At any rate, my eyes have really been opened to the boosting while in closed loop "issue". My EGT's raise pretty quickly when I'm on the highway cruising at 75-80ish and I just want to accelerate a little. I can't do that without building boost on my smallish T3 turbo. Seeing the boost gauge around 5psi in that RPM range and the watching EGT's rise from 1425 to 1600 in a matter of seconds and looking at the wideband and have it hover 14.5 to 15 is a bit frustrating.

So here's my theory (even though I while thinking this through I've determined this probably won't work) As the turbo starts to build positive pressure (while in closed loop of course) the EIC kicks on the secondary injectors just as it should, but since the factory ECU still thinks it should keep the engine running at 14.7:1 so it starts shutting down the primary injectors to compensate for the extra fuel that it really doesn't know the engine is getting from the secondaries. Why the ECU doesn't freak out about that is probably a small miracle. So my thought is, just dump a shit ton of fuel (in that problem window) from the secondaries until it maxes out the trims and gives you the desired A/F. The problem with that is the engine will run stupid rich in that "problem window" during open loop operation. But I didn't think of that until I had most of this typed, so I thought I would see what you guys thought anyway. Although during open loop acceleration the time it would be in that window would be relatively brief. So that might help the being rich situation. :shrug

This 034 is nice and I like tinkering with it. But I can already see it's limitations, between this closed loop thing and no temperature correction, I've already planted some MSnS seeds. Rather than wasting more money on a separate timing control something or other.

Also once I get around to installing my FMIC I'm hoping that'll help a bit. But with being married now and my daily driver all kinds of f'ed up it's hard to find time to do things to the Talon other than road tuning to and from work...LOL.

Hmmm... Ive thought about this myself and thats why most went with MS.

That is what happens, but I wouldn't suggest that you try to over run the fuel trims. The stock ECU can't tell the difference between 0 psi and 10 psi boost. If you max out the fuel trims to cool down your EGT's at 10 psi boost closed loop, you will be 50% too lean at 0 psi boost before the secondaries kick in. So, your boosted tuning would wreak havoc with your pre-boost tuning. I think the best bet is to just keep your tuning close to stoic at the lower boost levels where you are often in closed loop. At higher boost, when it just isn't safe to run stoic, tune for whatever keeps the EGTs acceptable in open loop. If you are boosting in closed loop and think the EGTs are getting too high, just kick it into open loop to cool things down. But, yeah this is a limitation of the 034. The MS is more powerful.

Corbin

'95 ESI-T
Now with more power and fewer leaks



Gimme fuel...Gimme fire...Gimme that which I desire

Im confused (be patient, please) If you are running lean in any spot during boost cant you just make a change to that cell(s) in the map, richening that lean area?

or

Couldnt you just trip a CEL on purpose making the stock ECU run open loop all the time in attempts to alleviate the dry spot?

Again be patient I haven’t been around for a few, and I am trying to learn more about these fuel systems you guys are all running now. Im used to just going in to my DFI and adding fuel in the area that needs it according to my AF readings.

Later
Brian

OMG he LIVES! car looks good.

What we are talking about is the fight between the stock ECU in closed loop and the EIC. Add fuel to one cell in the EIC and the stock ECU will pull fuel to compensate (in closed loop). Closed loop is a good thing for low to moderate loads. The car would not run well if you forced the stock ECU into open loop permanently by creating a fuel related CEL.

Corbin

'95 ESI-T
Now with more power and fewer leaks



Gimme fuel...Gimme fire...Gimme that which I desire