Wolfman928

Hi Guys !

I had some work done on my 928 S4 (1988), repainted cam covers and intake replaced some bad plug wires and 2 knock sensors and their connectors, cleaned and fixed some earth cables all around the engine and replaced the pre-owners 20w50 used mostly with 5w40 full synthetic.

When I drove my car back from the shop I noticed some nippy feeling that was not there before, the car was not slow before this but in the back of my mind I felt like this 928 is sluggish something not on...

the car feels really fast now, overtaking unbelievable, I have more power than before ! I believe the old plug wires could have cause this and maybe the lower viscosity oil a bit as well, maybe the long trip to the shop has something or I drove the car more loose by putting foot down a little !

got the car for about a year now, unless I missed something ? tuning ?

what do you think ?
rgds
Johnny

ammonman

If your old knock sensors were failed then the ignition computer was pulling 6 degrees of timing to protect from knocking. With working knock sensors you have that timing back which makes a noticeable power difference.

Mrmerlin

20 w 50 is what you should have used
If you find the power is reduced its a good bet that its something you have worked on may be you shorted a knock sensor lead

merchauser

nice to hear: i'm jealous keep driving (preferably FAST) and enjoy.

Christopher Zach

Are we sure it wasn't painting the cam towers? I know that mine are dirty, and that costs at least 5hp :-)

More seriously, probably the knock sensors. Glad it's working!

Koenig-Specials 928

What about the Cam Sensor? Was it replaced?
I just replaced mine and I don't believe the old OE was working.
It fell apart in my hands

Stan what does it do for performance?

NoVector

If they adjusted the cables on your throttle quadrant, that will significantly change the way the car feels too.

Wolfman928

none on the cam sensors that I know of,

maybe on the throttle quadrant, could be, thanks guys !

I did plenty DIY the last year on the car, got it all shiny with some good polish, fixed the small red door lights, replaced some interior lights with leds, restored the 928 S4 logo, got the dash removed and recovered, fixed some cluster lights, back lights instrument panel, lubricated the window and sun roof switches, they were sticky, installed a battery disconnect switch..removed faded windows tint on the door windows, treated rubbers and window rubber lining, replaced the inner bonnet material, the car is coming back to life !

Bigfoot928

a combination of the above will drastically change the feeling of an auto S4. Often the cables need alot of adjustment to get the throttle plate fully open, then adjust the kick down cable. replacing the Knock sensors and cam sensor should be on the list for any 928 since they are about 30 years old. The area under the intake is an oven. 30 years of heat cycles, along with the common coolant and oil leaks will accelerate the demise of anything plastic or rubber under the intake.

Wolfman928

thanks 928sg, I agree, I was thinking the same thing, plenty of things is neglected on maintenance over the years,

some more pics,

worf928

Koenig-Specials 928

Wow, 6 degrees. That's a lot.
Thanks Dave

worf928

Yup. Bad Hall sensor with a bad knock sensor equals: "can't pass a 2CV" on the highway.

Wolfman928

thanks guys !

where is the Hall sensor situated ?

hacker-pschorr

Like Jim Baily always says: The #1 performance modification is making sure everything is working 100% as the factory intended.