Jump to content
SAU Community

Missfire Boost@4500-5500 RPM - The Answer! (for me at least!)


Recommended Posts

  • 2 weeks later...

Hey all... I'm havin some problems with my RB20DET thats in an R31... Its a silvertop RB20 from an R32 and its running the standard R32 ECU with basic mods such as FMIC, 3" exhaust and pod filter... I went through a huge puddle a few weeks back and ever since its just been problems... That day after going through the puddle, it started stalling when the revs were coming down as i was clutching in and braking to stop... The first few times it started staight back up but after a while it started being a real bitch and took a good cranckin as if it were flooded or out of petrol or somethin... The thought came to me that some of my coil packs or the ignition module got wet or somethin so i went and fuelled up the drove it around for a while... After about half an hour it seemed to be all sweet again so i drove around for the rest of the day...

When i went to start it up the next day, it just fired up then died straight away... I pursisted with this until finally with a little bit of pedal pursuasion it spluttered to a steady idle... When i went to drive, it was fine whilst taking off and going slow with boost pressure still in vaccuum but as soon as i start to put my foot into and it starts coming onto boost i just lose all power and it starts broad minded persontering and fuelling up then usually lets of a big backfire with a nice flame... It is the same in all gears in all conditions... Recently i have replaced 2 coil packs, had the alternator overhauled, cleaned the AFM, checked all intercooler piping, replaced the O2 sensor and checked the fuel pressure, pump and regulator...

Has any1 had similar problems or have any ideas on what the problem might be??? Its really starting to do my head in!!!

Cheers every1...

  • 2 weeks later...

take off the intake pipe going across the engine to the throttle body, take off the cover between the cam covers, then rip em out

Fark!

mine were fine but couldnt get the spark plugs out to check them, they are only 1 month old too!

every size socket except the one i needed, will check them on the weekend.

BTW, mine only started after i cleaned the aac!

take off the intake pipe going across the engine to the throttle body, take off the cover between the cam covers, then rip em out

Fark!

mine were fine but couldnt get the spark plugs out to check them, they are only 1 month old too!

every size socket except the one i needed, will check them on the weekend.

BTW, mine only started after i cleaned the aac!

Damn spark plugs, issue fixed.

even though they were 1 month old iridiums! lower gap now too! :mad:

once I replaced my coil packs with spitfires my problems when away...I also replaced with soem NGK XIs later on...works awsome now.

hope it does for me. Tracking the package from japan shows that they arrived @ aus post from customs yesturday, so should be here today, whoo hoo!!!!

I just replaced my lecky tape with industrial grade silicon. Works perfect. Pretty good for $11.00.

Feel sorry for all the guys out there who have bought splitfires when all the time it was just probabaly just a crack in the coil.

results are in.

I checked my coils twice and even had a mech check them, nothing visable!

Just due to general wear i guess

Put in my split fires last night, all good now and car feels smoother!

Sweet. up the boost goes again :(

Let me also say that I could not spot any cracks either. But apparently I had them. There was no scoring or lines anywhere but it was guarenteed to miss at 4500RPM.

I would suggest that all people at least try this mod before buying splitfires.

Let me also say that I could not spot any cracks either. But apparently I had them. There was no scoring or lines anywhere but it was guarenteed to miss at 4500RPM.

I would suggest that all people at least try this mod before buying splitfires.

The dark shed is a good way to tell, warm the car up and run it in a dark shed with the valley cover off, spray some water mist over the top, if they are cracked you should see small blue arcing. Go easy on the water though.

  • 1 month later...

Well I finally got some splitfires, at the same time I replaced the plugs with new ones with a 1.1 gap (old ones were down to .6. Took it for a spin then and it poped once at 5500rpm out of about 6 high rpm 2nd gear runs.

Pretty happy with the result, it used to pop like crazy and loose lots of power once I hit 5k.

Ill see how it goes this week and if I keep getting a few even minor pops at those revs Ill gap the plugs down to .8 and it should be perfect.

Edited by Rolls
  • 3 weeks later...
4 days later with the new plugs. the problem returns.

Has anyone got some decent pics of what they taped?

Might have to try this before i fork out 600 for splitfire coils.

Jase, before u shell out for coils let me try something on mine first and ill let u know if it works....going to try the silicon & tape trick

Might just save us some $$

Jase, before u shell out for coils let me try something on mine first and ill let u know if it works....going to try the silicon & tape trick

Might just save us some $$

Try tape first as it will only take 30 minutes or so. Tape works fine...but it doesnt last longer than a couple of months. If the tape works then silicon is the way to go.

I had no visible cracks on mine either but silicon fixed it.....after I narrowed it down to the coils with tape.

Good Luck

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



  • Latest Posts

    • Howdy all Im in a little predicament and wondering what everyone’s thoughts are? I’ve had my long block rebuilt and am in the market for a turbo due to my old one having metal shavings from crank bearings (cause of rebuild) go throughout the turbos oil lines and there wheel has a little play. I’m not really aiming for any power, just trying to keep it as oem as possible, but I can’t find a turbo that’s built for the stock ecu or find something that would be a standard replacement. Anyone have any ideas or suggestions 
    • How's everyone going? Just a shout-out introducing myself. I'm James, I live on the north side of Brisbane. I bought an R33 that had been left to rot in someone's front yard for 14 years. Apparently, it has immobiliser/fuel issues. Long story short, it's suffering from a seized engine, plus whatever else turns up once it runs. The car is pretty good considering it sat for so long. It pretty much died after being imported. It has a bunch of Jap parts and a full Top Secret body kit. It's painted Fiat Turchese Festival, or aqua blue if you're not French. Another project to throw money at!
    • So the clockspring is responsible for the indicators cancelling on their own? I thought that was the function of that white thing in the center (any idea what it's called?)
    • Can you log IAT? Whilst WTA coolers have their place, doing any sort of sustained run is not one of them There are fixes that slow down the heat soak, like ice boxes, which don't last that long, and interchillers, which are fairly expensive, up grades to the WTA cooling radiator, which may require a bigger pump, and upgrades to the reservoir size,  and upgrades to the cooling fans, but, it all still heat soaks, and takes ages to come down in hot weather  For a turbo, that isn't locked into WTA like my PD blower is, can you not possibly swap to a nice air to air intercooler????, it would be better for sustained runs then, and have alot less things that could go wrong in my opinion 
    • So, the other thing I've sorted is a baseline dyno run up at Unigroup's new location. The auto trans was a little unco-operative by both shifting down when the throttle was floored on the dyno (so Mark had to ramp it up more slowly than in a manual) and also by shifting up at 6,000 even in sports mode instead of the indicated redline of 7,000 Still, on a hot day it made 240rwkw at 16psi which seems about right for 300kw (400hp) through an auto at the wheels.  The shape of the curve is not quite right because it was not full throttle to about 4,500 to stop it kicking down, but until I can get a tune on the auto trans control this was the best we could do.....full boost will be well below 5,000 once that is sorted, I'll get some data logs when I can to confirm For comparison, the R32 made 255 at 12psi (at 4,500) on the same dyno with tune, n1 turbos, cam gears, big exhaust but otherwise all standard so the v37 is likely a little better out of the box. One thing that is very clear is that the standard water to air intercoolers are not up to sustained use at full throttle in warm ambient temps. After about 5 runs (so only a few minutes full throttle), it was pulling boost and timing and dropping 10-15% power. Unfortunately I didn't get that printout and the Unigroup guys are away at the moment, will try and get hold of it on their return. So, looks like a healthy engine to start modifying and the only real area of concern is the w2a heat exchangers which the aftermarket has plenty of solutions for    
×
×
  • Create New...