Bad Batch Of Fuel? Causing Car To Run Crap?

[Drivebai]

Hey all,

I have an R33 GTST with PFC, GCG hiflow, profec bII, with all supporting mods injectors fuel pump z32 etc etc.

Now for my first tune i managed 220rwkw on 10psi.. could not run any more boost due to misfire.

After that i got Splitfire coilpacks which cured the misfire problem however my car was running worst.

there was just no power it needed 16psi to make 215rwkw.. nowhere near as good as the first time.

so less power at more boost.

My tuner said it had to be a bad batch of fuel.. i ran BP ultimate for both of these runs.

So my tuner said to run this tank out and put in new fuel.

So i ran it out and put in Ultimate again from a different servo.. took it back

and he said it was pretty much the same maybe slightly better..

My tuner was sure it was another bad batch of fuel.

Now here's the thing.. we put octane booster in it and instantly the car was running heaps better finally making 240rwkw on 16psi.

My question is could i really have 2 bad batches of fuel? the octane booster kind of proves it was the fuel, but could the octane booster be masking a bigger problem?

With octan booster my max knock reading was 19. he detuned the car back down to 232rwkw to compensate for octane booster

I have since tried Shell v-power ( not racing) and it seems alright on cool nights but during day engine light flashes at me constantly reading of 74 at one stage.

i was thinking about trying v-power racing. Could anything else cause the car to have no power?

thanks for any help

[mattymagoo22]

is there anything loose on or around the engine that could be vibrating causing the knock sensor to pick it up???

sounds like a bit of a head scratcher man!

Have you checked your spark plugs? could they be fouled???

What sort of exhaust temps is it running??

Good luck

[Drivebai]

Nah my tuner sticks his head in the engine bay while it's on the dyno and he can hear it pinging. Plus i figured it would still be pinging with the octane booster in it if it was something loose..

Spark plugs are new as i replaced them when i changed coilpacks. using 7 range sark plugs

Haven't checked exhaust temps yet.. what should i be looking for?

It's damn frustrating..

Thanks for your reply...

Edited December 15, 2006 by Drivebai

[markk]

I had a bad batch of BP fuel last week from a Melbourne servo. Now i'm using the vpower racing. Much better..

[DVS JEZ]

I had a bad batch of BP fuel last week from a Melbourne servo. Now i'm using the vpower racing. Much better..

wat gap did you set your plugs too?

could be blowing the spark out if the gap is bigger than .8mm

[markk]

wat gap did you set your plugs too?

could be blowing the spark out if the gap is bigger than .8mm

Not sure. Ben from Racepace does all the servicing.

[Drivebai]

just filled up with Vpower racing.. yet to fully test it out..

will update

[paulr33]

read the powerfc faq in my sig

it covers dealing with knocking and how to debug it correctly and combat the issue. suggest you read all the mentioned topics

http://paulr33.skylinesaustralia.com/docs/...powerfc-faq.htm

Tuning Information

49. I always have knocking, is it true, is it lies or is something wrong?

50. How do I debug knocking, how can I make it go away?

Technical Issues

52. Why does my engine light flash when I drive with the PowerFC

[Drivebai]

Thanks Paul,

Putting in V power racing seems to have fixed the problem so far..

Although it hasn't been that hot in Sydney lately but still highest i've seen is 15 so finger's crossed.