AndyDoh

I'm looking for a bit of help guys,

My car is currently at the tuners on the dyno and it keeps leaning out at after 5krpm!!
They have just fitted a 255lph fuel pump with a FPR set at 50psi but its still doing it, the injectors I originaly purchased I was told were 550cc items but I'm now thinking otherwise as I didn't think they would lean out so low down?!?! my tuner is going to fit a set of HKS680cc injectors to see if it cures it, but before that happens I wanted to get anyones thoughts!

Thanks in advance

Andy

davepk

Hmmm... Did your tuner bother checking the fuel pressure in the rail?

S2000_Europe

Andrew the fuel pump is 255lph at what psi?

AndyDoh

Not sure guys?!?!

I'll ask him this morning when I call him.

Thanks

HondaS2000Tuner

I'm having the same problem as well. I read 13.5 with a one second jump to 11.3 or so during WOT than comes back to 13.5 or so (I'm still WOT). I have 600cc injectors with Walboro 255Lph fuel pump. I'm trying to figure out the problem as well but I think itz the tuning so far. I'll keep you guys updated if you'd like.

Tuner

AndyDoh

I don't think its the tuner in this instance as the guy I'm using specificaly to do my MAPing is a well seasoned AEM tuner, he suggested I use bigger injectors (ie 680-720's) than the 550cc's I already have, but I thought alot of the guys on here already boosting were with 550's apart from one or two with 600's & 720's?!?!?

I'll post any info I get back from them, same from you Tuner, let me know how you get on?

Andy

AndyDoh

Spoken to the tuner and he has run my set-up through various calc tables (one courtesy of S2000 Europe ) and they are all saying I need bigger Injectors so thats the way to go!!

He said they had checked the pressure in the rail which has been set to 50psi and this rises when the boost comes on

I asked what psi the fuel pump was but he said thet deffinately isn't the problem as they have a consistent flow of fuel in the whole system through the range upto 5krpm but after that the injectors start fluttering and crying (I am told they are trying to fit .44 milisecond into .22 milisecond opening time of fuel spray!!!!)

Andy

AndyDoh

I did originaly close this thread as I thought my issue was a straight forward bigger injector swap to sort it out!

Well I was wrong so I thought I'd put my findings here just incase anyone else has this issue again, I purchased the 680cc HKS injectors $

beroznikmal

So basically you bought low impedance injectors????...without installing a resistor pack....

alexf20c

Low impedance injectors on a high impedance system...

BTW, you can safely "overclock" your 550cc injectors to around 600cc by simply increasing fuel pressure.