Jump to content
SAU Community

Recommended Posts

Hey everyone... My RB20DET is f**ked at the moment... Well in most aspects its fine, just when it starts coming onto boost it loses all power and backfires like a shotgun... When taking off and driving slowly with boost pressure in vacuum its fine but as soon as you put the foot down it dies in the ass... I've replaced 2 coil packs, the AFM, the o2 sensor, o/hauled alternator, checked fuel pressure, pump and reg.

Can anyone give me any ideas on what might be causing this??? Its starting to do my head in...

The ignition module is next on my list then the rest of the coilpacks but if that doesn't fix it then i don't know what i'm gonna try... its weird coz it idles fine and mostly revs fine when in nuetral, just when driving it and trying to boost it up its got nothing... (except huge backfires and flames...)

Double check sparky's. Its fairly easy to accidently crack the porcelain when torquing them up.

When my coil packs die I'm not going to waste time fiddling with second hand items, straight to nengun and a 3 week wait for me.

To me... it sounds as if spark is jumping to the point of less resistance, in other words look at your coil packs and or spark plugs.

Read the sticky thread on missfiring up the top of the General Maintenance section. Have you checked spark plug gap? You should try 0.8mm gap, using NGK Copper BCPR6ES spark plugs.

The thread also mentions steps you take to identify arcing coils, and how you can solve some of those issues. Try these steps first before anything else.

Fixxxer

hey guys... i'm still having problems... i replaced my plugs the other day with the gaps set to 0.6mm... I also pulled all my coil packs out, checked them, and taped them all up. I also replaced the ingition module on top of the cam covers and it has all made no difference... It still dies in the ass as soon as it starts coming onto boost!!! i'm gonna pull my fuel pump out next and upgrade that as one of my mates had the same problem and he said thats what fixed his... but other than that... any1 esle got any more ideas???

I am having the same problem...what u need is a fuel cut defender. r u running non-factory boost? if so, the ecu cuts fuel as the boost is raised to prevent damage. if u get a turbosmart fuel cut defenfer ($120~) and fit it, it tricks the ecu and ur car will run fine. When my car was doing it, i spent like $200 just on the iridium sparkplugs, thinking it was them, but its just ecu. Alternatively, u could replace/ tune ur ecu...hope this helps

if 2 coild have been replaced I'd be 98% confident its the coil packs. What power/boost u running?

There is a a sticky with about 500 members with this problem, most were fixed with new coil packs and/or re-gapped plugs i..e from 1.1 to 0.8 etc

I too had this problem and dispite all the DIY about taping them up etc, the coil can break down inside and die..just replace them. If you buy thorugh nengun expect a good 4 week wait. but good prices.

mine were crapola running 0.5bar with 175kw...Now I'm running with somew new packs and 275kw, 1bar and no worries with the spitfires (and the same plugs / igniter cos I have a S1)

that dude over in NSW will do a retuned eprom for the same price as the defender. could fix your problems plus performance gains...

sorry cant remember his nickname or website but u can get him at nic.danger@hotmail.com

speaking from a similar experience i had this week although mine was missing rather then backfiring. the problem started when platinum plugs were fitted by a smartass without my authority. i then replaced the plugs with cheaper copper plugs 0.8gap (as per SAU recommendations) and still had the same problem. if the gap is too small i was informed by someone (in another thread somewhere) that it also could have a negative effect causing it not to ignite the excess of fuel if the car is running rich.....?

in the end i lightly sanded back the contacts of my original old iridiums and it worked a treat.... i cant explain why the coppers didnt work but its gonna be iridium all the way for me now.

copper, platnium or iridium they all should work. I use the iridiums just cos I feel like it, but I have seen numberous results from others with copper stds which were really just as good.

there is nothing wrong with platniums..I'm guessing the gap was wrong in the first place or they were the wrong heat range.

as for the other issue, I put $5 down on coil packs if others have already failed and been replaced. Its like only replacing 2 plugs that are faulty. its likely the other are on the way out also just do the lot and don't waste ur time.

Someone had one a few years ago - similar to this problem. Turned out to be a crack in the weld of the IC endtank; it was fine under normal driving, but open up as soon as boost was applied.

The coughing and farting suggests overfuelling because the AFM has told the ECU how much air, but that air then escapes on boost.

Check all your connections and welds in the induction system.

mines playing up too, replaced the plugs with a smaller gap and has corrected a bit, as soon as i hit around 9psi it starts dying.

Have new splitfire coils on the way from Japan!

thanks for all your ideas guys... i've still got the problem and its now a little worse... i had a Walbro 550hp intank fuel pump fitted and now its mega overfuelling... I'm gettin pretty fed up with it now so i've gone out and bought a Microtech ECU and i'm just gonna fit that and start from scratch... i've done basically everythin except ECU... the plugs, coils, alternator, AFM, ignition module, I/C piping and fuel pump have all been covered so i think this is my last straw...

I'll let you all know if i have any luck...

  R31HOOCH said:
thanks for all your ideas guys... i've still got the problem and its now a little worse... i had a Walbro 550hp intank fuel pump fitted and now its mega overfuelling... I'm gettin pretty fed up with it now so i've gone out and bought a Microtech ECU and i'm just gonna fit that and start from scratch... i've done basically everythin except ECU... the plugs, coils, alternator, AFM, ignition module, I/C piping and fuel pump have all been covered so i think this is my last straw...

I'll let you all know if i have any luck...

wouldn't the fuel pressure reg stop it from over fueling?

im thinking that the ecu would be a work around rather then a solution. Iv done the plugs afm etc.. but still waiting to replace my coils, they should come in today or tomorrow!

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


  • Similar Content

  • Latest Posts

    • Well, I was going to say, "Is the wastegate set up so that it is not leaking?" That's actually a different thing to what you're asking about. In theory, if you have allowed the two halves of the manifold to commmunicate (more than the stock manifold does - which is at least a little bit) then the negative effect should be apparent in delayed spool, not in outrigth power. OK, maybe just maybe, a badly set up twin scroll wastegate "crosstalk" might kill the top end, although it's hard to see how. What is happening with the original wastegate in the turbo? is it sealed off properly. If it's left flapping in the breeze, it will f**k everything up. If it is still there, and can be returned to service, I'd be capping off the external (presuming the two halves can and will be isolated from each other after doing so) and have a go with just the stock wastegate. I have an internal wastegate in my highflowed rear housing. The bigger opening and flapper should be fine to >250 rwkW. So there's not exactly a pressing reason to have the external. Done right, an external will give better results. Done wrong, it might just be possible to have worse results. Report back!
    • Hi Rob It's a nistune ecu. Yes same shop, good reputation. Apparently the computer on the dyno is compensated for temperature.    Chris was saying that the lean or richness of the mixture would be covered in the actual tune, but he's already picking up in advance that it's under what it should be. Regards the dyno, it's also noticeable on the road. But I just want to add something that has just come in, it appears there might be something in the setup of the external wastegate. In the exhaust manifold there is a centre divider between the front three and rear three cylinders. The external wastegate has a pipe from each side that join at the wastegate. Theory is those two pipes just might be pypassing that divider and introducing a problem somehow. Is anyone familiar with the divider in the exhaust manifold and the effects if the two wastegate pipes were to create a bypass path? Thanks for your questions Rob, interested in your thoughts on this external wastegate bypass theory. Regards Rob
    • Meh, At 60 years old, I have been doing dumb stuff for much longer than you mate, I am the true King And unfortunately I cannot be a maroon, as I am not brownish red As for not getting ITB's, the plenum intake will apparently show typical gains across the board and increase induction noise a bit, but, have all over less dort than ITB's Cost difference for the extra ITB dorts was significant though, the total parts for the plenum set up is "around" $2kAUD plus shipping, the ITB's were $4kAUD plus shipping, I was contemplating really hard about paying the extra $2k for all of the dorts, but weirdly, some form of common sense, from listening to the platform experts prevailed  As for the NA mod hate by some, I've had a few boosted cars, with all their inherent issues, I'm now looking at simplicity and legalities for a street car, maybe I'm just getting old, and I'm quite happy to spend some of the kids inheritance, 5kw at a time 馃ぃ And think of all the money I'll be saving on consumables that something with boost needs, like engines, gearboxes, diffs, clutches,  tilt trays... etc. etc. etc. 馃お
    • Haha.  I wouldn't say I am either but I've definitely been around it plenty.  I'm guessing you know the dial in is basically to make a handicap to level the playing field between racers.  The car with the slower dial in goes first and in theory if they run their dial in time and the faster car also does then they cross the finish time if they also have exactly the same reaction time - if you go faster than the dial in them you lose, but if you are too slow there's a good chance the other person will get to the finish line first. I'm normally supporting other cars but they were all pretty dialled and were egging me on to race as well, here's one of the cars I tune (Starlet) which ran within like 1 hundredth of its dial in through the competition: https://www.youtube.com/watch?v=inEBu-d9Gn4&t=69s
    • Where ever the fuel reg gets it reference is what I use to T into for map reference been a very long time so where it goes to plenum/runners I have no idea but never had issues. 
  • Create New...