correction really high on low trim with 550's?

[jim90TSi]

OK guys i finally got the hint on working the safc with the logger. I'm in a bit of a stump though. I thought i had my car tuned in on low fuel trim at around 12% correction across the boards......this was giving me pretty good percentage (mid-high 90's). So i go back out and star messing with the car, drive it to get a log on it to see what happens. Next thin i know my low fuel trim is at 118.7%. I'm like wtf, so I'm messing around and i took the correction up to 23% and it finally settled down around 100%. I have 550's in my 1g running 18 psi, any idea why i have to use to much correction, that varies, to get a smooth fuel trim. I read a good starting correction for injectors my size, is -10%. Why am i way up in the (+) range toward 20% correction? What would cause this?

would also like to add. im not getting a cel light but i disconnected my battery earlier to reset my fuel trims and im getting a code 12 ( MAF)

 

[jim90TSi]

hmmmmm, no ideas anyone?

 

[steve]

Without making any allowances for deadtime differences the basic formula for injector correction is (old/new) - 1 so, (450/550) - 1 = -0.18 or -18%

Steve

 

[jim90TSi]

i know,and i understand that part. What confuses me is that to set my trim to 100% I was all the way up tp +23% as opposed to -18%. Im running way lean down low. My high trim is around 97.6 unmodified(0's).

 

[steve]

Are you still getting a 12 CEL? What does the SAFC show for Kar?

What kind of MAF are you running? (1g, 2g. hacked?)

Steve

 

[jim90TSi]

code 12 is gone and has not shown back up. I have my safc settings zeroed right now and the cars low trim runs up to 118.7%, then varies between there and 117.9%. o2's are good, and i am running a stock 1g maf

Karmen readings are around 40Hz idle and around 1400Hz wot I believe

 

[weith1111]

I'm in the exact same boat, I've left it at +10 and my LFT is like 127%, I'm letting the ECU do the rest of the correction.

I boost leak checked everything, the system holds 20 psi indefinitely. Everything is setup right, timing is on, checked base fuel pressure=37 psi.

I'm convinced my FP gauge is innacurate, so I might turn it upa few pounds. Before I had the FPR to turn down the pressure my corrections were only like +1.

You don't have a pump or AFPR but have 550's? That may be an issue in and of itself.

 

[jim90TSi]

thats one thing i have yet to check, fuel pressure. I am ordering my walbro 190 pump asap, but im not going to go with a regulator, since i do not need one with the 190.

 

[Sharkcus]

Wow. I am having the EXACT same problem. 550's, 190lph, safc2

To get my car to idle right, I have to have it AT LEAST +5% which is weird because it should be at -18%

I am extremely curious to find out how you resovlve this. I am changing my fuel filter this week, so I will let you know if that has anything to do with it.

Are your 550's brand new, or used?

 

[jim90TSi]

Wow. I am having the EXACT same problem. 550's, 190lph, safc2

To get my car to idle right, I have to have it AT LEAST +5% which is weird because it should be at -18%

I am extremely curious to find out how you resovlve this. I am changing my fuel filter this week, so I will let you know if that has anything to do with it.

Are your 550's brand new, or used?

i bought the car with the injectors, and he said they were used. I would like to verify that they are 550's........i dont have a 190 yet but i will be doing that

could loose intercooler pipes cause this odd condition......i had a few loose, fixed now....runs a bit better

 

[weith1111]

My injectors are new.

And yes any leaks would effect this.

I think I may need to mess with my idle some more, as it has to be directly involved. It's such a small amount of air moving through at idle it amazes me that any fuel correction would be necessary.

 

[jim90TSi]

well i tightened up all my pipes and on my drive home from the work the car ran really good. My low trims unadjusted were around 109%. Im gunna get my pump in and do some other testing on some sensors and then see what happens with the logging results.

 

[weith1111]

Unadjusted as in the AFC at ZERO?

 

[jim90TSi]

yes, my afc corrections were all at 0, the afc was unadjusted.

 

[steve]

yes, my afc corrections were all at 0, the afc was unadjusted.

For me, that would be serious cause to go, WTF.

Unless your MAF has been modified or you don't really have 550cc injectors there is something really wrong. I'd start making sure of those two and then check the fuel pressure and perhaps change the O2 sensor depending on how old it is.

Steve

 

[jim90TSi]

Yea, my reaction is kind of like WTF , when i see that. My car runs and drives good with the afc zeroed out, should it not run like crap zeroed out if I have 550's? I assume so, but my car runs/idles fine, but does run lean.

Supposedly, my o2 sensor is new, looks new and gives off good readings....so now im getting pointed to fuel pressure as my next test.

 

[steve]

Should it not run like crap zeroed out if I have 550's?

It should be running very rich with the SAFC set to 0.

Check the fuel pressure and pull the injectors to make sure they really are 550s.

Steve

 

[jim90TSi]

It should be running very rich with the SAFC set to 0.

Check the fuel pressure and pull the injectors to make sure they really are 550s.

Steve

Will do tommorow, i noticed that when i am at wot......totally leaned out, no a/f gauge lights on at all, cruising and idle is fine.......foes from first bar lean to first car rich

 

[jim90TSi]

Calculated gas mileage today and it was around 11.5mpg, so it is running lean and using gas.

fuel pressure test today

 

[steve]

Calculated gas mileage today and it was around 11.5mpg, so it is running lean and using gas.

I think you mean it's running very rich or the gas is pouring on the ground. Unless your always boosting you should see in the 20's for MPG.

Is it possible you have some exhaust leaks before the O2 sensor?

Steve

 

[jim90TSi]

The exhaust reaks of gas smell. and I dont generally get into high boost, maybe sometimes but not that much. No exhaust leaks that I can hear of before the o2....It idles smooth and sounds good.

Anyway, i took a picture of my injectors, there are 3 alike and 1 different

Denso 195500-1370, that is the part number on them

If you take note on the picture with the 4 injectors being shown, 3 have a red oring and 1 has a black o-ring. The 3 with the red fit in the rail snug and fine, that black one is very very loose, to the point of just falling out almost.

here are the pics

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[weith1111]

Wow, what a hack job! A bastard injector? Getting that injector to seal/getting the correct injector will make a big difference. Did you have air leaking from there when doing a leak test? Long ago someone had left out all 4 of the lower bushings to my injectors...air was whistling out. That's a pretty critical place to keep everything sealed up.

 

[jim90TSi]

Have not done a leak test yet, how should i go about doing that? The buschings in the tops of the injectors look like shit, only was is still whole.

Did a search on google though and they are in fact a 550cc injector.

 

[steve]

Three of them are missing the black pintle caps.

Those things are likely very old (like 20 years) used RX7 injectors. At best they need to be cleaned, flow tested, and the caps replaced.

There is also some question if they are really 550cc low impedance injectors. Measure the resistance of the coils.

http://www.stealth316.com/2-fi_pics.htm
http://rotaryresurrection.com/rotary pages/injector folder/injector.html
http://www.injectorservices.com/FlowDataPix/d1955001370red.jpg
http://www.injectorservices.com/FlowDataPix/d1955001370tan.jpg

Steve

 

[weith1111]

Very attentive Steve! You are right, there should be a plastic cap over the bottom portion. The "bushings" I was referring to are plastic or rubber, and are seats for where the injector meets the rail, you should have a fresh set of those, and new o-rings before you reinstall, along with what Steve said.