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Old 03-15-2021, 10:16 AM   #26
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Join Date: Apr 2009
Location: Peoria, IL

Originally Posted by 84B23F View Post
Find an automotive multimeter

The air mass meter depends on the measurement of current flowing through heated wires to measure air flow. It is also known as the hot-wire sensor because of its heated wire design, hence the "H" in LH. In the unlikely event that a wire should break, the warm engine runs, though without fuel compensation, in a "Limp-Home" mode. For "Limp-Home" operation, injector pulse time is fixed. For any rpm above idle, the ECU is programmed to deliver fixed pulses, typically 7.5 milliseconds.

I don't know if this could be measured with Infrared Thermometer

The LH hot wire is found within the air passage tube of the air mass meter and is made of a platinum filament. The hot wire is heated to a specific temperature differential above the incoming air when the ignition is turned on (the differential is measured in degrees Celsius).

LH 2.2, aluminum: 212F (100C)
LH 2.2 and LH 2.4, plastic: 248F (120C)
LH 2.4.1 and 2.4.2, plastic: 311F (155C)
Thanks for the continued assistance! I will check that out and report back. I did notice last night that the 2.0 AMM (002) does have a broken wire. I know it wasn't broken previously, but maybe it was already cracked or just on the verge of breaking. That would explain what was happening when I was using the 2.0 AMM/ECU.

I ended up taking the AMM, intake tube, and throttle body off last night and found a lot of oil or gas/oil in the intake, intake tube, and throttle body. It was puddled in the bottom of the intake and in each corrugated section of the intake tube. Looks like I will be cleaning my flame trap as well...
Lord Volvomort - 1984 244 GL - 175k and stock as a rock at the moment

Last edited by yugo4life; 03-15-2021 at 10:45 AM..
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Old 03-15-2021, 11:29 AM   #27
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Join Date: Feb 2008
Location: Kansas, USA

RE: cleaning my flame trap as well...

Cold weather and short miles may be related....but rings do get sludged, and stick.

1. 5w-30 Dexos2...every 1,000 miles change oil and filter several times

Stronger Method

2. Johnson/Evinrude/OMC Engine Tuner (0777185)...get engine warm, remove sparks, rotate crank so all pistons are down, then add to each cyclinder...let sit for say 1/2 day...slowly rotate crank in case fluid comes out...install plugs, fire up with higher RPM. May have to replace plugs and O2 sensor. Note - Don't get it on paint/etc...just in cylinders.
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Old 03-20-2021, 10:18 PM   #28
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Location: Peoria, IL

Final verdict.....bad AMM. Well, 2 bad AMM's actually! 2.0 had a broken wire and was running very rich, 2.2 physically looked good, but was running lean enough to cause a stall when load was applied. I installed a new Spectra unit and it runs better than it every has before! Naturally, the new fuel pump, filter, cleaned IAC valve, new vacuum hoses, O2 sensor, and corrected timing didn't hurt either! I know I have read bad reviews about the refurbished AMM's, so I will keep an eye on it and probably buy a good used OEM one as a backup. Thanks for all the help!!
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Old 03-21-2021, 06:47 PM   #29
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Location: Duvall, WA

That would do it.


1982 242Ti - black, M46. 1985 245Ti - blue, M46 - soon to be for sale.

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Old 03-22-2021, 01:47 PM   #30
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Location: NW WA

Thanks for the update, and good job resolving your issue. Makes me wonder if my “good” AMM is bad also.
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