Bum

working on 2001 civic DX 1.7. water pump went out and overheated. i had head redone and installed new timing belt and pump kit when i started it up it had miss on #3 coil was bad replace it and ran fine for 10 minutes then another coil started missing. long story short it has all coils replaced new plugs good fuel pressure and will start idle and run good for about 20 miles then looses power and misses at idle and eventualy quit but can let set for and hour will start and do the same thing. has no hard codes but 300 / 301 / 304 codes pending HELP

ezone

Valves not adjusted correctly?

Bum

i rechecked valve and are adjusted to specs

Bum

when i'm driving it starts by falling on it's face between 20 to 30 miles an hour then will speed up but not like it should. also when i come to a hill and i live in the mountains of eastern ky. the engine light will start blinking about 500 yards from the top then go out when i start down the orher side which act's like the coils missing. but has 4 new ones from rock auto. no hard codes but 300/301/304 pending about time also a po740 trans code every now and then but i assume it is because of miss.

OneJzSupra

Check timing marks and make sure everything is lined up. When it starts running rough, what happens if you disconnect the battery and then reconnect it? There is no ignition computer with this motor so the coils go straight to the ECU. I had an issue that ended up being that the ECU was faulty and causing all kinds of hell.

ezone

So the miss only happens when the engine is working hard? (uphill is sure more work than downhill)
On flat ground?

How about if you floor the gas pedal from a dead stop, does it run bad right away or earlier than 20-30 MPH?

If you stop and let it idle, does it continue to miss or does it smooth out immediately?


How many miles on this car?

You had the cylinder head off.....Ground wires loose on the front of the engine?
Worn out terminals inside fuel injector connectors?
Same check on ignition coil connectors?


P0740 shouldn't be caused by an engine running problem.

Bum

when you start the car cold and take off i can set cruise control and top the hills holds speed and no light after about 20 miles it will start backing off about 5 to 10 miles an hour and blinking engine light.i have double checked timing marks and valve adjustment they are good.it idle great when i first start driving but once it starts blinking engine light it is missing at idle and will stall after awhile then just gets worse until you let it set for a couple hours then is fine again. has 161000 miles showing.have checked for manifold leaks and is grounded good.

Bum

it loses power but you can't feel a miss unless it is idling.i'm going to check valves again and switch coils 1and4 to 2and3 then go for a 50 mile test ride will get back later

ezone

Probably need to catch it in the act of missing then figure out if it the misfiring cylinder(s) is missing spark or missing fuel.

Ohm check the injectors....then recheck them when they are hot and even try checking again when it's hot enough to misfire.
Swap injectors?

Bum

found the problem has a crack in the cylinder wall that is opening up when hot under pressure. steam in cylinder was causing miss.will need engine which is more than car is worth. thanks for help.

OneJzSupra

Part out?