Rich Decel

[rxrz]

I started tuning my VE table and am getting most of the table under 4000 rpm and 80 kpa within +/- 3%. But on decel, I am going rich (11.5 to 12.5 afr) and despite making major changes to VE table at 30 kpa, my wideband continues to read rich. With the last decreases in VE that I made, although the wideband was still 12 afr, the trims were going positive and adding fuel to the motor! I think something must be wrong with my SD 60 injector setup relating to min pulse. I have the min pulse set to 1.3 but all the logs will not go lower than 1.8 . What should I be looking at or doing differently. In case it is something with my injector set-up, I want to get it corrected before I start tuning in PE and BE area’s of VE table.

Vehicle Data – 2004 Corvette , LS1 , Procharger P1SC-1 SC @ 7 PSI , 216/220 112 cam, 9.5/1 CR, SD 60 Injectors, 2 Bar OS

[Pekka_Perkeles]

I think something must be wrong with my SD 60 injector setup relating to min pulse. I have the min pulse set to 1.3 but all the logs will not go lower than 1.8 . What should I be looking at or doing differently. In case it is something with my injector set-up, I want to get it corrected before I start tuning in PE and BE area’s of VE table.

Your Short Pulse Adder is wrong. Multiply all values by 0.2. It will help, even though not exactly right. Use 0.8 as minimum and default pulse.

[rxrz]

Thanks for your tip on adjusting these values. The data sheet that I got with the injectors gave a minimum PW of 1.391 @ 39.15 psi. I used that MINPW value not realizing until now that it was a 39 PSI rating. Would the MINPW at 58 PSI be a straight ratio reduction of (39/58=.672) *1.391= .935ms?

What is the proper method to determine the short pulse adders? Is this manufacturers data or is there a generic guideline on how to develop this table? The injector data sheets don't reference this item at all.

[jimmyb496]

Thanks for your tip on adjusting these values. The data sheet that I got with the injectors gave a minimum PW of 1.391 @ 39.15 psi. I used that MINPW value not realizing until now that it was a 39 PSI rating. Would the MINPW at 58 PSI be a straight ratio reduction of (39/58=.672) *1.391= .935ms?

What is the proper method to determine the short pulse adders? Is this manufacturers data or is there a generic guideline on how to develop this table? The injector data sheets don't reference this item at all.

Just out of curiousity... the flow rate values that the mfg provided, were they rated at 39psi as well? If yes, you'll have to convert the FR for your line pressure.

[rxrz]

The vendor (Fuel Injection Connecton) tested the Injector flow rates of 63 lb/hr at 43.5 PSI. I used a fuel flow calculator to adjust it for the 58 PSI in my car which took the flow rate to 72.7 PSI.

[jimmyb496]

Thats good, so that's at least not part of the issue.

[Cobalt]

Search for Transient Fuel - Min Fuel Miligrams

Fixed my rich decel by halving that value... Seem mislabled in HPT

It is really Min Pulsewidth ....

Check your logs at decel and see what the Inj Pulse is.... My minimum was 2.2ms... now got it down to 1.6 and no more rich decel....

Cheers

Chad

[flame]

There is no transient tab in the OS he is using