Bill Ball

No cloud of smoke. It was odd. The car has been stone reliable, but vitually every part in the system except the LH brain and the throttle switch is original. I did replace the fuel check valve a few weeks back as preventative maintenance. I probably should have left that alone. Relays and fuel pump are original. Once it started on the 4th try, it ran w/o issue. If it does it again, I'll look further. At 182K miles, I guess I shouldn't be surprised.

Oh, and I just remembered that I have been having problems with the electrical part of the ignition switch. The headlights and instruments would go on and off unless I jiggle the switch a bit after starting the car. Perhaps this is just another sign of that switch needing replacement. I have the part. Just have to pull the pod.

Peter F

I don't think you will need to pull the entire POD, just get it loose.
At least that was enough to change the electrical portion on my -81.

/Peter

Bill Ball

Right, it just needs to be slid away from he dash enough to get at the retaining bracket. Out to the garage!

Leon Speed

Can I conclude that 9/10th throttle is normal, or did you manage to get it to 2/3rd Bill?

worf928

I've never seen an S4 wot switch trigger at 2/3s. Every one I've ever tested - that triggered at all - triggered at 90%.

Dictys

Mine only triggers at above 90%, it has to be nearly on the floor before I get WOT. Even at very high speed cruise the WOT is not engaged, we were only seeing it the last 10mph in top gear and harsh accelaration.

Landseer

Bill has some other posts that suggest the switch is defective, specifically that the base of the contact can actually be broken.

Leon Speed

Right, so a WOT signal at 90% on my car is how the switch works. Good thing the knock sensors work. Will be interesting to see what the AFR shows when I install it.

John Speake

If you check the switch on the bench WOT switch triggers at 65% or so, but with the 928s throttle actuator setup, 90% of pedal travel is typical.

Bertrand Daoust

Mine triggers at about 90% and was wondering if it was ok or not.
Now I know it is ok.

Thanks guys for the clarification.

Landseer

Electrodes can be bent to engage it very early on the actuation cam.
I've done this on the 85 car

FredR

Well at least this thread perhaps explains why the WOT fails. I found this failure afte using ST2 for the first time after I purchased it. I tuned out the problem by programming cells on the base fuel/ignition maps. Even so it still useful to have the switch working even if it is not triggering anything given ST2 uses it show full load cell values.

I recently reverted to stock FPR and stock and got some surprisingly rich results.This left me wondering if the WOT is kicking in at some stage late in the game but even so does not explain AFR's in the mid to high 11's. I have tuned out the richness but I am still wondering if the switch is in fact kicking in when the pedal is really hard to the floor.

Yet another quirk of these these things but to be fair, I have not seen any increase in dot size on my ST2 output in sharkplotter so I assume the WOT switch is not working.

These cars are a right PITA!

Regards

Fred

Bill Ball

As has been discussed in other threads, a common failure mode for both the idle and WOT switches is the solder points in the right side of the picture John shows in the 6th post. You can split the case along the middle seam with a Dremmel cutting wheel, cutting in enough to break the glue seal, resolder the switch mounts and reglue the case back together.

pacman777

does the transmission kick down before you get to wot?

Leon Speed

If you're referring to the kick down switch behind the gas pedal, I feel you should get WOT first then activate the kick down switch. The tranny does shift down before the kick down switch is activated depending on the gas pedal position and rpms. If you have a GTS, there is some sort of kick down function possible by playing with the gas pedal but cant recall how it works exactly.