trigeek37

I did my first dyno runs today, and I am glad I did. I am running way to lean, off the dyno charts in fact. Everything is fine till 5k rpm, then it goes a little rich, and then it goes lean as hell. By 5400 rpm it is over 18 a/f ratio. Between 3k and 5k it stays between 10.5 and 11.5 (this is good, yes?) My HP peaks at 4800 rpm at 191.1 (also sucky) and torque at the 4600 @ 212 ft lbs. this was all at just under .7 bar (setting 1 on my PFS ecu)

I realize I need to do some fuel mods right now, and I am wonder what is the best course of action. I am planning on getting an upgraded fuelpump, but there is just so much information about what secondary injectors are the right ones to buy. Should I just say screw it and get 1600s, or should I stay more moderate? if I do go for really large secondarys, will I be running really rich all the tim? Or should I stay with something more moderate like a 750 or 800 or 1300? I have someone in town that can help install injectors and rails if necessary, so that is not a problem.

and the bitch of this is that I was planning on running my fd to the MRR this weekend. I have been told that I should be more then fine as long as I keep it under 3500 rpm. first off, that would just suck... and 2nd, I don't know if I can do that

last thing: anyone have some experience witht he PFS ecu that is willing to share? that would be appreciated HUGE! please pm me, or look for trigeek37 on AIM, I am on quite a bit.

any help/comments etc would be greatly appreciated

thanks

-Eric

my mods:
PFS intake
PFS SMIC
PFS DP
PFS ecu
RB cat back
efini y-pipe
alum ast
blitz gauges

artguy

dont be a rikki is the guy to ask about that ecu...he is perty well connected to that line.

you shouldnt be that lean with your mods...

1200-1300 cc injectors are fine....i run 1300s and have a thick list...can run so much fuel that the car will chug like mad...no danger of running lean

ditch that shi##y ecu and get a haltech or similar...even the pia pfc.

dont run any more than 11.2:1 11.5 is pushing it.


good luck....


j

trigeek37

is the PFS ecu the reason I am running so lean?
I got a really good deal on it used - but if it is going to cause my engine to blow up, it is not such a good deal.....

trigeek37

could this all be caused by a clogged fuel filter?
according to PFS, I should be fine with the stock fuel system.... or clogged injectors?

trigeek37

does this sound like a good fix?:

RP aftermarket O2 sensor
RP competition fuel pump
bosche 1600 cc injectors w/ rail

oh, and I should probably swap out the fuel filter I guess....

pfs ecu should be able to handle this I think

turbojeff

iTrader: (30)

With a intake, IC, DP and CB you should be OK with the stock ECU unless you go over 10psi boost.

With the PFS I'm not exactly sure what you can change or not but adding larger injectors and bigger fuel pump won't solve your problem.

I'd replace the fuel filter if it hasn't been done in a while and check the fuel pressure.

191 hp is lower than stock, something is wrong with your car, fix the problem first before you throw a bunch of $$ and fuel at it.

Jeff

trigeek37

191 hp was at 4800 rpm, which is way lower then my max HP should be coming at. but yeah, you are right I do have a problem...

and according to the PFS website, the PFS intake/dp/ic/ecu should be good for 16 lbs of boost & 320 - 330 rwhp with the stock fuel setup.

trigeek37

I still have the origonal spark plugs? could this be adding to the problem? I wouldn't think so, but I am not trusting myself all that much right now....

Trout

You should be able to add enough fuel through the PFS computer. The stock fuel system should be able to support your mods at 0.7 bar with some tuning. I suspect you have a problem with your injectors or fuel pump. Give us more info.

Did you try tuning the computer or was this just a run to see what the current settings would do?

Did you monitor fuel pressure during the run? If so, did pressure drop off?

With the problems coming above 3500 rpm, I would lean towards clogged secondary injectors? Have the injectors been replaced or cleaned recently?

The PFS computer is not the best out there but it should be able to meet your needs at this point. Something else is wrong. I'm shocked you didn't blow the engine going that lean under load.

Jack

trigeek37

after seeing the dyno results, I am shocked my engine is still in one piece - thankfully I have only had the car running since Saturday, and got it on the dyno as soon as I could...

the fuel system is stock, nothing has been changed - everything is original
the PFS ecu is stock, as far as I know, no changes have been made to it.

Nathan Kwok

Unless someone took the PFS ecu and purposely messed it up its not the ECU. Every aftermarket ecu is tuned richer than stock, and according to your HP numbers and A/F ratio, you are running much leaner than even a stock ecu. In fact if you stay at 10psi your stock ecu will still probably be in mid 11s throughout the powerband, with any aftermarket ecu being even richer. I'd definitely check the fuel pressure, I'm thinking its the fuel filter but it could be clogged secondaries, dead MAP sensor, dead air intake sensor, or a simply fried ECU, but these are all pretty rare.

RX7Elmo

how many miles are on the car? meaning how many miles on the fuel filter, and the primary/secondary injectors??

I'd say it isn't the ECU as well, 18.0:1 is lean enough to blow a piston motor let alone a rotary.

If your injectors are old, send them to RC Eng to clean, it's about 130 total. Send all 4 of them. You'll need to do it sooner or later. Then change the fuel filter.

Bad plugs wont make u go lean. Also, good fuel pressure means the pump/filter are okay, doesn't say much about pressure at the injectors.

It 'could' be that the secondary's aren't even working? not sure how u would check that too.

Danny

trigeek37

45000 miles on the fd - first engine

rynberg

First of all, did I understand correctly that you still have the ORIGINAL plugs? At 45000 miles? That can't be.

Also, going to 1600cc injectors is ridiculous. Artguy stated that he has a large fuel reserve with his 1300cc injectors and he has larger fuel requirements than you do. Stick with 1100-1300 cc if you're going to upgrade.

My bet is on what others have said -- bad injectors, bad filter, etc.

Wade

iTrader: (1)

trigeek,

Are you sure the reading was accurate? Is your car able to rev happily up to redline? Because if your a:f was really 18:1 it would have trouble revving at all.

You don't need any fuel mods, if your car is really running that lean you just need to fix what is broken. Could possibly be a clogged up fuel filter, a broken secondary injector, or fuel pump or regulator problem allowing fuel pressure to drop.

Wade

trigeek37

I am not sure what to do now...

I talked to comeone at RX7.com this morning, and they warned me that it could be my PFS ecu. they have had issues with them in the past, and no longer sell them. I was also told that it could be the dyno a/f testing method. They were using the up the tail pipe wideband sensor, and I was told that my cat would cause a high a/f ratio compared to a cat-less car. I was also told that if I hit 18+ a/f at 5350 rpm, my engine would be toast, no questions....

so, do I:
1) replace the filter & injectors
2) replace the filter, injectors & pump
3) take off the PFS piggyback ecu & run the stock one
4) get an Apexi Power FC ASAP
5) ????

artguy

you dont drive it til you get a decent ecu and the rest of the fuel mods.

trust me on that.

youll spend thousands more if you arent patient


j

SPOautos

you cant trust a tail pipe sensor, especially on a car with a cat. You need to get the reading from a sesor mounted before the cat.

I think it you hit a 18:1 a/f under boost you wouldnt be asking how to richen it up, you'd be asking for the best place for a rebuild. I think the a/f ratio # is bogus.

Have it redone with a sensor mounted in the dp

Also most aftermarket ecu's do NOT run more fuel than the stock ecu they just have maps that go past 10psi of boost. The stock ecu is very rich at 10psi, as a matter of fact I remember seeing a post where someone had a healthy stock 3rd gen tested and it was 10:1 at WOT and full boost. Also 10:1 was the lowest it would register so it was really prob in the 9's. Thats why the aftermarket ecu's make more power, they are leaner but still within saftey. You can actually do alot of mods to with a stock computer but if you let it go past 10psi of boost your toast.

Regaurdless of what the prob is you need to go ahead and change you fuel filter and plugs. Fuel filter should be changed every 15K or so and plugs about 10K.

STEPHEN

SPOautos

sorry double post

trigeek37

I also think the a/f ratio is off after talking to people this morning
I think I need to find a new dyno place....
but I should probably still do some fuel upgrades though....

thanks again for all of your input guys

SPOautos

The need for fuel upgrades is not dependant on mods, its dependant on boost. If you are going to run 14psi of boost you need to upgrade you injectors and pump. Untill then you dont need anything except to change your filter.

You might be running that much boost, I have no idea. If you are they upgrade you fuel setup

STEPHEN

trigeek37

according to my boost gauge I was running a consist > .7 bar peak during the whole dyno run

Pressurized

You're A/F readings might not be off, the place you are dynoing at could be correct.

I recently dynoed my car, and in the lower rpm range, my a/f was bouncing around in the 16-18 range, then dropping down to 11.2 in higher rpm's. This doesn't make much sense to me either, I am non-seq so the lower rpm's barely see any boost. But this was done on 15psi(97octane, racing plugs, stock fuel system). My fuel pump is fine, injectors are fine, the only thing i have yet to check and replace is the filter.

trigeek37

ok - after talking to many people in town, and accross the country I have come to the conclusion that there is no way my car was running 18+ a/f ratio - it would have blown, plain & simple. that does not mean that I am not running lean, but I am not running that lean....

I think I need to find a wideband a/f meter that attaches to my dp, that should give me a much more realistic a/f ratio... I think I need to go to a better dyno shop...