injector timing gen 4

[LS ROB]

I've read for the past 2.5 hours on EOIT to help with fuel smell. Most of this seems complex to me. Can anyone dumb it down enough so that I can feel comfortable experimenting and not damage my engine?

Cam is Texas speed Stage 2 LS7
Specs- 234/246 .635/.635 @.050

Pulled this info from a Cam Calculator online.

IVO is 7.0 ? BTDC ( - indicates ATDC)
IVC is 47.0 ? ABDC
EVO is 63.0 ? BBDC
EVC is 3.0 ? ATDC ( - indicates BTDC)
Overlap is 10

The fuel smell is not terrible, but I feel it is not optimized.
Any info on what to look for or how to sneak up on the magical number would be greatly appreciated.

[07GTS]

yep set boundary to all 520 if not already, set the normal rpm to all zero, set the normal ect where it is 110 lower that figure by 5-10 deg ( or raise if lower dosnt help) at a time and go for drive and check idle trims to see if ur richer after the change, then if u go richer just go little lower/higher till it settles richer, then take that fuel out of the maf/vve so its back to correct and all good, i usually dont go below 80 from the 110 as u also dont want it too delayed so u may find it helps or not also cats or no cats will make a big difference to smell if no cats then u will always have some smell

[LS ROB]

Ill play around with it and see what happens. Thanks for your help.

[LS ROB]

ok so just re-read this and want to make sure to do this correctly. On the Normal RPM, set all to 0 and on the Normal ECT, only lower the figures that have 110 in the table? So from around like 154*F? Now, at this point I'm good to experiment up or down 5-10 degrees from 110?

[07GTS]

yea u can lower/raise the whole normal ect by the 5-10 each test if u want as it can help with cold starting too, 10 is a good figure just lower it ten and then go for drive and then see if idle is richer, if it is then take another 10 out see if it goes richer again, if first 10 or 20 lower dosnt do anything then try adding 10 and then another 10 see if it helps that way

[LS ROB]

Ok,thank you.

[LS ROB]

quick question. if you have a wideband, would you be able to tell right away if the fuel trims were richer or leaner when adjustments are made or should you always drive to find out?

[GHuggins]

This is what I do for what it's worth. With boundary set to 520 across the board, I dial in my MAF for the idle cells specifically and the rest of the MAF curve as close as possible as quickly as possible. Don't touch VE yet. Dial in injector tip temp as close as possible and idle controls somewhat close to where it will at least mostly idle smooth. Then I do a revision with 20 added to boundary, wait 20 minutes of idle time, do a wot stomp while logging the entire time - I made additional adjustments if needed to itt here. Repeat with 20 subtracted from boundary. Your looking for 2 things - quick crisp snaps and injector duty cycles to drop along with more (-) fueling controls in closed loop. Exhaust smell is another thing looking to improve. Then from there take some pretty big leaps - adjust maybe 40 or 50 using the rpm adder table and boundary both. Repeat all over again. Then I use the boundary table to retard it gradually within the entire rpm range as rpms increase - usually don't go above a 570ish setting here at peak rpms.

If NA with cats or even without - it will probably prefer and do better with it really advanced. If FI, it'll do better around 520 or retarded from there.

Honestly the cal I sent you way back when demonstrates a lot of this and even has some really close settings in it for your cam and engine build. If you use them along with the stoichio table it should all but alleviate a lot of your fuel bucking.

[317@Clubby]

This is what I do for what it's worth. With boundary set to 520 across the board, I dial in my MAF for the idle cells specifically and the rest of the MAF curve as close as possible as quickly as possible. Don't touch VE yet. Dial in injector tip temp as close as possible and idle controls somewhat close to where it will at least mostly idle smooth. Then I do a revision with 20 added to boundary, wait 20 minutes of idle time, do a wot stomp while logging the entire time - I made additional adjustments if needed to itt here. Repeat with 20 subtracted from boundary. Your looking for 2 things - quick crisp snaps and injector duty cycles to drop along with more (-) fueling controls in closed loop. Exhaust smell is another thing looking to improve. Then from there take some pretty big leaps - adjust maybe 40 or 50 using the rpm adder table and boundary both. Repeat all over again. Then I use the boundary table to retard it gradually within the entire rpm range as rpms increase - usually don't go above a 570ish setting here at peak rpms.

If NA with cats or even without - it will probably prefer and do better with it really advanced. If FI, it'll do better around 520 or retarded from there.

Honestly the cal I sent you way back when demonstrates a lot of this and even has some really close settings in it for your cam and engine build. If you use them along with the stoichio table it should all but alleviate a lot of your fuel bucking.

Sorry to bring up old thread but I've been researching how to get the injector timing correct after cam install and experiencing bucking/surging mainly in the 1200 - 1800 RPM range, mechanic that installed the cam hasn't touched the injector settings at all. I have managed to reduce bucking and surging somewhat by adjusting VE and idle/idle follower perimeters but have hit a brick wall so to speak.

I have been playing around with boundary, Normal ECT, Normal RPM etc... I am going to try this method you have outlined..

My question is what is it you mean by dialing in the injector tip temp?
It is my understanding and have been told to zero out the injector tip temp offset table to overcome the rich after reflash problem.

Cam I have is..
234/250 .610/.610 @.050 114 LSA or
284/299 .359/.359 @.006

any help or suggestions would be very much appreciated!

[rabbs88]

Took 10 seconds to type in google. https://forum.hptuners.com/showthrea...ip-Temperature

[Cringer]

Sorry to bring up old thread but I've been researching how to get the injector timing correct after cam install and experiencing bucking/surging mainly in the 1200 - 1800 RPM range, mechanic that installed the cam hasn't touched the injector settings at all. I have managed to reduce bucking and surging somewhat by adjusting VE and idle/idle follower perimeters but have hit a brick wall so to speak.

I have been playing around with boundary, Normal ECT, Normal RPM etc... I am going to try this method you have outlined..

My question is what is it you mean by dialing in the injector tip temp?
It is my understanding and have been told to zero out the injector tip temp offset table to overcome the rich after reflash problem.

Cam I have is..
234/250 .610/.610 @.050 114 LSA or
284/299 .359/.359 @.006

any help or suggestions would be very much appreciated!

Do not zero out the injector temp table. That has nothing to do with injector timing anyway.

If you want to learn you can watch this, and also use the EOIT tool in my sig line.
https://youtu.be/Td6oC9CIUas?si=SNGnXReIVRpaQ31n

The other common problem that happens after a cam is a slight surging related to the normal rich/lean oscillations by the ECM. I made this video to deal with that:
https://youtu.be/5hjzI8wSItk?si=RIPvNBTiJB2XlD2F

Both of these are more advanced topics, so it may be better for you to have a professional tune it.

[317@Clubby]

Do not zero out the injector temp table. That has nothing to do with injector timing anyway.

If you want to learn you can watch this, and also use the EOIT tool in my sig line.
https://youtu.be/Td6oC9CIUas?si=SNGnXReIVRpaQ31n

The other common problem that happens after a cam is a slight surging related to the normal rich/lean oscillations by the ECM. I made this video to deal with that:
https://youtu.be/5hjzI8wSItk?si=RIPvNBTiJB2XlD2F

Both of these are more advanced topics, so it may be better for you to have a professional tune it.

Thanks for this, had a quick look and looks awesome.. looking forward to get into it..
When I had the cam done I only had it installed by a mechanic as I didn't have the spare time or I would have done it myself.. I enjoy learning the tuning side of things and it's thanks to guys like yourself that don't mind sharing their knowledge that helps make it possible.