I have an 84 GL that I am debating what to do with. I just had my mechanic check it out. The only major thing it needs is an AMM. I tested it myself with the Haynes manual test. Resistance between pin 6 and 7 is supposed to be 3.5 to 4 ohms. My tested 4.5. The other test is pin 6 to 12, which is supposed to have a resistance between 0 and 1k ohm. Mine registered 980. The car had been off for about 10 minutes. I don't know if that matters or not. Anyway, does anyone know if the 4.5 ohm reading is enough to mean the AMM is actually bad? I happen to have another 84 240 I'm not driving with the same AMM. Is the switch easy? How delicate do I have to be? If I decide to buy a replacement, should I just get a used one? I thought I heard someone say the reman ones are not a good idea. Does anyone out there have any experience with that? Is there a more thorough test that can be done in a shop?

Any input appreciated.
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Tack så mycket - Ben

Does the car run ok? Usually when the AMM is bad the car won't run or start. If you have a lot of intermittant hesitation at highway speeds that could indicate it is going out, provided: you checked the ignition coil, spark plugs, spark plug wires, distributer cap and rotor. AMMs are expensive (around $200). i wouldn't worry about the increased resistance between the two pins on the connector. It's not that far out of spec. If you're not having any problems, I wouldn't worry about that reading.

Make sure the fuel system is clean. I clean mine every two months by runnin it down to less than 1/4 tank and add 5 cans of injector cleaner (cheap stuff is just as good as name brand, shouldn't cost more than $5.00 total) to the tank. I drive it around till it's almost empty. That high concentration of cleaning solvent won't harm anything but it sure does get the system clean. If you've never done that before; give it a try you might be pleasantly surprised. Stay away from the cheap no-name gas (in my experience Volvo is pretty fussy about what you feed it)....most of the time it's OK but; when it's not, it's not! I'd replace the fuel filter (around $15.00) also if you can't remember when you did it last.

The service record of the car is largely unknown. I bought it last summer for ninety dollars ($90). I only started driving it about a week ago. Its not even registered. The paint is great. The body is too with the exception of a small dent on one back door. It had brand new tires, radiator, brake discs and pads and a few other things. Its got all the GL stuff. The power windows work, the CC works, the sunroof works, etc. The AC does not work but I don't really care. The rear defrost does not work but I think its either the switch or relay. It even had brand new tiger print seat covers still in the box! Anyway, the car ran but had a shot transmission. AAA got it home for me. I put an AW70 in it from a turbo with only 130k on it. I did the rear main seals at the same time. I grabbed the sway bars too. Other than that I changed the oil. That's it. As far as how well it runs, it purrs once its been running for about a minute from a totally cold start. When its cold, it cranks over, fires right up, then rpms drop immediately and usually stalls out unless I give it a bit of gas. If it doesn't stall and I don't give it gas, it revs and drops between about 400 and 1500 rpms for about a minute. Any idea what that might be? I suppose I should do the cap, rotor, plugs, wires, and fuel filter before I get much farther. I'll probably wait on the fuel filter because its such a pain. I had an 82 which has the filter in the engine compartment. I wish they kept it there.

Anyway, thanks for the response.
Ben
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Tack så mycket

This happened to me. I found a wire that was missing insulation and was close enough to a sharp bare metal edge. The wire is yellow with a blue stripe. That is the power line for the fuel injectors. Look at the connector in the center of the firewall that leads to the injectors. Find the yellow and blue wire and follow it down thru the harness. It exits the harness jacket about 6 inches forward of the starter and is connected to a terminal on the starter solenoid.

My first fix was "temporary"...i just bent the wire out of the way. But I still had cold starting probles when it rained or when the dew point of the atmosphere is the temperature of your engine compartment causing enough condensation to get everything wet. When I thought that one thru; I reinsulated that wire and my cold start problems were cured. When it was wet under the hood the dirty water created a temporary intermittent short to ground which seems to confuse the computer. When I was still having problems I found that if I shut the car off I could restart to a perfectly purring engine. What had happened was that the condensation had dried up but the computer couldn't reset its self. Now I'm restarting a warm DRY engine to a rebooted computer that configures fuel needs, ignition timing, automatic transmission shift points correctly now.

You (we) need to take a good look at the wiring harness in any car over 5 years old. There are many places where the harness is directly over a sharp edge. Many of those areas can be corrected by bending the harness away from the sharp edge or pulling some slack from both sides (just a little) and slip a piece of rubber innertube secured with a hose clamp in that area with the hose clamp now in contact with the sharp edge. Inspect the harness for damage also and repair as needed. If you must splice a wire I would suggest soldering above a twisted connection (which can corrode and take voltage from the intended component...maybe even the ECU.

The worst areas for wear and tear are where the harness begins at the alternator and on around to the starter.

Yeah wiring harnesses are always fun. I rerouted all the wiring that goes under the crank pulley on my other 240. I don't really have a feel for whether or not it improved things because I did it before I really started driving the car more than around the block. From the looks of what I pulled off, I can't imagine I could have made it any worse.

"If you must splice a wire I would suggest soldering above a twisted connection"
-Always

Thanks for the tip. I will take a look at the yellow and blue wire.

Ben
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Tack så mycket

hi
maybe it helps. yesterday i replaced a faulty AMM on volvo 480 with LH-Jetronic. car refused to start and if was working, had very rough idle and bad rev-up. these numbers from haynes were better than yours (that 3 ohms), the other value depends on co potentiometer, which is built in the AMM. about AMM you can also read here in 700 FAQ. good luck!
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i prefer non-german cars