R34 Gtr - Missfire @ Approx 2500Rpm / Low Rpm

[iwanta34gtr]

Hi Everyone,

Getting a misfire / hesitation in my R34 GTR, at low RPM - approx 2500RPM.

Changed the plugs today and put in with NGK Platinums but its still there.

My initial thoughts are coil packs.

Is there anything else in particular that I should be checking or that could be causing the issue? (Injectors - etc)

Cheers in advance.

[Hadouken]

I would have said plug gap, but your off boost.

Lock in coilpacks eddy

[iwanta34gtr]

Thanks mate, time for some splitfires.

[Owgasm]

Packs

[iwanta34gtr]

Thanks Simon, appreciate the confirmation mate.

[GTRNUR]

I'll be different and say, virtually no chance at all its the coil packs.

You changed the plugs and it developed a miss. Therefore thats whats wrong.

Did you try your old ones again? Try that first and see how it goes.

What are the plug codes on the new plugs? I've used BKR6EIX with 22lb boost and 0.8mm gaps with stock coil packs, 470+hp atw no problems. If your tune is right they won't foul up.

Check you haven't left a hose clamp un-done if you also had part of the intake system apart recently. At 2500 RPM the turbo's start making a little boost. If you have an air leak post turbo's, it will run rich and can blow out the spark as a result.

[iwanta34gtr]

I'll be different and say, virtually no chance at all its the coil packs.

You changed the plugs and it developed a miss. Therefore thats whats wrong.

Did you try your old ones again? Try that first and see how it goes.

What are the plug codes on the new plugs? I've used BKR6EIX with 22lb boost and 0.8mm gaps with stock coil packs, 470+hp atw no problems. If your tune is right they won't foul up.

Check you haven't left a hose clamp un-done if you also had part of the intake system apart recently. At 2500 RPM the turbo's start making a little boost. If you have an air leak post turbo's, it will run rich and can blow out the spark as a result.

Hey mate,

Thanks for the reply.

The miss was there before I changed the plugs, was hoping that changing the plugs would solve the issue.

The car is completely standard. The plugs I used are NGK Platinum PFR6A-11.

Cheers.

[GTRNUR]

Ah, I didn't realise the miss was there before the plug swap.

In that case... you can try close up your plug gaps a little and see if that makes the miss go away.

Also, the checking for air leaks still applies.

Even split vacuum hoses, like the one from the back of the vacuum manifold that goes to the MFD map sensor can cause a sufficent enough leak to cause a miss.

If those checks fail, then I would also be inclined to think coil packs. Buying a set of splitfires to diagnose straight off the bat is a bit excessive IMO.

[iwanta34gtr]

Check you haven't left a hose clamp un-done if you also had part of the intake system apart recently. At 2500 RPM the turbo's start making a little boost. If you have an air leak post turbo's, it will run rich and can blow out the spark as a result.

Thats a good point, I was also thinking it may have a leak a few days ago?

Its just before it comes on boost it misses approx 2500 RPM and then boost will just kick in hard.

And also when just on a staight road cruising for example in 5th, low RPM - it will miss around 2,500RPM.

Havent been able to see any obvious leaks though.

Also put a new K&N high flow panel filter in this morning, no difference (still missing - before and after).

[iwanta34gtr]

Even split vacuum hoses, like the one from the back of the vacuum manifold that goes to the MFD map sensor can cause a sufficent enough leak to cause a miss.

If those checks fail, then I would also be inclined to think coil packs. Buying a set of splitfires to diagnose straight off the bat is a bit excessive IMO.

Cheers mate, will take a look in this area tomorrow.

[Owgasm]

Yeah, well replacing the plugs is the cheapest option and you hope that it fixes the problems.

Next i'd try coilpacks, as they are at least 10 years old now.

Just like the R32/R33s, they need to be replaced eventually.

edit: slow to submit post.

Perhaps try to borrow a set from someone in Sydney?

[iwanta34gtr]

Yeah, well replacing the plugs is the cheapest option and you hope that it fixes the problems.

Next i'd try coilpacks, as they are at least 10 years old now.

Just like the R32/R33s, they need to be replaced eventually.

edit: slow to submit post.

Perhaps try to borrow a set from someone in Sydney?

Hi again mate,

Cheers for the reply.

Yeah I've had coil packs fail for me in my S15's and R34's previously too. (Example - one day my S15 started sounding like a rexy)

Had a close friend help me change the plugs today and check out the packs, he used to be a mechanic by trade - he also said they looked like they weregetting on with age and would most likely need to be replaced.

I also did change the fuel filter the other day, made a difference for when it comes on boost, but obviously didnt fix the miss under low RPM.

[iwanta34gtr]

Also, jjust remembered when i picked up the car the timing was completely retarted.

My mechanic rectified this, and also fixed the idle as it was a bit high.

Dont know if this could be a contributing factor and would need some further attention?

Just thought it may be worth mentioning.

Ironing out the bugs. Love it.

[Owgasm]

The way I see it, not sure if correct:

When coilpacks get old, they tend to crack/split and with that the current isn't concealed and you get an uneven current to the spark and therefore missing.

Normally the cracks are hairline and you can't really see them, but sometimes you do.

Best bet and to save you money. Borrow another set if someone is kind enough down that way.

See if its 100% the coilpacks. If it is, replace them, or if you can be bothered, work out which one it is and replace.

[GTR-N1]

Yes, the pit holes or scorch marks may not show up very well > smear some silicone filler around the packs and cover with electrical tape to ascertain if there's an improvement albeit temporarily.

[iwanta34gtr]

Sweet, thanks again mate.

[iwanta34gtr]

Just thinking - while on the topic, curious on everyones thoughts.

Replacement coil packs - Splitfire or OEM genuine Nissan ones?

Recommendations?

[Hadouken]

yellow jackets

theres a big thread about splitfire vs yellow jackets vs oem

[Owgasm]

Genuine Nissan ones are the best.

But they're either really expensive or you can't get them anymore.

The rest are debatable.

[iwanta34gtr]

Genuine Nissan ones are the best.

But they're either really expensive or you can't get them anymore.

The rest are debatable.

Thanks for the tip, much appreciated.

yellow jackets

theres a big thread about splitfire vs yellow jackets vs oem

Thanks for letting me know, will have a search and read now.