Need help on 99 454, cant rev past 4800

[ScarabEpic22]

B1152 has been fixed as an out of range cell, I corrected it and set it to 80000. Doesnt matter in terms of when BTM will come in, B1149 makes sure it is never enabled, but it is important that the value is in a valid range.

Upshift RPMs are in Transmission Calibration -> Shift at RPM -> Upshift. Parameters D1127, D1128, and D1129. All set to 4800 in the tune you posted, I set the 1->2 and 2->3 to 5500 and 3->4 to 5200.

Hope this helps, you might have to play with the shift pressures if the truck bounces off the limiter at 5500 and doesnt shift for a second.

[schwoch1]

I hate to say this, I looked over your cal and I could not find a rev limit of any sort on it. My advice, do a 0411 computer swap, ditch the old Vortec black box computer and have fun!!! Hope this helps!

Mike

[slows10]

B1152 has been fixed as an out of range cell, I corrected it and set it to 80000. Doesnt matter in terms of when BTM will come in, B1149 makes sure it is never enabled, but it is important that the value is in a valid range.

Upshift RPMs are in Transmission Calibration -> Shift at RPM -> Upshift. Parameters D1127, D1128, and D1129. All set to 4800 in the tune you posted, I set the 1->2 and 2->3 to 5500 and 3->4 to 5200.

Hope this helps, you might have to play with the shift pressures if the truck bounces off the limiter at 5500 and doesnt shift for a second.

I think he said it is not a shifting issue.The changes you made wont address his problem immediately.OP hog said it correct but schwoch1 is alsocorrect. You cant seem to be able to raise the rev limiter in your ecm. With the mods you have done to your truck you would really enjoy a 411 swap on that rig. You will be glad you did and never look back.

[mathis]

I dont really want it to shift that high, i just need it to eventually after i switch to the longer duration lunati cam. And it wont. If all the 350s can rev to 5600 why cant i? And iv thought about the 411 swap, but iv read about quite a few small problems with them. something about 4low not working correct? For the time being i would really like to get this pcm to rev. I will try changing that out of range parameter. But im not sure this effects the spark/fuel cut out point. As for the shift points. I will leave them where they are at untill i switch cams. thanks for taking the time to go over it however.

[mathis]

okay so in your tune b1152 is not set at 80000. That exceeds the efi live limit that you can put there. Mine was set at the upper limit that efi live allows. I really dont even know what that table means. How can apply rate units be ft lbs.

[slows10]

Ignore those tables

[slows10]

Those have nothing to do with what your saying. If you have a stock cam in there now why do you need to rev it past 5000-5200 rpm. Imo 5600 is to high. You probably dont have enough airflow to support 5600 right now. Besides did you read the other posts? it looks like that ecm does not have that rev limit table. Also I think they have figured out every issue now with the 411 swap. Even the 4 low issue was fixed.

[schwoch1]

I dont really want it to shift that high, i just need it to eventually after i switch to the longer duration lunati cam. And it wont. If all the 350s can rev to 5600 why cant i? And iv thought about the 411 swap, but iv read about quite a few small problems with them. something about 4low not working correct? For the time being i would really like to get this pcm to rev. I will try changing that out of range parameter. But im not sure this effects the spark/fuel cut out point. As for the shift points. I will leave them where they are at untill i switch cams. thanks for taking the time to go over it however.

There have been a few incedences that 4 low would not shift correctly, most would shift too late causing the engine to bounce off the rev limiter before shifting. I am sure that there is a cure for that, just alot of people(IMO) don't really look into it too hard, as 4LO is used about .01% of the time in 99.9% of the trucks out there. I will say with a 100% certainty, your 454 would benefit greatly from a 411 PCM swap. It would open up alot of doors when it comes to tuning, namely Roadrunner.... once you use it, you will never go back to cutting and pasting corrections in your VE table!!! Most people with a reasonable amount of knowledge can perform the swap in a afternoon (I have) and have it tuned and running pretty good in several hours!!! That is the only way I see at the moment to get rid of your rev limiter, unless Ross or someone can get you the elusive table needed!!!???
Ditch the black box..... you won't be sorry!!!
Mike

[schwoch1]

Those have nothing to do with what your saying. If you have a stock cam in there now why do you need to rev it past 5000-5200 rpm. Imo 5600 is to high. You probably dont have enough airflow to support 5600 right now. Besides did you read the other posts? it looks like that ecm does not have that rev limit table. Also I think they have figured out every issue now with the 411 swap. Even the 4 low issue was fixed.

I was thinking the same thing, a stock 454 can barely make it to 5K rpm.... GM forgot to put lift and duration on the cams they put in them.......and the heads leave a little to be desired too...Although, after his cam swap, then the engine will prolly pull up toa good 6K or so!!!!

Mike

[mathis]

okay.. I do NOT have a stock cam, or valve springs. my cam now is a comp 212/218. I also have ported the vortec heads that came on the truck, and they flow quite a bit better. i know this because i ported them myself and flowed them myself. For this cam the limiter is not a real problem because i want to shift right at about 4900 anyways. But since building the motor, i decided to put a stall in. So now I want a bigger cam. So i bought a lunati 231/239 that is waiting to go in. and this is why i want to be able to rev higher so i can shift at about 5500. I am having a hard time understanding why i cant achieve this with the pcm that i have, since the 350s use the same pcm? Is it the operating system? Im pretty new to efi live so please try to bare with me. Is there anyone else out there with a 454 that will rev past 5000? With this 411 pcm deal.. IF i decided to go through with it. where would i find a pcm at a resonable price? and the connectors? is there anything else i need? And as far as the 4 low thing goes. Mine wont even shift right with this pcm. I guess im in that 1 percent that uses it frequently. Thanks for all the help so far! Please keep in mind for the time being i would like to stick with this computer if at all possible.