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Ford AX4N: Doesn't have line pressure sensor?

Posted: Mon Jul 23, 2012 2:07 pm
by sporqster
Does anyone here know stuff about Ford trannys? From the service manual, I see nothing about a line pressure sensor as an input to the factory ECU, but it does have a line pressure control solenoid, leading me to believe that there has to be one(?).

Entire list of inputs from the service manual. Each of these I have identified wires for, or have determined that I don't need for the megashift:

INPUT SENSORS Air Conditioning Clutch (A/C Clutch) Ain't got, don't need
Brake On/Off (BOO) Switch got it
Crankshaft Position (CKP) Sensor & Electronic Ignition (EI) got it
Intake Air Temperature (IAT) Sensor got it
Mass Air Flow (MAF) Sensor don't need
Indicator Light (TCIL) don't need
Transmission Fluid Temperature (TFT) Sensor got it
Throttle Position (TP) Sensor got it
Transmission Range (TR) Sensor got it
Turbine Shaft Speed (TSS) Sensor got it
Vehicle Speed Sensor (VSS) got it

Didn't see anything about a line pressure sensor. Didn't find such a thing on the factory wiring diagram either. I guess the Ford ECU just doesn't need it? Is it using temperature to approximate pressure? Hmm. If yes, can the MegaShift be configured to do the same?

Has anyone got a MegaShift running on an AX4N or similar Ford tranny and want to let me copy their homework?

Re: Ford AX4N: Doesn't have line pressure sensor?

Posted: Mon Jul 23, 2012 2:36 pm
by Bernard Fife
sporqster,

Most trans don't have a line pressure sensor. However, MShift gives you the option to add one externally so that you can set the line pressure pulse width modulated output to mirror the factory line pressure PSI specifications when tuning the line pressure table. It isn't absolutely required though, and someone who was careful and observant could do much the same by judging the amount of 'slip' in the transmission.

The default unit is here: http://www.msgpio.com/manuals/mshift/wiring.html#lpsens , as is a guide for using it with a 4L60E (for other trans you will have to figure out how to do this).

However, there are cheaper sensors on eBay, see: viewtopic.php?f=4&t=315 I can't vouch for how well they work, but they seem like they ought to be okay. I will get some soon and try them.

Lance.

Re: Ford AX4N: Doesn't have line pressure sensor?

Posted: Tue Jul 24, 2012 4:21 am
by sporqster
Thanks! I somehow knew it couldn't be as easy as a weekend wiring exercise ;-)

Re: Ford AX4N: Doesn't have line pressure sensor?

Posted: Fri Jul 27, 2012 3:43 pm
by bondango
Maybe of some help

http://akpp-texpost.ru/AX4N.pdf

Page 4 - 2 ports available for testing both EPC and LINE PRESSURE