So I am new to the forums and also new to owning a 914. This monday I bought a 1970 914 and have had fun driving it around! But i have noticed a problem with the idling. After getting off the freeway and then putting it into neutral to wait at a light i noticed the rpms going from about 900-1000 (normal idle rpm) and slowly climb up to about 1700 or so and the only way I am able to make it normal for a few seconds is to tap the gas. Another thing i have noticed is it will occasionally bounce around from 1000 rpm up to 1800 rpm in a few seconds on its own without any input from the throttle. Does anybody know what my problem is and how I can come about fixing it?
Thanks, and my name is Colin

First off, welcome to the world of 914 ownership.

second, it's a whole lot easier to help someone if they tell us the motor, fuel system, ignition system etc.....

Rich

Its a stock 1.7L with stock injection. to my knowledge the entire fuel system is stock as well not messed with in anyway.

Sounds like a vacuum leak. Check all you vacuum hoses. Could also be AAR or leaky MPS.

Here is a great resource on D-Jet for 914's.

http://members.rennlist.com/pbanders/djetparts.htm

Although a vacuum leak is always a possibility, I had the same issue and it was my timing. It is easy enough to check that but do so after first setting your points.

Keith

I think tomorrow ill check around for a vacuum leak and also check the timing. Since I just got it and don't really know what is what on the car just yet I have been driving it around to see what is needed to be done.

Vacuum leak is first.
Clean the advance plates and re grease them inside the distributor....they stick in place as the motor gets hot and it produces exactly what you are experiencing.

Clean and reset the throttle position sensor.

Clean throttle body, make sure return springs are all setup properly.

Those things all will make idle get funky.

I would suggest you do the distributor cleaning first.....it's easy, cheap and after 40 years , it's due.....and it works wonders for 0.05 cents of grease.

Noticed in you description that this happens after you get off the highway, and no description if it does it when the motor is cold.

That would lead me right to the distributor cleaning.....it's the heat

Also, check the throttle cable for being too tight. It likes a little slack.

Alright so after checking out the distributor I have realized it's almost a brand new unit, so I have crossed out that possibility and did some more searching for the vacuum leak. I came across a line going from just below where you add the oil in that leads to the throttle body? (pcv?) I noticed that it was kinda loose and had previously been messed with but i was able to connect it and keep a seal so hopefully thats the end of my problem. I wont know for sure though until I take it out later to day on my way to work. (fingers crossed)

so after all my attempts today was a failure :/ i think i found the faulty hose and i tried to mend it for a quick fix with gasket sealer and its still idling high when up to temp. its the hose going from the decel valve to the air filter right next to the throttle cable.

You can try running without decel valve. Just block off connections with vacuum caps. See what happens to your issue then.

The air cleaner is at close to ambient air pressure, so leaks in the hoses that connect to it should not affect the idle much if any. I would keep looking for the source of the leak.

--DD

The car needs one single vacuum hose connected to the plenum to run.
The MPS.

I remove all the other hoses and plug the plenum at those locations.

Then see if you fixed it...
If so, start adding back ONE line at a time to see if the line is good, or the device is good etc....

Basic troubleshooting.

They sell rubber caps cheap at the local hardware store.

Unless you have an aftermarket distributor, there are no NEW distributors out there....maybe clean ones, maybe painted one, but no new ones.

Rich