Jump to content
SAU Community

Misfire In First Gear?

Ep82jm

By Ep82jm,
in General Maintenance

 Share

Recommended Posts

Ep82jm Rookie

Ep82jm

Posted
Posted

Hi,

So the r33 has developed a misfire again. Strange thing about it is it's only in first gear and very very seldom it happens in second gear too but happens every single time in first when I boot it,but if I build the boost up slowly it's fine.

It isn't like the coilpack related misfire I had before where it just stutters,this time between 4-5k it splutters and pops and bangs

Doesn't happen in 3rd 4th or 5th at all.

I'm running stage 1 mods plus walbro pump,benchmark coilpacks and rsp stage 1 ecu.

Coilpacks were newly fitted in February of this year so I'd imagine it isn't them although I wouldn't rule them out.

Spark plugs wer put in around 5 months ago and are gapped correctly.

Today I took all plugs and coilpacks out and all look normal.

Changed air flow meter with no difference.

New lambda sensor yesterday which again made no difference.

Car is running perfectly bar the misfire and is going as well as I could expect power wise through the gears.

Any ideas on what to try next?

Think I'll borrow a set of coilpacks from someone local to try rule them out or so I can sent them back under warranty if needs be but I'd imagine if they were at fault I'd get the misfire in all gears and especially in higher gears at full boost due to being under more stress/load?

Should I be changing the plugs again even though they are only a few months old and have done less than 1000miles? Again I'd imagine plugs would make it occur in more than just first gear though?

Any suggestions would be great.

Thanks

Link to comment
https://www.sau.com.au/forums/topic/457944-misfire-in-first-gear/
Share on other sites
Ben C34 Grand Master

Ben C34

Posted
Posted

What do you mean advanced timing is correct? First I've heard someone say that in relation to an efi car.

What's a stage 1 ecu?

Only in first is odd, but the rev range you mentioned is what a coil pack misfire would first become noticeable.

What gap plugs you running?

Ep82jm Rookie

Ep82jm

Posted
  • Author
Posted (edited)

What do you mean advanced timing is correct? First I've heard someone say that in relation to an efi car.

What's a stage 1 ecu?

Only in first is odd, but the rev range you mentioned is what a coil pack misfire would first become noticeable.

What gap plugs you running?

Ignition timing at idle.

Stage 1 ecus are made by a lot of different companies,it's basically a chipped ecu I suppose,company maps a skyline for x mods and then puts that map on multiple ecus. Obviously I know this isn't exact to my car but they are generally used to get rid of the flat spot from running higher boost etc on the stock ecu and the car has been fine for months whilst running this ecu. I have an apexi pfc lying to go on the car but no point fitting it while the car is misfiring.

Plugs are gapped to 0.8,heat range 7s.

Yea I just find it strange that a coilpack would only cause a misfire in first gear though,last time they went I had the 4-5k misfire in every gear. I'm going to fire a set of plugs in it tomorrow to check,again I'd expect them to show in more than just first gear and I'd especially think they would last more than 1000 miles.

Forgot to mention I also replaced the fuel filter incase it was causing a problem and still no luck.

Edited by Ep82jm
Ep82jm Rookie

Ep82jm

Posted
  • Author
Posted

This is not gran turismo. We use big boy mods. We don't have stages of hektik modification.

And it sounds like spark blowing out.

LOL! it was bought just to see if it got rid of the flat spot I was experiencing when I first got the car. Have collected bits to run "big boy mods" and will be getting them all fitted during the winter while the car is off the road.

Thanks for the suggestion! So new plugs and gapped to 0.8 again or should I drop to 0.7/6?

Ep82jm Rookie

Ep82jm

Posted
  • Author
Posted

Yep drop them to 0.7/0.6 and see if the miss is gone. It would be a quick way to see if you have weak spark.

Then report back

Ok so i dropped my original plugs down to 0.6 there and the misfire is gone!

So should i just leave them at that or is that only masking a problem? E.g coilpacks breaking down and not producing a strong enough spark? im only running .85 bar so i would have thought 0.8gap would have been ok for that boost?

Ep82jm Rookie

Ep82jm

Posted
  • Author
Posted

You need to get yourself a new set of coil packs then you should be able to run spark plugs at 0.8 gap again.

If it were my car running that little boost I'd leave it at 0.6 gap til you can get some new coils.

Coils are only new 5/6 months ago too so ill fire them back under warranty.

Thanks for your help in getting it sorted,appreciate it!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • PranK
      Should I use rust converter on this?

      By PranK · Posted

      Sorry the pictures suck. So hard to get camera and light in there
    • PranK
      Should I use rust converter on this?

      By PranK · Posted

      One of the first jobs with the E39 is making sure the tailgate stays up. In BMW fashion they made a little cavity under the roof to hide the dampers rather than putting them down the side like everybody else.  As you can see I have these little cavities that house the dampers. When I cleared one out and vacuumed as much crap as I could out of it I noticed a fair bit of rust. The cavity is bone dry, even after all that rain we had only a few days ago so I'm assuming that whatever allowed the moisture in is fixed but I'd like to treat the rust in there.  I was thinking of just blasting it full of rust converter but I didn't know if this would be beneficial considering I can't actually get in there to prep anything.  Maybe there's a better product?  Thanks guys
    • fatz
      Beers and skylines Fatz style

      By fatz · Posted

      Had a few skylines over the years anyway bought this a few years ago for skidz i think it’s been around these traps for a while anyway I plan to thrash and trash and I assume it’s going to send me broke good times
    • GTSBoy
      Help Understand GTT Boost Setup

      By GTSBoy · Posted

      The stock boost solenoid is just a valve. Power it and it is open. Unpowered, it is closed. When it is closed, there is no boost bleed out through the solenoid back to the inlet. The wastegate sees all the boost pressure, thus you get the wastegate's spring pressure as your boost pressure. 5 psi. When it is open, it lets some boost escape. This causes the static (boost) pressure in the line to the wastegate to be lower than the pressure in the intercooler pipe. There is probably a small restrictor in the solenoid or one of its lines to limit the flow rate of the escaping air, which limits how far the static pressure can fall, which limits the extra boost. The boost has to climb above the original/wastegate setpoint until the wastegate sees 5 psi. You get 7 psi in the intercooler pipework. A manual boost controller is exactly the same setup, just without the ability to change it on-off. It's always set to whatever you set it to. There is a small leak from the boost controller. The more you screw the adjuster in, the more it leaks, the lower the pressure seen at the wastegate and the higher the boost will be. So, yes, your diagrams are correct.
    • DraftySquash
      Help Understand GTT Boost Setup

      By DraftySquash · Posted

      Hi everyone, Apologies in advance if this feels like a topic covered multiple times. I'm only asking because some of the old topics I found are missing images now. I'm in the process of getting a manual boost controller (BC). Nothing fancy, just getting a manual one for now as I don't plan to go crazy with it and would not go over 10 PSI. My car is not jacked up on boost steroids to do crazy numbers. I want to understand the OEM setup of the boost solenoid and vacuum lines on the R34 GTT so I know what needs to be changed when I do install the BC. I sketched the current setup to the best I could see and it's on the diagram attached. If the boost controller 'Wastegate Arrow' goes from nipple 1 to 2. My understanding is that the red vacuum line's "F" connector-end should be connected to BC nipple #2? Nipple #1 is meant to have the "pressure source" so what vacuum line would that be? Is it the green vacuum line?  From what I have read here, the OEM boost solenoid is not used at this point. So that can come out and then I can just plug the nipple that usually connects to the blue vacuum line?  So would the final setup look something like this?   Thanks in advance. I don't want to already be knee-deep into pulling out vacuum lines before understanding this. I'm a noob when it comes to boost setups so trying to learn as I go.
×
×
  • Create New...