Diving in head first

[1morews6]

Well I just bought Flashscan/tune I have logged using EFIlive since ver.5 and done a few little changes with LS1edit other than that I am new to this game. First off I should give a picture of what I am working with.

99 F-Body
A4
3:73 gears

427 stroker
11.3.1 Compression
244/244 .618 112LSA
Long Tube headers
All the bolt ons.

I was running ok on previous tune but during dyno sessions discovered the shop that built the engine had screwed me on the heads and I was running out of air at about 5600rpm. (no more shops for me)

I changed the heads to TEA Stage 3.5 2.10 x 1.65

This moved the RPM range way up and I was logging some KR and a bit lean. A tuner had me make some VE changes and the car was running pretty good but I felt I needed to get more air into it so I went with the FAST LSX90mm intake (port matched by TEA) and the 90mm FAST TB, along with a 85mm MAF and Lid.

I changed the MAF table to match a 85mm table from LS1tech.com and fired the car up. Needless to say the car runs like crap

LTFTs are 25% both sides max out unless I snap the throttle and then it will fall for a sec then start climbing back up till it maxs out again.

Idle is all over the place, throttle response is also. I did not want to damage any thing so I pretty much slow cruised it home and headed here for advise.

I looked at my VE with the new Flashscan and it looked VERY bad so I played with the smoothing/blending and it made the table look good, but I have not tried it on the car yet.


Where should I start to try to get a handle on this?

Thanks for the help.

Maybe someday I will have something to add to this forum for the other nuts that had to have a 427 in an F-body

[Steve Bryant]

First of all, welcome to the group.

Now to tuning that 427.

First what size injectors are you running?
Do you have a WBO2?
Do you drive this car on the street as well as the track?
Will it idle OK?

For starters, it sounds like you are running out of injector and your VE Table doesn't match up with the engine.

All my best,

Steve

[1morews6]

38lb injectors, they were not a problem prior to the LSX 90mm install


No WB02

99% street, to look at it people think it is stock... But nobody will race me anymore :twisted:

It use to idle with a nice lope

I agree VE is most likely nowhere near what I need now but where/how do I start to fix it?


Thanks

[Steve Bryant]

Take a look at this post on setting up VE http://efilive.com/forum/viewtopic.php?p=8941#8941. Also, send me a PM with your e-mail address and I'll send you an Excel worksheet that is a work in progress on setting up VE.

Steve

[1morews6]

Steve I sent an email but am not sure it went, everything you post or send on the forum gives a debug error.

[1morews6]

I called FAST about the 90mm TB and they claim they have a problem with the throttle shaft being machined to small and throwing the TPS off. This must be why I cannot get a consistant TPS, mine varies from 2%-8% at idle. I wonder if thats why I get a lean condition. I am sending them the TB back tomorrow and I also ordered a new Z06 MAF to replace the used SLP one I have on now.

I can honestly say nothing I have done to this car has gone smooth. Everytime I overcome one problem I mod again and the nightmare starts all over. Someday I will have to learn not to mod anymore. But then again what fun would that be.


Steve I sent a PM this morning and it looks like it went through I look forward to working on the VE table and getting a better understanding of the tune for big cubes.

[joecar]

I'm not sure (...I'm learning...) but it seems to me that when you change your MAF sensor, you need to change the MAF calibration also (either copy a known MAF calibration for the specific MAF that you're using, or otherwise tweak your existing calibration (unless you're going MAF-less));
I know that porting a MAF makes the calibration incorrect.

[GMPX]

Joecar.....correct on all accounts.

[1morews6]

Joecar,

Thanks, I do understand that part. I am getting a new MAF to replace the used SLP one I tried first. The issue is, it has a resistor added to it and I think it is best to start with a known good 85 MAF that I can be sure the table is right for. I used the SLP used one because I had it (got free somewhere) but its not how I like to do things, I prefer to rule out the variables as much as possible (assuming the new MAF is working).

My concerns were that the FTC's 6-11 are all very lean and the upper cells seem to be on, I thought I read that was because the lower cells use the MAF and the upper do not. All this and then FAST tells me they have the problem with the TPS shaft. I wonder if the fact the TPS is not right that this may be what is causing the lean condition in the lower cells.

Well I guess I will see later this week.

Thanks for all the support.

[TAQuickness]

1more - I had to start tuning in about the same situation you have. I would suggest the following. Download a stock tune for a car matching your make and year (PCM OS specifically). From here you may want to make a table by table comparison to see what's been "tuned" and why.

After you comparison, start with your IFR table. Set it back to stock and then properly scale it to match your 38lb injectors. I don't have the formula handy, but it can be found easily by searching ls1tech. The point of this is to make sure you have at least one table right to start tuning from. The IFR table is the easiest to get right.

The next step will be to get your VE table right. This link (http://www.efilive.com/forum/viewtopic.php?t=1203&highlight=) is a step by step on how to do it.

When the VE table is right you can then work on the MAF table. Like you, I purchased a known good 85mm MAF. Mine was from an '02 Yukon to use in my F-bod. When you search the www, you will find that there are about 5-6 different tables for the screened 85mm MAF and 3-4 for the descreened. There could be more, but after I found as many as I did, I said hell with it, I'll rescale it myself. So I started searching for "how-to's" to scale the MAF. There are as many ways to scale the MAF as there are "known" tables for the 85mm MAF. You should decide which one works for you. This link is what I did to scale my MAF (http://www.ls1tech.com/forums/showthread.php?t=275204) It too me 2 passes and I have not had to touch it since.

I wish you good luck with you endevor. If you need any help, feel free to email me (i don't check my PM's very often).

[1morews6]

TAQuickness,

Thanks for the insight. I think it is great advice to get to a base and work from there. I should have a MAF today and the TB back from Fast tomorrow. It looks like I will have plenty to do this weekend :D I really have a lot to get done if I want to roll on the Hot Rod power tour again this year. Thanks for the help I will let you know how it goes.