Driving home last night in my old, dependable 85 245 wagon, and suddenly a problem arose. Out of the blue, it starts to stumble and miss when accelerating. It will clear up at cruising speed, but under load, it misses and cuts out. I also notice a smell like it's loading up on fuel, not a gasoline smell but almost like the exhaust is plugged. I'm going out now to troubleshoot, and will post any results. Anyone want to hazard a educated (by this board, of course) guess?
Thanks
steve

It's an '85, so don't overlook the possibility (probability?) of a decayed engine wiring harness. If the engine is reasonably clean, you should be able to tell what kind of shape it's in. Most problems tend to occur when the harness loops underneath the engine...so you'll need to spend some time on your back. Good replacements can be had with some searching. Good Luck and keep us posted.

Dee Jay

Yea, this 85 has the wiring harness problems. I've been selectively re-wiring this car for about 2 years...if it breaks, I fix it. The harness under the engine is gone and has been for a while. The more that I drive it, the more that I think the CAT is plugged. The miss is gone, but performance seems to be lacking, and I still have the exhaust smell. I'm going to remove it this weekend and check it out. I have a good used one from a parts car if I need it.
Thanks
steve

What a bunch of great responses. I'm sorry that I forgot to say that my car is a 85 245 wagon, B230 with LH Jetronic. I went out yesterday to hunt the problem and did the following. Cranked car and let it idle, it sounded sort of like a telegraph machine, dut dut, dut dut dut, dut dut, missing ocassionally on one cylinder. As I was cranking, I held the fuel pump relay in my hand, it clicked and the car started, so the ignition module and primary were OK. One by one, I un-plugged and re-attached the fuel injectors. By listening to the idle, I determined that the miss was apparently coming from the #1 cylinder because on cylinders 4,3 and 2 the random miss was still there even with the injector unplugged. When I unplugged the #1 injector, the engine had a solid miss on #1. and the randomn miss was gone. I pulled on the #1 plug wire and the wire (easily) came out of the plug end. It had burned off. I cut off about 1 inch and screwed it back on, re-attached it to the plug, and the misfire problem was gone. It's time for a full tune-up, especially with the gas prices as they are. The exhaust smell is apparently related to something else. I believe that it's probably related to the Cat convertor. Last week I was driving across a cow pasture (It's my work "truck") and a rock flew up and hit the underside of the car. From reading the (very informative) posts, it occurs to me that it could have damaged the Cat and that I probably have a partially blocked exhaust. I will post as I find out. If I could give one piece of advice from all my years of driving and working on Volvos it would be, Look for the simple things first if you have a problem, cause that's likely where you'll find it. Man I love these cars. Thanks for all of the replies.
steve

My first guess would be plugged cat.
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '82 Mercedes 300SD for sale

My guess: may be a lean condition causing stumbling under load. Vacuum leak from loose or cracked hose?
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1980 245 Canadian B21A with SU carb and M46 trans

I had similar symptoms on an '87. The cat innards had come loose and over time rolled themselves into about a 2.5" ball. On acceleration (especially uphill), this cat ball would roll to the rear and block the exit hole. This caused symptoms like yours.

When the ball rolled free, it ran OK till the next time.
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

Trouble under acceleration is a sign of a plugging fuel filter but there are a dozen other things like fuel relay, in-tank pump, AMM, fuses, knock sensor, ignition wires/plugs and more.

Agree, can be as simple as a dirty (carbon deposits) spark plug due to lack of maintenance. Been there, in a 240.

Bad ignition wire or Loose plug?
Crack in the Distributer cap?

When was the basic ignition stuff replaced?
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'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

Mine is doing the same kind of thing, though I have not noticed any change in the exhaust. Sometimes it will accelerate under load with no problem, other times is freaks out and stumbles.

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85 240DL 189k; 91 240 169k

Hmmm...

How about some more details? Is this a fuel injection engine? I think it is, and the problem may be different if it's FI or carburated.

I'd first check the exhaust, as that will cause the symptoms you describe. If it's partially obstructed, it will run OK (but not great) under a light load, but the blockage will cause excessive backpressure at higher PRM's.

I'd shake the muffler and the catalytic converter just to see if either one rattles. This would definitely indicate a problem. Otherwise, try to locate a Cat bypass 'test pipe' that will replace your catalytic converter and let you drive the car to see if it performs properly without that component. You can get by just running an open exhaust as long as you don't do it for too long.

I'd suspect the Cat first, muffler second. You might not notice a change in the sound of the exhaust if the Cat is bad, but a bad muffler should be obvious just by the sound.

The fuel management system is the next thing I'd look at. Fuel injection uses a series of sensors and a computer to control the fuel flow, while carburated cars from the mid-1980's might or might not have a computer.

Your description sounds like the engine is running rich - too much fuel at higher RPM's. Pull the spark plugs and inspect them. Virtually any car repair guide will tell you what the various colors and accumulations on the plugs mean, but dry black soot on the plugs usually indicates 'way too much gas. Wet, geasy black gook is oil, which you don't want to see. Try the smell test; if it smells like raw gas, that's what it is. :-)

You may want to get (beg, borrow, steal, buy) a code reader if you need one to determine what error codes the computer may be trying to tell you. I'm not familiar with your car's system, but generally the 1980's cars used the OBD-II code system. A reader for OBD-II costs about $39 at www.harborfreight.com.

Find out what system - if any - you car uses and read any codes in the computer. Some GM cars would flash the 'check engine' light when you jumped certain computer terminals with a paper clip. I still keep a paper clip in my tool box! ;-)

Another problem you may run into - although it would cause the car to stumble and stall at low speeds, not high speeds - is the fuel pressure regulator. Again, it's not a likely suspect, but something to keep in mind.

*Check your fuel filter!* a clogged fuel filter will prevent higher flow rates of gasoline, so this my be your quickest and cheapest fix. If you can't remember when you last changed it, it probably needs replacing anyway.

I'm sure there are many others here more familiar with your particular model, so you should be getting a whole lot of help real soon.

Good Luck! Steve, Ridgecrest, CA. (Just southwest of Death Valley)

I thought OBDII was a mid-90s system - there's no code reader for any LH system up to LH 3.1 that I'm aware of... though 2.4 & 3.1 had a form of on-board self-diagnostics. Was there some scan tool for LH2.2?
I don't believe Volvo used any sort of ECU with the carbureted cars for the North American market. I've never seen or heard of one, anyhow, but I'd certainly be interested to hear about it if there was one that anyone's aware of.
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Chris, Dartmouth NS Canada 70 M-B 280SE, 83 245DL, 84 244 turbo, 90 780 turbo, 92 VW Golf, 90 740 Rex/Regina