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[PhilStubbs]

So, I have been tuning my SBC 350 and noticed something that seems odd to me about the fuel it wants. It seems to want 13:1 for idle, cruise, and full throttle. I was expecting 14:1 or slightly richer at idle/cruise since they are so inefficient and 12.5-13:1 for high load. The plugs also look like shit. They look like it's running too rich. If I lean it from 13:1 it's not happy. Is that how these are compared to a honduh?

BTW, this is a 270hp crate 350 with cast iron heads and about 8.5:1 compression.

[snm95ls]

What are the BLM values like when in closed loop?

Where do you have your wideband installed; is it calibrated properly?

What is your base timing set at?  It should be 0 degrees IIRC.  Does your ignition timing ever deviate from module timing( 0 degrees)?

Do you know how to properly check base timing on one of these?  It is a little differet than a Hondur.

How stable is the MAP signal at idle?

Fuel pressure?

Do all of the spark plugs look the same?

[bigdaddyvtec]

base rtiming 0? uh... NO

[snm95ls]

base rtiming 0? uh... NO

We aren't talking about a carbed SBC with no EST tubby.

[PhilStubbs]

A lot of that info I don't have. I'm sort of tuning blind till moates gets aldl cables back in stock.

The timing is set at 0. I pulled the brown wire at the firewall and the timing is consistent with that unplugged.

All of the plugs look the same

The map reading seems to be pretty stable. I watched it with a scanner while trying to get it to idle pre-chipping and tuning.

The wideband is about 2' away from the right side of the engine and 3-3.5' from the left side. It is about 3" from where the 2 sides come together. The truck has a stock single exhaust for now. I plan to make a new exhaust for it as soon as funds permit. About 2 weeks.

[snm95ls]

Damn.  I have an ALDL cable at home that I will probably never use. 

Sounds like you are pretty much going by braille so to speak.

 

[PhilStubbs]

let me know if you decide to sell it. $$ shipped to 32084? lol

i have tuned quite a few cars with no sort of logging. just glancing back and forth between the tach, boost gauge and wideband readout on the laptop. i hate doing it that way, but i have always been successful with it.

[Robb]

So, I have been tuning my SBC 350 and noticed something that seems odd to me about the fuel it wants. It seems to want 13:1 for idle, cruise, and full throttle. I was expecting 14:1 or slightly richer at idle/cruise since they are so inefficient and 12.5-13:1 for high load. The plugs also look like shit. They look like it's running too rich. If I lean it from 13:1 it's not happy. Is that how these are compared to a honduh?

BTW, this is a 270hp crate 350 with cast iron heads and about 8.5:1 compression.

What do you mean not happy? Missing?

This screams plugs.

[PhilStubbs]

It doesn't miss, it's just sluggish. The plugs are brand new a/c delco stock replacements.

[Robb]

The timing is set at 0. I pulled the brown wire at the firewall and the timing is consistent with that unplugged.

I dont know which heads you have, but im pretty sure base timing should be between 8-12 BTDC on that engine. The total advance being somewhere 24-32ish depending on fuel, etc.

[snm95ls]

The timing is set at 0. I pulled the brown wire at the firewall and the timing is consistent with that unplugged.

I dont know which heads you have, but im pretty sure base timing should be between 8-12 BTDC on that engine. The total advance being somewhere 24-32ish depending on fuel, etc.

There is a set timing connector on all of the old Computer controlled HEI systems.  Disconnecting it revert the ignition system back to module timing which is TDC and is used mainly for start up.  Once the ECM detects that the engine is running(tach > 400 RPM), the EST system takes over ignition timing control.

I am not a noob when it comes to this crap.

Here:



The L05(VIN K 350) and the L03(VIN E 305) are the same way.


Now with the set timing connector connected and the ECU not in Field Service Mode, the ignition timing will be a more conventional number as observed with a timing light.

[PhilStubbs]

Now that I think about it. I originally set the timing to 0 with the wire unplugged. Then I had to advance it to 16 with the connector plugged in to get it to run decent

[snm95ls]

Now that I think about it. I originally set the timing to 0 with the wire unplugged. Then I had to advance it to 16 with the connector plugged in to get it to run decent

Either the module is fucked or something else is up.

[PhilStubbs]

Hmmm..... I had a somewhat similar problem with a civic once that i tuned. It had a bad ignitor and it wanted 12:1 in vac to run right. In boost it also wanted 12:1. I think you are on to something. Luckily gm ignition modules are cheap if I remember right.