Explode

I have recently built my first LS3. Its 4.065 bore, 416 ci stroker with an 4.00 Ohio crank. I have Manley 6.125 ultra light rods, LS3 heads that have a mild port and polish on the exhaust side, hollowed valves, and JE Pistons. LS3 intake, LS7 injectors, and a Iske Cam which has at .050 lifter rise intake duration 250 Deg and exhaust duration 256 Deg. Compression is about 11:1. I am using and EZ EFI with an Stand alone XIM for the ignition.

I cant get this thing to run right lol.

I need advice on what I should set my:
Idle timing at
Max timing at
All-in RPM
Vacuum Advance
and my Idle at.

I have the fuel set at 42 pounds per hour and at 58 PSI.

I am sorry for all the questions but I am new to this. I think I bit off more that I could chew when building this.

I put this motor into a 1972 SS Nova.. Everyone said LS was the way to go but I am dead lost and any help would be greatly appreciated.

Thank you.

Whistler

iTrader: (46)

Who built the engine? Who installed the EFI system?

Where are you located?

Clarify some in regards to "can't get it to run right"
What's the symptom? You can't just call the hospital and say " sick" and they fix you

A few observations- you're way overcammed for the rest of the combination, especially the intake. Depending on the advance, you've probably got like 7:1 or so dynamic compression
Stick or manual Trans? Does t he EZEFI have knock sensor(s)?

Tainted

iTrader: (9)

Yea I gotta agree that donket dick cam isnt doing you any favors

Explode

Im in California in the Modesto area. An engine shop here in modesto machined the engine and me and a friend assembled it.

So the issue is at 3000 rpm the engine does not create anymore power, starts to sputter, and has a little back firing.

Im running a turbo 400 tanny and to my knowledge I do have Knock Sensors. I have called fast several times and all they say is to try different things. It not like the video says it is. You don't just hook it up and go. This thing has been a nightmare. Any help too point me in the right direction would be great.

I was told to motor would be at 11:1 compression by the machine shop.

Tainted

iTrader: (9)

Thats static not dynamic compression

Whistler

iTrader: (46)

Does it have wide band O2 sensors like an XFI does?
Are the converter and trans new as well, or were they already in the car?
What timing set did you use for the camshaft? Did you advance or retard it aside from what the manufacturer ground in?

Explode

It does have an O2 sensor... Not sure if its a wide band though. 2500 stall and both the tranny and stall are brand new. The timing is what I am having trouble with.

Right now I have the max timing set at 30
The all in RPM set at 2800
Idle timing set at 20
and 0 Vacuum advance

batboy

iTrader: (6)

With 30 degrees of timing, that seems like a lot for 11:1 CR and pump gas, maybe try less timing until you get it running right and can log for knock retard. All in by RPM probably should be raised a little too. The backfiring is a big concern. That sounds like it's trying to fire at the wrong time or the cam is not set up correctly. Did you install the cam dot to dot? Do you have the correct cam sensor installed? Which reluctor wheel (I'm assuming 58X)?

Explode

I tried it at 28 deg on max timing and it got worse.. Cam was install by a gm tech... correct cam sensor is installed. and i have the D.I.P. switches set to 58 tooth crank...

Ive been researching this thing all night on google and cant seem to find a good starting point.

What should All in RPM be raised too?
What about Idle timing?
Should I be using Vacuum advance?

I had the timing set to 34 deg max timing and 24 idle and the car ran like a raped ape... But i read a couple things that said thats bad for your engine and could cause issues... So I decided to change it yesterday and Now I can go above 3000 RPM. the car just chokes out and does create anymore power. Low end power went away also. Car wont even do a Burnout.

Gray86hatch

iTrader: (83)

The joy of a system you can't tune with the lap top.

I run 28-29 at wot

Almost 40 at idle and mid 30's at anything in the drivability area.

You prob need more timing in it. Adjust the idle timing for the highest idle rpm.

You need to see if you can geting into the map and adjust as needed.

Tim

Explode

Gray86hatch::
so set my idle timing at 40?
my max timing at 30?

On my chart it says I can only set the idle time to 24 as the highest.

Do I use Vacuum advance too?
What about All-in-RPM?

Sorry for all the silly questions but i know nothing about any of this.
Thank you for the help

Gray86hatch

iTrader: (83)

Explode

Gray86hatch..

Very sorry but I dont understand that chart.... I understand RPM but no clue on MAP......

Gray86hatch

iTrader: (83)

You can see my map. The system you have prob dosn't allow this.

you need timing in it when you have no load on the engine and take a bunch out of it when the load comes in so you don't rattle it.

Explode

ok according to my chart the Highest I can set the Idle timing is 24 and the highest i can set the Max timing is 40. The max for All-in-RPM is 3600 and I can add vacuum advance.


With those values what would u set it at with my type of engine please. Thank you

John

Gray86hatch

iTrader: (83)

The best part of EFI is you don't have to set the total. Timing is baised on rpm and load.

This is why some of the fast efi stuff you can't get in and adjust the maps only work ok.
The fast reps should be able to walk you thru this.

The map I use has only has changes to the WOT and idle area of the map the rest is what holley provides in their startup cal.

Tim

Explode

The problem is though the system they sold me came with their XIM box which deals with all the timing and I have to set it. The XIM box talks to the EFI computer and tells its timing.

Gray86hatch

iTrader: (83)

If I were you I would get a system that you have full control over what you have sounds like a basic system you added the ignition controler to to run the coils but is not adjustable like it needs to be.

Tim

Explode

I have control over all of it.. I just need to get a base start. I dont understand timing on these LS motors.. I have a Hand Held Computer that came with my system that allows me to make any adjustment to the system, but this is all foreign to me. So all I need is a base so I dont blow up my motor.

should i set my Idle timing to 24 and my max to 40? Will that blow my motor?

Gray86hatch

iTrader: (83)

See that is the problem you need to build a map. That handheld is not going to do it.

Those kits were designed for use with a distributor. Not enought adjustment to make a engine like yours run correctly.

I have used xfi2.0 but it was tuned with the lap top not a handheld.

You really have the wrong system that has add on's to try and make it work on a ls.

Tim