So these tables are the base for the fuel trims I see? I think I'm beginning to understand. Long term trims are the first fall back in an open loop condition, push it hard and they go out the window to the original tables that are the base of the ECU.

Am I close??

 

Short/long term trims are like the second step to ECU's programming. When there's a change in any variable, say you give some more throttle, the first thing it's going to do is pull fuel and ignition data for the new amount of throttle from its table. Then it applies the trims to that (imagine long term as a percentage change, short term as a tenth of a percent, even though that's not quite accurate) and then using THAT number sends the appropriate pulse to the injectors.

Then immediately after it will record what the oxygen sensor sees in the exhaust as rich or lean, modify the short term trim, and go again. If the short term trim goes over a certain amount it will change the long term and then zero the short term again.

When you go open loop, it pulls the data from the table and applies the trims, sends the data to the injectors just like before, but that's it. It won't update the trims in open loop. The fact that it applies the trims in open loop is why people with bolt-ons observe their cars faster immediately after an ecu reset.

 

Could you expand on this; ecu reset via battery disconnect ot ecu catch-up.

 

I am really enjoying this thread

 

Hey Coyote - me to. I need to start basic. Will post a pic soon you'll like.

 

Bolt-ons tend to lean out the mixture which increases power; however as the computer picks up on the tendency to run lean under part throttle it can and will enrich it again, which carries over to full throttle operation, negating the gains. At least that's my running hypothesis. (Every manufacturer runs engines a tad richer than necessary to account for bad gas, engine behavior differences, etc.)

I'm becoming rather puzzled by the loop indicator indicating closed at 100% load / 14+ absolute psi and only going open with extra pedal pushing. If this is truly the case, if it can really run stoich with very near ambient pressure in the intake manifold, that would absolutely be the most efficient place to be during acceleration. I'm going to try a couple tanks at 95-100% load with closed loop during acceleration with my usual 2500 rpm shift points to see where it goes. So far I'm seeing less drop on the avg mpg on the meter for acceleration but whether that translates from the computer model to real world is yet to be seen.

 

polaski I wonder about the loop indicator as well. UG support has indicated the sampling rate of the unit effects the results seen. Not sure if this effects what you're trying to see. Could you post up your menu set-up? I would be interested seeing - will post up mine tomorrow.

 

I'll snap a pic tomorrow.

Not going to try 95+% load anymore. It's gotta be going open loop. The car's fuel gauge starts to do massive movements when I do it, not to mention the cat temp going to 1500F+ at 2000 rpm. Back to 85%. Smooth, calm, efficient.

For those wondering how much load 85% is, the car barely accelerates with the AC on at 85% under 2500 rpm. The AC button is therefore getting some exercise. If only this hot hot weather would just go away.

 

Is it really as simple as just plugging it in? My 2011 Fit isn't listed in the OBD Locater list. Any idea where it is? BTW, they're out of stock!

What does it mean when they say the UG turns off the Check Engine light? Will we still get Check Engine warnings?

 

Plug and play. The OBDII port is right above your right leg, under the dash a bit.

It says it will, however, I would refrain from doing it. It will pull codes if any exist. Then the issue is fixing the problem to make the CEL go away.

 

Well yea!!! It's like greek or somethin' ....right? Glad you guys know what you all are talking about.

 

just got mine and am excited about having it, but quick question:

can this be left plugged in all the time, or do you recommend pluggin it in occasionally to review guages?

seems like it can be left fulltime since they give you mounts and stuff, just want to be sure that leaving something connected to the OBDII connection wont harm it (like ETC's will eventually trip the CEL when left on all the time)


Thanks!

 

Once you have it calibrated and like the results leave it plugged in. If you're concerned w/ security it clips out of the holder real easy and can be placed out of the way.

I have mine mounted in the front quarter window, really not that noticeable from outside the car.


With the three screens you can set them up to your liking and monitor what you want.

I strongly suggest printing out the manual so you can do menu set-ups in the car with it plugged in. You can figure the set-ups at the desk and then go out and do them.

Banditti - we do love our toys!!!

K_C_

 

Yeah that's where I ended up putting mine. Setup the menus via the manual and am loving it.

 

Me too. I even shoved the cabling under the rubber strip. that runs along the door.

 

These gauges are great and so are the alarms. I get a pending trouble code alarm when I start up.

Its a p0171 code I've referenced and krimson believes is a vacuum leak. Are there any gauges I can look at to confirm if it is a vacuum leak, a fuel system, or o2 sensor issue?

 

quick google turned up this page OBDII codes P0171 & P0170 Need Help!!! - Hondahookup.com

there's a couple of things, but for the most part the error code is "fuel system too lean" according to them.

they suggest various things too.

gas cap not properly secure
gas quality lacking
MAF sensor failure (either dirty or whatever)
moisture in fuel regulator
and mention of a vacuum tube being disconnected.

 

Santiad I've been meaning to ask you about that. Have you checked the connection where the air filter box connects to the throttle body? That seems like a place for a vacuum leak. I'm leaning towards the MAF for some reason. But I was surprised to see the connection to the throttle body is a friction fit. Every other car I've looked at has that as connection secured with a screw clamp.

UG has two MAF gauges, but I'm not sure monitoring them would tell you anything concerning a vacuum leak. It's gonna be a search and destroy mission.

 

Mounted mine the same place, but unplug it and put it away every time I park. Trying to keep honest people honest... Besides my son drives it most of the time and don't think he cares much about having it.

 

I'm really tempted to get one of these for the fun of monitoring things. Necessary....no. Fun...yes. I know that it can read codes, which is awesome, but is there anything other than the dealers computer that can clear codes? Programmers I have owned for other cars let you clear codes, but nothing like that seems to exist for Fits.