I installed 880cc Precision injectors a couple days ago with a walbro 255 pump. I have been trying to figure out why the STFT likes the stock 513 injector scaling value. If I scale to around 700 my STFT pegs +25 and my a/f pegs full lean.

The car drives like normal with the 513 scale value right now. I am hitting 10.5 a/f on WOT.

So could it be bad injectors or bad fuel pump? The walbro wine does seem to change pitch. I bought the walbro used. The 880cc injectors supposedly have a few hundred miles on them.

Thanks.

 

Maybe you need to post this on the Evo Engine Management / Tuning Forums for a better/faster respond.

 

I'll assume two things here.

They aren't 880cc injectors

Or you didn't change the latency values

Maybe you can post a number found on the injector to confirm their size

 

The person I bought them from assures me they are 880cc inj with few hundred miles on them.

I did some more driving around and it seems about 600 is a better injector scaled value. My STFT still goes to +15 though at idle when using injector scale value of 600ish. I am using the voltage compensation values for PTE 880cc injectors.

 

I just scaled some at 812 they loved it... I did have to mess with the latencies a little but not a lot!

 

My 880s are at 522. On E-85. On pump, I'm at 812.

There are numbers printed on the side of the injector that we can use to confirm their origin, if you'd like to verify they are what you think they are.

If you're absolutely convinced that they're 880s, I'd start looking for fuel leaks.

 

Agreed. I had a customer buy used injectors that were "750cc" ended being "650" so I try to buy new on injectors especially aftermarket!!

 

That latency looks more like its for a 680cc injector are you sure you got the right ones? I'm pretty sure the 880cc's I played with were higher than that at 14 volts.

Whats your wideband telling you while you drive it?

 

Also agreed: I'm up around .744 at 14V with my 880s.

RoadSpike hits the nail on the head: I'd put money on you having 680s rather than 880s.

 

yea these guys are right 680cc look about right for that...what is you IDC at right now?

 

Needs way more latency

 

^^^ Maybe, I think the scaling is off if these are truly 880cc's. Maybe more like high 700's to low 8's. Latency is more for fine tuning...

Good luck OP.

Evan Smith

 

Latency is not just "for fine tuning"

 

Agreed.. the Car will run like *** unless you mess with the latencies as well as the scaling...

 

Yes, but what I mean is adjusting the latencies won't make up for a poor scaling to begin with, they should be the last thing to tune.

Evan Smith