honken

I have a my fuel pressure set to 28 psi at wot and 17 at idle with vafpr.
The car is hard to start when it cold need to push the pedal to start and
runs wery rich but when the engine is hot everyting its fine.
Were do i mod the chip to get it right with the cold start.

Grumpy

There should be a table with IAC Park Position vs temp., try adding some IAC counts in the cold temp areas where you're having the problem. That should help with how far you have to press the pedal. Then it sounds like your rich, so you might want to lessen the crank fueling at lower temps.. Then whatever choke afrs, lean them down.

Go slow, take notes, pay close attention, some of the adjustments are subtile.

honken

Tanks grumpy i try it out

dimented24x7

iTrader: (2)

The VAFPR is the issue. At startup, the fuel pressure is 28 PSI. You'll need to scale the startup PW tables to compensate for this, or the engien will flood out at startup. The tables should be scaled down proportionally to the increase in flowrate. For example, if you originally had injectors that flowed 65 PPH and you bumped the FP to get 75 PPH, then your tables would need to be scaled by (65/75) to compensate and prevent floods on startup. The table that needs to be adjusted is the Crank PW vs. cool temp table @ 4D92. This also has a scalar located at 4D90. The scalar is what you want to scale up or down. Scaling the table will zero out some values. See the hack I attached in 'TBI guys, its time to update!'. I list all the tables in there. Since the startup fueling is DRP based, there are more of them then you can shake a stick at so use care and ask questions before tinkering.

honken

Yes i tooth it was the high pressure at start.
Is the 4D90 a constant ???
If i adjust the 4D92 for the high pressure isint it to short when the pressure sets(its cold here im wery rich at cold start up).

dimented24x7

iTrader: (2)

The table is only used when your cranking, so you should have full fuel pressure only while using that table for fueling, so chaning pressure wont be an issue. Scale the scalar at L4D90, 91. This will change the PW for the whole table.

honken

Is it a constant and wath conversion has it.
Dide a constant with no and with conversion and got a value of 31 ??
The hack sas 123.49???

; CRANK BPW Vs. COOL
; L4D90 FOR SCALAR
;
; Dissassemby of BDWM LINES = 17
; 03-16-1994, 15:26:25
;
; TBL = 2.073 * Msec
;----------------------------------------------
L4D90 FDB 8093 ; 123.49, SCALAR, (SCALER * 65.536)

dimented24x7

iTrader: (2)

The values in the table are multiplied first by the scalar, and then divided by 256. A scalar of 8093 will multiply the stored pulsewidth by (8093/256) or 31.6. For example, a value of 30 in the table will be stored as 30 x 31.6 or 948, which is 14.46 msec. of pulsewidth per injector firing. Lets say you origninally had 60 PPH injectors, and now you have 80 PPH injectors, and the motor floods when cranking. You can deliver the same fuel as you did with the 60 PPH injectors by multiplying the scalar by (60/80). This would be (60/80) x 8093, which would be ~6070, or 23.7 in your tuning software if it does the conversion for you. Using the same table value of 30, this would give 9.64 msecs of injector pulsewidth instead of 14.46. With the vacuum AFPR, you multiply the scalar by 1/square root(new fuel pressure/stock fuel pressure), or, for example, 1/SQRT(28 PSI/12 PSI)=.655

Dont get hung up on the origninal hack, not all of it is correct and the code section is completly uncommented. Thats why I worked with the PCM, so I could see how it actually works, and whats right and wrong in the constants section.

honken

Thanks dimented.
I have tunerpro rt.
Played with the L4D92 yesterday and its the way to do it(done it before with to litte changes in the values).
Im going to try out the L4D90.