Engine Not Running Right, Appears to be running on 2 cylinders?? Options

[LotusJoe]

I removed all the tins and blower case to clean the cylinder fins and head fins, and replaced the oil cooler seals. I also changed the plugs, points, rotor, cap, and plug wires. Put everything back together and started it up. Set the timing and the engine appears to run correctly. I got out my Raytech temperature gun to check the exhaust pipe temps at the head. Cylinders 1 and 3 run about 450 degrees at the exhaust pipe where it connects to the head. Cylinders 2 and 4 are running 140 degrees. This tells me there is no fire in Cylinders 2 and 4.

Not sure on where to start checking. I'm thinking 2 and 4 are not getting fuel? Could there be a problem with the control module in the bottom of the distributor? If so how do I check it? A few months ago I did a compression check and got 165 on all four cylinders. Engine idles fine and revs smoothly. It's on a test bench so obviously there is no load on the motor. Would it run smooth on just cylinders 1 and 3?

[Dave_Darling]

The injectors are "banked" 1&4 and 2&3. Each bank is controlled by one of the trigger point contacts.

Are the front and rear injector wires swapped on one side? You can find pin numbers on the wires, at least near the ECU connector, and you can also just count the pins on the connector. If there aren't numbers on the wires near the injector, you may need to pull the connector off the ECU and check which wire is plugged into which injector.

If it's both front cylinders, I'd suspect a cam problem. (IMG:style_emoticons/default/sad.gif) Check the compression to see if those two cylinders have much lower compression than the rear two, if so I would definitely suspect the cam.

I believe the injectors are grounded with 1&2 together and 3&4 together, so a ground issue would not fit your case unless someone has rewired the FI wiring harness.

Oh, another possibility, especially since you were just mucking around with the ignition system: The distributor cap might not be on correctly, or the ignition points might be messed up somehow. It's often worthwhile to go back and re-check everything you touched since the last time the engine ran nicely...

Check the compression, verify the wires, and get back to us.

--DD