leads. I also checked my MAF with John Speake and all has been well. I have also changed my throttle and bowden cable with brand new replacements.

The only thing I haven't changed are the spark plugs. They were changed 5000 miles ago approx. and yes I have been hammering the car quite a lot. The other thing is the fuel guage is close to the empty red mark when this happened. Thus anyone have any leads as to what could have gone wrong ?

With the fuel guage just at E slightly above the red mark, is there a reserve fuel below that guage reading ? How far can you drive ? When I start the car the fuel red indicator below E lights up but I have never seen it light up when I am close to empty ! How far does the needle drop.

So far, I have narrowed to spark plugs, impurities in the fuel, injectors slightly blocked, bad electrical etc. (Oil pressure fine, temp fine, voltmeter fine)

Any other suggestions ?

Thanks

Nadine

steelworker2001

I would add a bottle of Techron fuel additive and fill it up with good fuel. Take it for a spirited drive over a couple of days and see if this helps.

Ken

Mrmerlin

after you install the Techron lots of short drives are better. ( IE starts and stops are better than one or two longer drives) Is it possible that anyone has siphoned off your fuel or was the fuel cap locked

Nadine

Fuel cap was locked

jcorenman

On our '88 the "reserve light" comes on when the pointer reaches the red "E" mark-- the red segment below "E" lights up and the central-alarm indicator also comes on (push to reset). The pointer then continues to drop below "E" into the lit-up red indicator-- the reserve beyond "empty"-- and then we get scared and fill it. I don't recall ever putting in much over 20 gal's, I don't know whether the reserve is larger than spec'ed or the tank is smaller. Spec is 86 liter tank "of which approx 8 liters is reserve"-- i.e. 22.7 gal total including 2.1 gal reserve.

Good advice on the Techron, particularly if you normally fill with no-name gas (which has no cleaning additives, or less-effective ones). Also on the short drives-- Techron needs time to sit and work-- but we've read elsewhere that adding it to approx 12 gallons is better than a full tank.

Cheers, Jim

VehiGAZ

Nadine, it's impossible to say for sure, but this sounds a bit like the intermittent "4-cylinder" mode that can be triggered under certain circumstances on 89+ cars. There is an ignition monitoring circuit that looks for significant temperature differences between the left and right banks of the engine. If it senses a difference or if one of the temp sensors fails, it will shut off the fuel injectors to half the cylinders (2 in the left bank and 2 in the right). That gives you low power, a loud and shaky engine, and a definite propensity to stall. To learn more about it, search for the thread called "90 GT suddenly running very rough" by Stan Shaw.

Good luck!

waveflux

I had this problem, I also drive a 89s4. It was a vacuum leak. Check the hose going into the Head. I used some loctite to make the seal, problem solved. After that, trace the hoses to see if they're old and brittle, a lot of heat is generated in the engine compartment, not good for rubber and plastic in a 20 year old car.

waveflux

I think you're talking about the "limp home mode"

Nadine

Hiya Waveflux,


Do you have a picture you can upload and circle which hose please ?

Also how did you check for leaks ?

sorry for the basic questions but its a girl thing !

Thanks

Nadine

marton

Maybe the valet people got water into places it should not be; although it should have dried out by now.
Are you still getting problems?

Marton

Nadine

I filled the car up yesterday with Shell V Power fuel to the full.

I then added a bottle of STP Complete Fuel Cleaner.

The hesitation has definitely reduced a lot however only have done 20 miles so far.

Now and again at the traffic lights while stationary and in drive, it kind of hesitates by a shake as if it wants to cut out but doesn't.

Any ideas what I need to do now ?

Thanks

Nadine

the flyin' scotsman

There's an idle control switch under the intake; with the engine off open the hood and move the throttle linkage, it should click after minimal movement.

You changed the throttle cable recently so I suspect you need some more tension.............the processis outlined in the WSM but if you dont have them shout out.

waveflux

I tried to upload some pictures but they failed. Anyhoo, Open your hood, on the driver side of engine, you will see a small hose with a clamp going into side of your cylinders ( top of engine with PORSCHE lettering, should be right under the "P") Trace this backwards feeling for cracks or age. Remove the clamp apply loctite inside of hose, replace clamp.