Max Effort Tune Popping

Quick question for you guys, working on an 03 6sp manual for a friend. Truck has SB64mm charger, 90hp sticks, twin pumps, and studs, when working on a max effort tune I get a pop, and or cylinder miss in 3rd (some times 4th) gear around 2500 rpm. 5th and 6th gear pull fine. Fuel pressure is following along as it should, and the tune does not show that it is pulling fuel (mm3) or rail pressure. I have tuned countless 06-07's with EFILive and never had one do this. I have maxed almost every limiter, and it has not helped. The truck feels like is is hitting an air limiter, but we don't have any air tables for the 03's, and it's not pulling fuel?? Usually when you hit a limiter it shows in pulling fuel, but I'm not seeing it in any of the 20 or so logs. They look as if everything is fine. At the moment I'm running around 45-50% timing not deg around 2300rpm to 3400rpm @ 100mm3-140mm3 of fuel, do the 03-04 motors not like as much timing do to the different pistons? Any help would be greatly appreciated.

Thanks

Sam

Quote:

---

Originally Posted by 30 RUM

Quick question for you guys, working on an 03 6sp manual for a friend. Truck has SB64mm charger, 90hp sticks, twin pumps, and studs, when working on a max effort tune I get a pop, and or cylinder miss in 3rd (some times 4th) gear around 2500 rpm. 5th and 6th gear pull fine. Fuel pressure is following along as it should, and the tune does not show that it is pulling fuel (mm3) or rail pressure. I have tuned countless 06-07's with EFILive and never had one do this. I have maxed almost every limiter, and it has not helped. The truck feels like is is hitting an air limiter, but we don't have any air tables for the 03's, and it's not pulling fuel?? Usually when you hit a limiter it shows in pulling fuel, but I'm not seeing it in any of the 20 or so logs. They look as if everything is fine. At the moment I'm running around 45-50% timing not deg around 2300rpm to 3400rpm @ 100mm3-140mm3 of fuel, do the 03-04 motors not like as much timing do to the different pistons? Any help would be greatly appreciated.

Thanks

Sam

---

My first thought is it might be pulling pulse width. Are you logging pw? What is the state of your pulse width limiter? I can't give you any input on timing, sorry.

The 03-04 is a very different animal from the 04.5+. There are no "air" (air density) limiters in the 03-04 as they don't have wastegate control.

-Matt

Thanks for the response Matt. Yes I'm logging pw, it is holding desired pw with no signs of it pulling back, well at least not until you get close to the soft rev limiter and pedal maps. Main pulse limiter is set to disable, and type is set to minimal. I pretty much have it narrowed down to to much timing in to low of RPM, just wanted to see if anyone else has run into this yet. The thing that is throwing me for a loop is how the motor is happy in the top gears, it just does not like spinning up fast. Maybe the fuel is coming in to fast and putting out the flame. As usual the way to find out is a another flash, should know more this evening.

Thanks

Sam

Well it's confirmed, It was to much timing.

Glad you resolved it!

-Matt

Quote:

---

Originally Posted by 30 RUM

Well it's confirmed, It was to much timing.

---

Please log pilot timing...Ill bet youll find that without tweaking the co-efficient tables, your pilot timing is going too high...

I was thinking that as well, but pilot pule is shut off by 2200RPM. Pilot Pule is zeroed out (factory table) at that rpm but not the timing tables. I'll log both pilot timing and pulse to see what it's doing. If my math is correct this thing is getting 79.73deg @ 2400rpm of pilot timing with multiplying the ECT timing Adder by the ECT Coefficient table for that temp, then adding it to the pilot base table (Wow!!). Does that sound correct?

BTW it's good to have you over here Les...

Thanks

Sam

Quote:

---

Originally Posted by 30 RUM

I was thinking that as well, but pilot is shut off by 2200RPM. Pilot Pule is zeroed out (factory table) at that rpm but not the timing table. I'll log both pilot timing and pulse to see what it's doing. BTW it's good to have you over here Les...

Thanks

Sam

---

Have you verified your pilot is in fact going away? These 03-05's act different than their 06-07 brothers do

I have not, I guess I just took it for granted that it was. One other thing, it seems this truck wants a lot more pulse than the 06-07's to make mild/hot power. It's the first 03 that I've messed with. I will check it out in a day or two and get back with some data.
Thanks

Quote:

---

Originally Posted by 30 RUM

I have not, I guess I just took it for granted that it was. One other thing, it seems this truck wants a lot more pulse than the 06-07's to make mild/hot power. It's the first 03 that I've messed with. I will check it out in a day or two and get back with some data.
Thanks

---

You may think so..but a log may show you that your not actually hitting the desired pulse...thus feeling like they need more, when in fact you just need to adjust the tune accordingly.

The CMB 845's are NOT as easy as the CMB 849's...they do require more "tuning" to make them act as desired.

I have logged fpd, fpa,main injection pulse and main timing (and the rest of normal pids) and it was hitting desired with no problems in the high gears. The only time it doesn't want to hit desired is in lower gears, 3rd on down, when the engine is not hitting full load, it acts similar to a CMB 849 in that aspect, it also will fall of load in the high gears around 3200rpms, which is okay as he does not want to run high rpm's. (I didn't go through and re scale everything for high RPM). The truck has 90hp sticks, I know that is not huge by any means but it seems like it wants a big US # to make any real power. Way more than I like, or would even think of using. It's a friends truck, and he is used to the TST smoking all the way through the rpm range. So in his mind, that is the only way it's going to make any real power; gotta love that way of thinking. In all reality it does seem to be a little down on power for the numbers being used. I will check Pilot pulse and timing and get back with you guys to let you know what it is doing.

Thanks