MOD500

Nearly met my maker last night; the gas pedal stuck to the floor going round a corner in 3rd. Luckily I knew the roads and it was getting dark too so could see there was no oncoming traffic, hence was able to use the whole of the road to get round the bend. Very scarey none the less.

The RAC chap came out, poked around with his torch and located a frayed accelerator cable. The damaged one is the right hand one of the two present behind the intercooler. Because the wire was frayed, when I put my foot down and then released the pedal the frayed peices were sticking into plastic sleeve of the cable surround and jamming preventing the pedal returning under the spring load. Rather like the fishing hook barb principle I suppose. Have taken some pics of the cable, and will post one up soon.

Has anyone else had this before? Its real easy to check the cables; just pull the rubber shrouds back and you can see the bare wire cable where it goes into its plastic sleeve. Its worth a check if you have chance, I'm pleased it didn't happen to me an hour earlier when I was on the red line in 5th........

On a lighter nore, I have noticed certain surges in the power delivery when the turbos are boosting on full. There seems to be a surge at 3.5 and then 5K revs or so, has anyone else had this? Sorry if it has been covered before.

With Best Regards


Martyn.

fc-racer

MOD500, the surging you feel is normal. From what I've gathered, it is the Motronic detecting slight knock and pulling back the boost during the peak torque area and then dialing it back up as it moves away from peak torque. I've noticed that if I run 100 octane unleaded, the dead spot goes away and it has more mid-range torque. Initially, I thought the dead spot was programmed into the Motronic, regardless of fuel quality, but running the 100 octane seems to prove otherwise.

I just wish there was a book or something available that talks about how the Motronic controls boost and fuel and under what parameters it changes the settings.

dbf73

I think what we need to do is find the person that did the maps and buy him/her a few cold ones to get the real story. :-) Everyone here on Rennlist could chip in.

gooseNSJ4

MOD500.

That sounds like a worst nightmare. Good to have you with us. :

chris walrod

This should be a 'warning shot' for all of us... Lets all go out in the garage and have a look at our throttle cables condition. They do fray internally and get sticky over time..

A scary moment with a good outcome!!!

MOD500

Thanks for the replies.

I have spoken to the OPC after the car was sent back to them this morning on a flat bed truck. They say they have NEVER come across this throttle cable problem before. I also spoke to a respected Porsche tuner in the UK for a 2nd opinion who also confirmed that they have never seen such a problem on a 993 turbo. MMmmmmmm!!! Not sure what to think now after my near miss.

Have enclosed a picture of the offending cable, the picture was taken when the gas pedal was set at 2, 500 revs...so there are lots more frays on the cable within the plastic sleeve that you can't see. The throttle was set at these revs so I could drive the 3 miles home last night,after the RAC man manually pulled the cable back reducing the engine revs from the limiter back to idle.

Please check your cables……mine may have been a fluke, but don’t take the chance.

I must admit I really enjoy this forum by the way.

With kindest regards


Martyn.

911/Q45

There is a rubber bellows cover over that part of the cable. Did you pull it aside to show us or is it missing? If missing, that might be the cause of the abraded cable.

MOD500

Yep, pulled the rubber shroud back to take the photograph. Cannot think how the wire has worn away, or maybe its just wear and tear?

Thanks

Martyn.