1975 1.8L with original L jet injection. I solved the fuel pump issue, yellow wire on terminal IV instead of III. The car started and ran. I let it warm up and shut it off to checked for leaks. Went to restart it, the starter cranks but the engine won't start. I let it sit for 10 minutes and it starts. Let it run for 5 minutes, shut it off and it won't start. What should I be looking for???

This exact thing happened to my car a few years ago. Go out in the morning, or any first start of the day, and it would start and run fine... park it, go into a store then come out and it wouldn't start.

IIRC it was the Cylinder Head Temperature (CHT) sensor. I had my mechanic replace it (Rich Bontempi) and it was all fixed!

mine was also a '75 1.8 L-jet.

-Peter

As said, CHT or fuel pump check valve is leaking, not holding residual pressure in the system for a period of time.

That is located on the passanger side under the engine tin. Can I remove the tin and replace the sensor without dropping the engine?

13 mm socket with a groove or part of the side ground out for the wire to fit through. No need to remove tin. A pain in the ass due to location, but it can be done.

I cut the corner off a 3/8" extension. Cheap and very easy. I think you need to use a deep socket.

yes a deep socket helps a lot, if you get a long enough socket, the pigtail wire can hang out the end and you might be able to turn it with a vice grip, else grind a slot in the sockets side to let the wire hang out.
I strongly suggest liberal use of penatrating oil the day before, they can get stuck, and I have had one where teh senodr top twisted off, leaving the threads behind!!

us anti-sieze on install

ps often the wires fails intermitantly breaks in insulation cause shorts, or open wire stands cause opens. these can be reapired often!!!!!!

I had a bad cht once that I could pull the wire taught and it would run great. Let the tension off the wire and it would die. I tied a string around it and tied the other end off to something, pulled it tight and drove it that way for several months before replacement.

you can oft re-solder teh broken wire usually breaks near the sendor. if insulation fails you can oft slip some sleeving over teh missing insulation. you may need to cut teh crimp on the sendor back a bit, use a fine hack saw blade.

after repair or when installing a new sendor, go ahead and add some extra shrink sleeve opver teh pigtail wire to the top os the sendor, shrink it down then add a second sleeve over that, this will act like a strain relief and prevent flexing of the pigtail at the sendor, (this is where the wire often breaks)

This fix can save you some money. I have repaired wires/or insulation on numerous sendors