yosip1115

Hey guys,
I am a member of g35 driver, but I know I'll get a much better answer here on my350. I have done a lot of mods to my car including a dyno session using uprev. When our cars are running on stock fuel maps, with bolt ons I noticed a gain in power after a few hundred miles. Unfortunately, my engine produces the most power before the fuel maps are modified. I hate resetting my ecu using the gas pedal, and I came across just one forum suggesting implementing an OBDII workaround switch. This forum said switching the clock/ radio fuse under the hood will allow a switch to cancel all learning and memory of the ecu. I noticed nothing after pulling the fuse, but did notice something after pulling the ECU fuse right next to it... Which fuse is the correct one to put a switch on that will allow me to keep my fuel maps where my tuner set them? Am I going about this right to maximize my engines performance? This topic has been avoided because of the various ways to reset the vq ecu, but I think it deserves some discussion!

DunZcon

So are you trying to save your ECU uprev tune? Your question really isnt clear at all. If you want your tune leave it alone and keep the battery plugged in. if not delete the uprev

yosip1115

No, it is commonly known with OBDII vehicles or so I hear that over time the computer will de-tune the engine and it will lose power over time until it is reset to the factory map. This is true if there are bolt on mods, but for a stock engine I have read the car will become faster over time once the computer "learns". I have experienced that in my situation; uprev tuned with bolt on modifications that over time my ecu learns and backs off engine performance, which drives me nuts. I read here
https://my350z.com/forum/engine-and-...-ecu-info.html

a switch can be added. Which wire do I tap into? I'd like to tap into it right inside the cabin on the ECU harness if possible. This mod avoids the entire resetting the ECU every couple weeks because it never learns to change the fuel maps, correct?

JCITY

iTrader: (2)

??Basically you want a "switch" to turn your tune on&off?
What are you using now for your various MAPS?Seems your tuner
could figure this out.Who is doing the work on your car?

yosip1115

You really don't understand anything I'm asking. I have a tuner, I do everything to my car except for tune it...

str8dum1

iTrader: (11)

he wants to disable long term fuel trims....

bmccann101

iTrader: (16)

Ill throw my 2 cents in.. i thought the OSiris reflash etc does away with that feature of the stock ECU.. that sucks otherwise.. in for sure for answers from any ppl who know them ..

str8dum1

iTrader: (11)

the reflash sets new targets, so if the car was tuned properly, all it wil do it try to hit those new targets better.

I dont think the OP knows what he's talking about.

SparkleCityHop

iTrader: (30)

If you're worried about the ECU "learning" things that are adverse to the performance of your flashed tune, just pull/disconnect the battery overnight. Anything "learned" is in volatile RAM and is wiped when power is no longer present. Only things that are flashed to the PROM remain when power is removed.

Also, as st8dum mentioned, the tune changes your targets as well as your compensation and timing tables, etc… so your engine "should" be learning how to better hit the targets of your tune. That is ASSUMING that your tuner actually knows how to tune properly with UpRev.

For some basic information about how Uprev works, check this thread: https://my350z.com/forum/tuning/5188...ing-101-a.html

yosip1115

Im asking if there is a way to make this happen with a switch... Do I put a switch in line with the ECU or the clock/radio wire to cut the backup power to the ecu? I'm only asking this because I think it's odd that it was stated in a different post to install a switch in line with the radio fuse under the hood, not the ECU fuse. Anyone know which wire is right?

SparkleCityHop

iTrader: (30)

It isn't as simple as a single wire that you can put a switch on.

Here is another method that you can do to reset your ECU:

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.
A stop watch or an analog clock with a second’s needle will be useful.

Operations Procedures

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.

If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

djamps

iTrader: (1)

op what you need is an uprev dyno tune. This will set the targets correctly for max power on your mods and won't 'steer away' over time. Hooking up a switch to reset your ECU, even if it were a good idea, is really ghetto way of avoiding to get tuned.

e30cabrio

iTrader: (30)

I have a map that allows me to revert to stock as well as a valet that keeps revs under 2500 (I never valet) I also have a dead map that won't allow the car to start.

You have to be careful otherwise this might happen:

SparkleCityHop

iTrader: (30)

OP, if your car is truly "steering away" from the intended targets after an Uprev Dyno tune, then IMO you need to find a new tuner.


No, you are not going about this right. You need a proper tune. There should be no reason to clear the learned adjustments on a regular basis if you have a proper UpRev tune. Who tuned your car?

yosip1115

I was tuned by Matt K at Dent Sport Garage in Boston. They know what they're doing. Could there be something up with my car causing the ecu to learn using improper values, such as old o2 sensors? I'm not sure how to measure for a fact that my car loses power after a few hundred miles. My car has 111k on it, should I change out the o2 sensors when I put in my catback and Y pipe?

Edit: I got a terrible, terrible tune from someone else in CT, I won't mention the name. But coming into my tuning session with Matt, my AFR's were quite lean. I replaced the plugs, but not the o2's.

binder

iTrader: (8)

no, the o2 sensors wo'nt be the problem.

Here is what you are missing. When the tuner "tunes" the car he should set the target. The target is the a/f that the tuner makes the best for that car. Long term fuel trims will do everything they can to meet that target. So as you drive the car will do nothing more than work it's hardest to hit that target a/f that the tuner set. The computer has NO KNOWLEDGE of what the stock a/f values are anymore because the tuner deletes them and changes them to new targets.

So, there is NO WAY the car will try to target the OEM a/f unless the tuner was stupid and didn't re-adjust them. So if it truely is changing to another a/f like you said then you need to get a new tuner like everyone else has suggested.

Does that make sense now? I guess i can use numbers to explain:

stock WOT is somewhere like 12.5. When you drive the ecu will adjust it so it's always hitting 12.5.

tuner changes that to 13.0. Now the car will only make adjustments to 13.0. Since the tuner changed it from 12.5 to 13.0 the car will not always adjust to hit ONLY 13.0. 12.5 no longer exists in the tune so the ecu would not know to change back to that.

A properly tuned car with correct targets will only get better the more you drive it. Plain and simple.

SparkleCityHop

iTrader: (30)

But if your tuner did not change the targets, but just changed the fuel adjustments to get results on the dyno that particular day…

…you would end up with what you are describing. As your car begins to learn how to get itself closer to the targets, it will do so over time.

Some tuners are great at providing that one "monster pull" that looks great on the dyno at that moment… while some tuners understand that what really matters is spending the time to provide a tune that responds not just on the dyne that day, but every day, in a variety of driving situations and environments.

By your description of the symptoms, it sounds like a poor tune from the standpoint that the guy probably tuned it for the best possible dyno chart, but either didn't understand Uprev well enough to tune it properly - or just wasn't willing to spend the time to do it right.

yosip1115

What do you mean by fuel adjustments?
Also, O2 sensors don't tend to read less o2 over time as they get dirty/ old? 111k miles seems long for a sensor to last...

jerryd87

iTrader: (4)

no they dont they either work or they dont. basically what everyone is saying is you have several adjustments in your ecu, what you are referring to is fuel if you know it or not. it has long term fuel trim, base fuel and i believe the 04 and up have widebands stock for short term? anyway when you first get tuned the car is going to run off of is the base fuel map, as you drive it the computer is going to constantly look at your long term fuel trim targets and tell itself "well im currently running this but my goal is actually something else" such as it currently runs 13 but the goal is 12.5. because of this the ecu is going to try and change itself to run at 12.5. what your tuner SHOULD have done is tune it so your base fuel is correct and then changed the long term targets as well so that they match but should something change it will try and go back to where it needs to be.


cliff notes is like everyone else is saying, your current tuner might be better then your old one but he still is **** find yourself a new tuner because if your car is actually doing what you say it is then he definitely DOES NOT know what he is doing.

SparkleCityHop

iTrader: (30)

Fuel compensation tables

No, they work or they don't work.
No, your symptoms are not evidence of anything other than a poorly designed tune.
No, you can't use a switch to fix a poorly designed tune.
No, you can't pull a fuse to fix a poorly designed tune.
No, a new O2 sensor isn't going to fix a poorly designed tune.

99 to 1 odds that your tuner did not go through all of the steps of properly tuning with Uprev, but he skipped to the last two steps and just made changes to your fuel compensation and ignition timing tables while on the dyno. This gave good results while creating a dyno chart that day, but left you without the foundation for a good long term tune since he didn't make the other necessary changes to dial things in (like your MAF table), set targets appropriately, etc. This is what some shops will do if they want to minimize their dyno time and maximize their profits (if you paid a flat fee for the tune). If getting you a good dyno chart result is all that you asked him to do, then that's one thing. But if you were asking for a good tune, that is not what you received.

Sorry, man. But I would encourage that you read the Uprev 101 thread so that you know a little about it. Then you can be educated about what you're paying someone to do on your car, and you can make sure that they do it right.