New '73 914 owner, high idle issue

MarkRobinson · 04-19-2007, 06:46 AM

HI guys,

I've had 914's before, but been a LOOONG time. I just picked up this car to save my 911turbo & turbo928 from excessive miles: I think it has a 1.7 in it, but unsure...at least it's still fuel injected & runs pretty well.

2 things: it has a high idle, ~1600rpm or so: knowing more complicated EFI systems, Can I assume that I can just lower the set-screw on the throttle body to lower it, assuming I have good vacuum & hence, no vacuum leaks that are assisting with the higher idle?

Are there other things to look for with higher idle? Started the car after 4 days last night: idled at about 700 until it was warm, then was up to about 1600 again.

Thanks in advance, Mark

Tobra · Tobra's Garage

It is likely you have a vacuum leak. Hoses can look good, and not be.

If it is a 1.7 or 2.0 it will be a D-jet. Change out the fuel hoses, you don't know how old they are, you might want to put the fuel pump in the front too, relatively straightforward and not a bad idea

MarkRobinson · 04-19-2007, 07:51 AM

The fuel pump is in front, so the hoses may have been replaced: calling the mechanic tomorrow to see what he's recently done to the car.

How do I tell what size the engine is & what EFI is on it? Thanks, will replace the vacuum lines this weekend.

Nostril Cheese · 04-19-2007, 10:28 AM

If it's a 2.0L, the throttle body will be on the top of the intake plenum and the air cleaner will be rectangular.

if it's a 1.7L, the throttle body will be on the side of the intake plenum and it will have a circular air filter.

another way to check is where the intake runners bolt to the head.

2.0L's use three studs, 1.7L's use four studs.

MarkRobinson · 04-19-2007, 10:31 AM

ah, the rectangular air box, I remember those now. I have a round one.

D'oh!

glennholmes · 01-04-2009, 12:43 AM

Auxilary Air Regulator---as I understand it, is a big intentional vacuum leak to increase idle at cold start. constant 12v with key closes it within a couple mins, check voltage to it, then pull off hose when warm. If it doesnt restrict flow completely, it isn't working properly. I got one working again by boiling it and smacking it around. It wasn't available here last I looked.
If it is stuck closed the timing was probably advanced to compensate so that it would idle when cold. if so fix reg, retime and then adjust idle screw.