Flite

When I got dynoed my initial thought was that I'm simply running out of injector as I'm on a base kit with a rising rate FPR and stock injectors. I didn't sweat it too much despite being a little put-off by a >12.5:1 afr at redline.

I talked about it to the guys at Science of Speed (SoS) though, and apparently something is amiss. The kit comes with a FVM (injector pulse, timing, and VTEC control). Other cars with the kit have dynoed and have a very flat AFR right at 12:1 with about 10% overhead on the stock injectors to support better breathing mods (Exhaust, header, etc).

When I put mine on the dyno, we had to crank a good amount of pressure on the FPR over what should have been a good preset amount from SoS. Now I've got a very fat initial AFR that goes a bit lean on top. The guys at SoS are very helpful and willing to do pretty much anything needed to fix the issue. I don't know what my static fuel pressure is, but I've got a fuel pressure gauge coming in the mail now to check that. I think my static is higher than it should be because I'm running too much fuel pressure to compensate for something else. My thoughts right now are that the FVM isn't increasing the fuel pulse like it should. To me, that would cause it to run fat at low RPMs (higher fuel pressure, near stock fuel demand) and lean out on top (Higher fuel pressure, but not enough to compensate for the increased demand on it's own). Does that sound logical? If not, what are some other ideas? Could a faulty FPR cause this? Is it possible I've got a fuel flow restriction?


Here's the dyno. I expanded the afr section (no idea why it tilted) and added some lines for easier reading, all the numbers are correct though:

Spike_Spiegel

yer supercharger is broken. sell it to me fer cheap.

nismo

what exhaust are you running and what size?

Grease Monkey

perhaps the stock pump isn't 100% that would explain why it can't meet the demand

Flite

Exhaust is stock, plenty of people run the stock exhaust on s/ced cars without issue.

nismo

that counters my theory..

nvm.


throws that out the windows...



im with dave now, check your fuel pump.

Jay

Agreed. Bigger pump time and service the fuel filter.

You'll have to crank that FPR back down, but just baby it to the dyno and do it there.

(On a side note, I'll go to a single weldon pump before I go with twin walboro's again. Was always nervous about dropping a pump under load.)

GL on getting it sorted Chris, and lank when you're back in town.

Fabrik8

Rising rate regulators are crap. They aren't especially linear devices, and the one you got could be one of the not-so-linear ones. Could be an O2 sensor problem or you might have some wierd fuel trims. Reset the ECU and see what happens. Rising rate regulators are a really crap tuning solution though.

Flite

I should have said that I'm not on the stock fuel pump.

I'm familiar with the rising rate FPR issues. This won't be the final setup, it's just what I've got for now until I do some supporting mods and switch over to a Kpro setup. There are quite a few cars out there running this rising rate FPR without issue though, so it can work just fine. The ECU has been reset and I don't think I should have any O2 sensor issues. Up until now, the car has spent it's life 100% stock, it's only got 35k miles, and I've never had an O2 problem before.

I'm with you on the FPR though, I think it's either that or the FVM isn't increasing fuel pulse. Is it even possible that there is some sort of install problem on my end that could cause this? I just want to eliminate that possibility before I send parts back to SoS.

sohc_mshue

I really don't trust those rising rate regulators. I would switch it to aem or kpro as soon as you get a chance so you know exactly whats going on with the tuning rather than relying on that regulator and piggy back they give you.