270 ohm resistor, whats it for? Options

[orange914]

When an MPS goes bad, nothing works. They are either working or ruptured. Small leaks can develop, but they immediately affect all modes of operation. The car may not even start. Should flood out if the MPS diaphragm ruptures.

The CHTS is also critical, and a broken one will prevent starting at all times.

The AAV could be bad and it would mess up idle until the car is warmed up, but it will be hell getting there, and the idle will be at 2500.

Any exhaust leak will push idle up and ruin acceleration, and make it run rich.

You should be able to be no more than 3 clicks off of click 11 on the idle adjustment on the ECU. There are 21 total clicks, 11 being the dead middle. I am 3 clicks counterclockwise to lean, but then again, I have an out of spec 017 CHTS that gets replaced this week with a 1200 ohm at 70 degrees ambient working CHTS for a 73 2.0L.

You have to go one by one through things like dwell at 50, .017 point gap, dizzy timing (27BTDC at 3500 rpm), all intact vacuum hoses, no ignition wires near MPS, a working AAV, decel valve working and hosed correctly. No split elbows into the throttle body, a correctly set TPS, plugs at .026 and all grounds working.

And then the right FPR setting at 30PSIG.

Each item contributes to rich/lean and acceleration. Especially no plug wires near the MPS. The coil in the MPS is sensitive to plug wires too close. I was a victim of each of the above, and the MPS one was a shocker to see the difference when I moved the 3 plug wire under the intake pipes away from the MPS.

Good luck!

John

wow, good pointers!

[avidfanjpl]

Thanks! These are things I almost have tatooed in my brain at this point 16 months after getting my 6th 2.0L in 35 years.

They are just plain hard to come by nowadays, and everyone thinks theirs is worth 25K.

Not yet, anyway.

All the tips were painful to learn. Maybe I can save some people some trouble?

I love the 2.0L, but even that love is not unconditional.

I have lots of pain to prove it. Especially my right lower back.

John

[Bleyseng]

When an MPS goes bad, nothing works. They are either working or ruptured. Small leaks can develop, but they immediately affect all modes of operation. The car may not even start. Should flood out if the MPS diaphragm ruptures.

The CHTS is also critical, and a broken one will prevent starting at all times.


John

with a blown MPS you can still start and run the car but it will be running really rich as the core is pushed against the WOT stop.
with a shorted out MPS nothing works
with a dead CHT the car won't start as its too rich, smell the raw gas coming out of the tailpipe.