Need help on a major tuning problem with fuel adjustment

[redgst95]

I've researched everywhere and i guess nobody has ever had this problem! but anyways..... I have a 60-1 with all supporting mods but my fuel is all jacked up i have 850's, a 255 hp fp and a buschur fpr but for some strange reason my wideband (plx m-300) reads lean with the fuel sliders at zero on the link......so now after alot of pulls i finally get the afr around 11.8 12.0 and that is at +25% from 4k up!!!!! WTF.......also the afr is inconsistant through different gears,say for instance tune for 11.8 in third, it will be 13.0 in fourth!....all this is confusing me and i need help!!!...Why am i having to go +25 on 850's i would think that it would be on the negative side?..... and one more thing i need to find out how to get the afr on dsmlink to read?!..... any help on any of this would be great!!!! and all this is tuned with 22psi 93octane

 

[T9S1i]

did you set your deadtime and global with dsmlink for the larger injectors? After you did that did you tune your fuel trims?
when was your last boost leak test? Are you sure your fuel pressure is correct? with the vacuum hose off?

 

[redgst95]

did you set your deadtime and global with dsmlink for the larger injectors? After you did that did you tune your fuel trims?
when was your last boost leak test? Are you sure your fuel pressure is correct? with the vacuum hose off?

yes global and deadtime are set on what they are supposed to for 850s.... i have not yet tune my fuel trims the only thing i have messed with is the sliders in the fuel map thats it......i pressure tested it about a week ago all was good....im running 38 psi with the vacuum hose on i have not set it with it off would that make a big difference?

 

[nicknorth11]

My friend, Shane2GSX, and I made this tuning guide for dsmlink users. It tells you what you need to do. If you don't know how to do what it says, you can search on the dsmlink website.

 

[T9S1i]

yeah fuel pressure is set with the vacuum hose off, not on. Make sure you are at about 43-44psi base fuel pressure. Then go follow the dsmlink instructions for dialing in your fuel trims. Its pretty easy.
Id also make sure that all settings in dsmlink are the same, 2g's loose all memory if you disconnect the battery so if that has been done recently you will have to re-load in all your settings.

 

[CanadianTSi]

Sounds like Fuel Pressure isn't rising with boost, its possible that the hose popped off or the FPR has gone bad.

 

[zippyshoe]

I would second T9S1i's suggestion to check/adjust your fuel trims - this should be done before beginning any WOT tuning. Are you using a factory 2G airflow sensor? The reason I ask is because inaccurate airflow metering (due to a defective or uncalibrated airflow sensor) can also cause you to run rich or lean.

 

[scottsee]

+ 25% on the fuel sliders at WOT? Wow. Post up an idle log with STFT, LTFTlow and cruise (freeway) log with STFT and LTFTmid. Best thing to do is go on a cruise for 10 mins on the freeway at a cosistant speed and capture the 11th minute. Same with the Idle log, 5 min idle, then capture for 60 seconds.. That eliminates a lot of worthless data and keeps the logs small..

I'm with the guys. definitly mechanical and most likely FPR or pinched/clogged line..

 

[redgst95]

Sounds like Fuel Pressure isn't rising with boost, its possible that the hose popped off or the FPR has gone bad.

I wouldnt be able to adjust my fuel pressure if the FPR was bad would i? and the hose is still on......

 

[redgst95]

Another thing i thought it could be is thati have my wideband sensor in the o2 housing.....now i know thats not a good place for it and i plan on changing it soon but would it be possible that the sensor got to hot and burn up which is causing inaccurate readings on the W.B? the reason i ask is no matter wut the readings are im boiling black smoke under wot!!! and also at idle the WB reads sometimes 15 and 16 but yet the fuel smell is so bad it burns your eyes!!....thanks guys for all your help i really want to get this thing running right but im still a rook with dsmlink!

 

[nicknorth11]

I wouldnt be able to adjust my fuel pressure if the FPR was bad would i?

Yes, but if it were kinked it may not be able to rise at a 1:1 ratio due to limited flow ability.

Would it be possible that the sensor got to hot and burn up which is causing inaccurate readings on the W.B?

Yes, very possible. In fact, this is probable. Try to move it as soon as you can, the heat can permanantly damage your sensor.

At idle the WB reads sometimes 15 and 16 but yet the fuel smell is so bad it burns your eyes!!....

This may be due to the ecu getting a false reading of being too lean and adding fuel to compensate.


Good luck

 

[redgst95]

Yes, but if it were kinked it may not be able to rise at a 1:1 ratio due to limited flow ability.



Yes, very possible. In fact, this is probable. Try to move it as soon as you can, the heat can permanantly damage your sensor.



This may be due to the ecu getting a false reading of being too lean and adding fuel to compensate.


Good luck

Thanks for the information guys im gonna get to work on it ill keep you guys posted! thanks again!!

 

[olmytsi]

Definitely set the afpr correctly (takes 2 secs) and move the wideband to the rear 02 sensor bung.

What are you using for the primary o2 sensor to the ecu? Simulating it using the plx?

What made you put it in the o2 housing when you have a second o2 bung with a pretty much useless 02 sensor?

And lastly, what is your estimated a/f ratio showing (to see if it matches the plx) although it is probably useless if you are simulating it with the plx.

My estimated matches pretty closely what my plx says.

 

[redgst95]

Definitely set the afpr correctly (takes 2 secs) and move the wideband to the rear 02 sensor bung.

What are you using for the primary o2 sensor to the ecu? Simulating it using the plx?

What made you put it in the o2 housing when you have a second o2 bung with a pretty much useless 02 sensor?

And lastly, what is your estimated a/f ratio showing (to see if it matches the plx) although it is probably useless if you are simulating it with the plx.

My estimated matches pretty closely what my plx says.

im not using anything for a primary o2 sensor. I just put the wideband sensor in a rolled with it but my intentions was to simulate the o2 sensor with the wideband but i have no clue how to do it....... last time i checked the link the af on it was not reading accurate at all not sure what to do!!.....so as far as reading the afr on dsmlink i dont have to do no wiring into the ecu just log the afr and thats it???

 

[olmytsi]

Well, you need an 02 sensor otherwise your ecu has no idea what's going on with the fuel.

 

[redgst95]

Well, you need an 02 sensor otherwise your ecu has no idea what's going on with the fuel.

So do i need to just put the stock o2 sensor back in a put the wideband on the downpipe? I was gonna get a bung welded right after the flex section/ And just start tuning from there? is there anyway i can replace the sensor for the wideband incase its burnt up?I really hate to play the stupid role but im lost on this one!!!

 

[T9S1i]

first id hook up DSMlink and log at idle, if your o2 sensor cycles then it should be fine. How long have you had it in the stock o2 sensor position? I was going to do this with my m-300 but its too hot there for it so i put it inbetween my flex section and cat.

After that, you are already in your car and its warmed up, dont be lazy, go hop on the freeway and log your fuel trims as scottsee said. After that, tell us what you've got and we'll help you from there. Its pretty straight forward, i was real intimidated by it for a while, but once someone broke it down for me it was easy as using a light switch!!!

 

[redgst95]

first id hook up DSMlink and log at idle, if your o2 sensor cycles then it should be fine. How long have you had it in the stock o2 sensor position? I was going to do this with my m-300 but its too hot there for it so i put it inbetween my flex section and cat.

After that, you are already in your car and its warmed up, dont be lazy, go hop on the freeway and log your fuel trims as scottsee said. After that, tell us what you've got and we'll help you from there. Its pretty straight forward, i was real intimidated by it for a while, but once someone broke it down for me it was easy as using a light switch!!!

ive had it the stock location for several months now!now would it be as accurate to put the sensor in the 2nd o2 like olmytsi suggested? Now logging on the freeway i am to log LTFT and STFT is that the specific name on the link i look for cause i seen alot of like LTFTlow,LTFTmid etc..... Just wanna make sure im doing this right....now once i have the right fuel trims i hop on the freeway and log just these together? or is there anything else i need on the screen at the same time?.....I plan on posting up a log of this so this is why so many questions.So what do i just cruise at a certain rpm while logging or what?

 

[olmytsi]

Your fuel trims (LTFT LO, LTFT MID, STFT etc) don't work right now because you don't have the stock front o2 sensor.

It's more accurate if the wideband is in the rear 02 sensor location, you are not supposed to put it that close to the engine where the sensor gets too hot.

Remove your wideband sensor from the o2 housing and put it in the rear o2 sensor location (which is after the cat) but you can only do that if you don't run a cat. If you run a cat, you will need to get an additional bung between the flex section and the cat because otherwise the cat will cause the wideband not to read acurately.

Put the stock front o2 sensor back in because your ecu needs it.

ps: if you don't have a cat and you decide to put the wideband in the rear o2 sensor location, you have to go into dsmlink and disable the check engine light for it (but dont worry about that right now, just get everything installed correctly first).

 

[redgst95]

Now isnt the fuel sliders only for WOT? so if i was to tune idle and part throttle i would have to use the airflow sliders correct? if so...school me on this if you could....thanks

 

[olmytsi]

You use the global and deadtime.

ps: LOTS of good info on the dsmlink forums...use it.

 

[redgst95]

Well I Already Would Have Been On Those Forums But The Guy I Bought The Link From Moved And I Cant Get In Touch With Him So I Have No Way Of Logging In!!

 

[94Jettameowpsst]

and there my friend....is the end of your help...join the club...same thing is happenin to me :<

 

[scottsee]

Follow these instruction for the PLXM300 Rear-02 location. If you want to simulate your narrowband you can follow the PLX link dirrected in the notes. I strongly suggest connecting the front 02 sensor for tuning your LTFT's. I used a wideband simulation for 9 months with poor MPG & LTFT tunning results. It's just to far down the exhaust stream for accurate LTFT tuning.

For tuning your LTFT use this

Any other questions. Ask..

 

[olmytsi]

and there my friend....is the end of your help...join the club...same thing is happenin to me :<

Who said we won't help him anymore?

Im willing to help but he needs to at least learn the basics or do research before modding. With a setup like that, he should know that a car needs an o2 sensor