A whole bunch of work on the FD this winter, I get the car to a dyno to get a 'safe' map in the PFC and the tuner says I am 85%+ on injector duty with only a 8-6-8 boost pattern. I don't dare even turn up the boost to stock levels at this point!

Mods:
K&N CAI
M2 Med SMIC
vacuum simplification (DT, ACV, etc removed)
stock twins
ported wastegate
DP, MP, Racing Beat N1 exhaust, basically 3" open all the way back
stock fuel pump and injectors
PFC

I had the tuner get me a slightly rich mix (don't recall the exact AFR number but on the rich side) so I can get it 3 hours down the road to a more experienced rotary tuner. This tuner didn't know much about tuning a PFC so didn't know to increase the boost duty cycle to get the boost levels to increase. Thus I have a 8-6-8 pattern.

After doing lots of research on this before delving into the mods, I thought this was a safe and reliable, no brainer list of things to do. I see lots of folks running up to 12 psi (.83 bar) without have to replace injectors or pump. Near the limit of the stock injectors and pump but relatively safe. I only want 10 and 12 psi, nothing more.

Anyone have an idea as to why the injector duty cycle numbers are so high with this set up? Something I missed? After doing a search, I seem to be the only one having a low boost level/lean fuel problem.

Do I take the plunge and go to a high flow pump and 1600cc injectors anyway? I was hoping not to have to do that with this set up.

If there is a particular thread someone can head me to, please point it out.

Thanks ahead of time.

 

I don't think 85% is particularly high or anything to really worry about.

However, what are you using for boost control? Are you familiar with adjusting boost on the PowerFC?

I suggest you spend some time searching and reading the posts in the PowerFC forum regarding injector duty cycles and boost control.

 

get a new fuel pump...I'm not sure why it's maxing out at 8 psi, but maybe it's really tired. Fuel pump is the root of the fuel system. Without pressure there's no flow. It's worth the $250 investment.

Greg

 

I have and I am now familiar with the adjustment within the PFC after experiencing the problems with the tuner. Right now I am using the PFC to control boost. If need be I will install a Profec but was holding off. I am not intending to push this engine to the limits just use the tried and true tuning parts and have some fun with the car.

This whole thing is snowballing out of control now. Another $1k+ in fuel system and $300 in Profec just to have a safe enough system! What's next!

I just don't understand how I can make these mods and be at the limit already.

 

perhaps oneof your injectors has crapped out on you as well. flow test them individually

also, check your fuel filter and wiring to fuel pump. have you tried hotwiring the fuel pump?

 

skunks, if one of the injectors has crapped out, the AFR would be very lean considering that there would be only one primary or one secondary running, yes?

Wouldn't I get bad hesitation or poor high RPM response if one injector was bad? Engine pulls hard and smooth to redline. The PFC even fixed the 3k hesitation! But now I have idle surging instead. But that's another story and I want this problem fixed first as idle hunting won't pop the motor, just annoy me to the point of selling the car.

New fuel filter in hand. Just haven't had the time to crawl under the car to replace it. That's the next step.

 

Your temporary tune is likely EXTREMELY rich, almost unsafe rich. Either that or you have a problem with your fuel delivery system. What a/f ratios are you seeing under boost?

You should be able to hit 11-12 psi at 85% duty.

 

Don't do anything until you take it to your "experienced tuner". It's most likely that you don't have a problem, just not a very good tune. The experienced tuner should be able to tell you **IF** you have a problem.

 

Drive it to Banzai Racing...Chris will help you out for sure.

http://banzairacing.net/

 

rynberg is right. 85 is not that high. the AFR is an important figure. assuming like ryn did that you are healthy otherwise.