What's up folks? Here's the skinny: my ECU is going into limp mode at WOT. There are no CELs nor pending codes.

I've verified the fuel dump with a WBO2 and my butt The AFR goes from an acceptable 12.7 at 55% throttle to a dog-**** 9.6:1 at anything above 60% throttle.

I believe the eManage was working when I went to the dyno, but I don't have any way to really prove that. For all I know my mods were such that the ECU taking over was still giving me a 12.x AFR just by virtue of taking in a bunch more air.

I just installed firmware 1.39, but the same issue was happening with v1.20.

Someone in the eManage group at yahoo says that evo guys haven't been able to use this because their ECUs resist any attempt at change. That's believeable, but he didn't say that they go limp, just that the ECU doesn't respond.

Any thoughts or suggestions? I'm getting really irritated at this. It's already cost me about 10 points at my last autocross (because there's no power to get around the track) and I don't think it's safe to drive around like this with no power.

 

i've worked with a few of them and never had those issues... even the afc doesn't. Possibly you are taking out to much in an area it doesn't want you to. If you do that the MAS can read extremely off and throw you into limp mode.

This usually happens when you adjust in a driveability area(closed loop)... you should have to adjust in that area at all unless you have bigger injectors or a cam that is throwing things off.

You need to get an obd-2 reader and check fuel trims... if at any point in the closed loop area you go over 25% fuel trim the ecu with go into limp mode.

 

I'll check that, but even when I add up to 30% fuel, it still goes limp.... hurumph!

Does it matter if it's long or short term trims? I'll get on that tomorrow night.

 

Man, reading these posts makes me feel stupid I've got a lot of research/studying/reading to do

Good luck getting this fixed.

 

i love posts like this!

 

so you can do 55% throttle all the way to 6k with no problem?

he *might* mean STFT since LTFT only changes over time.

 

is ur stock O2 sensor working correctly?? Is it possible that when u get up over 55% throttle that the stock o2 sensor is reading a leaner afr and overriding the emanage?? I don't really know Im just throwin ideas out

 

The signal from the O2 sensor to the ECU goes through the e-manage first, so it shouldn't matter much. I think Boe's got the right idea. Something the e-manage is reporting is out of the parameters of the ECU, so it's screaming, "Oh ****! limp mode!"

 

Andrew - maybe "Oh ****! Limp mode!" would make a nice signature?

 

wow- that was not even nice

 

nope but it was damn funny though...

I did mean short term fuel trims... that will let you know if you're within the parameters of the ecu and how far you can go till your out. If your adding 30% fuel to your setup you could be going way out of specs already. As a rule start stock with the emanage zero'd out and read your fuel trims.

If you've done a bunch of mods and your seeing the fuel trims go possitive... meaning the ecu is adding fuel then add the fuel to get the trims to zero. Sometimes you can get them close and remember the car is constantly adjusting so seeing trims of +/- 5 is fine and during shifts you could see some as high as +/-15 due to the shift from closed to open loop operations during decel.

During constant driving you should see +/- 5 trims or better. Once you have that in line then and only then try throttles above 75-80%. Below that the car tends to stay in closed loop. Keep an eye out though as RPM's rise you must lessen the throttle to stay in closed loop. Keeping it at 50% or more at RPM's higher than 3k can result in a shift to open loop.

After you get all the rpm band dialed in and trims are constant then it's time for full throttle pulls. Full throttle pulls don't care about O2 readings since its already in open loop then. Just remember that at 100% throttle the ecu tends not to shift into open loop till after 2500rpms... sometimes closer to 3k rpms. Thus i usually tune 3000 and lower to closed loop and then tune 3500 and up to open loop specks. That way you don't run into issues in driveability.

Good luck.

 

why not save you map... and then clear it to see if the problem continues... if it doesnt then you know its not the emange and you can rule that out... if it does stop... then do what boe says

 

If you mean "why don't you try a map that's all zeros and see if that effects the AFR" that's been done. It's not the eManage, per se, but rather how the ECU is interacting with the eManage.

 

so your problem stops with all zeros then?

 

no, the problem persists regardless of what the map looks like.