MSefi.com read only forum (Jan.15,2018)

I have an MSII V3.57 on a 289 Ford small block. Mustang intake and injectors. I am using the DIYAutoTune wiring harness. I have all of the left bank of injectors joined together to one wire and all the right bank all joined to another wire. I did this because my wiring bundle included one INJ1 and one INJ2 wires. When I went to connect them to the relay board I have places for two INJ1 and two INJ2. Can I only use one of these posts to drvie my injectors or will I cook something? Or should I split them back out into two wires for each bank?

Second question - I have a Ford TPS and I thought I had the wiring figured out. If I do not and I power up my MSII will it damage anything? There is some question as to which wire is return and which is signal. I thought the worst is it will read backward.

Thanks for your help!

I'm not familiar enough to comment on the Relay Board.

For the TPS, measure the resistance across two pins with the throttle closed, and again at full-open. If the resistance stays the same, you are measuring across the main body, between the Vref and GND pins. If the resistance increases, you are measuring between the wiper (signal) and the VRef pin; if the resistance decreases, you are measuring between the wiper and ground.

The two INJ1 connectors, on the relay board, are common, as are the INJ2 connectors.

That is to say, you can connect bank 1 to either INJ1 connector on the relay board. The same applies to bank2 and INJ2.

Ken

Thank you. I'll leave the injection wires alone.

For the TPS I just checked between the leads and when opening the throttle the resistance goes up. Is that correct?

pcf_mark wrote:For the TPS I just checked between the leads and when opening the throttle the resistance goes up. Is that correct?

As Don pointed out, you are measuring between the wiper and Vref. Now, just follow Don's directions to sort out which is which.

Ken

The reason for the two parallel outputs is the same as the multiple ground connections - the restriction on how much current a single DB pin can handle. If your pro harness has only one wire per circuit, it likely is soldered to both pins. If there are two wires, and you wish to use just one of a high enough current rating, connect them together where you go to one wire.

Sorry - what I said about the wiper vs VRef or wiper vs GND is BACKWARDS. You want a low voltage with the throttle closed (wiper near the ground), and a high voltage at full throttle (wiper near the VRef). Increasing resistance means you are measuring between the wiper and VRef.

DonTZ125 wrote:Sorry - what I said about the wiper vs VRef or wiper vs GND is BACKWARDS. You want a low voltage with the throttle closed (wiper near the ground), and a high voltage at full throttle (wiper near the VRef). Increasing resistance means you are measuring between the wiper and VRef.

Don't feel too bad about it. I jumped right in there and agreed with you!

Ken

At my age, my excuse du jour is dementia!!!

"Second question - I have a Ford TPS and I thought I had the wiring figured out. If I do not and I power up my MSII will it damage anything? There is some question as to which wire is return and which is signal. I thought the worst is it will read backward.
"
Mark
It could damage something if you mis-connect...you need to find the two wires with fixed resistance and connect these to Vref and Grnd...the third to TPS in...next is "suck it and see" if it works in reverse...reverse the Vref and Grnd connections

John

it's easiest to do off the vehicle, but can be done on it. Set the pot so it is neither fully open or closed. Measure the resistance between all three connections in turn. The two with the highest resistance will be the track. Then close the pot. The two with the lowest resistance will be wiper and track ground.

I have been hunting about for a good diagram for the TPS I have. I found this:

http://sbftech.com/index.php?topic=29736.0

I have the oval shaped version at the top of the first diagram. This should allow me to hook it up right with each of the wires specified I can match them to the relay board. I was having some difficulty connecting what the wires did to the proper connection on the relay board.

Thanks fellas!

A few more hours of detail work and clean up and it will time to fire it up!