What are the symptons of a faulty WUR?

[Moke81]

Trying to nail down a small problem that occured during cold running. It idels fine once at operating temp. But during cold temps around town stop and go the idel is low and a little rough around 300 or 400 rpms. Is this a potential WUR problem?

Thank you
Moke81
1981SC

[RickM]

Moke,

A search will yield a google of information.
You may want to look here as well, especially under the Troubleshooting info..... http://members.rennlist.com/jimwms/CIS/CIShome.html

Good luck.

[Paulporsche]

Moke,

I think you are on the right track. You may be able to adjust your WUR back into spec if that is what's wrong. Besides searching WUR, also check out the AAR and AAV.

[Elombard]

Get a book on Bosch FI (or factory manuals or the Bentley) and get a set of gauges for bosch or modify one that is not. You can tell alot by knowing the fuel pressures.

There is a bunch of stuff you can try for free.

12V at the WUR and the AAR?
Remove the AAR and put 12v to it and make sure it closes.
Check the decel valve by taking it out of the system.
Check fuel pump output

Like Paul said probably a fuel pressure issue (WUR) with the low idle but it seems like a vacuum leak in the wrong place might make a low idle too?

[Moke81]

I'm sure I know what they are but the abbrv. I don't know. What is the AAR and AAV

Thank you
Moke

[RickM]

Auxilary Air Regulator and Valve.

[Moke81]

Thanks Rick, I looked it up in the Bentley and found them. Great Book.

Moke81

[vash]

check your pm's. i got gauges you can borrow. (unless you are not trustworthy )

[350HP930]

Originally posted by Elombard
Get a book on Bosch FI (or factory manuals or the Bentley) and get a set of gauges for bosch or modify one that is not. You can tell alot by knowing the fuel pressures.

+1

Once you understand how CIS works and know the pressure and voltage testing procedures there is not a CIS that you can't diagnose and fix yourself.

[Moke81]

Vash, check your pm