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So, my car had been suffering from a hot no-start issue, I’ve solved that with a new (well, pick n pull, but it’s brand new) main relay. I also had a random idle misfire and a misfire under load. That seemed to go away with a new ignition coil (and pick n pull special dizzy).
Well, yesterday I did a burnout (I know, dumb, but it was on a private road and my good friend and I were having a competition). And after that my random idle misfire came back with a vengeance. What’s odd is it isn’t burning any oil, it’s not mixing coolant and oil. I did a compression test at work, and here are the results:
Cylinder One:
Cylinder Two:
Cylinder Three:
Cylinder Four:
as you can see, it’s at about 90psi across all cylinders. From what a lot of searching has said, the car shouldn’t run at all at that low of compression. I did the test after driving for about an hour, dizzy disconnected and the car at WOT. My misfire is pretty much only at idle and below 1100rpm. Any ideas on what else I can try?
Do a leakdown test to verify or try another compression gauge. Sounds like it needs a rebuild or new motor to me.
I’m gonna try another compression gauge
Originally Posted by Lord Orange
make sure you do a compression test with the throttle body open
I held the gas pedal all the way down, that should be good right?
Originally Posted by CandyRedRC46
I would check the valve lash, mechanical timing and ignition timing. Then go from there.
Last I checked mechanical timing was absolutely spot on but I’ll check it again. Ignition timing no clue, it’s set about in the middle. I’m gonna check valve last now that the car has been sitting all night.
Alright. Adjust the valve lash according to the under hood sticker (after it had been sitting all night so it was properly cold. The exhaust valves were wayyyy too tight. Did those at 0.007 and intakes at 0.003) still misfires at idle when it’s warmed up. When I turn it over by hand I can hear a bit of air escaping. Leakdown test should be next right? Also timing is dead on at TDC.
Which year and engine do you have, looks different than my 2000 B18B1 and definitely different lash specs. Hopefully after correcting your lash and using a working pressure gauge, you get betting compression pressure numbers..
Last edited by CandyRedRC46; May 11, 2018 at 10:42 AM.
Which yeah and engine do you have, looks different than my 2000 B18B1 and definitely different lash specs. Hopefully after correcting your lash and using a working pressure gauge, you get betting compression pressure numbers..
93 b18a1. Although the valvetrain got WAY louder at the correct specs.
Interesting.... Well did you compression test after correcting the lash?
not yet. I’m gonna now that I just re did the lash properly. Turns out, I made a mistake my first time and was measuring the gap wrong. Now we don’t have any horrendous tapping.
not yet. I’m gonna now that I just re did the lash properly. Turns out, I made a mistake my first time and was measuring the gap wrong. Now we don’t have any horrendous tapping.
Awesome news. Yeah it didn't seem right, for the tapping to get louder.
Alright so, I double checked mechanical timing, this is where we’re at.
I guess I can only do a leakdown test now and see where we’re at. The car runs like hot garbage once it warms up. It’ll misfire at like anything more than a quarter throttle at seemingly any rpm and coming off the line it’ll run on seemingly one cylinder down til I get to about 3k.
So, I got an ECU code, code 8, the TDC sensor. I swapped the pick n pull dizzy with the old one I had (and put the new stuff in it) and we’ve still got the misfire once the car is warmed up.
New oem plugs, wires, cap and rotor? Are the plugs properly gapped (the gap is way way off out of the box). Also I have had very good luck with my new Rich Porter distributor, supposedly they are the best out of all the aftermarket distributors (I know that doesn't say much lol). Also is your ignition timing correct?
Alright! So! Big update: my buddy and I re-timed the car. I haven’t done a compression check yet but the car runs quite a bit better and I just got 34 mpg highway, which is the highest I’ve ever gotten. Normally I get about 25mpg regardless.
We’re both pretty sure the exhaust cam was off a tooth. The car still lightly misfires at idle, but it doesn’t run anywhere as bad as it used to. I’m going to get new plug wires when I get paid, as that’s the only part of the ignition system I haven’t replaced. I’m also going to re check compression, fuel pressure, and actually check my alternator, as I’ve had back luck with Honda alternators (my EF hatch went through three and I owned it less than a year!).
But yeah, the idle misfire is nowhere near as bad as it was. I’m willing to bet the compression is gonna be way up now too.
Time for a new one and may as well slap some ARP studs in.
so, we put a new one in it. Given the B18A1 head bolts are not TTY type bolts they can be reused, which is what I did (which is something a lot of people here said you could do). Torqued to spec, in two steps, 22 and 61 ft lbs. aaaaand the car idle misfires worse than before. Curiously, I unplugged the map sensor and ran it for a bit, it idled at 1.5k with a CEL. I turned the car off and plugged the map sensor back in and the car idled a bit high, but no misfire for the entire minute it was running.
I most certainly did not hah. It wasn’t overheating or mixing coolant and oil. I’m amazed the gasket was that blown. Also if I’m going to be real I’m 25 and extremely poor, I just didn’t have the money to get the head pressure tested and resurfaced. Also the engine got MUCH harder to turn over with the new head gasket, so...I think it was sealing well, haha.
(also, believe me, I wish I could do the job 110% properly. It absolutely bugs me not being able to do everything right, but I just don’t have the money to do so and my Integra is my only car. Had I had more money I would have gotten ARP head studs and a full gasket kit)
it is only 75-150$ to pressure test and resurface. Now you get to do the job again. I don't understand on mission critical items like the minimum of a cylinder head pressure test. Your last move doesn't allow for any to further diagnostics besides removing the cylinder head again. Good luck with repair.
Extremely low compression?!
