How to: MAFT Pro Timing Monitor

drjonez

Supramania Contributor
Mar 31, 2005
3,061
0
0
18
the motor city
www.4cefed.com
INCOMPLETE.

The MAFT Pro is capable of monitoring timing advance/retard via the MAF input when used in speed/density mode. In order to enable this, you must disconnect the MAF input pull-up resistor (R7 on the back of the MAFT Pro PCB). You can either desolder R7, clip one of the legs or put a switch inline with it. Properly done, this mod won't void any warranty of your MAFT Pro. If you are uncomfortable doing this mod, contact me to arrange for free modification of your MAFT Pro. Why do you have to disconnect R7? Because R7 "pulls up" the MAF input to 5V, creating a default value given no input. When monitoring timing, you don't need this pull up.

After clipping R7, connect the MAF input wire (yellow wire, pin 9 on 10 pin connector) to G2 on your engine wiring harness at the ECU. Set Fin to 20 (older software, <4.60). After enabling the timing monitor, you'll need to verify that it is reading correctly. Stick a timing light on the engine and check timing at warm idle, compare this to the timing monitor's reading and adjust Tm Base to make the readings match. Then rev the engine to a higher RPM and compare readings again, correct any difference via Tm Correct.

In short:
  • Disconnect R7
  • Set Fin to 20
  • Connect MAF Input wire to G2
  • Compare timing readings at idle, correct with Tm Base
  • Compare timing readings at higher RPM, correct with Tm Correct
 

Justin

Speakers?
Mar 31, 2005
1,699
0
0
39
Spokane, Wa
Do you lose anything by clipping the resistor? Is this a trade off for a different feature?

Because R7 "pulls up" the MAF input to 5V, creating a default value given no input. When monitoring timing, you don't need this pull up.

It sounds like the answer to my question is NO, based on the fact that clipping the the resistor just changes something to do with the MAF input and when doing speed density I wouldn't think that would matter.... but that's why I'm asking :)
 

drjonez

Supramania Contributor
Mar 31, 2005
3,061
0
0
18
the motor city
www.4cefed.com
Justin said:
Do you lose anything by clipping the resistor? Is this a trade off for a different feature?

It sounds like the answer to my question is NO, based on the fact that clipping the the resistor just changes something to do with the MAF input and when doing speed density I wouldn't think that would matter.... but that's why I'm asking :)

yup, you do lose something- the ability to use the MAFT Pro in AFC mode.....hence the need be running speed/density mode.

again, the timing monitor uses the MAFT Pro's MAF input to monitor timing.
 

prsrcokr

Motörhead
Apr 3, 2005
349
0
0
103
Richmond
Doc, does removing fuel in Speed density alter timing like it does with AFC controls?

Just wanted to make sure I'm safe since I'll be adjusting on the Techtom map.
 

prsrcokr

Motörhead
Apr 3, 2005
349
0
0
103
Richmond
Thanks for clarifying that. I'll be sure to get the timing monitor working before removing much fuel since that map is already advanced.

Brian