I have an 02 RK injected. It has 83k on it. Was coming home from a 800 mi. ride yesterday and it started missing a little. Well by the time I got home it was missing alot. This is what I have done. Front cylinder not firing. I have spark. Tried new plugs. Did'nt help. Done old school test with paper, front cylinder sucking in on the exhaust pipe. Ok, thought I have a valve issue. Took a compression test and both at 150 psi. Is it possible to have good compression and still a valve issue? Should I do a leak down test? Just a little time consuming to set up. Any ideas or input?

 

First thing I would do is check for codes.

 

not possible to have good compression and valve issues. even if valve just wasn't opening (due to broken pushrod) your compression would be low but still have some. any burnt valve, stuck valve will give a very low comp reading. make sure the plug wire is good, just because you see spark coming out of it, there may not be enough voltage to fire plug. also coil could be suspect take ohm readings between primary and secondary windings. My first thoughts could be a faulty injector. if you have a noid light, install it on the injector harness, to verify the signal from ecu. then the next thing is to switch injectors front to rear, and see if problem moves with it. you could also have a bad vacuum leak at front cylinder. start motor and spray with carb cleaner and see if it picks up significant rpms. it may also die immediately.

 

a leakdown test with 150 psi is a waste of time, checking codes isn't a bad idea , but will most likely tell you what you already know, missfire at #1

 

Sounds like to me an injector or a connector to the injector. I would check for codes and start to troubleshoot whats not working. You can get or rent a noid light set from autozone and see if your getting a pulse to the injector so it will fire the injector. You just remove the connector and plug in the noid light. If no pulse more troubleshooting. If you get a pulse and it still runs like *** after you reconnect the connector the only thing else it can be is an injector

 

I'll do the coil and wires here shortly, but the thing that gets me is how the front cylinder pulls the paper in but the rear dosn't. Not tryin to say I'm real old but thats the way we use to to do it. And most of the time it gave you a pretty good idea where the problem lied. I said most of the time but not always. Goin to go and do the ohm readings. I'll let ya'll know what I find. Thanks

 

I'd be looking at the coil myself. might be cracked and only causing the issue when it gets warm which won't take long once started.

 

Wire 53K, primary .53, secondary 6k . All within spec per manual . I'll do the fuel tomorrow. Still wondering about the paper thing. Thanks for the heads up where to borrow a noid light. Use to use a test light but I hear they don't get along well with the electronics.

 

My neighbor has an '02 RKC with very low miles and he had a firing issue on one cylinder and it turned out to be a broken injector wire.
Seems that the factory used plastic tie straps, pulling them too tightly and breaking wiring internally.

Check closely before wasting a lot of money.

 

Had a similar problem with my 07 SG. Ended up being a broken injector wire just above the connector.