Wow this thing is frustrating me… I just finished working on the engine, Doing the heads and fixing it up a little. Now that I have it all put back together everything sounds pretty much alright, as long as I don’t want to idle.

When I first got the engine back in the car it started right up (that god) but the idle was at about 1800 RPMs just a little too fast… I knew that I needed to do the timing on it, so I did that, there was a little red line on the fan that is what I used to time it, is that correct it looked about right. But The engine seemed to run a little rich…. Ok so I have been adjusting the intake air-flow meter, and the screw on the throttle body, but to no avail. Now the engine just plain WONT IDLE, it might start up for a little, maybe 10 seconds and than poof it dies. Now if I start it, and rev it up it sounds great, I can rev it all the way up, and I can even hold it up at lets say 2500 RPMs and it will do that just fine, but the real problem is that once I let it go back down to idle it slows down, and than poof dies at idle…

BTW on both the throttle body and the intake meter which direction dose what on those two screws?? And are there any other adjustments available?

And one last thing… there are 3 white wires that come from the EFI set of cables that are not connected to anything, and I can’t figure out what they should be connected to, I have the tach wire to the (-) of the coil, and those 3 orphans are just lost!

I unpluged the the decel-valve, and that seened to help...


Thanks for your help!!!

i nominate this thread for 'Classic' status ...

sorry i can't be more help.

the Haynes and Lash manuals don't have a lot of information of the L-Jet, but there is some.
the Haynes manual and the Pelican Parts technical site have wiring diagrams for the car that will help you track down where the wires go. we have a very active community in your part of the world and if you're willing to meet the people halfway, i suspect you'll get all the help you need on getting it running again ...

good luck.

I have a 74 1.8 too, and the 3 wire you are asking about are orphans on mine too.
2 words of advice: Vacuum Leak

Steve

Yes... vacuum leak is a possibility. You can spray something around to look for vaccum leaks (somebody help me out with what the safest spray solution is)

Also, check the boot for the airflow meter to throttle, that it isn't cracked underneath.

Check the resistor pack for broken or cracked wires.

I remember seeing a white mark on my flywheel, but a previous owner may have marked it.

Check to make sure the distributor is clamped down all the way.

Is the idle rough only at startup and it eventually gets better.

You may have the air flow meter adjusted wrong (too lean). There is a fine line betwen adjusting the AFM and the throttle bleed scew properly.

Ummm... that's about it for now.

Check all of your plug wires. Are they in the correct firing order?

Question for you:

How did it idle before the head work?

If it was good, then you have a vac leak.

It is amazing what a tiny hole can do to fool the system into thinking it's running rich, lean, fast or slow depending on size/location of leak.

track down and eliminate all " FALSE AIR ".

best place to start: manifold sleeves and old braided vacuum lines. Check that injectors are seated.

I always use Permatex brush on form-a-gasket on all surfaces. Not only does it seal out the gremlins, but; it acts as a lube when installing new hose parts.
Permatex can be messy. so have a little acetone on a rag handy for easy clean up.

I have a spare AFM with air box/boot and brain from a'74 1.8 if you need them.

Kill the leak!

trekkor

I would also agree that it sounds like a vaccuum leak. You just had your heads worked on? Check the breathers at both heads to make sure they aren't leaking. My 1.8 (when it was a 1.8) had a loose breather tube in one of the heads and would leak (until I sealed it). Another often overlooked place (on my car) was the oil filler. The crankcase has to be sealed. Check the O-rings in the Oil filler cap. Also make sure the valve cover gaskets are sealing well.

You could also try something.... Try running it at idle but manually hold the air flow meter open and see if it could be the airflow meter shutting off the fuel pump at idle. If you have a massive air leak, it could be possible that the air flow meter isn't sensing enough airflow to keep the fuel pump running at idle, causing your car to run out of gas.

Bypass screws:

On the air flow meter, there is a bypass that lets air into the intake without going through the measuring part of the AFM. The adjustment screw plugs that opening. So when you unscrew it, it lets more unmetered air in, and the mixture goes leaner. When you screw it in, it lets less unmetered air in and the mixture goes richer. Generally effective only for idle, but may have some small effect off-idle.

On the throttle body, there is a bypass that lets air into the manifold without having to go through the main bore of the throttle. Air can "go around" the (closed) throttle plate that way. The adjustment screw plugs this hole. So when you screw the screw in, less air goes around the throttle and the idle RPM drops. When you unscrew it, more air bypasses the throttle and the idle RPM goes up.

--DD