Ok! I have a 1993 Civic DX. I bought this car used and it needed a head gasket so I replaced it. I did head gasket kit (manifolds, thermostat, other seals etc), distributor, plug wires, and e3 spark plugs, and fuel filter.
This car also has a 4-2-1 header and is completely straight piped. It has one o2 upstream sensor, no cat, no muffler. the only other modification is a K&N air filter (stock intake). After replacing all of this the car ran perfect... for about 4 tanks of gas. Now, the car will rarely start and bogs and wont rev. It started bogging and hesitating after stoplights and progressively got worse to where it wouldnt run at all and now rarely starts. I checked for spark at all 4 cylinders and have it. One thing I did notice though is that the plugs are very blackened (and were recently replaced like I said) they have carbon build up (not oil) but yet I still have spark. So seems to me like it is running very rich.
My timing is correct, so that is not it either.
One other important detail is my CEL does NOT come on. it comes on when I turn the ignition on but goes off several seconds later as it should. I also reset the ECU (pulling the back up fuse) and I still have no CEL.

Any help would be great! Thanks

 

fuel, spark, and combustion so check combustion

 

How can I check combustion besides noting that it doesn't run

 

throw those shitty e3 plugs in the trash and go buy oem NGK spark plugs, these plugs will cause huge driveability problems, it doesnt matter if they are new or not

 

Okie dokie I'll give them a shot, thanks

 

Put in new oem plugs gapped at .40 and.... Problem not solved. Started wont rev past idle, then died. Any other suggestions?

 

come to think of it, we just did a headgasket on my friends dc and it had the same problem? were u cleaning the intake manifold while the head was out? because we were cleaning his and i his sensor got dirty, did they same thing as your car. so take out one of those sensors and clean it good

 

well plugs were a good cheap starting point, first induce a vacuum leak by pulling off the brake booster hose off the intake, and try and start it up, if no change or worse, put the hose back on and pull the air box open and spray carb cleaner into the intake while having someone crank and start the car, if its no change or worse, pull the fuel line off the fuel rail and turn the key on a few times collect a sample of the fuel and let it settle, moniter the amount of fuel as well, three key cycles should be at least 8 ounces or more, as far as doing a compression test that would not be a bad idea, you need a compression tester kit, you pull all the spark plugs install the hose with the spark plug threaded end into the spark plug hole of the cylinder, disable the fuel system and crank it a few times to get the excess fuel out of the combustion chambers prior to installing the hose, you want to check the amount of compression your engine has while cranking usually i do three cranking cycles, as in crank the car over for 3-5 seconds then check the reading, a good engine usually 150+psi in all 4 cylinders anything under 100psi usually will not provide enough combustion to ignite the air/fuel mixture, you may be able to rent a compression tester at a local auto parts store, otherwise there not to expensive at discount tool stores like 50$ or less