Sensor calibrating - Holley efi
 

I've been working trying to learn as much as I can about the Holley efi and I'm stumped on something simple... I've set up the boost controller and got to where instructions say "IMPORTANT! It would be good at this point to save the GF, send to ECU, and verify the Dome Pressure sensor is reading correctly. If there is a zero offset of more than about 0.25psi for a pressure transducer (from 0.0 PSI), or .25 kPa for a MAP sensor (vs the Baro reading), you can correct that here." But I can't figure out how to do that? Do I need to datalog it or where can I actually view dome pressure in real time while online? I want to hook the dome pressure line up to regulated air and confirm my transducer is reading correctly and adjust the offset. MADDENING... While I'm at it I'd also like to do something similar with my fuel pressure transducer - compare it to a mechanical gauge for accuracy and adjust in the custom sensor etc.

that's the screen you use to change the offset for the MAP, is that what you are asking?

that's where you change the offset for the dome

Dome
 

Yes that’s the part where I’m stumped. It says to verify dome pressure is reading correctly. How do I do that? What screen will show a live dome pressure reading?

you have to add a custom ICF, use the blank one. Add the dome sensor, select 5v, attach it to an input. Then go to the screen above, select the correct sensor that you are using.

On the dash screen, you can click on a gauge and it will show all the sensors and inputs. select "Dome Sensor" or whatever you called it and it should display it on the gauge. Changing that offset is just like changing the offset for the regular MAP sensor.

As far as the datalog, Holley logs EVERYTHING on it's own. Which is nice but can make the datalog files huge.

To see it in a datalog, go to the screen where you can edit the PIDs/channels that are being shown in a particular group. You should see the dome sensor in your inputs. I can't remember if it lists still as an input or what you named it. I "believe" it should be what you actually named that input to be.

If I didn't answer your question let me know and I will try to get you the info you need.

Ok THANK YOU! I think that is the part I was missing. I will try that tonight. Is there also a good way to view/check my fuel pressure transducer raw voltage vs psi? It is currently reading differently than my mechanical guage at higher pressures. I need to set up the custom sensor correctly.

As far as I know there isn't a way to monitor sensor voltages in Holley EFI. The only way I know how to do it is use a DVOM and check the voltage at the sensor itself. Since it's a 3 wire 5v sensor, check the signal voltage wire.

What fuel pressure transducer are you using? What type of mechanical gauge are you using? How big of difference is there?

If you are using a good transducer and it's scaled correctly, i would be more inclined to trust it over a mechanical gauge unless you are using a really really good mechanical gauge.

Worked like a charm :) Got both sensors dialed in. Thanks a bunch.

thats awesome man! :nod:

You can monitor sensor voltages its just not published anywhere that I know of.

That's good to know. Next time I talked to Rick Anderson I'll ask him about it. Thanks for the heads up

Im sure Rick knows..he is my account rep and awesome to work with IMO....if he doesnt for some reason pm or call me I'll help you.

He is ours too. Definitely great to work with.

Fuel Pressure
 

Well rats... I thought I had it figured out but I discovered I have a fuel system problem. You were right the mechanical gauge was wrong and the transducer was right. However when I tried to set the fuel pressure properly I couldn’t get it below 51 psi. I’m running a A1000 pump with a -6an return line. Looking for feasible options?
Replace fuel pump with dual pump.
Run -8an return fuel line.
PWM the pump.
Start a new thread lol.
Or is it possible to just run higher base fuel pressure and set it accordingly in the EFI software?

i should add I’m only planning on running 15 psi max for 800 ish HP.

What exactly are the problems with the fuel system other than you can't set the base pressure?

What regulator are you using and how is it plumbed up?

Do you have a bunch of 90's, 120 and 180 degree fittings?

Fuel system
 

I think that’s the only problem. I’ve added up to 20 psi on the reference port and fuel pressure rises very close to 1:1. I’m using a cheapo regulator. I have -10 feed line reduced to -8 to the PS Holley fuel rail. I used the -8 joiner across to the DS. At the DS rear -8 to the regulator. Other side of the regulator is plugged and I’ve got the -6 line right back to the tank. No bend fittings on the return line. I suppose I should mention the -6 line I’m using was the existing nitrous line. I suppose it’s either the line or the regulator?

Did the regulator come with 2 springs? Most of, if not all of Holleys regulators do. They come with the low pressure spring installed for a carb pressure, and you have to swap out the spring for EFI pressure. I've seen them do some really goofy things with the carb spring when using EFI pressure.

There also might be some debris in the regulator. It should be pretty easy to take apart and check.

If you want to see if your return system is a problem, you need to put a pressure gauge in the return line and see if there is any pressure. If there is more than 1 psi there's an issue with the line not being big enough, partially restricted or pinched.

Ok 2 steps forward one step back. Maybe time for a new thread? I took the fuel pressure regulator apart and drilled out the return housing hole - which was tiny. Opened it up 1/32" and with engine not running my fuel psi dropped to 49. So I opened it up some more and it dropped to 46 psi. I started it with vac line on and fuel psi was 37 psi. I just need to check it with the line off running and hoping it will be close or close enough? So my next mission was to test/tune the boost control solenoids and dome pressure. I hooked up the supply line to shop air and regulated it to 25 psi, sync'd it all up and got strange results. I attached (or tried to) the GCF as well as a short datalog. First question is why would the dome pressure/target start right away. I figured it wouldn't go till after the trans brake release. Second question is after I hit the trans brake button it goes to launch psi good, but when released it seems to cycle.