fuel trims are stuck

[91-gsx]

hey guys,
i have a problem right now becuase i had my maft set for 450cc injectors and the logger read that i had really high trims like 136%-140%. for low, med, and high trims. so everybody said that i was running to lean and that i needed to change the base settings to 430cc injectors. i did that and the car read 106% for med and about 100% for low and high trims. so i thought that was my problem. well today i took 2 more logs and the trims are all back to 139%, it is saying i am really lean when my maft settings are really rich and the car is no where near as fast as it should be and it just is not accelerating as hard. please help me if you can, i do have other people working on this problem as well.
thanks for the help

 

[Echo5Zulu]

There is a really big thread and a guide on this website I believe its called the definitive guide to fuel tuning or something to that effect. Try to find that it answered all my questions and really helped me tune my car. My car feels sooo much faster and gets a whole lot better gas mileage after tuning with this info. If you cant find it give us some more info about your car and what you have available for tuning and maybe we can lend some assistance.

 

[kanderson111]

I'm assuming that none of the people you have helping you is the owner of a wideband meter. This is what you really need to see whats going on with your A/F ratio. I also have a maft and my trims were reading 99% at about 9.5/1 AFR, after leaning out to about 10.8/1 AFR my fuel trims still read the same. There was a huge increase in power and spool up was much quicker but fuel trims remained the same.

 

[SBstar]

http://www.racingknowledge.org/topic.asp?TOPIC_ID=1011
It may help you out although I believe its centered more towards other tuning devices then the Maf translator. It may help you out though, it would be a good idea to get a wideband as well.

 

[GPTourer]

Maybe your o2 sensor has gone bad. If it is the original one that came with the car and it has 100K+, its probably no good.

 

[92redman]

Do you have any leaks in the exhaust before the O2 sensor? What type of O2 housing do you have, recirc or dump? Do you have a good O2sensor with a working heater?

 

[91-gsx]

i do not have any leaks before the o2 housing. i have a recirculated o2 housing. well i have a few log on tis page take a look at my readings, the o2 sensor seems to be working, but i ma not sure. any way to check?
here is the page:
http://www.dsmtuners.com/forums/showthread.php?t=199197&page=3&pp=25
i am the one posting the logs on this page. it started as a tuning problem you guys, but now i think there is something electrically wrong or mechanically.
thanks for the help

 

[SBstar]

The O2 sensor will read so many volts on the logger. anywhere from 0-1 volts. If it isn't reading any volts, there is a good possibility its dead.

 

[steve]

I also have a maft and my trims were reading 99% at about 9.5/1 AFR, after leaning out to about 10.8/1 AFR my fuel trims still read the same. There was a huge increase in power and spool up was much quicker but fuel trims remained the same.

Since fuel trims are neither used or updated outside of closed loop operation you leaning the car out at WOT isn't going to change the trims just the A/F.

Right now he doesn't need a wideband, he needs to learn how to use his datalogger to diagnose the basic problems he's having. The first item that is questionable is his 02 sensor and he need to drive the car around staying in closed loop and monitor the O2 feedback to decide it's shot.

Steve

 

[91-gsx]

well i just did a little boost leak test and i was using a bike pump which should work for gradually building boost, whether i use a bike pump or not it should not make a difference, a leak is a leak. and i do not have a compressor. anyway, it would not build past 5 psi, and when i would stop pumping to hear where the leak is coming from, i heard a hissing around the intake manifold area. man this sucks, i would not mind so much if i had more time to work on this car. i do not think that dsm's are unreliable, but they are older cars and cars need this stuff changed every once in a while, it just so happened they gave out when i had them.... so i don't know what to do, have any of you experienced this, i do not know where to start?
appreciate the help.

 

[SBstar]

First things first, tighten down those IC pipes, (mine had a nasty leak). Make sure all your gaskets are good and all your bolts are torqued to spec. Don't freak out thinking its a huge problem before you fix all the little things.

 

[kgtalon95]

Why do you have the base set to 430cc I know that a lot of people say that the injector compensation doesn't work but I would try and set it to your size.....750cc according to your profile. You need to set the base then start making your adjustments. If you set you base to low...you won't be able to get your curve to where it needs to be. Right now you're setting the base too low that your choking your fuel. Set the base higher, then adjust from there. I had the same problem, trims maxed lean, set the base to 680cc, and started tunning from there. Low is 108, I like it lean for economy, 105 at mid and 99 at high.

I noticed that with the maft it took awhile for my ecu to adjust to the new setings, like 50 miles of driving.

Try re-setting the base and then tuning. Make sure that your o2 trim, not the low,mid,or high....is oscilating around 100%, once you get that, you'll be in good shape.

Go back and read your maft instructions....there is a graph that explains what setting the incorrect base does. Hope it helps!!

 

[kgtalon95]

Since fuel trims are neither used or updated outside of closed loop operation you leaning the car out at WOT isn't going to change the trims just the A/F.

Right now he doesn't need a wideband, he needs to learn how to use his datalogger to diagnose the basic problems he's having. The first item that is questionable is his 02 sensor and he need to drive the car around staying in closed loop and monitor the O2 feedback to decide it's shot.

Steve

Agreed....Also a really lean or really rich ratio even in closed loop can make your o2 sensor not work properly. Listen to steve.....Figure out your closed loop trims before going WOT

 

[Ludachris]

You need to find that leak. If it's near the manifold, try to see if it's near the throttle body. I had a good leak there and all I needed to do was replace the TB gaskets. Also check to see that it's not coming from your BISS screw. I also had one there too. Once you get your leaks figured out, then you can move on to checking the other stuff. Leaks will drive you crazy trying to get a good tune. It really would help if you could find a small air compressor - rent one from Home Depot if you have to. Trying to find a leak with 5psi in the system will be tough. It's much easier to locate when you pressurize the system to 20psi. I never did have luck with a bike pump myself.

A wideband is nice, but you should be able to get this figured out with the logger. And be sure you've read this Tech Article in the Tech Guide:
http://www.dsmtuners.com/forums/showthread.php?t=58403

 

[91-gsx]

well i found out that my 14b might be leaking some air somewhere around the housing but it is really small and takes a long time to release all of the pressure, no biggy. i disconnected all of my tubing up until the throttle body elbow and tested it. that is when i heard the turbo leaking a little. other then that if i kept pumping the bov would open up, so i seem to have pushed it quite a bit before it opened up. so the piping is nice and tight. to bad i cannot say the same for the intake manifold... the injector seals are the things causing my boost leak. i cannot push more then 4 psi before they begin to release the pressure, if i pump to 7 psi, they work the psi down to 0. i took the seals out that are basically new because i put new ones in with my injectors, and put gasket maker on them to maybe seal better. put everything back together, they hold about 4 but anything above that they just hisssssss... if you move the injectors while i pump the air in, they just release the pressure. i thought i had other leaks and tried to fix them but it turned out that it was the injector seals for now. i could see some gas around the seals as well. i have 750cc RC injectors and I'm not sure i should use the stock replacement injector seals. they do not seems to push into place like they do on the stock ones. does RC have a special seal? another thing i did was cap off the intake manifold were the valve cover breather attaches to it in the back of the valve cover. has anyone done this. i think it is good because the breather that hooks up to your stock intake, is bypassed by me and many others that want to eliminate oil in their intake. but if you pressurize the intake manifold, you will notice that air escapes out of that valve cover hole, on the left side of the valve cover, which has been already counted by the mas. next time you pressurize the intake manifold or tubing, put your finger over the valve cover hole on the left side and pressurize your intake and remove your finger, it will release the pressure. not good... so i bypassed it. this is getting long, but if you know why my injectors are not sealing please help, or have gone through this.
thanks for the help

 

[steve]

if you pressurize the intake manifold, you will notice that air escapes out of that valve cover hole, on the left side of the valve cover, which has been already counted by the mas. next time you pressurize the intake manifold or tubing, put your finger over the valve cover hole on the left side and pressurize your intake and remove your finger, it will release the pressure. not good...

Check the PCV valve, if it's still there, to make sure it seals. It shouldn't leak any air from the manifold back to the rocker cover.

Steve

 

[91-gsx]

Check the PCV valve, if it's still there, to make sure it seals. It shouldn't leak any air from the manifold back to the rocker cover.

well when i blow on it with my mouth it does not, but when you apply pressure with a pump it releases pressure into the valve cover, which in turn goes into my catchcan...wasted boost and already metered, very bad. anyway i just plugged the intake manifold fitting, and ran another hose to my catchcan. the problem i am having now is getting my injectors to seal. a quick question, are the 3 seals that are fitted under the fuel rail, where the bolts go through them and bolt down the fuel rail. are they supposed to be hard or soft. mine are very hard and they will not allow me to tighten down the fuel rail a lot. so maybe they should be softer to push the injectors in a bit more?
thanks for the help

 

[steve]

There are three hard plastic spacers that fix betwen the rail and the head where the bolts go.
Those bolts only get 7-9 ft lbs of torque.

When the engine is running the fuel pressure in the rail is trying to spit the injectors out and helps push the injector down onto the injector insulator (the seal) in the head. The injector sheet (the grommet) between the rail and the electrical connector on the injector is what holds the injectors against the insulators.

Steve

 

[91-gsx]

do different brands of injectors need different seals? mine are 750cc RC's. could that be why?
thanks