Fuel pump PWM control... fuel pump relay output function?
Moderators: jsmcortina, muythaibxr
-
- MS/Extra Newbie
- Posts: 7
- Joined: Sun Dec 25, 2016 11:03 am
- Location: Oklahoma
Fuel pump PWM control... fuel pump relay output function?
I'm in the process of wiring my car up for a PWM controlled fuel pump (open loop) with a MS3-Pro. My understanding is that this overrides the default behavior of the fuel pump relay output even if a different output is chosen for PWM control of the fuel pump. This seems to be in conflict with the recommendation that all other engine related devices be powered up when the fuel pump relay output is active so that they are powered up when the engine is cranked and then are turned off when the engine stalls.
In this scenario what is the best practice to allow the MS3-Pro to control the relay powering the FPDM, lift pump, wideband o2 sensor, fuel injectors, coils, etc?
Thanks.
In this scenario what is the best practice to allow the MS3-Pro to control the relay powering the FPDM, lift pump, wideband o2 sensor, fuel injectors, coils, etc?
Thanks.
-
- Super MS/Extra'er
- Posts: 17507
- Joined: Thu Apr 16, 2009 8:08 pm
Re: Fuel pump PWM control... fuel pump relay output function
If you set the output to the fuel pump pin, it will use PWM on the regular fuel pump relay output.
If you select a different output pin in current firmware, the regular fuel pump relay output will operate as normal.
If you select a different output pin in current firmware, the regular fuel pump relay output will operate as normal.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
-
- MS/Extra Newbie
- Posts: 7
- Joined: Sun Dec 25, 2016 11:03 am
- Location: Oklahoma
Re: Fuel pump PWM control... fuel pump relay output function
That is great to hear Matt. I had the impression from searching old threads that the normal operation of the fuel pump pin output was overridden no matter what output was chosen for PWM . Maybe it was that way in the past.
I glanced through some of the source code to try and figure it out myself but didn't have much luck locating the section that deals with that. It will take a bit of studying to figure out what is going on inside there.
Thanks again.
I glanced through some of the source code to try and figure it out myself but didn't have much luck locating the section that deals with that. It will take a bit of studying to figure out what is going on inside there.
Thanks again.
-
- Helpful MS/Extra'er
- Posts: 54
- Joined: Mon Jan 04, 2016 7:48 pm
Re: Fuel pump PWM control... fuel pump relay output function
I do not want to sound redundant. But ..
MS3x SBF says Purple Wire out to Fuel Pump Relay. Are you saying I need to verify that that is the setting ? Even though that's the normal setting
MS3x SBF says Purple Wire out to Fuel Pump Relay. Are you saying I need to verify that that is the setting ? Even though that's the normal setting
-
- Super MS/Extra'er
- Posts: 17507
- Joined: Thu Apr 16, 2009 8:08 pm
Re: Fuel pump PWM control... fuel pump relay output function
The MS3X always uses pin 37 of the main board connector as the fuel pump relay output, or as the main fuel pump relay output if you have enabled a secondary PWM fuel pump control output.darthmayndawg wrote:I do not want to sound redundant. But ..
MS3x SBF says Purple Wire out to Fuel Pump Relay. Are you saying I need to verify that that is the setting ? Even though that's the normal setting
Matt Cramer -1966 Dodge Dart slant six running on MS3X
-
- Helpful MS/Extra'er
- Posts: 54
- Joined: Mon Jan 04, 2016 7:48 pm
Re: Fuel pump PWM control... fuel pump relay output function
Thanks Matt I am aware of my mistake now. Also James corrected me and I have to adjust.
-
- Helpful MS/Extra'er
- Posts: 54
- Joined: Mon Jan 04, 2016 7:48 pm
Re: Fuel pump PWM control... fuel pump relay output function
Wired it correctly and now FP works when Test Mode enabled. IDK about the prime pulse though.