Fuel Injection Help Please, 74 1.8 LJet Options

[SteveL]

OK - this all started a while back with the engine dying after running for a while and getting warm. Extensive troubleshooting followed.
Here is Where I am at:
New SMP Injectors and injector seals.
Connected HF fuel pressure gauge. Fuel pressure is good.
After installing new injectors, it ran good, until I broke one of the fuel injector connector wires while buttoning things back up.
Checked out the harness, and it is pretty questionable, even if I made the repair I could see. So, bought a rebuilt harness from Bowlsby.
Installed FI harness, and while I was in there, I replaced all vacuum lines, including the manifold connector hoses, and intake manifold gaskets.
All back together, now it cranks and gives 3 outcomes:
1: No start at all
2: Fires, runs for a cycle or two, then dies
3: Fires, revs up to about 3k, then dies (throttle action makes no difference)
I have rechecked all harness connections, they are solid. Rechecked vacuum lines, they LOOK correct, but we all know that if it looked right the first time, it will still look right the second time.

Help!!!! I am in MN and only have a few more weeks before the dreaded white crap falls from the sky and ends the season.

[timothy_nd28]

Sounds like a vacuum issue or a dual relay, hard to say. What was your fuel pressure meter saying when attempting to start?
Are you using mechanical points or these newer pointless modules?

Having fuel pressure is a good start, shows the dual relay is kinda working. We need to test the other half though.

With the ignition switch to on and the ecu connector unplugged, grab your voltmeter and test pin 10 to battery post ground, you should have 12 volts. This proves that the ecu is getting the command to turn on.

If so, test pin 10 to pin 5. Then test pin 10 to pin 16, then test pin 10 to pin 17,,, all should show 12 volts. This proves that the ECM is getting all the ground wires.

If all is good, put your meter lead back on the negative battery post, and test pins 14,15,32,33,,,all pins should show 12 volts. This proves that the dual relay is sending power thru the dropping resistor, and testing the current path is continuous thru the fuel injectors and back to the ECM.

Finally, set your meter so that it can measure resistance, keep one lead of the negative battery post, while the other is probing pin 13, report the result. This tests the temp sensor, very important!

Finally part II, measure the resistance between pin one to the negative terminal of the ignition coil, report those findings too. This is an important wire for the car to run, ignition coil sends pulses to the ECM to fire the injectors.


This will help paint a better picture of what’s going on, or at least help isolate the issue. Make sure all injectors are seated correctly. And post some pics of the engine bay.