Ok, I know I've asked a TON of questions, and probably annoyed some, but here is my latest.

As I said in another thread, I had a temporary elbow on the line, test drove it and the car ran great for a bit and then it ran rough at idle. Almost like it was stalling/miss-firing. When I got home, I noticed that the replacement hose seemed to get kinked and maybe that was why it ran rough on the highway.

I replaced it with an elbow (finally got the kit), took it for a spin and car ran decent. A little rough idle, not as good as it did when I first got the car/before the timing belt/serpentine belt replacement. But I noticed that it was getting worse.


The car still runs a little rough at idle. Not looping, not detonating, just like it's miss-firing. At higher speeds, this symptom is not shown. Also when I test drove it, I noticed that as it it goes from 2nd into 3rd or 3rd into 4th gear (not sure which one) and the RPM's drop below 2000, the car runs a little rough. Above 2000 RPM's and its better.

I also noticed that when I'm sitting in the car, the exhaust/muffler seems to rattle some, but that could be completely unrelated.

Anyways, one of the thing i first suspected (what is now a month + ago) was the coil. When I tested it before, it seemed to be fine. But I think I didn't test it correctly.

So I checked the coil for OHMS again. This time, I unplugged everything from it, and disconnected the negative cable from the battery.

Checked the OHMS on the multimeter (setting it to 2, so it would read as X.000 instead of XX.00, etc). In a thread I found on here, someone said that the coil should read between .5 and 1.5.

Mine read as .225 or .250, depending on if I'm holding my breath or not.

So, could that explain why the car feels like it's miss-firing a bit? The car obviously still starts, but I'm just curious if I'm chasing something that isn't necessarily in need of being chased (the coil).

Again, thanks for all the help you provide, and putting up with my incessant questions. My issues always seem to come up when the shops arent open.
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1985 245. 246K Gone..but not forgotten.

instead of making another of my threads, I want to ask it here.

I checked the fuel injectors for resistance (all were similar), so I'm thinking that's potentially not the issue. So next I was going to re-check the timing. And to do that, obviously, you have to take up the radiator fluid reservoir. When you do that, you disconnect a plug into the bottom of the reservoir. This time, my plug was not plugged in.

What would that cause? My temp gauge works still, so I don't think that's it. I'm going to check my manual now. I can't start the car to see if it runs any different (I have the car taken somewhat apart now).
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1985 245. 246K Gone..but not forgotten.

It was the coolant level sensor. I can't imagine that had anything to do with rough idle.

shozbot.
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1985 245. 246K Gone..but not forgotten.

A bad coolant sensor can caused problems with Idle, the computer does not know how much fuel to add. The RPMS will go high, low, and everything in between>

is that what the plug in the reservoir does?

My idle issue isn't looping or high/low/high/low, it's just rough.

Taking out the #1 plug (I had labeled it #5, due to it's distance from the distributor, but the plug wire is #1) and having the car run doesn't change the idle much.
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1985 245. 246K Gone..but not forgotten.

I am following this thread because I have similar problems. My car is 98 V70R, so most things should be similar

The plug in the reservoir is a switch for the low coolant light; that shouldn't effect anything. The coolant temperature sensor is located in the thermostat housing. That will effect idle. I replaced mine, it made it better, but still a problem.

Have you checked fuel pressure when cold? It seems like the fuel pressure regulator was discontinued my Volvo, wonder where I could get a replacement? Is your idle rough only when there is a cold ambient temperature?

I haven't checked fuel pressure at all, don't have a gauge for that.

The issue with the car has only happened since it's been cold here. And it doesn't change when the car is warm or not.

I liberally sprayed water all around my engine compartment (don't take this literally, I just used a water spray bottle, but made sure to get the intake valve cover, fuel injectors, all of the vacuum lines i could find) and there was no change in the RPM's or how the engine ran.


Have you tried IPD (ipdusa.com) for the FPR? I just did a quick search on their website (guessing at some of the details of your car) and one came up.

I wonder if since the vacuum line TO my FPR was the only elbow i've found that was damaged (and probably had been for a while)...could that have had an impact on the FPR?
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1985 245. 246K Gone..but not forgotten.

When was the last tune up?
What do the plugs and other ignition parts look like.

I replaced the rotor, distributor, cam sensor, plugs and wires (less than a month ago). This symptom started after I changed the timing belt (same time frame) and serpentine belt (the new one actually had to be replaced with the old one..long story short, the new one was too big even though it was the one IPD suggested, and created a vibration).

The #5 plug (furthest from the distributor) is the one that seems to be the bad one. If I disconnect the plug wire from it, the engine doesn't change much, although if I accelerate it is more prominent. The plug doesn't smell fouled or anything bad.

I replaced 3 elbows in the vacuum lines, and initially that improved it. But eventually it returned to running rough at idle.

I'm going to re-check the distributor and rotor today.

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1985 245. 246K Gone..but not forgotten.

Update:

Decided I would break down and buy a new multimeter, since the one I had was an old OLD radio schlack one, and wasn't always friendly.

New multimeter showed that the coil's resistance was .5-.8

So, I can probably cross that off the list.
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1985 245. 246K Gone..but not forgotten.

I am not sure about the coil but check your fuel pressure regulator.

This regulator can lead to some strange behavior like engine running rough, poor acceleration, poor cruising speed. If the FPR is the original, I will just change it!!!

I will look into the fuel pressure regulator. Thanks.

On Matthews volvo page, someone said if it was a FPR going bad, you'd have black smoke in the exhaust. Also, another symptom was gas in the vacuum line (at the FPR) and I don't have any.
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1985 245. 246K Gone..but not forgotten.