I'm not sure if diesel's run in a closed or open loop stage, I would think not because there are no HC's catalysts and 02 sensors to warm up...

 

HMMM, I am wondering because it would be much simpler for conversion purposes and tuning to have just an all out closed loop. You would loose the benefit of selected cylinder shut off, among other things, when thing got out of wack though.

 

There is a chance they may use open/closed loop like a gasser, but I doubt it. Maybe someone who knows for sure will chime in...

 

there is not a open loop or closed loop on a diesel. This is controlled by catalyst and 02 readings.

 

I thought that it would be controlled by the something other than the o2 in a diesel. But I was wondering about Bigrpower's post when his was at Elite and the puter was selectively shutting down whatever injector was not contributing. Bypassing all of this may be an easy way to keep it all very simple in my conversion. I think that is why there is so much buzz about the more affordable stand alone computer's for the common rail Cummins and Dmax. Just curious, I will just have to talk to Eric when I have him write my tunes about this stuff, thanks!

 

Part of the reason that its done is to protect the engine, If you ran all the time with a cylinder that was over fueling, you would end up like a dmax guy and throw a rod or break a crank, as for some other aspects of it like the EGT sensors, EGR sensors and that kinda stuff, i get what you are saying.

 

I just received a polite reminder that I have it backwards, OPEN LOOP is what I intended. Closed loop makes adjustments per sensor input, sorry all for the confusion!

 

I was thinking it was backwards. That is why I was wondering why you wanted to do a closed loop tune when they are technically is CL anyway. I guess what was said could work, just have the tuner disable any sensors you don't want.

 

I think the VW diesel acutally uses a wideband sensor unless that was in a dream I had recently.....

The 6.4 does have protection based on EGTs so if you wanted to you can simply lean on the EGT probe at WOT......

 

Tuning closed loop or open loop is more of a gasser option(O2 sensor), but there is close/open loop in a diesel. It's not used the same way without an 02 sensor.

The proper way to tune a vehicle is to leave part throttle in closed loop, so it uses the 02 sensors, etc. It will switch to open loop at WOT only. Speed density and MAF vehicles tune a bit differently, but the principle is the same. Closed loop uses the 02 sensors to maintain stoich.

On heavily modified gas vehicles, especially with larger cams, it's sometimes easier to leave the vehicle in open loop. If the tuning software package is limited in parameter or it's tough to figure out, some tuners will resort to this. I never recommend it.

The VW TDI does have an 02 sensor right after the turbo in the downpipe. You can read and tune a diesel by the a/f ratio, it's just much different than a gasser.

 

Tuning closed loop or open loop is more of a gasser option, but there is close/open loop in a diesel. It's not used the same way though.

The proper way to tune a vehicle is to leave part throttle in closed loop, so it uses the 02 sensors, etc. It will switch to open loop at WOT only. Speed density and MAF vehicles tune a bit differently, but the principle is the same. Closed loop uses the 02 sensors to maintain stoich.

On heavily modified gas vehicles, especially with larger cams, it's sometimes easier to leave the vehicle in open loop. If the tuning software package is limited in parameter or it's tough to figure out, some tuners will resort to this. I never recommend it.

The VW TDI does have an 02 sensor right after the turbo in the downpipe. You can read and tune a diesel by the a/f ratio, it's just much different than a gasser.

Thanks Eric :bowfast:

 

:whs: