I'm having problems with cylinder number 4, its not firing. I have spark (checked it with the old screwdriver trick) and I have fuel because I can see it on the top of the piston. For some reason it is not combusting. I don't know why... I haven't done a compression test yet, and I know it doesn't have any bent valves because It was checked by the machine shop. this is an Ls vtec w/ a gsr head, obd0 currently. any help or pointing in the right direction in appreciated. -Ben

 

maybe the plug wire is bad....try swapping the #4 wire with the #3 wire and see if problem moves to #3....

also you can see it ontop of the piston? maybe the injector is leaking like crazy...if you have too much fuel it wonr ignite.....if the swapping of the plug wire doesnt show anything try swapping the injector and see what happens.

 

you have the right firing order 1-3-4-2

 

if it was bent it would aleast misfire I would think then not fire at all? I guess it depends on how severe the bend. disconect the injector to number for and keep starting the vehicle. Since you have all that fuel on top of the piston it might be fouling out the plug? Maybe a bent rod?

 

come on now. We tried that....

 

of course

 

The internals are brand new, so a bent rod is out of the question. . And i changed the plugs w/ brand new ones , and still the same thing.

It was not combusting at all. IMO i think it is the wiring, cause it is pretty ghetto.

We are going to start on it again next week, but right now we are doing another car, we'll update soon

 

did you check your compression in that cylinder?

 

Let me know the outcome to this, b/c I think Im having the same problem in my car...only on cyl 1. Does the car combust atfer a certain RPM?? cuz mine will misfire at idle and lower RPMS, but if i give it gas im pretty sure it goes back to 4 cylinders.

 

Yea I haven't got a chance to dig into any more, but I even at higher rpms, no fire. I'll keep an update. Thanks for all the info -Ben