R32 GTR misfire / fueling issue

[Gonzola]

Harro.

Most folk know the GTR I have now, went from stock GTR to awesome overnight and changed colour haha.

Anyway the new one has a miss. Isn't really worse when it's hot or cold weather. Haven't yet looked at plug colour.. will do this tomorrow if i get time.

It gets a LOT worse when its 1/4 full tank or less, so thinking its time for a surge tank and low pressure lift pump??

It runs a 044 in tank, sard 800cc, rail, FPR, derp... anyone have similar setups and surge issues? Or am I barking up the wrong tree?

[DISTRBD]

Surge tank time :)

[esky]

^+1

Does it completely go away when full?

[RRob]

So it has a permanent miss?

Surge tank won't fix this.

[Gonzola]

Hmm.. there's sometimes a little miss when full, but seems almost like ignition. very quick to come and go, very inconsistent.

1/4 tank or below = big surges in power sometimes, doesn't seem consistent with cornering, direction change, big braking, etc. Pretty random but who knows what's going on in the tank.

It's also like all power goes, then comes back... ie not like when 1 coil pack shits. It's all or nothing kind of miss.

Hmm time to make the cabin a lot more noisy eh, then if small miss is still there and big one is gone, ignition investigation I guess.

[_oz]

I also think the absence of a surge tank has nothing to do with the problem, usually you lean out and get knock readings if the engine is running out of fuel on full boost.

Check how well the fuel pump is mounted in the tank, if you dont trust the fuel pump just change it for a new one and make sure its mounted properly. Id say most of your issue is in your ignition system, most probably the spark plugs.

Im running splitfire coilpacks and BCPR6ES copper s/plugs gapped to 0.75mm and i have no mis-fre at all.

[Gonzola]

BCPR6ES here too... not sure on gap. Will check this when I check them and smash a new set in regardless.
Hmm fuel pump wasn't fitted by me, but I trust the prev. owners work 100%.

Car has splitfires already, just checked. Can't check plugs as all my tools are locked up at a mates place. Will do later before heading out tonight.

Will see if it's worse tonight with full tank of fuel and hopefully cool air.

I have a 044 sitting around too, will swap pumps to see if that changes anything. Fuel pump wiring has been modified properly.

tbc : /

[-Luke-]

Its not something as silly as a partially split intank fuel line is it?

[Gonzola]

Yet to take cover off and have a look, will keep that in mind when checking. Hopefully today or tonight.

It's not all the time though, where as if line was split above fuel level i'd expect shit fuel supply all the time.

We will see.

Vipec data logger says 0 knock recorded. Car is going back to Sean at ASG for a touch up and cold start when I get a chance and some dollars, so will get him to have a look also.

Oddly enough at 100% throttle the TPS read out on Vipec is 90%, TPS will be reset anyway for rotational idle 20% = 0%, blah blah.

It's throwing a coolant temp or IAT error, can't remember if it was coolant or intake temp.
Car doesn't get hot, possibly bung sensor or settings.

[-Luke-]

Yet to take cover off and have a look, will keep that in mind when checking. Hopefully today or tonight.

It's not all the time though, where as if line was split above fuel level i'd expect shit fuel supply all the time.



True, Unless it doesnt open up till your up on boost and fuel pressure increases.

Coolant or IAT temp error could also be throwing it into a part of the map that isnt setup correctly

[Gonzola]

Yeah the Vipec is pretty comprehensive with error conditions seemingly.

Will start with the simple stuff first and see what Sean says also before going too deep into it.

I think the main issue here is it needs skids, longest I've owned a car without doing a skid haha.

[_oz]

Yeah the tune does need a clean up, saw abit of black/dark grey smoke comming out your exhaust when i spotted you on benara road overtaking that 4wd haha, i think i actually herd a couple mis-fires too

but yeah just double check over everything, dont assume its ok unless you know so, im sure it will be something rather simple as the previous owner looks after his cars pretty well

[Gonzola]

hahah when was this?

[_oz]

yesterday arvo

[Gonzola]

Ah righto, missed you obviously.

I was probably stuck behind someone in the outside lane prior to this if gate was used. Normally drive pretty slow around there as there's cops everywhere and my neighbours haha