How does one lower the IDLE on a 1970 911E

oren77 · 03-15-2009, 01:04 PM

HI,
I have a 1966 912 with a 911E engine. The idle seems pretty high at approx 2000 RPM's. Is there an easy way to lower this? Where should it be?

Any advice is appreciated...

haycait911 · haycait911's Garage

carbs? MFI? regardless, first disconnect the throttle actuator at the manifold to make sure it's not a linkage issue. then set idle, then connect linkage.

Zeke · 03-15-2009, 04:18 PM

Yes, you do have to tell us if that is an MFI car. All 911E's started out as fuel injected cars. If yours still has the injection, there are several possibilities for the high idle. You can start reading about troubleshooting here:
http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm

Pay particular attention to the "Check, Measure, Adjust in the 2nd "Documents" section.

john walker's workshop · 03-15-2009, 04:37 PM

how high is it?

oren77 · 03-15-2009, 09:43 PM

HI,
It is a 1970 911 E engine, it has a (I believe) 1974 K-Jtronic fuel injection added to it...it idles around 2000 RPM...

haycait911 · haycait911's Garage

how about an engine number and a couple of pics? that's an odd combo, to say the least.

oren77 · 11:01 PM

Yes, it is an odd combo...6202184...CIS

haycait911 · haycait911's Garage

other than working thru the usual CIS tuning/trouble-shooting. could it be an injection system designed for a 2.7 just not working well on a 2.0? is it a recent conversion?

if it was working fine previously, the CIS tuning/diagnostic should do it.

oren77 · 03-15-2009, 11:09 PM

no..it was working fine...I remember seeing my mechanic turn a knob in back of the air-box and lowered the rpm's very easily...does this sound right?

pwd72s · 03-15-2009, 11:16 PM

i'M WONDERING...COULD THIS BE A 912E engine???? 4 cylinders or 6?

oren77 · 03-15-2009, 11:29 PM

6 cylinders, it has an airbox, it is not carburated, it is fuel injection, CIS.

oren77 · 03-16-2009, 08:09 AM

after thinking...is there a knob that adjusts the throttle? This would raise / lower the idle, right?

berettafan · 03-16-2009, 08:45 AM

points adjusted lately?

JB · 03-16-2009, 08:50 AM

Yes, the knob on the left side of the throttle body is an air bleed past the butterfly. Screw it in some and the idle should drop.

john walker's workshop · 03-16-2009, 10:15 AM

if the knob bottoms out and the idle is still high, maybe the auxilliary air regulator is not getting 12V in order to close off. ( then the warmup regulator wouldn't get it either). pop the black plug off and check with a test light. another thing that causes high idle is a rotted out brake vacuum hose down where it attaches to a tube in front of the rear torsion bar tube. clamp off the hose up in the engine area and see if the idle drops. left side near #3 intake runner.

berettafan · 03-16-2009, 10:42 AM

but start with timing/points. no sense getting the fuel/air right if spark isn't.

oren77 · 03-16-2009, 08:48 PM

Thank-You for all your help, tightened the screw almost to max, and it lowered the idle a bit...but, I am sure I should have mentioned this earlier (or maybe it does not matter)...the car has an MSD Blaster Coil and MSD Ignition...

JohnJL · 03-16-2009, 09:27 PM

If it was working fine then started idling high all of a sudden I'd check for any vacuum leaks.

signature65 · 03-17-2009, 09:49 AM

Vacuum retard on the distributor come off?

jluetjen · jluetjen's Garage

Quote:

Originally Posted by oren77

Yes, it is an odd combo...6202184...CIS

Could you post a picture of your engine? Putting CIS on that engine is about as strange as putting a 4bbl on it. Given the overlap on the cams, I'd be curious if you could get the idle down to 1000 RPM or less and keep it even. With it idling at 2000 RPM, it must be tough on first gear synchros!