Lately I've been driving the 85 on a daily basis. I drove the s4 today and it felt a bit sluggish due to what I believe is a difference in the throttle between the two. Power not being the issue, there is quite a notable difference in the pressure required to press the go pedal giving the illusion of a slower response from the s4. It just doesn't feel as snappy as the s. I realize the s is a 5sp and this can also attribute to the fact but I also remember my old 86 auto as feeling more responsive than the s4.

Does anyone know if there is anything available (such as the quick response throttle cam for the 944) for the s4 or has anyone done any custom mods to increase the response feel?

 

A poor throttle response can be due to a somewhat weak mixture. This could be low fuel pressure, or an aged MAF. How many miles has the S4 done ?

A well sorted 928 doesn't need a fast throttle cam !

 

Dave- I had the same stiff pedal. I re-adjusted everything from the pedal to the linkage and it is very easy now. You also have to be sure you are getting wide open throttle, the kickdown switch is being switched, and your throttle position switch is working. I had help from Dave C. the last time those things were adjusted. My throttle position switch was working in June and was not working a couple of months later.
Carl

 

Dave,

Also check the throttle cable under the intake. It runs on a pulley and may be binding in that area.

Jim R.

 

John,
Fuel pressure is good. It was checked when I was diagnosing what turned out to be an LH failure. As for the MAF, I'm planning to swap it out with the on from my 85 to see if there is any difference(I'm told they are interchangable). The S4 has 150000+ miles


Carl,
The kickdown switch works fine as did my throttle position switch when I last checked it 8mo ago. I'll give it another go over. BTW How are things with lastest aquisition?



Jim,
I had the intake off a year ago for good r&r I know all was well then but I'll take another look.
Thanks all for the suggestions.
-Dave

 

Dave: not much happening yet, just some cleaning and the hood is getting paint. I have some major stuff to do- tb/wp, pan gasket, motor mounts and rack. But I have all winter....

 

Dave
I have noticed this with my 88 S4 compared to a friends 87S4 and 78.....his 87 S4 has a much heavier throttle than my 88...it also is slow to kickdown when you floor it....probably an old kickdown switch or a out of adjustment kickdown cable.... Could be the cables need to be cleaned too?

 

Dave,
Swapping over the MAFs is OK. They are all the same. 150k miles on an original MAF would mean it is badly aged, and would give a weak mixture..

I understood the issue to be poor throttle response, rather than stiff throttle/poor kickdown etc. Am I correct ?

 

Just swapped out the MAFs between the 85 and 88 and WOW, what a difference! the MAF from the 85 has < 40000 mi on it and now the 88 feels reborn.


John,
I had thought that the throttle felt stiff, but now I believe this was due to the poor response I was getting.
Although my kickdown engaged with no problems, the car didn't react with much power until the the pedal was stomped and the kickdown engaged. With the MAFs switched out, the car has now become responsive with just a blip of the throttle. My next step is to put the MAF from the 88 into the 85 to see how it detrimentally affect performance. Once again, thanks all!
Dave

 

I think you will find areciprocal effect. Also the idle may ned resetting on the '85.

I can supply a rebuilt MAF. Also see the MAF FAQs on my website www.jdsporsche.com

Regards