Gi-Pizza

Hi my name is Adam and im new to this forum and hondas in general last week i bought a 93 civic si coupe with the stock D16Z6. ive been having a misfire issue with the car since last night.
Cylinder number 4 isnt firing or its flooding its self out. I searched the forum to see about any other cases of a random misfire, found one read it and didnt really help
my situation. Im going to list what ive tried to do to solve my problem and hopefully i can type something in detail and hopefully that makes sense.

Last night car started running rough and sounded like a subaru, prob not the best sound to be making, as well as idling rough and having white smoke coming out of
the tailpipe, no i would think honda burning oil not uncommon although this was a lot, or maybe head gasket went, but the car isnt burning coolant or oil, the smoke
smells like gas. I drove to a friends place where he has a garage and the same car just a 94 and has done gsr swaps and others to the many hondas he has owned
(figure my best person to go to). On the way there it was still running on 3 cylinders and still smoking and also has a rev limiter in the 3300/3500 range(limp mode?).
The drive is about 10 mins and on the way there i monitered my temp gauge it stayed just under the half way mark which is usual for it. The next morning we put new
plugs, wires, and used his distributor, which runs his car fine. The car still ran on 3 cylinders and we checked the plugs and number 4 (assuming that 4 is the cylender closest to the
distributer) plug was soaked in gas and gas vapour came out of the spark fluid hole. We checked for spark from the distrubuter to the plug wire and there was lots,
then put the spark plug in the wire but not in the motor and set it on the valve cover and it sparked as well. We had spark but no detonation. Someone mentioned
that maybe an injector was stuck open and was just flooding the cylinder. After swapping the injectors for 3 and 4 around the problem remained in the number 4.
We did a compression test on the motor when cold using a new digital gauge, and the readings came back, 1- 195.5, 2- 188, 3- 190.5, 4- 192. So were
assuming that the head gasket is not gone and the rings didnt let go and there is no hole in the piston. I replaced the the grounds that are attatched to the motor/tranny
as one of my friends said that may cause the problem. Also just to be sure we made sure the wires were going from the distributer to the plugs were the proper positioins
using another thread on the forum.

As of now with everything checked/changed it still runs on 3, tomorrow im going to check the fuel pressure regulator and the vacuum line going to it. Does anyone else know
of similar problems or have tips on how to solve this problem is it maybe a bad ecu that just decided to give up or could the wire harness for the injectors be possably be
damaged and that is just causing the one to put too much gas in. Could it have jumped timing and still run but just on the 3 cylinders? Any advice would be greatly appreciated.

Thanks, Adam

taylorboi

The things you are saying is leading towards and bad cylinder either burnt or bent valves but I think others on here could correct me or back me up . Try doing a compression test on all four cylinders .

Gi-Pizza

did the compression test i had a fairly even spread, We did a compression test on the motor when cold using a new digital gauge, and the readings came back, 1- 195.5, 2- 188, 3- 190.5, 4- 192. bent valve could be the issue still as i havent checked them but would it still build close compression ratings with a bent valve?

HondaPartsHero

With the car running, pull the plug from cylinder 4. If the engine speed/idle doesn't change then you obviously have an issue with something in that cylinder. You have fuel and spark so the obvious thing is compression. If you have someone that has a gauge type tester try that vs the readings you just got. Sounds to me like valves or rings. I just had this with a friends Accord that had the same symptoms. He took it to the shop and awaiting diagnosis.

Gi-Pizza

did the plug pull, only when pulling plug 4 did the rough idle stay the same, and your saying try a analog compression gauge as well to double check the digital ones readings? (not being condescending just making sure im understanding)

Former User

The cylinder compressions look fine.

Any CEL codes?

What color is spark at plug #4 versus spark at the other plugs?

Does fuel injector 4 spray fuel?

Gi-Pizza

changed plugs but old ones were just old looking little brown but haynes manual said that they were a normal colour, and yep after having the car running for about 30 sec you can take the spark plug out of number 4 and gas vapors follow, and we swapped injector 3 with injector 4 and the problem stayed with the cylinder, cel codes ill read in about 20 mins when i get back over to my car, hopefully its something helpful not "misfire", but knowing obd1 i shouldnt hope for much. ill reply back when i read my cel code

HondaPartsHero

Did u pull off plug 4 and look for a change in the way the motor runs at idle?

Gi-Pizza

So CEL code 16 came up which is injectors, looked at injectors and ecu made sure connections were tight on the ecu and the problem went away... After all the work something simple fixed it thanks everyone for the advice I'm definitely grateful for the help, and turns out that my motor is a jdm d15b one of my friends pointed that out to me.