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11 Posts
Discussion Starter #1
ok... Im gonna try to explain everything i have seen and done in the past 4 months and see what u think i should do next. this is my DD car and getting 40mpg is much more important than getting an extra 20hp so i keep almost everything as close to stock as i can.

On my 93 Civic EX, the engine (d16z6 w/ 320,000mi) started acting really shitty. hesitation, poor power, poorer gas milage, constantly overheating. I came to believed this was due to a cracked head and possible piston ring issues. the engine had 320k on it! a true testament to hondas abilities, but it was old and had to be retired. (its still sitting in my friends carport for nostalgia though)

So my uncle and i got a JDM D15B installed. i did a full tune up, new timing belt/tensioner/waterpump as it was installed. everything i was supposed to do when installing a JDM except new engine mount hardware and we had to use my D16Z6 intake head on the D15B, but everything lined up nice and these forums and others noted that this was ok. other than that i put a k&n air filter for better mpg.

it ran great for the last 10,000mi. Solid 40mpg highway. first oil change looked a lil dirty, second looked great. so heres whats goin on now...

It starts up fine on the second or third crank if shes been sitting a while. but by the time the choke dies off its idle is horrible. seems to be idling a lil lower than usual also. there is severe hesitation when accelerating into traffic, though high speed travel (so long as its not hard accel high speed) is fine. severe loss of power overall.

first i checked the wires/cap/rotor and electrical in general. its all good so far as i could tell. next i replaced the fuel filter, then used some seafoam to clean out my fuel injectors. checked for vacuum leaks, with none found (could've missed something though).

when none of this helped i finally got my rachet and pulled a plug (THE FIRST THING I SHOULD HAVE DONE!). apparently chamber 3 and 4 are ok after the car has been sitting with only a lil oil on them and ignite when starting the car. once started though they get covered with oil and no longer ignite in the chamber.

My thoughts or questions are this...

Should i pray to the gods that it is just a head gasket leak, get the gaskets and do an in car repair? how can i isolate it to that and be sure its not an injector leak? or how can i make sure it not bad valve seals? or how could i see if it was worn rings? since its chamber 3 and 4 (next to each other) it makes me think a gasket would be the prob, would i be wrong? i dont see rings on 2 chambers goin at once, that would be improbable, right? and since the car was never overheated and does not get over-revved i would believe the head would be ok, right? is there a way to check?

i've got 50$ in credit waiting at the advance auto to figure out whether to get the valve seals or gasket set. just not sure what to do.

i'm pretty poor at this moment (like so many others), and this car is the only thing keeping me from homelessness. So PLEASE help me try to find the cheapest solution!!!

and if anyone in the 21740 area wants to donate time and maybe learn something by helping, please respond. my 73yr old mother is only 200 mi away rather than 1700 so i'd like to see her fobefore she goes back.

11 Posts
Discussion Starter #3
The SAGA continues...

ok... heres the leakdown results

cyl1 ~20% loss - sound is coming through valve cover and dipstick (oh shit)

cyl2 ~10% loss - sound is coming from its own chamber. not from anywhere else. we were only handtightening the plug so I figure that was its prob. though i did the test 4 times on this chamber.

cyl3 ~5% loss - sound from dipstick

cyl4 ~5% loss - sound from dipstick

since the plugs were out we did a compression test too. (we had time and he had beer)

cyl1 ~212psi
cyl2 ~210psi
cyl3 ~210psi
cyl4 ~209psi

upon inspecting the plugs this time i noticed alot of different things.

first off, the plugs from chamber 1 and 2 (mistaken in the original post as 3 & 4) wasnt covered in oil this time.

and the plug in chamber 1 was covered in dark carbon powder residue this time. like its not firing off or on time and that would explain the carbon buildup right? also the connector end of the plug was scorched electrically. this made me think of 1st year Electrical Engineering class. so i put a multimeter to it to see if there was resistance in the plug. only the plug from chamber 1 had resistance in it.

YAY!, we got a new spark plug to solve the problem.

BOOO! still has hesitation and similar problems though it runs a lil better.

i was thinkin of changin the wires even though they have less than 15k on them, that scorched plug really bothered me. but i'm not really sure where to go next. chamber 2's 10% and not hearing it anywhere other than its own chamber makes me think a cracked head is possible. but the 20% on chamber 1 tells me the piston rings are bad, but not bad enough to cause this much problems. also i thought it funny that the chamber with the most loss in the leak down test had the highest compression.

still no error codes from the obd1


Premium Member
95 CX Hatch
5,910 Posts
Maybe you are over thinking the entire thing. Do you have a fuel pressure gauge? Hook one up and reply back plz. Hard start after sitting, low idle, hesitation/loss of power on hard accel.

Hook up the fuel pressure gauge with a long hose and tape it to your windshield. Monitor the fuel pressure as you drive and take notes. Also check to see if the pressure is bleeding down while sitting.

It could also be something as simple as a coolant temp sensor. When bad it may not throw any CEL codes but it can fool the ECU into thinking its much colder than it really is. I have seen shorted/cracked/open temp sensors send a -30 degree signal to the ECU and yes they will run, but it causes the ECU to dump excessive fuel into the cylinders fouling plugs and causing those concerns. Hard start, hesitation etc.

11 Posts
Discussion Starter #7
i wanted to say thank you to the guys that have helped so far. unfortunately i wont be seein mom. and due to not finding someone with a pressure guage and lack of funds for new wires/parts i just have to drive this thing as bad as it is till i make some. pray for me to the honda gods that i dont break down.

so i was brainstormin... with my self; which is always dangerous. since i cant seem to find a pressure guage for my fuel line, what else could be goin on.

i swapped the sensor for coolant temp from my old d16z6 and there was no change. but that engine overheated a few times. wouldnt that kill the sensor?

next i was thinkin; if its not the coolant temp sensor making it dump a bunch more gas than it should into the chamber. maybe its the dizzy not puttin out enough spark. or maybe the wires not lettin enough current through. it seriously sounds like its missing. could a skipped timimg chain do this?

gonna try swapping the old dizzy from my d16 on saturday unless some1 tells me it wont fit before then.

thanks again guys. knowing my leakdown and compression #s were ok is invaluable.

i bet its something real simple.
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