my '01 crv was sputtering while stopped in gear and stalled a few cold mornings. i had a shop change the pluggs and fluids. i got my car back and it drove great for a day. the next day the check engine light comes on and its sputtering again.
I checked the code and it said cylinders 3 and 4 were misfiring. I checked the order of the wires, and bought new wires. it still sputtered & light still on.
I pulled the plugs that were misfiring. #3 looked awefully sooty at the spark for one day of driving, but otherwise it did appear to be new plug. #4 looked much cleaner.
I switched the plugs to see what would happen to the code. here’s what’s weird - car still sputtered & light came on (after I cleared codes) but no code was read. code reader said ‘pass’. I resent and tried it a few times but it passed each time even though car’s sputtering and light is still on. what’s going on?
If it keeps it up, you can expect the light to come back. How about doing a compression test on all the cylinders. A miss-fire does not equal spark plug, and may not mean spark plug wires. But if those are original plug wires, they are due.
I’ll do a compression test on the cylinders. If its low, does that mean i need a new head?
I’ve been reading the forums and i now know that i should have had my valves adjusted. My mechanic said i don’t ever need a valve adjust even though i’m almost at 100k. I’m sure now that was bad advice. what damage could a valve out of adjustment do? could that be the cause of a bad head?
Change the distributor cap and rotor. Move those two spark plugs to the other positions. For the misfire code to come on, it takes two “trips”, in which excessive (over 2%) misfire occurs, to set the misfire code.
Remove the distributor cap and check the inside for carbon tracking. When a spark plug cannot fire that spark is going to attempt to burn through the plug wire and if it can’t go that way it will jump from terminal to terminal inside the dist. cap or even jump through the rotor to the dist. shaft.
Over time this will create a very faint squiggly line that is referred to as carbon tracking. The spark will then find that track is easier to follow than attempting to jump a plug gap which is under compression.
(This was also an old trick to mess with someone’s mind. A pencil was used to draw a line between some distributor cap terminals and voila! Instant misfire. This is not your problem; just pointing out the analogy.)
The recommendation about not checking valve clearance (lash) for an extended interval such as 100k miles is a bad one IMHO. This is not the car owners fault at all; it’s a bad factory recommendation.
Excessively loose valves (clattering) will damage cam lobes and lash adjusters over time and excessively tight valves (TOO quiet) will burn the valves (exhaust) and the cylinder head valve seats if ignored.
A compression test and use of a vacuum gauge should show if tight valve lash is the problem. Even one tight valve will affect a vacuum gauge reading.
Burned valves or burned valve seats do not mean the head is automaticaly junk or even bad.
In severe enough cases it could be but often removal of the head and performing a proper valve job along with replacing any valves/seats that are too far gone will fix it right up.
Normally shim and bucket adjusters maintain their adjustment better than screw and lock but you never really know.
(This is a hot-button issue for me because I’ve had to do a fair amount of cylinder head work due to ignored or improperly adjusted mechanical valve lifters.
In one case, I had to replace not one, but BOTH cylinder heads on a Subaru; and this car only had a measly 7k miles on it at the time. Yes, they were too far gone to save.)
Hope some of this tome helps. 