Jump to content
SAU Community

Recommended Posts

Currently have annoying misfire problems. The engine is RB30neo, after taking car to reputable tuner he replaced cas with secondhand cas , a coilpack, std fuel reg, fuel filter and said the fuel injectors are dirty and fuel filter was blocked.  So he road tuned car and said its better now.

Original issue was it running like a wrx for first 10mins, after that it was a rocket.

So now after it being at the workshop, it still starts like a wrx and now it has a strong misfire at 4k, right at the point it used to start breaking traction.

So i started it up and pulled one coil out at a time, cyl 3 and 5 not firing.  These coilpacks are brand new, have replaced them twice now.

So my question is what can cause cyl 3 and 5 to randomly not fire? Or are these splitfire coils fake copies?

Link to comment
https://www.sau.com.au/forums/topic/475431-misfire-problems/
Share on other sites

3 hours ago, iruvyouskyrine said:

1. get a new tuner 

2. never seen fake splitfires

3.get your multimeter out and start continuity and voltage checking. Also inspect loom for damage.

Yep that workshop gone to shit for sure.. not happy..

This morning i tried again, and cyl 3 and 5 dead, so i put 2 old coilpacks in and she ran sweet except heavy breakdown under load later when was hot.

So whats the chances of 3 brand new coilpacks failing on a cold start?

Loom is brand new from kudos, plugs new also..

What about the cas or ecu, can they play these kind of games?

I dont really have a clue about multimeter testing.

CAS "might" be cooked and the ECU is unable to determine a home signal, i.e. 1x full revolution of the CAS to determine TDC.

This could affect your car starting, however without using any tools it might be hard to diagnose.

 

Maybe try record your PowerFC hand controller with a GoPro or phone and see if there's a RPM when the CAS is rotated OR the car is cranked.

19 hours ago, AngryRB said:

Yep that workshop gone to shit for sure.. not happy..

This morning i tried again, and cyl 3 and 5 dead, so i put 2 old coilpacks in and she ran sweet except heavy breakdown under load later when was hot.

So whats the chances of 3 brand new coilpacks failing on a cold start?

Loom is brand new from kudos, plugs new also..

What about the cas or ecu, can they play these kind of games?

I dont really have a clue about multimeter testing.

The coilpack harness might be new but i bet the main engine loom is not. I would start looking where is passes the exhaust, where it passes through the firewall and around the ECU header plug.

Youtube how to continuity test with a multimeter, its an excellent skill to have and difficulty level is 2/10.

1 hour ago, mr_rbman said:

Sounds like a similar issue i've had...

You running a Z32?!

Yep a z32, today again cyl 5 so i switched it with cyl 6 coil and just like that all 6 firing...

Will start looking into the multimeter idea and the cas test.. 

 

4 hours ago, AngryRB said:

Is this plug helping? Last set was a BKR7E that had a split in the electrode

20181123_094525.jpg

20181123_094548.jpg

That's a hot plug man, no way would I use that in a higher boost application (or any boost for that matter)

  • Like 1
On 11/23/2018 at 7:49 AM, AngryRB said:

Is this plug helping? Last set was a BKR7E that had a split in the electrode

 

 

 

On 11/23/2018 at 7:49 AM, AngryRB said:

Is this plug helping? Last set was a BKR7E that had a split in the electrode

 

20181123_094548.jpg

Is it just me or is that plug gap huuuuuge?!?!?!

  • 2 months later...

Small update, i changed the plugs back to BKR7E and she has all the power back with no misfire's... 

The issue still remains, that is i start it and its on 5 cylinders until i drive up the road and load it up in second gear , then it seems to clear up and runs perfect.. except for it usual jerkiness on very light throttles which i assume is the camshafts or maybe tailshaft slop..

So what could it be that clears up with some load applied, could injectors be need8ng cleaned after 10k and using ethanol? Diesnt ethanol clean shit???

Tuners explains it as it must be dirty injectors but after he put shit plugs in not sure if hes right...

Coolant is not going down and fuel economy is good, power is good, its just cold start on 5cylinders till loaded up.

Edited by AngryRB

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

    • Sounds like you've got an interesting adventure ahead here with local support if you have trouble! My guess is that, unboosted, you will be OK with a small upgrade like -9. What will happen is that once the stock ECU sees more airflow than it expects it will add a heap of fuel and pull a heap of timing to be safe because it can't understand how it could get that much air without there being an issue. You will see clouds of black smoke and it won't pull hard through the midrange and top end. So, overall it will be a bit frustrating but should be OK. If you are still nervous set the base timing back 2o through the CAS, but it will be even more sluggish everywhere. As said above through...this is not my guarantee your engine won't be blown into a million pieces, leaving you looking for very hard to find parts A better idea is get a computer with logging ASAP, wire in a wide band O2 sensor and a use remote tuner. I've done multiple cars this way and while it is not as good as a specific tune on a dyno they can get it 90% right. I'd suggest if you can afford an R33 GTR these days you can afford an ECU and tune. And if you can't afford that you sure won't be able to afford the rebuild if it goes bad in the meantime,.  
    • Yeah it would be nice if someone took the time to put that sort of information together, but there are a lot of variations in looms. I think you are making this way hard for yourself if you just want to get it running....sourcing an SR20 with the right wiring will be a billion times easier than matching the RB loom to an S15 chassis. If you do end up going this way, you just need to trace every wire in the loom with a multimeter, 95% of them will go to a location you can confirm at the ECU.....and then post it up for the next person who needs it  
    • Just top it up with water, and keep a general idea of how much you added. It is normal for water to be pushed into and pulled out of the reservoir through the cap, and it should not be more than half full or it will be likely to overflow when hot. Any decent mechanic can do a pressure test of the cooling system to confirm if you have a leak. Keep in mind if it is only leaking a little and when hot it may well evaporate before you see it hit the ground
    • I'd ask the shop what they used and use that. Mixing coolants is sometimes OK, sometimes not, and you have know the details of each coolant to know whether it's a good idea or not.
    • Is it alright to top up with just another green coolant?
×
×
  • Create New...