'90 Accord EX: Vibration when engine at load

[1BadBoy]

I have a 1990 Honda Accord EX. I bought it new, so I am aware of the things that have been done - everything maintenance to this point. About 15 months ago or so I noticed a very pronounced "miss" (at least that's what I thought at the time) while going up a hill. However, for a long time after, it would come and go - mostly go. Lately, for the last couple of months, it has gotten so that it occurs much more often than not.

The strange thing I realized today, after doing a complete tuneup, including timing and measuring the compression on all cylinders, and then having the fuel injectors cleaned last week, is that the "miss" seems to increase in rhythm as the car speed increases (today was much more pronounced than usual). It made me wonder tonight if it could be something mechanical. Such as possibly the drive shafts (CV joints?) or something in the engine/transmission area (motor mounts). The car runs smooth at idle and when going down the road at a steady speed - at least if not accelerating. But if I start to press the gas or have to climb a hill, the "miss" gets much more noticeable. It can get really bad if the hill is big enough.

Does anyone have any thoughts about what could cause this?

I have changed the plugs, plug wires, cap, rotor, fuel filter and I have the fuel injectors cleaned last week. I even checked the compression of all 4 cylinders. The highest was about 138lbs with the lowest at 126lbs. There was another at 130lbs and one at 134lbs. All within an acceptable range I think. I was next considering replacing the coil as I was convinced it was a "miss" in the engine. However, tonight when I took the daughters for haircuts, the engine missed the whole way there and back. And it got so bad coming up a hill on the way home I was concerned. If I drive it tomorrow it may not miss at all.

I would appreciate any helpful responses and/or thoughts on what might cause this type of behavior.

[EyesofFreedom]

Check your coils...also note anything that happens when the car acts up...like less than half a tank of gas...raining...turning left...using lights and ac...

[1BadBoy]

I had thought about the coil and ignitor, but began to wonder if it could be something more mechanical since the "miss" seemed to change in rhythm with the speed of the car and not the speed of the engine. I will be ordering a new coil and ignitor here this week. I need to pull the old ignitor to compare as there are 2 possible replacement parts (same part #) according to the local Honda dealers (I checked more than one to be sure).

I don't really notice anything that can I can attribute to a possible cause (e.g. half tank of gas, turning right/left, using lights, etc). I do, however, notice a squeak sometimes when the engine is "missing" particularly badly. I really wondered what causes this, but I have no clue at this point.

To reiterate, I have changed the following all within the last 2 months trying to isolate/repair the cause of my trouble:
> Plugs (Bosch Plus-4; I have heard that many don't like these :-)
> Plug wires
> Cap
> Rotor
> Fuel Filter
> Fuel Injectors (cleaned, not replaced)

I'll try to get the coil and ignitor replaced this week or early next and report back.

Thanks for the suggestions!
Dave

[1BadBoy]

Sorry for the delay in posting my follow-up. However, replacing the ignition coil and igniter did *not* resolve the issue. After installing them, I took the car for a test drive and about a 10 minute drive on the freeway. All the way there, and then all the way back (on the freeway) it ran fine. But I noticed a slight vibration coming up a long hill from the freeway toward home. Not too noticeable right away, but after a short bit, it was back to its usual rough running (vibration).

Actually, at this point, I am leaning toward it being a "mechanical" issue. The reason I say this is that the vibration increases with the speed of the car and *not* with the speed of the engine. So when I shift into a higher gear (with the engine running slower), I would expect the vibration to slow too. It doesn't slow, though. And I've noticed that if I really pay attention, I can feel the vibration at slow speeds too, though it is noticeable at about 35 mph and faster.

If I am not accelerating at all (e.g. coasting or holding the speed steady), then there is little or no vibration. However, accelerating even slightly, uphill or downhill, causes the vibration to occur.

I am planning on taking the car to Les Schwab to have the tires and front end examined in case it could be something obvious. If they cannot find anything, then I'll have to find a repair shop I am comfortable with here in Seattle.

If anyone has any other thoughts on possible causes, I would appreciate any ideas at this point (e.g. CV joints, etc.).

PS This was posted elsewhere, but I wanted to answer this thread too. Is there a better way?

[EyesofFreedom]

Is this in automatic?

Do you drive in heavy traffic often?

If both are yes then there is a long shot but I have heard of main shafts that ever so slightly warp or bow...

It is a real long shot but if it doesnt adjust with engine but with speed than it has to be in the transmission somewhere or in the driveline.

One thing to test is to try and make a hard turn...both left and right. If at anytime you feel a wobble in the steering wheel or a snatching motion, then you have a warped cv axle...remember which way you were turning and that will let you know th other side is bent...try turning with the wheel cut as tight as it will go.

[1BadBoy]

Actually, this is a 5-speed (manual). And I don't even drive the car much these days. I put maybe 2,500 miles a year for the last 4-5 years. Because I drive so seldom (once or twice a week), I am not in heavy traffic at all unless my drive time coincides with rush-hour(s).

However, I hadn't noticed anything unusual while turning, but I'll try that soon to see what, if anything, occurs. It's possible it could be there, but I hadn't really noticed it occurring when going slow either until I finally thought it could be mechanical and started paying more attention at slow speeds. At slow speeds, I can feel it, but it is so faint that if I didn't know to look for it, it would not be noticeable at all. It's more noticeable at slow speeds going up a hill than down or on a flat road.

Thanks for the tips and I'll report back soon.

[1BadBoy]

Hi All. I finally got the Accord fixed. After replacing a lot more than was necessary, though it all might have been good for general maintenance, it turns out the driver's side CV joint (axel) was bad. I had it replaced last week for $200 and the car drives like a dream again. What a difference!

Thanks for all the suggestions!

[HondaME]

awesome! glad to see you're up and running