Misfire issues

Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
in Engine & Drivetrain
My RT4wd has heavy misfire issues at lower idle with load, and misfires occasionally at all other RPMs. I have been dealing with the occasional misfire since I bough it 5 months ago.

The heavy misfire occurred on the first 70 plus degree day up here, when the engine was sitting in traffic.

I did a tune it when I bought it and adjusted the valve lash. It does need a timing belt. I'm leaning towards it being a valve lash issue.

Any tips?

Comments

  • greenteagodgreenteagod Moderator
    Based on what you've said my first tip would be adjust your valve lash. Sounds like you might have gotten em too tight.
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    that's what I was leaning towards. I have a tough time situating the feeler gauge on the intake side plus the engine was slightly warm when I did it. i think I'll pick up an angled type feeler and do it when the engine is stone cold..

    Thanks! I'll let yo know how it turns out.
  • greenteagodgreenteagod Moderator
    Yeah set it cold and the easiest way to know is you can't fit the next larger feeler. Just in case your are having trouble getting the "slight drag" sweet spot.
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    Alright, been hunting this issue for a while now. Valve lash is perfect. Timing belt redone, new injectors, ignition coil replaced (primary winding slightly out of spec), and "metal shavings" removed from the inside of the distributor. Oddly, the shavings just messed up my tach readings. No idea why they were there.

    I have not confirmed the ignition timing since my light broke. However, the misfire happens after the engine is very warm, usually after sitting in traffic or about a half hour of driving. With the cooler weather rolling in, the misfires are less frequent. So it is definitely temp related.

    I'm thinking it is sensing knock. What do you guys think?
  • AbideAbide Council Member
    I had a misfire around 3-4k not too long ago and man it was rough. Found the plug hole full of oil. How are your plugs? any vac leaks?
    You need to check that timing too. Where in NH are you? Im actually just west of Nashua a bit.
  • jb2wheelsjb2wheels Wagonist
    Misfires on my bone stock DPFI 90 2WD wagon have been either:
    - oil in plug hole
    - bad plug wires

    The care ate plug wires until I put a set of NGKs on it. No problems for quite a while now.
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    Wires and NGK Plugs are new and the last time i pulled them, the color was normal. I do not recall if there was any oil in the hole. I'll check that and the vac lines.... and the ignition timing. Thanks!

    When I bought the car last December, the misfire was rough. At speed it felt like someone slammed into the car. It has been much better since i replaced a bunch of parts and did the timing belt.

    I'll located near Lee.
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    Update: I haven't been able to do any work on the Honda. However, today was unusually warm and my commute was longer than normal due to detours. So, engine was hotter than it has been. After a couple miles of doing 70 mph, the engine light comes on. It missed under load below 2k and above 3k. It missed A LOT. It was so bad below 1k that at a stop, I had to try to rev the engine to 2kish until the misfires stopped and then drop the clutch. Otherwise, dropping below 2k led to no power (many misfires). Then, 3k became my new rev limiter.

    This seems to be a limp home mode? I also noticed the engine bay was very hot... likely the EFI is retarding the ignition. The car is not overheating.

    I feeling the pressure to do the ignition timing this weekend. Any tips on doing that?
  • klumklum Senior Wagonist
    Live Fee or Die RT4WD wrote: »
    Update: I haven't been able to do any work on the Honda. However, today was unusually warm and my commute was longer than normal due to detours. So, engine was hotter than it has been. After a couple miles of doing 70 mph, the engine light comes on. It missed under load below 2k and above 3k. It missed A LOT. It was so bad below 1k that at a stop, I had to try to rev the engine to 2kish until the misfires stopped and then drop the clutch. Otherwise, dropping below 2k led to no power (many misfires). Then, 3k became my new rev limiter.

    This seems to be a limp home mode? I also noticed the engine bay was very hot... likely the EFI is retarding the ignition. The car is not overheating.

    I feeling the pressure to do the ignition timing this weekend. Any tips on doing that?

    mine has a slight misfire due to sticking injectors
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    klum wrote: »
    mine has a slight misfire due to sticking injectors

    Ruled that out with new OEM injectors.

    Engine light came on again this morning when it was cold outside! The wagon manual says to check the ECU for the LED flash count.... I counted 4 flashes. I can check what that means when I get home tonight.

    I did retard the ignition a tad just for peace of mind. I would rather it be low on power than ping.
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    4 flashes = check crank angle sensor. Resistance was within spec when cold. On a hunch, I pulled the distributor to get a closer look. I found a coupe things..

    -more metal shavings and shards
    -oil leak from the distributor (gasket is hard)
    -shaft play
    -shaft would bind when spun by hand
    -wear marks on crank rotor teeth (smacking against pickup coil)

    Regardless it this is the actual issue, the dizzy is being replaced. It's shot. Although, I have a pretty good feeling this is it given how a wobbly shaft would affect rotor positions. AND it'll fix my oil leak.. BONUS

    New one is on the way, I'll let you know how I make out. Driving the VW MK1 in the meantime.
  • Live Fee or Die RT4WDLive Fee or Die RT4WD Band Wagon
    Problem solved. Dizzy was broken. Not a single misfire now.
  • AbideAbide Council Member
    nice work, not long now before were gonna need em.
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