Im surprised in open loop your numbers arent repeatable? I have always used mefi which is slow and painful to tune BUT once its tuned my afrs have stayed the same, I would expect the same from holley unless you are getting erratic map readings or tps readings (they have the most effect on something in open loop on any system), how do your map/kpa readings in boost look, thats where I would look hard, coolant temp, iat etc is miniscule once warmed up?

I reran the pulls on my last motors and they were right on. I also logged all the time and would check both motors files after every day out on the water. Never any variation. All that was in open loop with the original tune being in closed loop.

I would see some variation on my supra with the gen 1 aem or my pro efi with some RF noise.

Which Holley system are you running?

Agreed, but not that there's an issue with the software. If your base map isn't very good, you can see rich and lean dips when not in closed loop. If your fuel pressure fluctuates you can see dips as well. Bad connection on a sensor, poor wiring connections or routing, etc. there's lots of things that can cause issues for any system. Luckily, the Holley system allows anyone with basic computer skills to datalog and review the information. It's not rocket science, you're looking for X amount of fuel at X rpm and load. If the base map is asking for 354lbs of fuel at 6000rpm and that's what the engine wants to maintain 12.5 AFR but you're at 13.5 AFR, then there is a problem, and the datalog will show you what it is. I do remote tuning for dyno shops all the time, if those guys need help I'd be happy to link up and sort it out.

You might have an injector issue or one of the other problems mentioned by Haxby. I doubt its the ECM.

I have tuned and installed/wired a few different systems. First let me say I do not mean any disrespect to you or the shop you were at.

Did you keep your sensor grounds isolated from any outside sources?

What WB sensor setup are you using and where is the sensor located? (WB sensors do not like water or high heat)

What is the engine setup? Blower? (Heat soak is a big problem especially on blown applications, unfortunately I have WASTED many hours chasing my tail trying to tune around heat soak, that was until I figured out it was heat soak)

On your pulls was the air temperature, coolant temp, engine load, fuel pressure, battery voltage, baro etc all consistent?

What fuel injectors are you running?

Before you do anything harsh and remove the system with all the money and time you have in it, let's see if the helpful members of this site can figure out the issue. You could remove the Holley, install another system and still see issues, just saying.

I would like to look at your logs if you don't mind. If you don't, please email me the logs and cal to [email protected]

John

I am far from a efi expert but I have little knowledge of basic control theory and coupled with a basic understanding of how the systems work and something isn't right. A carburetor is a mechanical system to , control airflow , atomize fuel and set AF ratio. Been around for a long time and painfull to setup and basically impossible to make effect for all conditions, Along comes efi. Granted a closed loop feedback adds a level of real time self tuning and optimization but even as a open loop system it should be at least as repeatable as 100yr old technology if not considerately better.

I run my e85 turboed 900hp small block street car in open loop. Once you get it dialed in it should be repeatable.

It sounds like the closed loop setup is able to compensate for something that's not doing its job.