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Old 07-16-2019, 09:44 AM   #1
240-FAN
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Default Whelp! '91 244 seems to have the chills (shudders!)

Last year, I did a major (for someone of my skill level) project on my '91 244. A lot of you on here chimed in and helped me along in getting my car back together

By the time I had the car buttoned up, I could only drive it for a week, maybe two before she went into winter storage. During that time, the car would stutter and stumble and struggle to accelerate. During that time, I refilled my gas from less than half a tank to full and it seemed to make the problem go away. Based on what I read in older threads, that typically meant the in-tank pump is dead or about to be dead.

I finally got her out and this past weekend drove about 230 miles without any problems. Drove her right till the gas gage was just above "E" and no issues. Filled her up at Costco (where I've been filling up for years) and within about 20 miles of the fill up, same issues.

Bucking, shuddering. Weak acceleration. No CEL up until this point. Pulled the car into a lot, shut her off and unplugged the AMM. She started but shuddered and then eventually evened out. I decided to drive a 1-2 miles like that to back home. About 0.75miles away from home, the stumbling became really bad and I pulled over to the side and shut the car off. It smelt like the car was running lean. I say running lean, because, it didn't smell like gas (which I understand is an indication of it running rich). Au contraire, it smelt mildly burnt.

Plugged the AMM back in and didn't clear the CEL. Drove the car about 7-8 miles since then and it runs fine. However, I cannot clear the CEL.

OBD I codes that are present:
1. 1-2-1
2. 3-2-2

Does this mean that I had a failing AMM and that unplugging it was the final straw?

Side note: For the past year or so, the car would need to be cranked longer on a hot day after it had been driven and it hesitate some before it would have a smooth idle. This specific behavior was present before I did all the work on the car. FPR is a new Bosch unit from last year. 4 plugs, 3 wires (I f'ed up one while doing it) and distributor were new as of 20K miles ago.

Last edited by 240-FAN; 07-16-2019 at 09:49 AM..
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Old 07-19-2019, 01:33 PM   #2
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Anyone?
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Old 07-19-2019, 02:16 PM   #3
ZVOLV
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Define the codes.
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Old 07-19-2019, 02:23 PM   #4
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ooops...here they are:
1-2-1 – Mass air flow meter signal faulty or missing
3-2-2 – Mass Air Flow sensor burn-off signal missing or faulty (MAF wiring fault)
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Old 07-19-2019, 03:27 PM   #5
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Looks like an MAF to me. If you've got a "known good" local to you that you could try, that would be good.

Also, and not related, stop buying the cheapest gas you can find.

https://www.toptiergas.com/
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Old 07-19-2019, 03:35 PM   #6
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Inspect the terminals for corrosion.

Make a tool with spare male pins from a donor MAF and "drag test" the female terminals for looseness.

Confirm power and ground, or skip to below test.

Maybe put a meter on the signal wire (backprobe) and monitor the voltage. Tap on the meter and see if you can get it to glitch.

Or just try another one.
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Old 07-19-2019, 03:37 PM   #7
240-FAN
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I don't have a used MAF, I was going to post in the wanted section under classifieds once that seemed to be the consensus here. My family has been filling up the gas at that Costco for years. They are toptier and cheap. Most other gas stations in the area don't have the top tier sticker on their pumps.
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Old 07-19-2019, 03:40 PM   #8
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Quote:
Originally Posted by ZVOLV View Post
Inspect the terminals for corrosion.

Make a tool with spare male pins from a donor MAF and "drag test" the female terminals for looseness.

Confirm power and ground, or skip to below test.

Maybe put a meter on the signal wire (backprobe) and monitor the voltage. Tap on the meter and see if you can get it to glitch.

Or just try another one.
The second test you list - would you happen to know which wires are what in the connector?
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Old 07-19-2019, 03:59 PM   #9
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Nope. Refer to a wiring diagram. These old Volvos don't have problems with the terminals like modern cars, but it can happen. Red/white is signal, I think. Blue yellow is power.

I had a car recently with and intermittent electrical issue and it was poor terminal tension. I have access to the correct special tools for front probing female terminals for testing the circuit and also for checking for proper terminal tension.
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Old 07-19-2019, 11:47 PM   #10
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Well I'll be damned.
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Old 07-21-2019, 03:10 AM   #11
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Quote:
Originally Posted by 240-FAN View Post
Bucking, shuddering. Weak acceleration. No CEL up until this point.

Pulled the car into a lot, shut her off and unplugged the AMM. She started but shuddered and then eventually evened out. I decided to drive a 1-2 miles like that to back home. About 0.75miles away from home, the stumbling became really bad and I pulled over to the side and shut the car off. It smelt like the car was running lean. I say running lean, because, it didn't smell like gas (which I understand is an indication of it running rich). Au contraire, it smelt mildly burnt.

Plugged the AMM back in and didn't clear the CEL. Drove the car about 7-8 miles since then and it runs fine. However, I cannot clear the CEL.
.
Unclear narrative.
getting AMM codes after running with it unplugged is not unexpected.
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Old 07-21-2019, 10:52 AM   #12
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I guess what I was trying to state in my original post was that after plugging the MAF/AMM back in, I did the reset procedure for the OBD port and I continue to get the 2 error codes listed above.

I’ve unplugged the MAF before (like a year and a half ago) and I was able to reset the CEL by following the procedure, thereby making it go away.
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