Please help with ignition problem. Just purchased a 1990 accord 5spd with 164k. I have no previous history on the car. Car idles extremely rough at cold start and has a popping sound that sounds like it's missing. The exhaust is missing a muffler but has converter and resonator. I have also discovered that the car did not have an air filter. When I first drove the car it missed badly at low rpm then begins to smooth out above 2500 rpm. Once the car gets warmed up the cel light comes on and the car will only rev to 4k then feels like its hitting a rev limmiter. I'm guessing it is in limp mode.

Here is what is what ive done so far.
1. Pulled code from cel it was code 8 tdc fault.
2. Checked plugs and they looked ok and were gapped properly. There was some oil in a couple of the spark plug tubes.
3. Replaced distributor and plug wires
4.Seafoamed the engine via vacuum brake booster
5.Added Lucas fuel sytem cleaner to gas tank
6.Reset ecu

The result so far are as follows.
1.The check engine light is gone.
2.The car no longer seems to be in limp mode, at least it does not stutter past 4k rpms like its hitting the rev limitter anymore. It revs freely now just not silky smooth.
3. I still have a miss at idle and low rpm (very noticeable below 2500 rpm and although it is still missing is much less noticeable or annoying above 2500rpm)

My next step will be changing the spark plugs out even though they looked good and trying to get the timing checked. Please let me know if I am on the right track and advise what to do next.

thanks

 

Is it missing on one cylinder? A power balance test is a good way to find out. Getting spark to all cylinders? Getting fuel to all cylinders?

 

Thanks for the reply. Not sure but feels/sounds like only one cylinder. How do I perform a power balance test?

 

Well in that case I would suggest perform the compression test on each cyln, if all of them Are in range then your save. It also could be weak sparks but you already replaced the distributor. check the evap they always clogged up with unburned gas. Which octane of gas you use?

 

So far I have put about 50 miles on it with the work done above. I jsut filled the tank with 87 octane gas from mobil.

 

I thought I may have heard a very faint whistling sound one time while reving it from under the hood. Could this be valve related issue? Adjustment?

 

Well here is an update...still not sure what a power balance test is or how to do it but here's what else i have done.

1.Changed out the old ngk iridiums for some fresh ngk v-power plugs. This did not have much affect towards improving the missing problem.
2.Then i removed the egr and iacv and cleaned them out with carb cleaner and sprayed a good amount in the egr opening in the manifold.
3.Readjusted the distributor by ear for now as I dont have a timing light.

Results were very good! The combination of cleaning the egr and iacv along with playing with the position of the distributor seemed to offer the most benifit. i also cleaned the pvc as it seemed gunked up.
Car revs much better now at lower rpm and the miss is all but gone. I suspect that once i get the timing set spot on it will be a happy car again!
One thing i noticed is that there is a small diaphram at the front of the manifold just below and to the right of th iac and in front of the egr with a vacuum line attached. when I removed it the car seemed to idle with less restriction but has a nasty hiss so i am wondering if it needs replaced or can it be cleaned too?

 

Lol that what I couldn't remember egr, I'm glad you got
Some success gl.