I've set my ZT2 up to replace my narrow band O2 sensor and have set the switching point to 15.6:1. I was expecting some reasonable fuel savings, but after a few tanks, its made very little difference, if any.

What I'm noticing is the ecu is switching to open loop alot, so I would assume I need to increase my load tables to keep the car in closed loop at higher load. My load tables are currently set as standard Evo 8. Has anyone else played with these load tables, and am I safe to be running up to 4psi at AFR's around 15.6:1?

I've also noticed when letting off the throttle coming up to stop that the AFR will most of the time go very lean, up to 21:1 and the car nearly dies, and then it slowly goes back to 15.6:1.

Has anyone else had any experience using this and is prepared to share their wisdom?

 

Exactly the same symptoms as I'm having, and I also have a ZT-2. I may change the WB sensor and see what happens.

Let me know if you get it fixed.

 

I'm going to try and have a play with the load tables this weekend hopefully and do some logging. I do get the rich spike sometimes after letting off the gas which I would expect, but it still then goes really lean. For the AFR to go so far past the switching point before reacting it must be a speed issue with the ZT2. The factory narrow band was really good, generally a rich spike, then would settle into 14.7.

 

Well, I took out the glove box today to check the wiring for my ZT-2 and it turns out the purple wire (the one used to change NB output) isn't connected, so I guess my NB switching wasn't even working. I'm being told that it's most likely my front o2 sensor that's starting to fail, so I may get that checked out.

 

I've made open loop load #1 the same as #2. It stays in closed loop abit longer which is good. I'm also playing with my injector setup, so will see how things go in the next week.

 

Any updates on your end? I just received a new o2 sensor today, hopefully I can install it today/tomorrow.

 

I've been talking to Marc at Zeitronix, but no suggestions there except to drop my switching point back abit. I set it this morning at 15.2 and on the 5 minute drive to work, it seemed to be better, in that the afr only swung to about 16.4 instead of 21. I'll get a better idea in the next few days, but I may try running the car in open loop all the time as I should be able to run at 15.6 without any problems.

 

If your trying to gain MPG, then just set your ECU to open loop during cruise and tune the AFR to 15.5-16.2.

I use & recommend the ZT2 but I would not use the narrow band switching feature and just tune the ECU to gain the MPG gains on this application.

If you need help with a fuel saving tune, PM me.

 

Thanks, thats what I'm thinking too.

Whats annoying is it this feature sounded really good, and yet my ZT2 came up with an error everytime I tried to set it. In the end, I sent my ZT2 in and got it updated to 2010 specs and the feature worked. They could find nothing wrong with my old ZT2, yet it wouldn't do the narrow band switching. I'm now finding out this feature isn't as good as I expected and its cost me quite abit to get it sent in and updated. I could have sent it in and not done the update, but with international freight, I thought I mose well. At least I'm using User2 for gearbox temp, only issue is Evoscan can't log that yet, but Hamish said hes working on it.

 

I have been using this feature for over a year now and it is very useful. I adjusted my tune to keep the car in closed loop much longer and you could also add a little timing in the cruise area. on E85 i was able to get 300 miles on my last long drive. when i was on pump i get around 300-320 hway for reference.

 

I'm back to the factory narrow band, and the car drives so much better. In time I'll switch to open loop all the time and see if I can get some economy.