jwbeck17

Latest update:

• MAF: I sent the MAF to Louie Ott and he was able to confirm that it was 5% under across the band, so that could have an impact on performance. I got a rebuilt MAF back and installed it today, and overall the idle has improved, but not back to normal.
• TANK VENT CONNECTOR: I was able to get a replacement pigtail connector for the tank vent connector and it is soldered in and connected. All connectors on that part of the loom have been recently replaced now.
• IDLE: Once warmed up, the idle rests around 600rpm (just above the second small white bar under 1000 RPM on the dash). Usually it is a little higher. It stalls out when cold starting, and will stall when off throttle and the AC gets turned on. Acceleration performance has improved since the MAF has been replaced, with car performing as expected under normal acceleration, but has a slight hesitancy under hard acceleration.
• NOTE: Car originally had a catalytic converter however it was removed some years ago. Not sure how the car adjusts the fuel mix in that case, so maybe the idle just needs to be adjusted slightly higher?
• TUNE-UP: I have all the parts to do the tune-up (replace plugs, distributor caps, rotors, coils, spark plug wires, and also hall sensor replacement) but I wanted to see what the MAF would do first.

I have reached out to Stan to see if it may make sense for me to bring her over to his place to look at it and get his thoughts. I am very lucky to have him fairly close by!

RET

Did you disconnect the battery before installing the rebuilt MAF? I understand that the LH needs to forget about the old MAF and lrearn about the new one through a power on reset.

jwbeck17

That is correct. In order for a calibrated MAF to be optimized, LH needs to "relearn" all the settings, and a battery disconnect does that. I did disconnect the battery prior to installing the rebuilt MAF, so it did relearn the settings. It's clear to me the recalibrated MAF made some positive difference in that the idle is smoother, a little higher and hunts less on throttle, but it is still below normal and can stall while cold without throttle or warm with AC on and no throttle.

I am continuing with my tune up process since I plan to do that anyway, as that will eliminate factors such as coils, plugs, distributors, spark plug wires, and am replacing the hall sensor as well. Once I have those addressed and if I still have a performance issue, I'll check the vacuum per Stan to see what that is telling me.

jwbeck17

Latest update...

I had reinstalled the MAF, completed the full tune-up, replaced the spark plug wires and was able to replace the hall sensor as well.

In the test after that (after a few seconds for the MAF to relearn everything), the idle was maybe a touch lower than what it originally was, but was very smooth. So that seemed like a win...

...until I started to push the throttle a bit. Once I got it above 2K, the power started cutting and starting again in a cycle about once per second. I guess this is what many would call "hunting".

The other problem I noticed was a little white smoke coming from the hall sender area. I quickly shut the car down and ran over to check. No signs of fuel, or fire or anything, and hall sender looks new. However the cable to the sensor from the injector harness was pretty well fried and broken apart. I suspect that shorted, and probably created the smoke, unless the smoke was the burn-off of the penetrant I used to loosen the hall sensor bolts.

So, I can't say that I have resolved the issue yet. I'm replacing the injector harness next, as that has too many patches and fried points now. Will update further as I go.