Good Morning everyone, Wondering if someone can help me out. I just got a 1987 328 and someone has been tampering with with the settings on the fuel injection system. Can someone look at their car and tell me a couple of things. 1) the number of threads they see on their idle screw. (the big brass screw). Basically how many turns is it out. 2) the number of turns they see on the butterfly screw. This is the screw at the top of the throttle body. The car runs fine however i dont have a high speed idle when cold. I know its not the correct way of doing it but it does give me a idea of where things should be. tony
The cold start high idle is controlled by the AAV located under the coolant expansion tank. Plenty of threads on that topic. The throttle body screw adjust idle speed, once engine is warm.
Reason i am asking is that the throttle body screw is completely out. Not even touching the throttle plate. And the big brass screw is out quite a bit.
Your airflow adjustment screws being set wacko wouldn't have anything to do with not having a higher idle when cold so check the AAV operation for that as cmt6891 suggested. Although if you are in a very mild climate (like TX ), it won't be doing much this time of year. With regard to the airflow adjustment screws, this thread has some information which I'd summarize as: 1. With air bypass screw fully closed, adjust the throttle plate screw to give 700~800 RPM warm idle. This would be something like 1/4~1/2 of a turn from rest (although you need to make sure that the throttle microswitch is not impairing the throttle plate motion AND the idle switch portion of the throttle microswitch is closed). 2. Then open the air bypass screw to increase the warm idle to ~1000 RPM -- maybe something like ~1 turn open (not 5 turns). http://www.ferrarichat.com/forum/threads/idle-input-please-8-900-rpm-warm-with-air-bypass-screw-fully-closed.465076/#post-143465486 Good Hunting!
Steve, thanks for the help it worked out well. I knew that the car had been tampered with and i knew that the screw not touching the throttle plate was not right either. I just did not have a idea of where the screws should be as a starting point. Usually as with most cars it turned out to be 1 - 1 1/2 turns in or out depending on how the screw functions. The car doesnt run any different but i am sure its setup the way it should be. Thanks again.
Glad that you've got it better sorted. Yes, that's a "flaw" that wouldn't cause much noticeable runability problem as the two air paths are in parallel so it's the sum of the two that's more important to get the ~1000 RPM warm idle. Maybe something like the change in RPM during very fast throttle opening or closing might be affected/different. Can you put values on how many turns the throttle plate screw had to be turned past initial contact to get condition 1, and how many turns the air bypass screw had to be opened to bring it up to condition 2?
I can verify tonight as i usually keep a repair log on all my vehicles as to what was done and how it was done. However it got late last night and i did not fill it out. I know for sure that the bypass screw was about 1 turn. i will check tonight on the idle screw. The only reason i keep the log is that most cars usually end up with the same problems, its just easier to remember how i did it.
