Still no start

[Jay Kempf]

1991 20VT avant 220k miles.

Still working on the problem where it quit on me last year. I dug under 
the intake and refreshed the ignition system with new cap, rotor, wires, 
knock sensors.  checked all rubber that contains vacuum and /or boost, I 
rebuilt that bracket on the firewall that had all the bloody connectors 
stuck on it so it is perfect and rust free now and all is connected I 
think perfectly. I haven't moved the distributor since it quit and it 
was running fine with it in that position.

Just got blink codes 2121, 2112, 2111   Idle switch fault, G4 Timing 
Reference sensor fault, and G28 RPM sensor fault. SJM says to possibly 
ignore 2112, 2111 if you don't do the test running which I can't. The 
idle switch will mess with the injector output tests because that's how 
you cycle through the codes. So I did output tests and have no evidence 
of injector firing even though it cycled through all the codes. Never 
heard or felt any injectors clicking 5 times. The rest of the ouput 
tests were fine.

I ran the fuel pump off of a jumper and tried to start with the jumper 
in place of the fuel pump and nothing.

Checked coil input and outputs, all wires for correct resistance, all 
good. Plugs, relatively new in terms of miles.

Checked for fuel pressure at the rail while jumper was on and you could 
feel the pump slow down against the pressure and there is certainly fuel 
in the rail under adequate pressure.

So what am I missing. The idle switch won't stop it from running. The 
ECU is reporting properly and I swapped ECUs with someone a while back 
when I thought there was a running problem and no change so I am pretty 
sure my ECU is functioning properly.

Both timing reference and RPM sensing will keep the engine from knowing 
it is running, correct? So I guess I should go back and test that stuff. 
Still have to do basic coil output spark tests but I am solo today.

I am running out of things to check. I am starting to guess I need to go 
continuity checking harnesses looking for which wire which rodent ate. 
Frustrating.


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regards,

jfk

802 272 5868