83-944_DRM

Problem: Engine starts fine and Idles at 1200 rpm for approx 30 secs and then drops to 200 and bounces back up to 600 then right back down. Some times it dies, the exhaust is very rich. Based on my reading of " How to Understand, service and modify Bosch Fuel Injection and engine management" Bently publishers, author Charles O. Probst, SAE. ( from Pelican Parts ) the problem seemed to be related to a vacum leak or a faulty air flow meter. I visually checked all vacuum lines and saw no obviouse signs of cracking so I moved on to the air flow meter. The procedure for testing is on " Clarks Garage - ELECT-22, Air Flow Meter (AFM) Operation and Testing". I removed the air meter and manually moved the air vaine back and forth. The vaine moved freely, but did offer a little resistence when it first started to open. I sprayed electronic contact cleaner on the vaine and the resistence went away. I also followed the procedure listed in Clarks Garage for adusting the internal wiper arm and the potentiometer conducting strip. This did the trick, my idle is steady with no fluctuation. Hope this Helps!

John_AZ

Excellent!

Your research is understated.

I put your solution on the Pelican forum in hope it will help another member.

http://forums.pelicanparts.com/porsc...tion-idle.html

Thanks
John

Homer

just a side note in case someone comes accross this thread in their investigations of idle issues. My 84 would surge and almost stall when warm, so fluctuate 1000rpm down to 400 and back. The vacuum valve at the brake booster was cracked. The small vacuum line off of it was open. New part, rock solid idle again. Part 15 in this diagram (although that is a without air conditioning diagram part), was a $20 fix.

http://www.pelicanparts.com/944/944_...3-85/Pic70.jpg

83-944_DRM

Thanks John, I have benefited from all the great advise on this forum and I am glad to be able to contribute.

Thanks for the add Homer.