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Misfire problems

AngryRB

By AngryRB,
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AngryRB Grand Master

AngryRB

Posted
Posted

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?

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AngryRB Grand Master

AngryRB

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  On 20/11/2018 at 1:13 AM, 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.

Expand  

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.

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

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.

iruvyouskyrine Grand Master

iruvyouskyrine

Posted
Posted
  On 20/11/2018 at 4:51 AM, 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.

Expand  

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.

AngryRB Grand Master

AngryRB

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  • Author
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  On 21/11/2018 at 7:58 AM, mr_rbman said:

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

You running a Z32?!

Expand  

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.. 

 

Ben C34 Grand Master

Ben C34

Posted
Posted
  On 22/11/2018 at 11:49 PM, AngryRB said:

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

20181123_094525.jpg

20181123_094548.jpg

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

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mr_rbman Grand Master

mr_rbman

Posted
Posted
  On 22/11/2018 at 11:49 PM, AngryRB said:

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

 

 

Expand  

 

  On 22/11/2018 at 11:49 PM, AngryRB said:

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

 

20181123_094548.jpg

Expand  

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

MrStabby Grand Master

MrStabby

Posted
Posted
  On 26/11/2018 at 7:08 AM, mr_rbman said:

 

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

Expand  

The 11 in the number will refer to 1.1mm gap, so yeah that big gap would explain the break down under power.

  • 2 months later...
AngryRB Grand Master

AngryRB

Posted
  • Author
Posted (edited)

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

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