Well dang it, guess it wasn't the Ignition Control Module -- got a "good used" one, and the car seems to run exactly the same. I suppose the chances of it being in exactly the same condition as the old one are pretty slim...

What I believe I've figured out so far: it runs fine until it gets good and warmed up, then often hesitates (sometimes severely) on acceleration, and often dies as soon as it gets near idle speed. When it dies or I shut it off, then start it again, it runs fine for a little while again before it starts hesitating again.

WTH???

thanks
Joy

Well, now the OBD is chock full o' codes, and the check engine light is still on. Maybe I wasn't understanding the different tests...
in #2:

1-2-1 - Bentley says fault in signal to/from AMM
1-1-3 - fault in fuel injectors
2-3-1 - fuel system compensating for ... mixture

So I guess the first thing to do would be replace the AMM ? Anybody have a good used one for a reasonable price? the last 3 on this one is 020. Or found a good brand for a new/rebuilt one? I paid the ridiculous $300 for a rebuilt one from the local Volvo shop a few months ago, for my other 240, and am currently on the third try... (supposedly has a three-year guarantee)

Before you spend any money, momentarily pull the 25A blade fuse at the left fender, under the hood. That will completely reset the ECU. Give it about 10 miles of driving to see if the code(s) come back. If you get a repeat of 121, remove the AMM connector and inspect for corrosion -- especially if the rubber boot on it is ripped. Clean it. Repeat the reset and 10 mile drive. If 121 persists, get a spare or trade an AMM from another 89-93 LH2.4 car. An 89 should not have an 020 AMM, it should sport an 016* AMM. If you need to buy one, get one used from someone who says they've run it in their car to test it.

*The only exceptions I know of are for a manual shift LH3.1 car (-001) or a genuine Bosch replacement unit (-101)


--
Art Benstein near Baltimore

Two antennas met on a rooftop--, The wedding was O.K., but the reception was great!

Thanks, Art! I should know by now that these old cars very often have had the wrong parts put on them...

After poking around the interwebz, I decided to try the 007 AMM from a car I no longer have. So far, so good...

Check the resistance on your negative battery cable. You'd be surprised how often something so simple can cause something that seems impossible to troubleshoot.

Best,
Afton

'68 220; 88 & 92 245s; 98 XC

Have you considered a piece of the cat is loose and plugging the exhaust? It can be a pretty variable effect as it bounces around in there. You can remove the plug from just upstream of the cat to test it.

I am not really sure what you replaced but the ICU rarely if ever fails. Certain ECU's however are know to be problematic.
Dan

Are you sure that the thermostat in the Air filter box is functioning?
I'm thinking that you are getting Hot Exhaust air through the Filter and into the AMM.
Disconnect the Silver Hose from the Exhaust manifold to the heater box and see if the problem persists
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/

Could be a catalytic converter problem, the innards will will begin to fail and bounce around until it takes the shape of a ball and then will position itself in a way that clogs the exhaust until you shut off the engine at which point it rolls back out of the way. Do you hear any rattling when you shake the exhaust?

This sounds like a failing pink label ECU (in front of the passenger side front door). Locate a white label ECU and replace the pink one... problem gone.

jorrell
--
92 245 317K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently being enjoyed!

The ECU sure has a pink label on it - 3 517 407. What number ECU will work on '89 B230F?

I replaced the ECU on my '83 with a "better" model of used one, and it didn't make any difference. Well, that turned out to be the AMM. Or something else, don't remember.

The ECU would have the last 3 digits of 561, if the engine runs I don't think this is the problem.
Dan

Did you use a heat sink thermal paste when mounting the power stage?

Is the throttle body and idle air control valve clean?

I had a hesitation that turned out to be a failing AMM.
Dan

Yep. The original ICM had been removed from the heat sink to have the corrosion cleaned off the contacts, and I put new heatsink compound on there.

Did yours run fine for a little while every time you shut the engine off and re-started it? The last few days, when it starts hesitating, and I turn the key off and then right back on within a few seconds, it has normal power for a few more minutes. Took me awhile to figure out that's what was happening. It doesn't always hesitate on acceleration, and it doesn't always die when it gets down to idle speed.

No mine just hesitated momentarily just as the gas pedal was push at cruise speed.

Do you get any OBD codes? Pull fuse 6 to reset codes and adaptive settings in ECU.

If the engine runs it's not likely a problem with the ECU.
Dan