The title sums is up. I recently rebuilt the FI harness on my '74 1.8 L-jet. I also replaced most of the vacuum lines.

Now the car idles low and rough. Seems to run rich. Idles rough when cold, and worse as it warms up. Wants to stall unless I give it some gas.

I just reinstalled the engine this past weekend and started it up. After I heard it run, I calmly turned off the ignition and told myself that I would take a a few days away from it, and then tackle it when I was ready...

I'm getting ready.

Obviously, I need to check the vacuum lines for proper routing and leaks.
I'm nervous that I may have a loose connection in the harness that I built, but I really was pretty careful with my connections and routing.

These are the two areas I will concentrate on, since they are what was changed since the car idled smoothly.

I did notice one thing when I had the engine tin off, and that was broken insulation on the head temp sensor wire. I was cheap, and instead of buying a new one, I simply wrapped some tape around the exposed wire. Perhaps it wouldn't hurt to try out a new sensor at some point? I had the engine running today and pulled the CHT sensor lead off the FI harness and the car died immediately. On a related note, I read on a previous thread about an in-line resistor with the CHT sensor and harness. I don't have this. Is this something from the factory, or just an after market "fix" for another problem?

As I tackle this problem, can anyone recommended something else I should specifically look at, or a specific fuel injection component? (meaning, the wiring leading to it).

Thanks,
Bryan

If the insulation is the only broken part of the CHT sender, then the tape is OK. The resistor was only used on the 73 2.0, not the other 914s. Installing a new CHT is a b*tch, as they love to take the threads out of the head with them. Disconnecting the CHT will make the mixture go full-rich, which almost always leads to the engine stalling.

Sounds like you are looking in the right directions, apart from the CHT thing. Check over everything you've touched since the last time the car ran OK. Then move on from there.

--DD

Thanks Dave... God how I hope it's just a vacuum hose...

Quick update...

The vacuum hose routing looks fine.

I just noticed a broken wire on the resistor bank (That silver thing that screws on to the battery tray). It's the connector to wire 51, which leads to fuel injector #1. I'll play around with it more tomorrow. I wish I could do it now, but I live in a condo and I don't want the neighbors to hate me.

Just for grins, when it is running badly, unscrew the oil filler cap.

Does the car run worse? (hint, it should)

If it runs about the same, you have a vacuum leak somewhere. A tough one to find can sometimes be a valve cover. The o-rings in the filler cap can also get old and not seal well. (that crankcase must be sealed tightly for it to run smoothly).

Your broken wire at the resistor pack will more than likely cause some sour running as well.

I'm pretty sure the add-on resistor was for 2.0 914's with the D-Jet, not the 1.8 914's with L-Jet.

Good luck with it.

On the L jet used on VW bugs, there is an idle speed screw. If no change in idle when turned, it indicates an air leak somewhere. Not sure if similar setup on 914, but I suspect it is.

L jet is air flow controlled, so if unmetered air is getting in there, it runs lean and runs worse when it warms up. My bug had the exact same symptoms that were cured by replacing the oil breather connection.