Motronic 3.2 wide open throttle switch setting

dave7320 · 04-15-2017, 09:41 AM

I'm setting up my throttle body for reinstall. Set the throttle plate clearance. Then set the closed throttle switch. Then I tried to set the wide open throttle switch. There isn't enough adjustment in the switch. It makes contact with about 80% throttle opening. Can't get it to be open with throttle wide open. Do I need a new switch?
I'm new to the 3.2. So any info will be helpful. I'm using the Bentley manual and following its instruction.
Thanks
Dave

Hendog · Hendog's Garage

I just did this last week. Loosen the two screws, one at the top the other at the bottom, and you'll have lots of play. The whole switch mount braket will move. I had a friend help me which made it easier. I would adjust the position of the switch and hold in place as he moved the throttle. I had my ohmeter on the swith terminals to verify the switch was closing when at WOT. Tighten down when you have it right.

Hendog · Hendog's Garage

There are 3 terminals but only the middle and top are the switch contacts you need to check with your ohmeter.

dave7320 · 12:43 PM

The problem is that the switch makes contact for WOT at about 80% open throttle. Too soon. I don't have enough play to not make contact with the switch with the throttle wide open. And yes I'm checking the top two terminals.

Hendog · Hendog's Garage

Are you able to move the switch along the bottom and also along the top screws?

dave7320 · 04-15-2017, 01:00 PM

Yes. Both screws loosen and the switch rotates. We are talking about the throttle position switch.

Hendog · Hendog's Garage

Yes, full throtle switch. Bentley page 240-19. Also 200-6 for an illustration.

dave7320 · 04-15-2017, 02:52 PM

Quote:

Originally Posted by Hendog

Yes, full throtle switch. Bentley page 240-19. Also 200-6 for an illustration.

Ok. We're on the same page. Literally. Hehe. What I'm saying is that I cannot adjust the switch to show wot with less than 80% throttle. So it will think WOT for the last 20% of throttle opening. The manual says it disregards O2 sensor after this point and uses an optimum power map. Will this be a problem?

Hendog · Hendog's Garage

I'm glad I fell onto this thread because I mis-adjusted my WOT switch last week. My throttle was hitting the hose clamp and stopping there which is where I mis-adjusted my WOT switch. Now that I have moved the hose clamp out of the way, I too am getting the WOT to come on a littler early, before actual WOT; this is the best I can do with the adjustment, there's no more room to move the switch.
Switch comes on here

...and this is actual WOT

dave7320 · 04-15-2017, 03:08 PM

I have the exact same situation.

techman1 · techman1's Garage

I seem to recall a spec that 80% was correct....

dave7320 · 04-16-2017, 05:49 AM

Quote:

Originally Posted by techman1

I seem to recall a spec that 80% was correct....

We're going to give that a go. If I have any issues I'll have to dig deeper. This was a running engine. I disassembled it for detailing and wanted to check the setup before I tried to fire it. This was something I wasn't sure of.
Thanks for the feed back.

Quicksilver · 04-16-2017, 07:47 AM

Not really a big deal. Remember that 80% is way over 90% of flow. Yes you do want to make sure that the butterfly is opening up all the way because who wants to leave anything on the table? But the last 10% of throttle opening is only going to get you one or two percent of flow.