I've had this '96 Accord since new with virtually no problems. At 90K miles I did a full tuneup (obviously my mistake) and it ran better. A week later, the idle started dropping and then recovering in a couple of seconds (It didn't do that before the tuneup). I complained, and they did a bunch of diagnostics stuff till they ID'ed a serious problem that could be causing it. Specifically the compression was precisely 120psi in all four cylinders with the minimum compression supposed to be 135psi. I did have them adjust the valves to see if that would help but it didn't. Their recommendation - don't put any more money into the car. Duh!

My question is, what caused the low compression in all four cylinders at the same time to the same level? The car does not leak or use any oil and has been maintained. I normally think of compression varying between cylinders because there is a leak somewhere in a gasket or a valve but that shouldn't affect all cylinders equally should it?

I really don't know much about cars, but I'm really not happy having to replace the car. I really expected that the car's motor would last at least 200K rather than 90K A '96 accord really isn't worth enough to justify replacing/rebuilding the motor. I don't feel right even selling it because I'd just be passing the problem off to someone else.

More than anything I'm just putting this out here just to vent. But I'd really like to know what went wrong and of course if there is any good solution.

 

Get a second opinion. Equally low compression on all four cylinders on a well maintained, 90K engine is a suspect diagnosis. Perhaps an the shop used inaccurate compression gauge did the compression test wrong. In any case equally low compression probably has nothing to do with the choppy idle, nor did your full tuneup.

Does the car run OK other than the choppy idle? Since you've had it since new, has the power dropped off noticeably? If not, the problem may simply be air in the cooling system or a dirty idle air control valve.

 

The tuneup was done at an Independent shop. After they told me they couldn't adjust the distributor timing claiming manufacturer defect and wanted $$$ for further diagnosing, I went to the dealership. One would think that the dealership would have the expertise and proper equipment to do a compression check.

The idle control valve was cleaned during the process of diagnosing the idle problem.

I'm really not an aggressive driver so I tend not to use much of the avail. power but yes, there is a significant power loss, compared to new but that is not particularly recent event more like a long slow event. I do notice that going up hills on the freeway, I'll have to shift to a lower gear where I didn't when it was new. More noticeable is that when using cruise control the slowing button doesn't really slow the car much rather it is much more like engaging the clutch (yes it is a manual).

Now that you mention cooling the car operates slightly hotter than it used to but nowhere near overheating. Rather, it runs somewhat below the 1/2 mark of the gauge rather than historically slightly below 1/4 of the gauge. Sorry about the roughness of the estimate but the gauge really isn't marked for high precision. The temp is not something that bothered me much because it was nowhere near overheating so I didn't mention it to anyone previously.

If it matters, the check engine light is not on. I know that they did check for codes on the computer, but nothing was reported back to me as a problem. Other than the idle, the car does not run rough at all with virtually no vibration in the steering wheel. Matter of fact before the compression test, I was totally willing to solve the idle issue by simply increasing it a few hundred rpms slightly above the point of total smoothness so that when it dropped slightly during idle it wouldn't be noticeable.

 

The base timing isn't adjustable on your '96; it's not a manufacturing defect, it's by design.

A car that you've owned and maintained well almost since new, with 90K on it, I would think is worth spending $100 to get another compression test and a leakdown test if the compression test still shows low numbers. It's not a case of having proper equipment, rather it could be a case of using a compression gauge that reads 30lbs low. A pessimistic take would be that the dealer is trying to sell you a new Honda because your 90K Accord isn't worth "putting any more money into it." Call me suspicious. It's common for Gen5 Accords to go two or three hundred thousand miles with zero internal engine problems.

 

Did you have these problems before the tuneup?

List all that was done on this tuneup.

Take a look at where the distributor bolts to the cylinder head. Are the holes for the distributor (not the distributor cap) slots? I thin that the three bolts for the distributor should be able to be loosened to allow the distributor to rotate. We can give you more details on how to adjust the timing.

 

Fair enough, I'll visit another shop and get another compression test. Your analysis is good enough that it is worth testing and I'm perfectly willing to put in another hundred if there is a reasonable chance that I won't have to just throw the car away.

The primary reason I bought the Accord, as opposed to anything else, was the reliability of the car. So you are preaching to the choir. I had every intention to drive it till it, or I died and that was supposed to be 200K+ miles, not 90K. Before this event, I had been incredibly happy with the reliability having to spend virtually nothing other than normal maintenance (oil, brakes, tires, etc.). I've never had a car that was even close to this in reliability. It was a good problem-free 15 years and I find that impressive. Then this happened...

 

It was a full tune-up where they outright replaced wires, plugs, cap, ... for it had been over 30K miles and many years since it's last tune-up. Matter of fact, the dealership was not happy that the original shop didn't use official Honda OEM parts but supposedly they tested the tune-up and found nothing wrong there. I personally don't have a particular problem with using 3rd party tune-up parts to save some money as long as they are good parts.

My experience with Honda doing tune-ups was that they would test the car and only replace the parts that their machine told them needed to be replaced. I suppose that if you have a good enough tester, that will work fine but I come from the era that one didn't test as much as replace regardless. I feel more comfortable with that and that is what the original shop did at what I would call an outrageous price but things are more expensive now days.

The timing was just a little off, but the independent shop said they couldn't adjust it at all for the rotor wouldn't move at all. I was incredulous, so they explained that there were slots in the block and tabs on the rotor. When the rotor was cast, some slag had formed that created an extra tab preventing it from rotating. They wanted to cut one of the tabs off so it would rotate so they could adjust the timing. The shop also wanted $379 to clean the idle control valve and the throttle body which is where they put the blame for the idle problem.

I was very suspicious, so I went to the dealership which said there was no problem with the rotor and supposedly adjusted the timing. The dealership also, cleaned the idle control valve which didn't fix the idle issue. They did more testing to see if they could identify the problem and came up with low compression. They did this all for a little over $100 which was a bargain compared to the independent shop. I then spent another $100 for the valve adjustment to see if that would help the compression which it didn't

As to what problems I had before the tune-up was that it was running rough, There was some power loss over the years. The temperature had already risen but that is something I didn't pay any attention to. The car did run significantly better after the tune-up. The only thing new after the tune-up was the idle problem, which I still have, and low compression which was discovered trying to diagnose the idle problem. It annoys me but I can live with the idle issue but low compression is a fatal flaw.

Hopefully, this describes better the process I've gone through to get here.

 

A little clarification of terms: the rotor is inside the distributor. It's plastic and from what you've said it was replaced during the tune up. The distributor is the aluminum cylinder that sticks out of the head and it's topped with the distributor cap with coil and spark plug wires coming out of it.

I have a '96 too. The distributor has three bolts holding it to the head. Two of the bolt holes are slotted but one is not which means that the distributor cannot be turned to adjust the base timing. From what I understand, the engine computer keeps track of both the base and dynamic spark timing. Neither can be adjusted except by the computer. And even if the timing was "just a little bit off" it wouldn't cause the idle problems you're having.

The fact that the shop told you that the non-adjustable timing was a manufacturing defect and wanted to modify the distibutor to "fix" the problem has me questioning their ability to properly diagnose and repair the idle problem. If you have good results from the compression test/leakdown test you may want to have a competent shop look into the idle problem.

 

Did they change the coolant and/or the thermostat?

One quick thing you can do is to remove the 7.5 amp backup/radio fuse in the engine bay fuse box for a minute. This resets the ECU and this helped on my 95 accord whenever I did anything with the idle control valves.

 

Forgive me about the misuse of the terms. I'm really not someone that is skilled in the mechanical arts.

The shop wanting to cut a tab off the distributor was why I went to the Honda dealership for the future work. I really believed that the dealership was competent, just more expensive than an independent shop. The dealership is the one that attributed the idle issue to low compression.