In an attempt to manipulate a fuel curve at cruising speed in my ecm, the fuel map shows a maximum throttle position of 88.7 degrees. I can probably ass u me that that equates to 100% throttle position, and half of 88.7 degrees would be the 50% TP. Am I on the right track?
A 14.2 afr at 60 to 75 mph is what I'm going to target, but that shouldn't be too lean as to cause the engine undue stress and hardship, correct? I think the factory setting is 14.6 but we don't want to go there. The increase to 14.2 is to try and regain some lost mpg.
Thank you Wise Ones for your ideas.
TG
Location: Winston Salem, Greensboro area of North Carolina
Posts: 130
Re: TPS degrees vs %
Quote:
Originally Posted by tommyglide
In an attempt to manipulate a fuel curve at cruising speed in my ecm, the fuel map shows a maximum throttle position of 88.7 degrees. I can probably ass u me that that equates to 100% throttle position, and half of 88.7 degrees would be the 50% TP. Am I on the right track?
A 14.2 afr at 60 to 75 mph is what I'm going to target, but that shouldn't be too lean as to cause the engine undue stress and hardship, correct? I think the factory setting is 14.6 but we don't want to go there. The increase to 14.2 is to try and regain some lost mpg.
Thank you Wise Ones for your ideas.
TG
I will assume that you you are using a SERT. Here is a link to an article on my website that should help. http://hemrickperformance.com/tuning.aspx It would take up too much time and space to post it here.
If you are using the data mode on the SERT or if you are looking at the throttle position on a Power Commander, WOT should be 100%, not 88.7.
The problem may be that the throttle cable is not opening the throttle plate all the way. If properly adjusted, you should hear a "slap" noise when snapping the throttle to WOT. The same type noise will be heard when the throttle is released quickly and the throttle hits the throttle stop.
Location: Winston Salem, Greensboro area of North Carolina
Posts: 130
Re: TPS degrees vs %
I have bored out several of the HD throttle bodies to increase their size including the new one piece style. When these are bored, it changes the TPS switch in relation to actual throttle position and the TPS no longer has the ability to reach 0% or 100%. To help correct this, we remove the TPS and knock the brass looking bushings out (where the mounting screws are located) so the TPS will be adjustable. You can also oblong the holes if needed. The problem is that you can only achieve 0% or 100%. You will have to find a happy medium. This is just another option that can be used if the throttle cable adjustment wont fix the problem.
When reinstalling the TPS it can adjusted by moving the TPS while looking at your computer screen. Tighten the screws at the desired position.
I think the mother ECU has to read 0 to 100% to function the map schedules. So, I would as is you is me youmm is did you zero out the idle screw and now that should be your 0% set. Then WOT the throttle; read 100% as does mother ECU.
88% at WOT? 12% is under the idle. You want to bring the TPS to a full close. Idle is already on the next few grids if we want to synchronize the piggy to the TPS. We are past 0 to 25 rpm or whatever that baby reads next; is that start map and who knows what is next in that mother of a board is I would have to steal the plans at Delphi or Mar/Merr or work for them and get in where they top secret the TPS to map to crank to mother board to ROM and RAM map it all up. And not in that order I am sure.
Do we understand what I just mentioned in the generic search for 100% WOT... Not 88% is do not show up at the line with that setup, I meant. A VW might turn one's face red is you couldn't pass it on the highway being dead even in the HP an tune.
TPS degrees vs % 
Linear Mode
