Cdeez

From the reading I've been doing on TBI tuning, there was a reference made to the procedure of setting your advance at the dizzy while a scanner (WinALDL) was used to monitor knock and let you know how much advance is 'enough' Can anybody explain this to me, because I've not had any luck in finding such an explanation by searching. How is this done, does it involve the spark talbe in WinALDL? ('7747 ECM 1990 350 TBI P/U)
Thanks

Ronny

iTrader: (1)

I dont think knock counts are a determiner to optimal spark tables. As you are aware the initial mechanical advance at dizzy has to match IMA in your bin. I think most sock applications are -6 SA. Mine happens to be -10 SA. they must match.

Other than that the accepted way to tune SA for optimal performance is on dyno. I believe you can do so by monitoring MPH as well. assuming conditions are repeatable.

I am using stock EBL.bin for now and only changed the idle SA a bit. I believe I am leavving some performance on the table however. I am certain the occasional KC I see are mechanical noise. More to look at next season.

Cdeez

Yeah. My friend stabbed the dizzy for me after I rebuilt the engine becuase I couldn't get the timing right... So I was trying to figure out if WinALDL would be of use to me here,

I want to check what my base timing is, to ensure it matches the bin becuase right now it probably doesn't....

How do I determine how far my dizzy is advanced?? Will I have to get a timing light or go through the procedure of brining #1 to TDC.......

Ronny

iTrader: (1)

I think there is a label under hood that tells you initial SA. you disconnect(I forget what it is called) the connector that communicates from the ECU to dissy and set the timing with a light to whatever GM suggests. It will then be stock SA and will match initial SA. Reconnect the ? Stock may be -6 SA or -8 SA. Not sure.

Cdeez

What is SA?

I know what connector you're talking about.

So I need a timing light to check this out?

What is this setting (the base timing @ the dizzy) called in the bin file (7747 - 42.xdf)?

I think I recall from Fast355's thread on budget tbi 350 buildup that he used around 6 degrees of base advance on a mildly cammed 350 tbi....

So if I had a timing light, and WinALDL running, could I set the base timing to 0*, then play with advancing it until I get knock, then back it down a notch??? Am I grasping this theory correctlY??

Thanks for the help Ronny!

Ronny

iTrader: (1)

SA is spark advance. To set "initial timing" you disconnect the EST and set SA to whatever that model requires 0, -6 etc. with timing light. Then reconnect EST and it will be under control of ECU and move it to around 20 or so at idle.

It is called initial base timing in Tunerpro XDF. Not sure what winALDL calls timing or if it addresses it at all. It may not deal with it. It should show in log what timing is at with car running. IBT has nothing to do with your cam nor any mods.

Advancing timing till you record knock it not the best way to tune. Often knock is mechanical noise. To test for mechanical noice pull 5 deg where you see KC. If K does not go away you know it is mechaical in nature.

Back to initial timing. I have mine set at -10 deg. Both at physical distributor setting and in .bin. with EST connected I idle at -22 SA. so -10 is due to positioning of distributor with EST disconnected. I told .bin that so it adds -12 more giving me -22 SA at idle as indicated in SA table 800 rpms at 38 MAP. In datalogs I see -36 deg max as tables command that plus I have a "maximum SA" constant(36) that caps it regardless in .bin.

Cdeez

Ok, I don't have that tag underhood anymore that specifies the initial timing.. Hopefully a Chilton's or Haynes has this in there..

Okay, Initial base timing (IBT). Where in the log (WinALDL I assume?) does it show the timing w/ vehicle running? Okay I think I got this, set the IBT to whatever the model calls for, then do all manipulation of the timing through TunerP-RT??

And if it is mechanical in nature you can continue advancing the timing a bit in the bin???

Gonna have to digest this one for a bit..........

Ronny

iTrader: (1)

1. I would pst a Q on 454SS website and they should know inital timing set. It really makes little diff if you have say -6 SA at dizzy with "disconnect" and same in .bin for initial timing.

2.winALDL will show you real time timing engine is experiencing.

3. Tunerpro is where you do the changes. TP-RT also offers datalogging if you wish to use that vs winALDL.

4. yes you can adv timing in .bin. You need to use a specific timing table for that truck(weight) and specific for auto trans. I would be careful in advancing timing. Again using KC's is not the best way to achive optimal SA table. You most likely need a WB02 if you want to push the envelope.

5. How does truck run?

Cdeez

Update:

My friend has ALLDATA, and accordding to it, the IBT @ the dizzy for my truck was 0*

Using a timing light, we determined the timing to be 4* retarded, so, we advanced it to 0* and the truck runs MUCH better....

I checked the bin for the IBT setting to make sure it matches what the dizzy is set at, and it is also 0*...

Thankyou for your help Ronny!