enel1221

To start off here are the mods on my car, downpipe, highflow cat, catback, intake, fmic, relocated battery, pfc, wideband sensor/gauge, boost sensor/gauge.

About 2 weeks ago I relocated the battery and installed the fmic. It ran perfectly for 2 weeks, correct af/r's high 10s to 11s under boost...yesterday I was driving around and all of a sudden when i tried to boost it choked as soon as i hit ~0psi and i noticed the af/r went way lean...so first thing i tried was resetting pfc data then i reset the idle, however that did nothing still when you try to go past 0psi it goes way lean (i've only done this twice now and i get out of it as soon as i get 0-1psi cause i know boosting lean is terrible for your car). I'm assuming maybe the secondary injectors aren't coming on, or theres something wrong with the fpr?

I'm posting on here to see if anyone else has had this same problem, and is there anyway to check this with the pfc?? Any suggestions would be appreciated, thanks.

enel1221

Futhermore i've been thinking about replacing the secondary rail with 1680cc injectors/rail along with a new fpr. Should I wait until i figure out whats wrong or replace it, then figure it out...

also i forgot to mention it has a supra fuel pump...

Aaron Cake

iTrader: (1)

Check the secondary injectors first, as well as the fuel filter and fuel pump filter sock.

enel1221

Whats the best way to check the secondary injectors? and i have a fuel filter so i'll just go ahead and replace that tomorrow

Aaron Cake

iTrader: (1)

Have them professionally cleaned and tested at an injection shop. Do the primaries at the same time.

misterstyx69

iTrader: (142)

did you check to see if any of the piping may have popped off?.or got loose?
you mentioned it was a fresh FMIC install.

RxManny

If your fmic piping slips off your gonna run like crap

enel1221

I would assume none of the piping fell off considering it will still produce boost, just it seems like the secondaries aren't giving me any fuel under boost...i'm going to inspect it tonight, and replace the fuel filter. I've had problems with solenoids before, i didn't know if there was a solenoid that controlled the secondary injectors maybe? could that cause the problem?

Aaron Cake

iTrader: (1)

The secondary injectors are solenoids themselves, as are all electronic fuel injectors. But no, there isn't a "secondary injector solenoid" or anything like that.

Just thinking about the battery relocation. Where was it moved to, and what gauge wire did you use? Breaker or fuse? Where did you run the battery cable, and to what point in the engine bay? How is it grounded?

enel1221

I used a battery relocation "kit" came with gauge 2 wire. It is currently behind the passenger seat mounted in a battery box. I ran the gauge 2 wire underneath the carpet through the center of the car, and i drilled a hole in the firewall and used a grommet. It is attached to the same connector that used to be attached to the positive battery terminal (the connections are filled and clean) Then i have the negative grounded on a bolt in the trunk of the car <-- this could possibly be the cause?? I checked it with a meter and it had 0 ohms resistance between the negative battery terminal and grounded on metal in the engine bay (obviously its not 0 but for the meter its 0 ohms)

I haven't checked this since the day I moved the battery, when i drove my car over lunch break it seems to be intermittent, a couple times it boosted fine in 2nd and 3rd gear correct af/r....so now that you mentioned that i feel like it could possibly have to do with the grounding, but wouldn't the car not start if that were the case? i feel like thats when your going to notice it, if it's not grounded but i may be wrong...

gracer7-rx7

iTrader: (16)

The relocation should be fine if it is as you described but I'd go and use the grounding location described in the battery relocation thread in the 3rd Gen FAQ. Hopefully you used a circuit breaker as described in the FAQ.

gracer7-rx7

iTrader: (16)

What exactly do you mean by "choked as soon as i hit ~0psi"?

What AFR did you see?

Resetting the PFC would have done nothing for this and could have resulted in you losing whatever tuning map was on the PFC - unless of course you were using the original map that ships in the PFC at which point resetting the PFC wouldn't have mattered.


That is a bad assumption. The secondaries only provide fuel after 3,000 RPM. 1600cc secondaries are a total waste on an otherwise stock car and won't fix your issues as described in this thread. Fix the problem first.

The FAQ thread has a good link to testing the fuel system.

Your issue doesn't sound anything like a fuel problem. It does sound like a boost problem though.

enel1221

When I would reach ~0psi the afr would go 16+...but like I said it has no boost leak, builds boost like it should.

I checked all grounding and everything is fine with the relocation.

Also by resetting the pfc I mean I reset it and reloaded my maps...Soooo I went into where you can change pim voltage settings, for 2.0v + I set it to ~110% and now the car runs with under 12 afr through boost, runs really rich this way...so I’m guess that means it can't be the injectors? I just don't understand how it can be running fine one moment then all of a sudden it’s like it's not tuned...

And I’m installing 1600cc secondary’s because as of right now I'm seeing ~90% duty cycle at 7k rpms (this was when it was tuned, before the problem came up) and running over 85% duty cycle isn't recommended...and the fact that I’m getting ready to go single turbo.

Aaron Cake

iTrader: (1)

It's starting to sound as though you have a fuel flow or wiring issue with the secondary injectors. Going full lean when they stage would indicate they aren't working very well. Assuming no other changes to the car of course.

enel1221

currently i have it setup for pim voltage 112% at 2000 rpm and 3000 rpm, so it's only low rpm when the fuel goes lean...according to gracer7-rx7 " The secondaries only provide fuel after 3,000 RPM" so the secondaries must be fine, sooo there's something wrong with my primaries...