Picked up this 99 Civic used. Knew it was messed up when I got it, but I have plenty of time to mess with it and I got it cheap.

Only mod is aftermarket header.

Symptoms:

No CEL. CEL is not burnt out.

Starts right up. Idles rough @ ~200rpm. Idle slowly climbs to 1500RPM. Then drops and stays about 800rpm. Idle still rough. Sounds rough until 2000rpm. Above 2000rpm you wouldn't know there was an issue. When revved up and let off throttle, car will struggle to idle @~200rpm and then most of the time stall. Pulled spark plugs, 1 and 4 are blackened and wet with fuel. 2 and 3 look perfect.


What I have tried (tested idle after every change and reset ECU several times):

Checked mechanical and electric timing. Checked for vacuum leaks with TB cleaner and Starting fluid. Checked PCV. Checked fuel regulator for leak. Checked fuel pressures(hose pinched 44psi, unpinched 36psi) Changed spark plugs(NGK). Spark plug wires(NGK). Fuel filter. Adjusted Valve lash. Cleaned IACV. Cleaned TB. Grabbed some parts from junkyard, swapped TB, IACV, distributor, cap, rotor, ECU, fuel injectors. Checked engine bay grounds.


Car does exactly the same thing. Definitely seems to be an issue affecting 1 and 4 only. Gonna check cylinder compression next.

Any other suggestions would be appreciated.

Thanks

 

I was having the same problems, looking forward to seeing the results

 

Post the results.

 

Busy season for me, finally had time to work on it a bit.

Cylinder Leak Down test results with 90psi applied:

Cyl 1 28psi

Cyl 2 87psi

Cyl 3 86psi

Cyl 4 25 psi


On 1 and 4 I can hear it leaking back through the intake, throttle bottle and such. So apparently I have a couple intake valves not sealing. I already checked the valve lash a few weeks back. But I will check it again on my way to pulling the head.

So I guess the head needs rebuilt. Am I on the right track?

Thanks

 

Replace the engine as a whole.

 

Why swap the whole engine? Do those numbers mean the lower end is bad too? Or just wanting to match new parts to new parts?

 

Also, something I find odd, that both 1 and 4 are within a couple psi of each other. I see the head on this engine is a P2J-1 and it is not listed in the D16y8 head code FAQ of the forum. All I can find is people saying it is for a VTEC-E. Could that cause the issue?

 

This being my son's first car I am not interested in spending a whole lot on it. Especially since he may smash it up. So I went ahead and picked up a used head. Got it on today and it purrs like a kitten.

 

What are the compression numbers now?