mpguino TDI feasability

[dcb]

I'd like to discuss the feasability of a TDI based mpguino since there seems to be a gap in the commercial offerings there. Does anyone know or have links to pertinent technical details and diagrams? Also will need a victim^H^H^H^H^H^H volunteer or two with a TDI who can help figure out the hookup details and appropriate parameters to use (might require road testing to calibrate).

Thoughts? Suggestions?

[dremd]

SUBSCRIBED!
Volunteered!
What do I have to buy?
I will try and scare up diagrams later today, or tonight.

[wyatt]

Originally Posted by dremd

SUBSCRIBED!
Volunteered!
What do I have to buy?
I will try and scare up diagrams later today, or tonight.

6 minutes? it took you 6 minutes to reply? Dang!

I have a friend that may be interested in helping/testing (I don't want to volunteer him). We have been kicking around the idea of building a few MPGuinos for our vehicles, but I didn't realize that it would be any different than my gasoline car. What are the differences, and would they be easy to overcome? I don't want to build and MPGuino and have it go unused if things don't work out. Thanks.

[tasdrouille]

You have my total attention and cooperation!

This diagram might help. It's for the AHU engine that was on 95-99 Jettas, but it should be good for all TDI engines sold in NA till 2003 though wire colors may vary.

[dremd]

Originally Posted by wyatt

What are the differences, and would they be easy to overcome?

IF I recall correctly the ecu sends a pulse to the injection pump which determines time + duration.

The only issue that I can foresee is that there are actually 2 injection events for every pulse. 1) Pilot event; low flow finer mist. On my car this occours (pop) when the injection pump reaches 224-229 bar and 2)the primary injection event at 307-309 Bar.

I am concerned about the different flow rates per unit time messing up the calculations. AKA at Idle the Pilot injection could be 50% of the injector open time and at WOT it might be 5% of the time.

And at higher RPM the pump is flowing more fuel therefore it will also affect the length of injection events versus time open. (Understand my concern?)




NOTE: 2004 + CARS WILL BE ENTIRELY DIFFERENT THAN MINE. They used Unit injectors.

[wyatt]

^^
I see what you are saying about the possibility of differences, but it was my understanding that for any vehicle you are kind of taking a "smeared" number, meaning that it's an average of numbers, and is meant to get you as close as possible. I think that's what is happening on the gasoline versions also. For that matter, I think that is what happens in all vehicles with this technology, since they are not actually measuring the fuel used, they are measuring the amount of time the valves are open or the amount of air used.

[tasdrouille]

This will get you better understanding of the TDI fuel management of pre-2004 engines.

[dremd]

Originally Posted by tasdrouille

This will get you better understanding of the TDI fuel management of pre-2004 engines.

That PDF gave me an Idea; does anyone know what kind of signal comes out of the needle lift sensor?

[dcb]

The signal to quantity adjuster N146 looks promising also, if anyone knows what that signal looks like. It might just be pwm:

"The quantity adjuster is a solenoid, a type of electric motor which adjusts the position
of the modulating piston via an eccentric shaft and thus regulates the fuel quantity
continuously from zero to max. delivery rate."

[tasdrouille]

Originally Posted by dremd

That PDF gave me an Idea; does anyone know what kind of signal comes out of the needle lift sensor?

The needle lift signal should look somewhat like the left or right part of this image:

What do you think about the modulating piston movement sendor (G149)? It is used by the ecu as a feedback on the N146 position to determine the actual injected quantity.

I have a pot between pins 2 and 3 of G149. When I increases the resistance, the ecu is fooled and the actual injected fuel quantity goes up. At idle I can see the consumption go down on the scangauge as I increase the resistance, when in fact the injected quantity actually higher.

I do not really know the signals specifics and do not have access to equipment to look it out.