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Advice Please - Injectors and Tune Issue

inmaniac

By inmaniac,
in Engines & Forced Induction

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inmaniac Community Regular

inmaniac

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Posted (edited)

Advice Please - Injectors and Tune Issue

Hey guys. 

I've been getting parts together for a couple months and finally installed them into my R33. I got the following installed:

 

-Hypergear G3 21U high flow

- z32 AFM and stainless intake pipe

- Walbro 255lph fuel pump

- 550cc Injectors (STI side feeds, part # 16600-AA170 with harnesses)

- Nistune ECU

- 3in turbo-back stainless exhaust and Blitz FMIC already installed  

 

Along with the parts I also did all the maintenance items, got new NGK coppers gapped to 8mm, new fuel filter etc etc. However, when I got Toshi to try and tune my car, he claimed that the AFRs were being whack and it was misfiring at 5k rpm. I immediately thought of coils and I also didn't do the earthing mod for the fuel pump, so this might have been my issue. 

I ended up buying Yellow Jacket coils packs and I also earthed the fuel pump and checked to ensure full voltage. The car started fine, test drive fine low revs, etc. However, again getting Toshi to try and tune and check AFRs etc and we still can't run boost into it as he claims the AFRs are still unstable. He now says it's the Injectors but I don't know if I believe that as when we're in the "base" tune he did, the car isles fine, revs fine etc albeit a bit rich. 

 

In short, 2 questions:

1. I know there are better options, but how likely is it these Injectors are actually the issue? They're not high flowed, but genuine STI Injectors. Anyone else run these? I can send back under warranty if needed.

2. How likely is it that the tune is the issue? I read another thread on here where someone had a problem with a Toshi tune that came down to injector latency being set wrong and another tuner fixed it. 

I really feel feel like after all the work done, and the fact that a rich tune revs fine but another tune doesn't makes me think it's the tune? Anyway, I currently am advised by Toshi not to boost the car as the AFRs are off and he wants me to replace Injectors and go back to him. I just want other opinions. 

 

Sorry for essay. Thanks in advance. 

Edited by inmaniac
GTSBoy Grand Master

GTSBoy

Posted
Posted

The very, very first step when diagnosing this shit is to put a fuel pressure gauge onto it and see what that is doing under load.  It is cheap (free) and it takes 90 seconds to do.  Speculating about the health of injectors is a waste of time before knowing this one fact.

Yellow Jackets are also famously variable in their quality.  Any set of 6 might be fine, but any one of them might be f**ked from the factory.  Ergo, they are a waste of time and money.

inmaniac Community Regular

inmaniac

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Posted

Thanks for the replies guys.

The injectors are remanufactured but have been tested and all ok (got the paper at home).

I haven't checked fuel pressure so I may have to do this.

Johnny (above) is going to have a crack at tuning for me, cheers mate!

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