Ed Wright

iTrader: (1)

Here is something that may help guys with Vortec trucks, that don't want to have to change to an LS1 style box. George runs a 4.3L S10. He is one of my NHRA stock Eliminator customers, from down in Louisiana:

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If you don't have the distributer right in the right spot it will act like a rev limiter. http://www.youtube.com/watch?v=OsE9OSm2UdE This was when I was trying to figure the problem out. You can hear what sounds like a rev limiter around 5400rpm. http://www.youtube.com/watch?v=PBM4SjJzZOE Here is me shifting at 6000 rpm with no problem. You have to grind off the lockdown tab and make it adjustable. I made a degree plate for the top of the distributer cap in 1 degree amounts. I then retarded the distributer a little at a time untill the problem went away.

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George Roussel Jr. 4262 1996 S10 p-q/sa

He has not checked the retard on a scan tool, so I don't have any numbers for that. He just retarded the distributor (which houses the cam position sensor) until it went away.

Hope this helps somebody. George said to go ahead and post this.

wait4me

iTrader: (10)

In the efilive software, i already posted the TUNE fix for this about 2 years ago. It is related to Coil dwell. The table name is B5605.

You can rev it till it breaks after making the correct change.

Ed Wright

iTrader: (1)

Ignition coil saturation effects the injectors? Old as I am, I haven't seen everything yet, but that would be a new one. We have been seeing injectors quit triggering on the lab 'scope. Have you not seen that?

hellbents10

iTrader: (10)

I agree with Ed here the L31/35.. problems have been related to fuel cut not ign.

This is something I have always got to zero on the scan tool when changing to custom intakes with regular injectors on forced induction setups. Of coarse I change to a old school style dist. hold down.

2002_Z28_Six_Speed

iTrader: (19)

He must have some nice mods because anything close to the stock intake, cam, and heads should see a nose dive in power after 4000 RPM for sure.

What all does he have? Sounds like some nice stuff.

Ed Wright

iTrader: (1)

They shift WOT from the factory at 5000, my tuning for stock Vortec 350" trucks is 5200. No nose dives at 4000. You thinking of TBI trucks? The vane in the intake bowls on the TBI engines kill them. Vortec heads on a TBI truck alone are normally worth 1/2 sec off the 0 to 60 times. The '96/00 (also '01 & '02 Mexican pickups) 350" Vortec heads ain't all that bad for factory pieces.

veee8

iTrader: (40)

IFIRC the 4.3L's had the slot on the hold down, the 5.7's did not. At least my truck, I put the distributor in, then use the scanner and rotate to zero it out, while snapping the throttle update. The only thing is if you have it off a tooth the cap will run into the intake before you get the adjustment.

Ed Wright

iTrader: (1)

What is "IFIRC"?

veee8

iTrader: (40)

"If I remember correctly"

wait4me

iTrader: (10)

I agree on what you guys are saying about it being fuel, but if a coil has to wait for spark to happen, it wont let fueling event to happen until it is ready.

If you are moving the distributor, that at any time should not be fuel.. That is spark.....

Ed Wright

iTrader: (1)

I have not tested his method myself. Can't seem to get a V8 Vortec truck with a bigger cam in it in here for testing when I need one. All he is changing by moving the distrbutor is cam sensor timing and rotor phasing. Unless the cam postion sensor timing has something to do with it, it's hard to imagine how it effects anything. He could not rev his until he backed the distributor up. Now I hear from guys with V6 trucks that don't have that problem. Got me. I just thought if somebody was having that issue they could try it to see if it helped anything. All I have is a 100,000 mile 454". I ain't going to try it with that one.