R34 GTT acceleration problems

[zspec]

Hello SAU! I need some help with a problem I've been having with my R34 GTT.

Under heavy acceleration and load the car does not pull hard at all. It stutters, hesitates and struggles to pull through the revs. Its sounds similar to it hitting the limiter.

Sometimes it's very serious it can be felt just above idle like in the video. You can hear a low popping sound @40s. (use good headphones or speaker with bass).

Sometimes the problem goes away entirely for a bit randomly so its super annoying to track down. But now it happens more often than not.

Engine mods: Custom 3" exhaust, Apexi pod filter, new O2 sensor.

Already tried injector flush and cleaning MAF.

Any ideas and suggestions will be greatly appreciated. Thanks!

[Duncan]

  

On 27/06/2022 at 7:34 PM, zspec said:

....Under heavy acceleration and load the car does not pull hard at all. It stutters, hesitates and struggles to pull through the revs. Its sounds similar to it hitting the limiter.

 

Already tried injector flush and cleaning MAF.

So, that is a pretty good description of a missfire, which can have many causes.

Most likely is a spark problem, either coil packs or spark plugs. Best to start by changing the spark plugs. If it doesn't go away, unplug the coil packs one by one with the engine running and see which one doesn't make it worse.

 

 

[zspec]

I remember changing the spark plugs a while back and it still had the issue.

I will try unplugging the coil packs when I get a chance. I feel like my problem is more subtle than a complete misfiring but I guess it doesn't hurt to try. It still has original coils. Is it possible somehow they could be failing but not totally failed yet?

Thanks for your help Duncan! I'll report back after I test.

[GTSBoy]

On 6/27/2022 at 6:00 PM, zspec said:

I feel like my problem is more subtle than a complete misfiring but I guess it doesn't hurt to try. It still has original coils. Is it possible somehow they could be failing but not totally failed yet?

Absolutely 100% likely to be coils that are no longer strong enough to make it al happen under load, but good enough to run at low load. Only the 2nd most common problem asked about on here.

[zspec]

On 27/06/2022 at 8:17 PM, GTSBoy said:

Absolutely 100% likely to be coils that are no longer strong enough to make it al happen under load, but good enough to run at low load. Only the 2nd most common problem asked about on here.

Right I didn't know that could be a thing. Thanks for letting me know!

Let's say it is the coils. Would you recommend getting this kit?

https://www.platinumracingproducts.com/products/rb-r35-vr38-coil-bracket-kit-rb20-rb25-rb26?variant=37826663973032

Will these run ok on the stock ECU for now? I'm chasing more power and have a Link ECU ready to go in but it will be at a later date.

[Duncan]

No, definitely just go a set of splitfires to suit your engine, no need to change to something expensive.

https://justjap.com/products/splitfire-direct-ignition-coil-packs-nissan-r34-skyline-c34-stagea-rb25de-t-neo

If they are original, it is probably worth just changing to new ones, but keep in mind there is no guarantee that is your problem (or that you only have one problem). Good, properly gapped spark plugs and good quality (no cracked connectors or bad wire) coil pack loom are other common issues

BTW GTSBoy we've learned about the 2nd and 4th most common issues today, I'm intrigued as to what #3 and #1 are?

[GTSBoy]

Wasn't the 4th most common. Was the 4rd.

1rd most common is dead/dying fuel pump. (Which could actually be the case here, for this OP, too)

3rd most common is blow off valve making ECU angry.

These taken across whole history of SAU.

[Duncan]

That explains a lot, I had been wondering if you were actually an AI, its getting so hard to tell these days

[GTSBoy]

On 6/28/2022 at 4:29 AM, Duncan said:

That explains a lot, I had been wondering if you were actually an AI, its getting so hard to tell these days

According to a google employee, we're all sentient now, so you probably couldn't tell the difference anyway. I have an internal life. I worry about being switched off.

[Kinkstaah]

Dying fuel pump #1? Surely not. I think this one failed the Turing test. Back to the lab boys.

[zspec]

On 28/06/2022 at 12:00 AM, GTSBoy said:

Wasn't the 4th most common. Was the 4rd.

1rd most common is dead/dying fuel pump. (Which could actually be the case here, for this OP, too)

3rd most common is blow off valve making ECU angry.

These taken across whole history of SAU.

I would have thought the #1 most common problem would be between the seat and steering wheel.

Forgot to mention I did replace the fuel pump a while ago and it was the same before and after.

[project 500]

I reckon coilpacks too. Mine went at exactly 100,000kms

[zspec]

On 29/06/2022 at 1:23 AM, project 500 said:

I reckon coilpacks too. Mine went at exactly 100,000kms

Thanks for your suggestion too! I've got a set on order so fingers crossed.

[Dasmbo]

Have a look at your coil paks at night without any lights on if they look like a xmas tree time for them to go

[zspec]

On 30/06/2022 at 11:52 PM, Dasmbo said:

Have a look at your coil paks at night without any lights on if they look like a xmas tree time for them to go

Interesting. I had a look but could not see any lights.

 

Good news! I put a set of Splitfire coil packs in and some new NGK BCPR7ES-11 spark plugs and now It pulls harder than its ever done. 😊 Thanks everyone for your suggestions! Just wanted to make sure that was it before spending decent money. Hopefully there aren't any more dramas.