ThomasC2

Hi,

A friend of mine has a Euro RS. Since a while ago a strange problem has occurred, and we need some help to solve this!

The engine starts up as it should and sets on idle very well. But then when he starts to drive the problem start to appear. For minutes everything is OK but the suddenly the engine starts to misfire, especially in mid-revs. You can hear that the engine doesn’t run properly and it almost dies (and sometimes it does) if you try to keep the revs up. It sounds like it almost suffocates, like to little air or fuel. It still runs fine on idle though. When/if it dies you have to wait a few minutes before you can start it again. Then it runs fine for a while again until the problems comes back.

Any ideas about this guys? Fuel pump, coils or where do we start to look?

And yes, we have replaced the DME-relay

Thanks,

Thomas

Indycam

I'd look to see if the spark is going away .
http://www.flamingriver.com/index.cf...d=67/prd67.htm

Then maybe I'd also look at the fuel filter .

Rocket Rob

Have you checked to see if there are any engine error codes? Maybe they can help narrow down the fault.

Geoffrey

Have you checked the distributor belt?

Twood

The O2 sensor

ThomasC2

Thanks for the tips:

- haven't read the codes yet, but we don't dare to drive the car to a workshop if it stops on the way so the easiest would be if we could borrow a hammer from someone.
- the dizzi-belt is ok
- the 02 sensor could be something. Is this an error that would show witt the Hammer? Or is just to replace it and cross your fingers?

Twood

The O2 sensor does send a fault code on my Scantool so I am guessing it will with a hammer.
The symptoms sound identical to my C2. I changed the O2 sensor and all the problems went away. The cost is only about $60US for a new sensor and O2 sensors do wear out- Bosch tell me about 3-5 years with normal driving. It is an easy cheap job. Have a look at this thread:
https://rennlist.com/forums/964-forum/406555-o2-sensor-what-i-have-learnt.html
Please note the part about do not solder and good luck.

ThomasC2

My friend ordered a O2 sensor and a new fuelfilter today, and he'll have the parts on Wednesday. we'll see what happens! any other ideas, just keep posting!

warmfuzzies

AFM, check the tracks are ok, check the fuel tank for a vacuum, when it stops undo the fuel cap, there shouldn't be much of a vacuum, anything that tries to collapse the tank is a problem, could be the carbon cannister under the LHS wing, or header tank causing vapour lock.

Kevin.

Indycam

This is such a nice thread .

NineMeister

Thomas,
Just remove the left seat and read the label on the top of the ecu. If it does not read "Motec" there's your problem!

Seriously, try fitting the pair of colis and ignition amps from another 964, sounds like a coil heating issue to me and we have replaced quite a few coils in the workshop recently to cure random misfires on 964s.

ThomasC2

Colin, we'll start with the O2 sensor. If that doesn't work we'll move on and do the coil-test as the next step!

Thanks,

Richard Curtis

Before you start throwing parts at the problem, try this very simple procedure: Disconnect the negative (ground or earth) cable at the battery. Disconnect the other end of the cable at the chassis. Thoroughly clean all connections (chassis, both cable ends, and the battery terminal). Reinstall the cable.

I had similar problem several years ago and this fixed my problem. Seems that German cars have problems with corrosion building up on earth (ground) connections. Might not solve your problem, but it's free and quick.

ThomasC2

Good tip Richard! We'll have a look at that to!

ThomasC2

OK, an update. today my firend changed the O2 sensor and teh car runs better than before (but not perfect). I could driver for almsot 20 minutes without a problem and when the car started to missfire and wanted to stall as before he could keep it running buy releasing the clutch and let it settle down on idle for a while. Before the engine died everytime. So 2 questions:
1 The weather is very nice today. sunny and 18 degrees. On previous test rounds it has been maybe 5 degr. Does this make any difference for the O2 sensor or is the new O2 sensor that makes this improvement?

2 The engine still doesn't run properly. What't the next step, is it the coils? We're planning for a coil-switch between his and my car tonight.
Thomas