Hello been lurking here for a while and finally joined. I have a cammed vortec 454 with a wait4me tune. I have in my possession a blue point scan tool. It shows my wot spark advance in the mid to lower teens. This cant be ideal. It also has a low curent knock sensor code. Would this cause it to pull timing or is it an issue with the tune? Also this scanner only updates about every three seconds, any recomendations on a faster scanner for viewing live data? It shows kpa of 99 with the engine off and 98 at wot, but i dont know how accurate it is being the scanner is slow. How much kpa drop is acceptable? thanks

 

The knock sensor code is going to cause your PCM to switch to the low octane table. It is probably a bad knock sensor or a pinched knock sensor cable.

98kpa at WOT is fine. Doesn't look like you have an intake restriction.

 

Knock sensor codes can definetely cause severe drops in timing.

 

knock sensor issue is now fixed. truck seems to run a little bit better but still seems like it should have more timing at wot above 3000 rpm, timing is between the mid/upper teens and 22 at wot. From my experience with mud drag trucks i feel like it should be closer to 30 above 3000 rpm. How does this compare with other tunes? How much spark advance do you have a wot? thanks

 

How does it feel? I don't think high twenties is necessary on these modern engines. In fact its usually too much. Older motors required more timing advance up top.

 

Every setup is different. You have a "canned" tune, by that I mean you have a safe basic tune. For comparrison to your mud truck make the motor the same and through it on the dyno. Otherwise unless you can dyno your current setup and tweak the pcm from there your kinda stuck.

Most tunes I've wrote depending on the driver and setup would be 20-26 degrees wide open throttle and air fuel wold reflect 12.6-13.2 NA depending on how the motor responded. Some vehicles wont take more than 19 degrees and some like 32, its just a crap shoor guessing what will work.

 

that all makes since. guess my best bet would be to get it dyno tuned. Anyone know of a good place in missouri for a dyno tune? thanks

 

in the kc area, or more towards st louis?

 

I have an 09 and I tuned mine to run 89 octane and i dont see over about 25* at wot. The more efficient the head design the less total advance it will need. It will vary from setup to setup but i havent seen an n/a ls engine that needed over 28*to 29*.

 

Im about the same distance from st louis and kc. generally bigger bores want more timing. Also doubt my heads are quite as efficient as ls heads. need to get it on the dyno. that might wait till after i change cams again however.