Help tuning 408

[SRT10KLLR]

I have a 2003 Silverado 2wd that I want to tune using the V2 I just bought. It used to have 5.3L but I replaced it with a bored/stroked 6.0L block. I need help getting it to idle to start with then PT and WOT. I want to be able to tune this thing myself but need to understand what changes to make.

Here are the specs:

408(6.7L) w/8.7cr
P&P 6.0 heads
224/231 .595 .595 LSA 114 cam


BTW, the stock 5.3 tune is what is in the PCM right now and it starts but I have to keep my foot on the pedal or it dies.

[ScarabEpic22]

Can you post up the stock tune? I dont know if I can help, but I know others will want it posted anyway. Have you looked for a 6L tune in the repository that you can modify the cylinder size in?

[SRT10KLLR]

I did check the repository and the 5.3 tune there was identical to my stock tune except for the top speed limit(mine was 109 vs 98). I also looked at the 6.0 stock tune and a 4.8 tune. What I thought was strange was that the timing table was not proportional to engine size. I thought the timing would either go up from the 4.8 to the 5.3 and then to the 6.0 or down.

I did do a log but could not see anything out of the ordinary but it could be that I just don't know what to look for yet. I had to have my foot on the gas while doing it otherwise the engine would shut off.

BTW, I noticed that the 4.8, 5.3 & 6.0 from the repository all used the same size injectors.

Thanks, any help would be appreciated. I am new to EFI but want to learn as much as possible.

[ScarabEpic22]

Im not talking about spark tables or injectors, Im talking about cylinder expected airmass. Look at table B0104, the 5.3 tune is 666, the 6.0 tune is 746. Yours should be even higher as its a 6.7L.

[SRT10KLLR]

The B0104 was 40.64 in my tune so I changed it to 51.02 for my 408. What else do I need to change?

Below is a copy of my tune with the only change so far being the B0104 cell.

[Bruce Melton]

What TB is on it now?

[SRT10KLLR]

Stock. I think it is a 78 or 80 mm.

[SRT10KLLR]

Any other suggestions/advice? I could use all the help out there.

[RonC]

Any other suggestions/advice? I could use all the help out there.

One thing I see is your VE table seems to be off and that would make it very lean. I looked at VE % on a stock 6.0L it peaks at 104% and your VE table peaks at 75%. I would suggest starting with a stock 6.0L VE table and tune it from there. It looks like you still have the stock injectors and it should run ok on the low end thru upper midrange with them but you will probably need 37lb to 42lb injectors for full WOT power. Hope this helps.

Ron

[joecar]

You need to either richen the last 3 columns of CFOL B3605 and /or
reduce the PE Enable B3616 throttle position (90% is too high),
otherwise you'll be too lean at load/WOT.

Are you tuning with a wideband...?

[SRT10KLLR]

I am just trying to get it to idle first before I can try driving it and tuning PT and WOT. Right now I would have to drive it with both feet so it does not turn off at a stop.

Would changing to the 6.0 VE table and adjusting B3605 and B3616 get it to idle better? I will make those changes and start it up again and run another log.

I have a LM-1 but I lent it to a friend so I am just using the stock O2 sensor for measuring A/F at idle.

[RonC]

I am just trying to get it to idle first before I can try driving it and tuning PT and WOT. Right now I would have to drive it with both feet so it does not turn off at a stop.

Would changing to the 6.0 VE table and adjusting B3605 and B3616 get it to idle better? I will make those changes and start it up again and run another log.

I have a LM-1 but I lent it to a friend so I am just using the stock O2 sensor for measuring A/F at idle.

Yes, increasing the VE table should help idle in open loop, it makes it richer. You're probably very lean. You really ought to get your WB back as you need it now so you can see where your AFR is at and to do your AutoVE tuning.

Ron

[SRT10KLLR]

Here is a log I did while at idle whit my foot on the gas to keep from stalling. This what before any changes were made so it still had the stock 5.3 tune from the factory.

I know the stock O2's are not wide band like the LM-1 but it was showing a pretty stoich A/F/.

[RonC]

In your log, it is "commanding" stoich AFR but that doesn't necessarily mean you get it. You can't read the NB O2's for idle AFR but they should keep it near stoich in CL, but when in open loop the VE table and/or MAF sets the AFR. To get it to idle, try adding more air to B4307 until it idles ok.

Do you still have the stock injectors? If so, when do you plan to change them to support your combo?

[SRT10KLLR]

I will be upgrading to the 60lb mototrons but not until I break in the engine. I will be putting a turbo on which is why I had the engine built with only 8.7 cr.

[SRT10KLLR]

I got a start up tune from a fellow forum member and flashed it to my PCM. I started up the truck and took it for a drive. It seemed to idle ok until I started driving then when I reached a stop it would start surging. At one point the CEL started flashing and the truck shut off. It also felt like power was lacking.

I think something might have been left unhooked (coil, spark plug, etc.) when the new engine went in. Any ways, I attached my new log. Can someone look at it and tell me if something is off. Thanks

[Adam Calley]

Im pretty new at this too, but i would turn your desired idle speeds up about 100 rpms at least, and your ve table is going to have alot to play in the way that motor will run. Also Joe is right get bigger injectors. Im runing 40lb in my 402 stroker.

[SRT10KLLR]

The tune I put in increased idle to 1000 along with many other mods but it still does not run right. I got a CEL for a misfire but I saw no KR or anything unusual, not that I would be able to notice as I am a newbie to this myself.

[joecar]

TTT

Would someone with similar mods be willing to post their tune as an example to compare with...?

[Adam Calley]

Here is my tune, my idle is almost working perfect

[joecar]

I got a start up tune from a fellow forum member and flashed it to my PCM. I started up the truck and took it for a drive. It seemed to idle ok until I started driving then when I reached a stop it would start surging. At one point the CEL started flashing and the truck shut off. It also felt like power was lacking.

I think something might have been left unhooked (coil, spark plug, etc.) when the new engine went in. Any ways, I attached my new log. Can someone look at it and tell me if something is off. ThanksSRT10KLLR,

Can you post your tune as it currently stands...

This log indicates to me that you need to hook a wideband to see what is going on;

everything from here on depends on 2 things:
- IFR table being correct for your injectors;
- VE table being correct for your engine's breathing ability.

[joecar]

Here is my tune, my idle is almost working perfectAdam ,thanks, I'll be referring to it. :cheers:

[Adam Calley]

Just keep in mind my ve table isn't correct yet cause im waiting for my plx wide band to get here, so ive done some guess work and it does run decent but not perfect yet! But ne ways i hope it helps you guys out!!

[joecar]

That's ok, he needs to getting it to run sufficiently to drive to a tuner... or to do a self-tune using a wideband.

[SRT10KLLR]

Here is my tune as it sits.

[Adam Calley]

You need to take a look at a bunch of my idle settings on my tune i posted. I looked at your tune and you need to look at your throttle cracker, rolling idle, and several others. Your desired idle speeds look a little low too especially when it gets warmed up. With that cam you got its proble not going to idle really well at anthting much under 950. Compare them to mine and copy them if you want. At least that way im sure it will run good enough to get it to a tune shop or to use a wide band. Im probly not as much help as joe cause ive only been using efi live for like 3 months but im getting a pretty good hold on it i think.

[joecar]

I couldn't tell you much about idle because I have never had to tune for it (I don't have a cam nor a budget, yet... :bawl:).

There's a tutorial on idle tuning: showthread.php?t=4661 (http://forum.efilive.com/showthread.php?t=4661)

Cheers,
Joe
:cheers:

[joecar]

Yes, I agree, he can get guidance by looking at your tune. :cheers:

[joecar]

Oh, I meant for SRT10KLLR to look at the idle tutorial also. :cheers:

[SRT10KLLR]

I was doing some reading and came across something that I may need to do. The 5.3L engine was pulled out and replaced with a 6.7L so should I do CASE (Crank Angle Sensor Error) relearn? And would not doing so be the cause of my CEL (misfire)?

[joecar]

When changing any of these: PCM, crank sensor, crank/reluctor...
you will need to do a CASE relearn to get the misfire algorithm to work correctly;
if you don't do this, then you will see either no misfires or false misfires.

[hquick]

In other words....yes!


Just stirrin' ya Joe. :D

[SRT10KLLR]

I just wanted to thank Justin and a buddy who lives close for helping me get the tune in and the truck running. :master: I still have a lot of work to do to it but not until the larger injectors are in.

[dc_justin]

I just wanted to thank Justin and a buddy who lives close for helping me get the tune in and the truck running. :master: I still have a lot of work to do to it but not until the larger injectors are in.

:cheers: