Just developed a badly running 1974 1.8 l-jet. Took it for a 4 hr drive and it ran better than in a long time until almost home, then seemed to have no power and running on 3 cylinders. Started to troubleshoot the next morning and all was fine again until it warmed up, then back to running badly. I first suspected the CHT sensor (even though I had just replaced it two months ago); to check the sensor I did an ohm check and it tested normal. I then warmed it up and got it to the point where is was running badly, disconnected the sensor and ran a ground to the ECU lead....ran just like before, badly. I'm at a loss and any suggestions are welcome.

Here's what I've done to fix to this point with out any luck:

1. New plugs, wires, and distributor cap
2. Timed to 7.5 BTDC
3. Adjusted valves
4. Fuel pressure at the injectors is 37 psi at idle
5. Compression test: 118, 119, 120, 121

Thanks in advance for any response

Greg

Have you tested each individual injector for spray pattern?

BTW

I am also in Clovis & have an L-jet car & would be willing to help you tinker.

I've experienced the same in my '75 L Jet and it's been one of the following:

1. A loose hose connection from the oil-breather to the TB boot; but could be any hose that goes to the plenum or TB boot. Sometimes the smallest hoses are the worst; try bending one of the small hoses between your fingers....A crack in the TB boot is very hard to see and will cause a problem. I've had to repair mine once; used a wet-suit repair kit from a dive shop.

2. Second thing is a bad connection at the base of the dual relay. But that usually shuts off the fuel pump entirely and the engine stops running all together

3. Check the resistor pack. A bad wire can cause irregular firing. If you have a broken wire there, you'll need a HD soldering iron.

I'm sure others will chime in, I just tried to relate issues I've had.

Check your injector spray patterns and the electrical connections for each injector. Could be that one is cutting out when your engine is at running temp. My car showed similar symptoms when I had a bad electrical connection at one of the injectors. Also, check your injector resistor connections and resistors near the ECU. Hopefully more knowledgeable members will be along shortly to provide their input.

Good luck.

-S

Ed: Looks like Jim posted similar suggestions at the same time.

My 75 1.8 would run fine....then randomly run like crap....when it ran like crap it wasn't firing on all cylinders (did the remove the spark plug wire test). Turned out to be loose connections (old wires) on the injector connectors. When yours does start running like crap find the cylinder not firing...check the injector connector (I actually could wiggle the wires going into the injector connector and get it to work).

PM me your e-mail address and I'll send you a PDF of the factory L-jet troubleshooting manual. Be forewarned it's a big file, so use an address capable of accepting it. I only send it once, 'cause I have better things to do than try repeatedly to transmit a free document.

The Cap'n

L-Jet trouble shooting manual online.

VERY comprehensive.

http://manuals.type4.org/ljet/

.....Go over timing again?