454 Starts-Idles-Stumbles

[Buick462.efi]

Matt,

Thank you for the quick response. Attached is my datalog for a short drive through the neighborhood. I know you're a busy guy and if you have a moment to take a look, I'd appreciate your insights.

Mike

[Matt Cramer]

Ok, here goes:

1. Fueling is tough to evaluate with a narrow band O2 sensor.
2. You have a bit of noise in the RPM signal and may need to adjust the next pulse tolerance or run a zener diode on the input. (20 to 24 volts, banded end towards the coil.)
3. Your battery voltage is unstable. Where is the MS grounded?

[Buick462.efi]

Thanks for looking, see my responses below:
1) I have a wideband on the way and will install upon arrival;
2) I'll try adjusting next pulse tolerance first, if it's still noisy then in goes the zener diode;
3) I have one big ground wire from the engine through the firewall then all grounds attached to that. Do you recommend individual ground wires with a common connection point on the engine?

[Matt Cramer]

3) I have one big ground wire from the engine through the firewall then all grounds attached to that. Do you recommend individual ground wires with a common connection point on the engine?

Ground the sensors to the MS, then use a single large wire or multiple small wires to ground the MS to the engine block.

[Buick462.efi]

Ken,

Taking signal from negative side of coil. I am switching to an 8 pin small cap so I can control timing with the MSII. Additionally, I am updating to the 14point7 wide band. I am sure I have not done everything possible to get a clean ignition signal but, I have done a lot - on the board and in the wiring from the distributor to the MegaSquirt.

Hope to have it updated this weekend - more to come.

Mike

[Buick462.efi]

Thanks, that describes what I have now. I am updating to an 8 pin HEI to control timing with the MS-II. Also, updating to a wide band from 14point7. Hope to have it all changed by this weekend. More to come.

Mike

P.S. Thanks for all your advice and support.

[trakkies]

Thanks, that describes what I have now. I am updating to an 8 pin HEI to control timing with the MS-II. Also, updating to a wide band from 14point7. Hope to have it all changed by this weekend. More to come.

Mike

P.S. Thanks for all your advice and support.

FWIW, I think it quite a good idea to start out fuel only (if this is easy) and get it running nicely before changing over to ignition too. It's what I did.

[Buick462.efi]

Dave, thank you for the advice. I appreciate your thinking - solving one thing at a time. Additionally, I appreciate you taking the time to read and respond to my posts. More to come this weekend.

[kjones6039]

Ken,

Taking signal from negative side of coil. I am switching to an 8 pin small cap so I can control timing with the MSII. Additionally, I am updating to the 14point7 wide band. I am sure I have not done everything possible to get a clean ignition signal but, I have done a lot - on the board and in the wiring from the distributor to the MegaSquirt.

Hope to have it updated this weekend - more to come.

Mike

Mike,

I agree with Dave (don't I always, Dave? haha) that starting with fuel only might be a very good idea. There are plenty of 8 pin HEI users around the forum, who will be happy to give you a hand at that point! I have run 7 pin in the past with fair success but moved on to EDIS before I had the wrinkles ironed out. Good luck!

Ken