logger readouts, reactions to why?

[tsigrl2016G]

coolant: 194 deg.
Throttle position: 8%
Battery: 12.68 v
Barometer: 96
Fuel trim hight: 100%
Fuel trim mid. : 196%!!!!!!!!
Fuel trim low: 137%

Forgot to check revs at idle and at driving when i logged this. I've posted about electrical problems, but nobody seems to have ideas on those posts. I've tied everything to MPI control unit circuit and that's as far as i got, i'm better at mechanical than electrical, so i took it to my friend (electrician). If anyone can throw some ideas at me to usual causes for these kind of readouts, so that i can compare them to mine, it'd be much appriciated. After my friend traces the short in the MPI circuit that's giving me problems, i'm gonna look at ign. coil. I'll log again and post ne findings, after the "short" is taken care of.

 

[tsigrl2016G]

ok, should've been more specific: i don't know why my fuel trims are so far off,

-the mpi circuit is fine, and complete, i traced the reason for the blown multipurpose fuse to the abs brake unit, or two wires that it feeds, but i don't have $to get another unit, so i left it unplugged, and now, fuse is fine.

-i wasn't sure if my ignition coil was going bad, but looked at spark plug wires first, one was swollen and when pulled them out, they crumbled and broke apart, put new one in, and car pulls and has power like normal.

-so....all of the circuit that complete the mpi circuit are fine, ignition is fine,,, i'm just not sure why my car keeps adding so much fuel. Unless, because i need to change it, a dirty fuel filter (don't think it's injectors) could cause my car to add fuel, but would it really add that much??

 

[kyle h.]

sorry can't help you much with your post, but my logs are in the completely opposite direction.

low - 80%
mid - 82%
high - 100%

where did you find your info on what to check involving the fuel trims? to fix them

 

[LandoAWD]

i'm just not sure why my car keeps adding so much fuel. Unless, because i need to change it, a dirty fuel filter (don't think it's injectors) could cause my car to add fuel, but would it really add that much??

A higher number means you are lean. I'm not sure what software you are running, as that was omitted from your post, but Pocketlogger will only read trims to 139%...

 

[LandoAWD]

where did you find your info on what to check involving the fuel trims? to fix them

Look in out Tech Articles section.

 

[kyle h.]

if a higher number means your lean, why do my plugs look lean?

 

[LandoAWD]

if a higher number means your lean, why do my plugs look lean?

I would trust the logger more than the plugs.

 

[kyle h.]

i trust my plugs over the logger.

also because i get a fuel cut at 6krpms.

 

[LandoAWD]

i trust my plugs over the logger.

Not the best idea.

also because i get a fuel cut at 6krpms.

Fuel cut is dependent on airflow, not rich fuel trims.


Did you even try to read the AFC setup and Piggyback Tuning guides in the FAQ?

 

[dthquazi1]

sorry can't help you much with your post, but my logs are in the completely opposite direction.

low - 80%
mid - 82%
high - 100%

where did you find your info on what to check involving the fuel trims? to fix them

You mid and low trims are rich. That to me is the treshold. I like to keep my trims around 90. That could easily explain why you are getting cut. You are putting way too much fuel in and so little air.

You plugs look lean because you hitting cut. What plugs are you using also?

Also witht hose trims i would check for boost leaks.

 

[kyle h.]

everything is stock. i read over the tuning stuff. im at school. can't really read it all now.

i have 2.5 downpipe and k&n filter. i'm trying to fix the car not tune it.

i've got an afc ready to hook up to it and a boost controller, but i want to make it run right before i do either.


also my o2 is reading about .82

 

[kyle h.]

on the plugs thing. the plugs are a physical property the engine does. the logger is just a number.

why trust the number the computer wants the engine to run at rather than a product of the engine? im not trying to start an arguement, just clear things up for myself.

 

[dthquazi1]

on the plugs thing. the plugs are a physical property the engine does. the logger is just a number.

why trust the number the computer wants the engine to run at rather than a product of the engine? im not trying to start an arguement, just clear things up for myself.

The numbers that the loggers show are representations of the physical properties. o2 numbers represent what the o2 sensor is seeing is seeing. If it shows a lean number that would be the same as seeing a lean spark plug theoretically. Except you see those numbers right now. Now the o2 number is a lot more acurate than what you see on a plug. Many factors can change the plug but only one factor can change an o2. Maybe you have a faulty o2 if you have those trims and have no mods other than the ones you stated above.

 

[kyle h.]

so, it does make sence that the computer (fuel trims) are trying to compensate for a lean condition. will an o2 sensor make the car run lean? i thought they made it run rich.

 

[tsigrl2016G]

i know higher trims mean i'm running lean, if the car is running too lean it adds fuel to try and compensate. I just don't understand what could cause it to continue to take in so much air, and make my fuel trims read what they are. I haven't logged again since i changed the crumbling/ "dead" spark plug wires...i let a friend borrow it, but those were the readings, and it is a pocketlogger, and that's what it was reading ...honest. I'm not sure how you came to the conclusion it only read trims up to 139%. It did read 196% for the fuel trim mid. my o2 sensor readings have been going nuts, i just replaced the o2 sensor about 7 months ago, but i suppose it could've gone bad again, and a more serious problem might be behind it. The car is running great now with the new wires, but i'll do a little more hands on and tell you what i found.

 

[tsigrl2016G]

oh, and a bad o2 sensor can REALLY mess up your air/fuel ratio, and if that is so, your trims will be off, i'm just trying to find out why i'm still running too lean

 

[tsigrl2016G]

and adding fuel

 

[kyle h.]

maybe my o2 is bad too, i've got a new one, but no time to put it in.

http://www.pocketlogger.com/index.php?pid=params&param=ftrims&type=dsm


pocketlogger is only able to read up to 140% from the website.

 

[LandoAWD]

kyle and tsigrl, do your O2s cycle at idle?

What does a log of a WOT pull look like?

Any knock?

I know kyle doesn't have an AFC right now, and that will make tuning (getting it to run right ) much harder. Do you have one tsigrl?

With no fuel control, getting your trims in check with a hacked MAF, boost leaks (I assume you both have checked for these), etc is going to be a bi***.

 

[tsigrl2016G]

i'm gonna do a leak test, i don't have an afc, and i put a diff. mass on, took the hacked one off. I'm really leaning towards having a vaccum leak somewhere which could explain why sometimes the gauge reads that i'm at 15lbs and it really doesn't even feel like 10.
But, last night (because i still have a weird burnt fuel and oil mixture smell--valve cover gasket's leaking---) i got on the car a lil to see how it was running. During acceleration, like between 4000 and 6500, it felt like, well sounded like a little backfiring and felt like it kept hitting fuel cut, like brief hesitations, but not really bad.
i still don't have the logger with me, i can't remember the exact for the o2 readings, but i had a little knock, the car never had a sig. knock before.

 

[tsigrl2016G]

well, knock when the throttle opened wider, i don't remeber exact readings, yesterday, i stopped by and got the logger to check my fuel trims and at idle, high was around 110%, mid was126% and low was 137% o2% was at 100% at idle, and it wasn't moving. revved up to 2500 and took it up to 5500, @5500, when i let off the gas, o2% was moving up to 167% and then back down, didn't check for knock. this was after i had driven it for about a half hour and let it idle for about 10 min.

 

[talon94es]

I think your O2 is shot. Those readings are way off. I don't think it should go above 100% ever. From what I recall you should be around 92% at WOT and much lower (smoothly going up and down) while at idle.

But then again, if your talking about 02 trim then those values might be correct.

 

[tsigrl2016G]

it was the trim, there are diff. readings for the o2 sensor. i do have a small vacc. leak, in the process of finding it now. The other day the check engine light came on and i pulled over and logged, it read that it was storing an error for the o2 sensor, but then the check light went out and the logger said there were no stored errors. i'm pretty sure the o2's goin bad again. Oh and the cutting out.....that i explained about my car earlier....i knew it was somethin with the ignition... started with the plug wires,,,,they crumbled as i pulled them out,,,,took out the plugs, on #3 cyl plug the porcelien was a lil cracked and the other's were kinda white too. #1 plug had some oil the made it's way down to the spark from the leaking sp seals and valve cover gasket.... car doesn't cut out ne more, but still having minor fuel problems... not blowin tons of black smoke yet though , so that's a good thing.

 

[tsigrl2016G]

Those fuel trims WILL all read 100% by the time i'm done!!! I have a few ideas, gonna try them out and i'll let you know.. Mabye that day that a got 196% fuel trim reading...the logger just wasn't reading right, i swear i was looking at fuel trim's but i heard about the up to 139-140% too,,