marklesal

Hi guys ,

I'm having a few issues with my s2000 99 jdm car I recently purchased,
On vtec the car feels fine, very strong infact but low down 2-3k the car feels very sluggish and occasionally goes off a cylinder. I pulled the plugs and coil packs for inspection, the cp's look like they have been replaced recently, the plug colouring is a little strange, cyl 1-3 are pretty much pure white, cyl 4 ( bulkhead ) is sooty and black. Iv plugged the car in to my diagun and the only code or fault is the air vacuum behind the bumper, I'm guessing this is not related. The car had been sitting around for a while, I was almost going down the route of thinking the sock fuel filter was causing the low fuel pressure hence the white tips on the plugs but why in only 3 and not the fourth. The engine slightly shakes and farts at idle but only very slightly. It also needs the valve clearance done but again I'm not relating this to my problem. Iv carried out a compression test all cylinders 240-250

Iv tried searching the forum and read the misfire topic but nothing is specific to my problem. Would appreciate your help!

Mark

Ps... The misfire is hardly noticeable when the car is cold, but when it's warm it feels like an exaggerated version of heat soak that is common on s2ks

s2000Junky

I wouldn't be quick to discount the valve adjustment. If they are too tight, this could be the culprit. I would start there at this point to rule out. Make sure all valves are in spec.

Soviet

Valve clearance that are not in spec can absolutely cause misfires, so I would not discount that at all. I had a misfire at idle and up until 3k RPM and it ended up being coil packs.
You said that some of your coil packs looks like they've been replaced already? Ideally coilpacks should be replaced all at once since they tend to fail around the same time, so that looks like a big red flag to me.

I know you've looked at the misfire thread already but my best suggestion would be to look at it and start substituting parts from a fellow forum member... Misfires can be caused by a number of things and its not likely that a solution can be determined with 100% accuracy.

marklesal

Cheers for the replies, sorry I meant all the coil packs have been replaced recently... Not just one or two... The engine does sound quite "tappety" which made me think the valve adjustment was needed

Soviet

For what its worth, non OEM coil packs have been known to fail prematurely.

Forziii

This.

I had one of mine fail about half a year ago. Replaced them with ebay ones which gave me no issues until now (6 months later).
Denso ones are on their way to me now.
The Ebay ones were good as a relatively cheap temporary fix I guess..

Clayton fenech

Hey guys i need help plz cause im going crazy. I have an s2k ap1 and I have installed a new stereo with screen and I have noticed some misfire and then I have installed a gps and the problem get even worst with misfire so I cleaned the throttle valve and the throttle bottle but still the same then I changed the spartin plugs and a coil and for one day it was fine but then the misfire continued and I have cleaned the injectors but still for nothing. What do you suggest plss its from the current cause when I installed the stereo begins the misfire thankss alot appreciatet for all your comments