I've been reading a lot of your guys' posts lately and I think that I want to try an open loop tune. I guess I am an idiot right now and can't find a good set of search words to bring up a good search. But my main question is where to start? 94 LT1 camaro manual tunercats

 

Simple! VEMASTER your datamaster logs a few times after driving awhile in closed loop with good exhaust and 02's.

The real question is why would you want to run in open loop?

 

Truthfully just to give me something to play around with. Never done one and just want to try it out.

Plus, I have my car to the point where I stuck this last program in there. With the one in there, it gets good gas mileage runs strong at WOT, runs smooth etc, etc, etc. For about 2 weeks. Then goes the gas mileage and starts to run a little rough while cruising in 6th gear and a low RPM (below 2000, still have 3.42's). I pull the battery plug it back in and its as good as new.

 

Assuming you know how to lock the pcm into open loop you will need a wideband to accurately tune in open loop. As stated in another thread there are two main tables that will need to be tweeked to get the desired A/F ratio. If you are still using a MAF then the MAF tables can be tweeked. If you don't plan on runing the MAF, and even if you do, the VE tables need to be tweeked. I am almost finished coming up with an excel program to tune my VE tables in open loop since you can't use VE master that relies on BLM feedback and a target BLM which is supposed to get you to stoich in closed loop. The excel program I'm working on is based off of RPM/MAP, A/F ratio that is determined by a wideband and the desired A/F ratio you want. Similar to VE master but this program will actualy use true wideband readouts to adjust A/F ratio instead of BLM's based off a narrow band system.

 

So what you're telling me is don't go with VEmaster and instead use a wideband?

 

Yes. Your problem could lie somewhere in the learning capability of your pcm which is influenced by your O2 sensors. This is one reason why folks including myself with wilder set ups choose to bypass the O2 sensors and get a wideband tune. It would be a good idea however to use VE master and the O2 sensors first to get your tune close before your problems occur that you speak of. Then disable the O2 and run it like that or get it fine tuned even further and use a wideband to get it right where you want it. The wideband that you purchase must have the capability to read MAP and RPM also if you don't wire it in through your A/C line into your datamaster reading.

Some folks have managed to get the LC-1 to work through datamaster wich would be and excellent set up if you can get it to work. I however have a more old school way of doing it with a seperate FJO wideband that logs all the data independantly.

 

Hey - Did you ever make that program for Excel for open loop tunes?

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