When you can't find the issue with your engine

"Hans Kuiper" (hanschepuve)
08/05/2017 at 10:23 • Filed to: None

Help me out brothers and sisters of oppo, Im really sad.

That feeling when your engine is performing poor, and everything seems OK but its not. No engine codes, have tested lots of things (which are fine) replaced faulty stuff and still the thing behaves poorly :(

Bought a 4dr/manual Integra with a blown engine.

Swapped it out with a fresh jdm b20, it started fine and ran well except for idling issues and random shake when lifting the accelerator.

Changed IAC, sparkplugs, fresh oil and Honda oil filter and got the timing and distributor checked.

Now the engine misfires everytime specially at low rpm, got the injectors serviced and boy they where awful. still the same misfire but engines got bit more power.

Checked cables, one has the boot a lil bit broken but works nice.

Fuel pump good, alternator good, changed fuel filter.

Still the same misfire.

No oil consumption, high compression, never been overheated and no coolant loss.

Is it that maybe the car doesnt like me? second time this happens to me.

Got a car with a slow, misfiring engine that shows no codes on ecu and everything is fine and healthy.

my mechanic will have a look into the ECU and chip it so he can see whats happening and will do a custom map to it.

DISCUSSION (25)

pip bip - choose Corrour > Hans Kuiper
08/05/2017 at 10:26

timing belt hasn’t jumped a tooth or two?

crank angle sensor?

cam sensor?

Hans Kuiper > pip bip - choose Corrour
08/05/2017 at 10:32

My mechanic says timing is A-ok

Havent checked crank angle sensor or Cam sensor, what are the symptoms of those?

pip bip - choose Corrour > Hans Kuiper
08/05/2017 at 10:33

possible flat spot.

Hans Kuiper > pip bip - choose Corrour
08/05/2017 at 10:34

Sorry for double reply, but just to let you know the computer has no codes on it, sometimes the CEL comes on and it says its the speed sensor (speedometer doesnt work) tachometer and every other gauge works well

Flavien Vidal > Hans Kuiper
08/05/2017 at 10:37

Does it get worse when you accelerate? If so, crap in an injector in spite of the service... Maybe clean up the fuel tank too. Clean them up again after and see how it goes from there...

If nothing changes, go after coils.

Hans Kuiper > Flavien Vidal
08/05/2017 at 10:39

It has gone progressively worse and yesterday took the injectors for service and boy they were dirty AF, they got cleaned thoroughly three times and replaced the seals, they got tested on the bench and were fine after service, all within specification.

Also, fuel pump pressure was fine said my mechanic.

Flavien Vidal > Hans Kuiper
08/05/2017 at 10:45

Yeah but if you have crap in the lines between the fuel filter and the injectors, cleaning them up is fairly useless as they get clogged up again right after.

The way you describe it, it really seems to be a fuel problem...

Unplug the injectors again, clean them up once more and this time run the car from a bucket of gas on the side, with the fuel pump plugged in a battery, bypassing the fuel lines (needless to say: be careful!).

If there’s still no changes, go after the coils, though I doubt is the problem.

DipodomysDeserti > Hans Kuiper
08/05/2017 at 11:27

Check for vacuum leaks.

Khalbali > DipodomysDeserti
08/05/2017 at 11:45

Agreed, if it gets better over 2k rpm or so that would indicate vacuum leak.

DC3 LS, will be perpetually replacing cars until the end of time > Hans Kuiper
08/05/2017 at 11:50

Like Skychismo said, check for vacuum leaks. I’ve had quite a few on OBD-I Honda’s and it never throws a code for it.

Also try bleeding the cooling system. Won’t help with the missfire, but it could help with the idle issue.

brianbrannon > Hans Kuiper
08/05/2017 at 12:31

That car has a very basic check engine detection. Pull the distributor cap and check the shaft doesn’t have play then replace the plug wires and cap

RacinBob > Hans Kuiper
08/05/2017 at 14:06

These are really simple engine control systems. Its hard to screw them up in a way where the run well at speed but not at idle. I would think it has to be a vacuum leak related. You had everything apart. You could you have a leak in the intake manifold to head gasket area, or in the idle control, or the PCV.....

One way to prove that there is an air leak us to pull off the throttle body inlet boot, start it and cover more and more of the inlet with your hand. If it keeps running, or starts running better, you know you have a leak. Then you just have to trace it down.

Hans Kuiper > Flavien Vidal
08/05/2017 at 16:05

Thanks a lot for your tip! Havent think of that! Will do that with my mechanic next week or try to, now im solving why the car is heating up, startef this morning, ugh its tiring for sure (appsrently its the thermostat/fan switch)

Thankfully I didnt overheat it to the red line/H

Hans Kuiper > Khalbali
08/05/2017 at 19:36

It doesnt get better, the misfire just becomes faster :(

Tristan > Hans Kuiper
08/06/2017 at 00:57

The whole time I was reading this I thought it sounded like an ignition issue (low rpm/high load misfire), then you mentioned the broken boot. Replace the wires.

Khalbali > Hans Kuiper
08/06/2017 at 01:45

Well that would seem to rule out vacuum leak then. I would swap plugs (and coils too if it has them not very familiar with older hondas) and maybe even injectors and see if you can isolate the problem that way, although you’d need a scanner that can show you which cylinder is missing.

Hans Kuiper > Tristan
08/06/2017 at 19:02

Changed the wires, nothing changed :( maybe its the distributor

Hans Kuiper > Khalbali
08/06/2017 at 19:05

New plugs and swapped cables nothing changed, after cleaning and servicing injectors!

Mechanic is also a tuner, he says he will chip my ecu and start from there checking every value, after finding the culprit hell tune it

Khalbali > Hans Kuiper
08/06/2017 at 20:55

Yeah that’s a doozy, that’s the usual suspects. Have you compression tested it?

Tristan > Hans Kuiper
08/07/2017 at 00:33

Damn... :( Have you replaced the cap? Small cracks or internal arcing could cause a misfire as well. Especially if it’s the type of cap that has the leads close together exiting out of the side rather than the top.

Hans Kuiper > Khalbali
08/07/2017 at 11:39

Bought the engine as high comp one, and mechanic says its fine,but there might be something wrong with the distributor, apparently its electric, ill let you guys know what do we find

Hans Kuiper > Tristan
08/07/2017 at 11:41

The b20b distributor that came with the engine was “fine” and the car came with a bunch of old parts from the blown b18 that included an msd distributor, the pro cap one.

Mechanic took them both and rebuild the msd one and it was apparently fine, but thats is the remaining wild card here

Tristan > Hans Kuiper
08/07/2017 at 17:54

Indeed... In my experience, MSD stands for “My Spark Disappeared”.

Hans Kuiper > Tristan
08/08/2017 at 22:58

Tbh, id like it to be an oem one but the jdm b20 had an obd2 and the msd one is obd1 so thats why he rebuilt it using the other. Still I think that might be the culprit.. will let u guys know when I chip the ECU

OIIIIIIIO Everything's better when wet. Just ask Steve. > Hans Kuiper
10/07/2017 at 09:38

Hear me out.....Double check the fuel pump. I was chasing those same symptoms for three weeks and $400 on a $600 Focus. The pressure checked good (40 psi), but after I finally bench tested the pump, discovered it would run 3 seconds and stop. even completely removed from the pump assembly, the little electric motor sitting there on the bench all by itself. Run 3 seconds and stop. My hair has mostly re-grown.