Fine tuning setup on a SBC 350

[scottastew]

Ignition coil was bad. So much time trouble shooting and stressing about everything and it was the dang coil. Bosch blue coil went out and the MSD was installed and it’s like a new truck. Thanks guys.

[scottastew]

Ok, I'll try that tonight DDSmith. I assumed that reset or cleared once I go through the setup process, but I'll specifically clear the memory tonight. I'll also call the techline tomorrow. Thanks both for the advice.

[ddsmith]

Did you clear the self learn memory on the fuel modifier tab? If you did not, I would do it. Then it will be learning with the original parameters matching your map.

[2700 Cast]

Not great. I've reloaded the MAP a couple times, went through the setup process, done the adjustments you and others have suggested, and I think I have it setup correctly and take a little drive around only to come back to it several hours later and have it idle rough. I'm taking it to a mechanic this week because I'm about to the limit of my knowledge.

Call the Techline 800-416-8628
We can help you get it right.

[scottastew]

How is it running now?

Please consult the E-tuners user manual for info on tablet settings & what they mean.

Not great. I've reloaded the MAP a couple times, went through the setup process, done the adjustments you and others have suggested, and I think I have it setup correctly and take a little drive around only to come back to it several hours later and have it idle rough. I'm taking it to a mechanic this week because I'm about to the limit of my knowledge.

[2700 Cast]

Well not sure how it can run so well last night and turn around and get back to it’s bad behavior. I drove around for about 5 miles, got some gas and all was good.

Today it was back to running rough and almost stalling.

I did increase idle spark to 20. Could any bad sensors be causing problems? Ecu issues? I’ve reached out to a mechanic and will probably be taking it to him next weekend if I can’t get things dialed in by then.

How is it running now?

Please consult the E-tuners user manual for info on tablet settings & what they mean.

[ddsmith]

You had a 43 psi map loaded with a 58 psi fuel pressure. With the self learn in fast it was taking the info and trying to adjust everything to make it run properly. That means there was some amount of learning done and some adjustments made by the system. I would not expect it to run very well, when the fuel pressure was corrected, unless you cleared out the stuff already learned. It will fix itself eventually if it gets run time on it or you can speed up the process by dumping the bad stuff in memory.

[scottastew]

Well not sure how it can run so well last night and turn around and get back to it’s bad behavior. I drove around for about 5 miles, got some gas and all was good.

Today it was back to running rough and almost stalling.

I did increase idle spark to 20. Could any bad sensors be causing problems? Ecu issues? I’ve reached out to a mechanic and will probably be taking it to him next weekend if I can’t get things dialed in by then.

[ddsmith]

Yes, that is what it is designed to do. Do not adjust the regulator if it was set correctly with the hose disconnected and plugged. Did you raise your idle timing to 20 degrees as suggested?

[scottastew]

Is it normal for the fuel pressure to be lower after installing the vacuum reference hose? It dropped to the mid 30s. Do I need to adjust the pressure again so it is 43 with the vacuum hose attached?

[Stryker]

Small block Chevys like more advance at idle which will help with your idle and stumble also. 2700Cast recommended you set your idle advance at 20. My experience with this system on 2 separate SBC's is that 20 to 22 is the optimal idle advance. Also idle speed on mine have been best at 850 to 900 rpm.

[scottastew]

When I first installed the vent hose, I used a 1 way check valve because I was worried about fuel traveling back up into the sump for some reason. Now that I think about it, I’m not sure why that would ever happen. I removed that valve tonight so it is just vented straight back to the fuel tank with no valve in the way. Maybe that was causing an issue...I also installed the fuel vacuum reference hose and adjusted the fuel pressure to the correct amount.

I tested it out with another test drive and I am cautiously optimistic that one or both of these things solved my problems. It ran very well (other than a slight hesitation when accelerating from a stop).

Thank you three who all helped me get this figured out. I’ve been ready to rip it all out and go back to a carb, but turns out it’s just my own dumb fault for not paying enough attention to the instructions. I plan on testing it more tomorrow and make sure we are good. Felling good tonight!

[scottastew]

If you have the vacuum reference hose installed now. Disconnect it at the sump and plug the hose. Adjust the regulator and then reinstall the hose at the sump. If you are pulling a good vacuum it will lower your fuel pressure noticeably. Did you installed the vent hose from the sump back to the tank? I have seen this being the biggest problem with the install other than heat related fuel issues.

DDsmith-I did not have the hose attached. I have adjusted the fuel pressure to 43 and will install the hose now. Would you look at this picture and see if this is the right spot for that fuel vacuum hose? Is is on the side of the IAC sensor. There is something installed there now so I will just T connect it if that is the right spot.

[ddsmith]

If you have the vacuum reference hose installed now. Disconnect it at the sump and plug the hose. Adjust the regulator and then reinstall the hose at the sump. If you are pulling a good vacuum it will lower your fuel pressure noticeably. Did you installed the vent hose from the sump back to the tank? I have seen this being the biggest problem with the install other than heat related fuel issues.

[scottastew]

If you are running the Edelbrock Fuel Sump then it has an adjustable regulator on it. That is also where the vacuum hose gets attached to provide vacuum reference. If you did not install a vacuum line from your manifold to that nipple, then it is not correctly setup. To adjust the regulator, loosen the lock nut and adjust the regulator to get 43 psi with the engine running. Then tighten the lock nut. Then get a vacuum hose and install it from the manifold to the nipple and you will be setup correctly.

Oh, thanks for sharing this. Sorry, it’s been over a year since I installed it so I’m forgetting things. I did NOT install it with a vacuum hose. I’ll adjust the pressure and report back. Thanks again.