I am trying to chase down vacuum leaks and get my car to idle proper and run well.


It is a 1975 California spec l-jet 1.8l

1st question, what is the big vacuum solenoid next to the EGR that goes from the auxilary air regulator feed on the intake boot from the flapper AFM over back to the intake manifold?

What does it do? It has a small 4mm or so vacuum feed on the other side of the two 1/2" inputs.

Is this necessary for anything? I believe it is a vacuum leak and I would love to eliminate it and plastic weld the fitting in the intake boot to keep it from leaking and eliminate more engine bay clutter.

How hard is it to change the intake manifold, injector gaskets with the motor in the car?

Sounds like the decel valve from your description. I removed mine, put a rubber stopper into the boot to plug it up. The manifolds and injector gaskets can be r/r with motor in the car.

I later installed a vacumm gauge in the engine compartment to watch for leaks. The vac line from the gauge can go directly to the plenum or T it in.

Thanks man. What does this do exactly? I am having an issue with my idle hanging at 2krpm then SLOWLY coming back down to 1k.

I tested my l-jet throttle switch and it seems to work fine when the throttle chagnes states from open to close to wot.......

I'm in MD but acquired a nice CA car. Trying to get it sorted out and running right stock motor and etc.

Could be the EGR valve as well. Check the diagrams on Pelican; the 75 1.8 shows that too. Can be capped off as long as you get all of the places it hooks into everything.

How is the advance mechanism in the distributor working? That can cause these sort of symptoms...

--DD

I went through the same thing. Ended up removing the decel and erg. So only the AAR and fuel pressure were still attached. If you don't want to remove the ERG and Decel, just undo the hoses and use rubber stoppers ( not cork ! ). This will eliminate several potential leaks. Try giving the real small hoses a sharp bend; they are sometimes the culprits and not readily detectable as leakers. If they are brittle and break--well, you know..

Once you get it straightened out, the L-Jet is very reliable.

I went through and replaced a bunch of small lines, added hoseclamps and zip ties to the 3-4mm lines, etc.

I am pretty thorough, I daily drive an 01 GTi with a 3071R Garret turbo, so I deal with the vacuum stuff as properly as possible the first time.

It is much better, but still has issues.

The advance mechanism was ok, I had the distributor out to install a hot-spark unit to get rid of the points. The car gained some mid range torque after that, a timing adjustment and some teflon tape on the idle screw and an idle screw adjustment.

The issue happened both before and after the changes made, but it is much less now that the changes have been made and more leaks fixed.

Come to think of it though the advance could be hanging, It did change and come back quick when I turned the distributor.........

After getting all the vac leaks fixed and timing correct, the 30 year old distributer was a weak link. Fortunately, you can replace it with a Mallory Unilite. You will get better idle, consisyance performance through the rpm range, reduce heating, and pinging. Everything else has to be working right first, of course. Chris a Tangerine Racing--a member vendor-- sells them and sets them up for the 1.8 L jet. Not cheap, but a quality unit that will make driving the 914 more pleasurable.

This is a good resource for L-jet troubleshooting: http://manuals.type4.org/ljet/