AFM redline issue
 

The stock airbox had been taken out by the PO and was replaced with a cone filter. I decided to put the stock unit back in as it was not mounted properly and the AFM was missing the cover. So I picked up a AFM/airbox with a K&N for cheap on ebay. It sat for a few months while I was working on the interior until I installed it the other day. This morning I fired up the car for the first time in 4-5 months and it ran terrible with a huge amount of smoke coming out the tailpipe. It seemed to me the car was running super rich. I didnt know what the problem could be so I googled "Porsche 944 rich" and noticed a thread here on Pelican about the differences between a early and late AFM. They look identical but work differently. I didnt know what version I had so I decided to swap out the one I got on ebay and replace it with the old one. The car started up great with no smoke but it decided to run up to redline all by itself without ever touching the pedal! I tried it several times but it did the same thing so there is something wrong with the old AFM although it worked fine months ago. I cleaned the contacts but no luck. Any help on this would be appreciated.

If this car ever gets back on the road it will be a miracle!

Thanks

My first guess would be the throttle plate is stuck open, even partially. If it were closed shut, I don't believe the engine would be able to get to redline. It would simply starve itself of air.

I still can't figure this out. The engine still revs to about 5k right on startup. I am still assuming it is the AFM I swapped out but will check the throttle plate. Any other ideas? Throttle position sensor?

Could be tps, there's a screw right by the throttle cable bracket that can affect idle if it comes loose, it pushs on the throttle. Mine came loose somehow screwed itself in setting the idle at 6k.

I will check that out tonight. I changed out the throttle cam so perhaps I knocked something loose. I hope it's something simple like this! Thanks

The culprit was the aftermarket throttle response cam. It is not a plug and play device as advertised as it opens the throttle. It looks like the cable will have to be adjusted at the pedal in order to use it. Anybody else have to do this?

That's weird. You usually have to tighten the throttle cable a bit when going to the round cam.