can someone tell me what these numbers mean?

 

injector lag time correction. lets say you are putting secondaries in the primary slots. secondary injectors have a lag time of .77ms. . . the primaries have a lag time of .73ms. you put the remainder of the difference of the two in that area. you subtract the primary "lt" from the secondary "lt" because you have to make the correction for the "more laggy" injector in the primary slot. if you were putting a larger injector in the secondary slot you would subtract the secondary injectors lag time from the new injectors lag time to get the correction value. so the formula is: c = a - b (c = correction value, a = new injector lag time, b = original injector lag time) b is constant. . . that is the value you will always subtract with. a is the variable since its the "newly introduced" injector. the pfc knows what the stock lag times are.

sorry for the bad post. . . a little tired

just remember. . . new injector lag time - original injector lag time = lag time correction value

paul

btw, this is all on page 26 of the pfc manual

 

right but what does it do? how does it affect the car technically

 

i figured that was the real question. haha. see above edited post


if you dont have the correction value in there. the injectors wont fire at the correct time. this could cause a lean condition. . . more than likely just a not so precise area in your tuning. . . making it hard to tune.

as displayed in your posted picture, the lag time correction has sped up the time on the primary injectors. just because the injectors size hasnt been altered doesnt mean the injector lag time cant be messed with. some "tinker" with it for driveability reasons or so-on and so-forth.

paul

 

thanks for the info paul, that helped a lot.....
i had my car tuned and noticed this change, but my injectors are stock, so i wonder if it was from a map the tuner loaded to work with and forgot these settings, or if he changed them on purpose... my car is not heavily modded so i would think they do not need to be changed with stock injectors, but ill ask the tuner...

 

I've seen XS change these values on stock injectors ... never understood why but maybe it works for them.

 

I tried verifying exactly what it did but the scope I used was really made to be used with radio frequencies which are higher than the digital signals in our ecus.

Could not get a real clear and steady pulse to see if timing or width changed. Chaning pulse width with the commander had the same affect as changing lag value.

It has yet to be proven which it really affects and nobody has done that on this forum.

So if you have access to a scope for lower rate digital signals, hook up to a primary injector and test it. Test the affects by both lag and Inj Adj, page 30 of the manual.

The challenge has been thrown again, second time by me!

 

dam chuck, that shizzy is beyond my feeble brain :-)

I got my car running almost perfect (idle/part throttle) and after I got it tuned it is kinda running crappy and I want to know if this is part of the reason

could be many things, tps setting, changed to all 9s for plugs, dunno but it is annoying to drive now in any range that is not WOT (hunts at idle, surges when at steady part throttle, hesitates on sudden throttle application, all that stuff)..... i just want it back to the way it was because it was a much better baseline of 'drivability' to work with....so im trying to get it back to my previous 'nicer drivability' state.

I guess I can just change the vales and see if it helps.

 

ooooooooookay, i see that the "tuner" is steve kan. . . you mean he left your car running badly?. . . was he in a rush?. . . that just doesnt sound like him.

paul

 

well, 'running badly' is a relative term.... to some my car may be just fine, but in comparison to the way it was before (not including WOT) it definelty took a step backwards

so for me, I would say 'yes it is runing poorly' in terms of the drivability, but i was not able to determine that until after I had some time to just drive the car for a few days, durint the weekend he was here it was too hecktic for me to focus on the drivability stuff

in terms of WOT, he obviously tuned it well, it was shown on the dyno based on the hp/afr results, so no complaints there, and he did spend a lot of time tuning as i drove to WI (many hours) to tune the drivability things (part throttle, et), but its just running all funky right now.

he and I are in the proccess of figuring it out, so I dont have a conclusion for you yet, I am still working on it with him. I am a bit frustrated since I paid for tuning and came out worse in every aspect but WOT, however I really like steve and think he tried to do tune all aspects, there was just something funny with my car or somthing because it really degraded. my idle vac reading is also a lot lower than before, so I need to check and make sure the engine didnt get damaged, it is probably some idle adjustments, but i have already reset everything mechanically (idle screws, et) so im a bit worried about that, but no conclusions there until i know for sure, could be a simple pfc setting...

pulls hard at WOT though!!! (heheheh)

 

by the way i should have mentioned to steve that I spent a lot of time adjusting my idle/tps setting, et to get it to run smooth and not to touch those aspects, that was probably my fault, if he would have known that then he probably would not have touched them in efforts to make it better.

 

Suggestions:
(1) check the TPS voltage using the commander and make sure both are correct for low and high voltages.

Some people do not realize that adjusting the mechanical throttle adjustment also affects the TPS voltages. If they are basically centered, then all is well.
But if on the edge, the they can go out of range when adjusting the throttle. The air bleed screw affects idle without affecting TPS voltages.

(2) At warmed up idle, play with the fuel using the Inj. Adj., page 30. this is the easiest way to determine if running too lean or too rich. Ideally, your fuel should be set about in the middle between lean stumble and rich stumble, to slightly leaner. If you need to change the fuel here for a good idle, then make the same changes in the fule map cells or PIM rpm map.

(3) if idle rpm in the idle map is set for 850 and can not stay steady even with correct fuel, then either the engine is getting too much or too little air through the ISC solenoid. It is running on the edge, play with the air bleed screw.

(4) performance tuning the PFC should not **** up a previous good idle unless something is not set up right in the PFC.

(5) never use O2 idle control without a working air pump. In fact my car idles better and runs smoother with O2 controll off and the air pump always blowing into the exhaust port, PAC always on. This way it never dumps air back to atmosphere as it will with O2 on. That is what causes the moo-fart sound.

(6) too many little tricks that one has to learn on their own, had my car for 11 years.

 

>>(6) too many little tricks that one has to learn on their own, had my car for 11 years.

hehhehe, thanks for the list chuck, I will check them all and see what I come up with.

 

also, what voltage is the O2 sensor during idle? My O2 just went bad for no apparent reason, other than I parted my hair on the other side this morning But since its only a 45 part from oxygensensor.com, I bought a new one and turn the O2 feedback off. Like Chuck said, it's idling great right now reading off the map. Mine was making -460ish at idle warmed up, then once it was warmed up, and idle dropped to the 770 range, it would cycle up and down, and almost stall out. I checked the sensors and saw the O2 was reading over 2.xx volts and the car was trying to pull out enough full to get a reading it understood and then was it would almost die out, add fuel and idle up. back and forth like this. Turn the feedback off and see what it idles like since it just might be the O2 sensor.

Tim

 

good suggestion, ill try that next, steve kan suggested that too... ill post what the o2 sensors sees for voltage

 

hmm. . . ive messed with the "inj. adj." deal and it didnt help me one bit. . . i went down 50%. . . my car idles pig rich. it may be due to the 850 primary injectors, but id assume i could get it better than it is. . . . ???

paul

 

ok, i did some testing with the o2 feedback disabled and it did run a lot smoother, idle didnt hunt, idled a bit higher, no funky surging at part throttle so far.... I checked the voltage it was returning and it was perfect accdording to the pfc, so the question is, why is having the 02 feedback on making it run like sh_t when it used to run fine with 02 feedback on? I guess thats a question for kan...

my next obvious question is what do i loose by having it disabled, but ill do some searches for that answer...

 

fuel economy is the main disadvantage to having it turned off.

Tim

 

thanks tim