Saturday, June 18, 2011

ECM wiring for 91 tracker won t start?

The tracker wiring:----

the pink and black wire is the power for the fuel pump

the black wire is the fuel pump ground..

there are one or 2 more wires there... one for the gauge.. one for the low fuel sensor... if equipped...

see the wiring below:--- for 1991 tracker:---




look at the connections A21 and A23 i think you need to study the wiring and see if it is a mistake you can correct...

A 24 Grey and yellow should have 5 volts on it.. it supplies power to a bunch of different sensors..

A 23 Grey and Red is the sensor grounds through the ECM...

A 21 Grey is the signal return to the ecm... it has variable voltage depending on your throttle position...

A 22 Grey and green is the signal return to the ecm for the MAP sensor... it will also have variable voltage that changed with changes in intake manifold vacuum...

one thing.. you may have damaged these TPS and MAP sensor doing the wiring swap...

i am taking that you have a digital volt meter...

set the digital volt meter to 20 volts DC scale... use a piercing type of test clips...

hook it to the grey and red wire...

and then .. one at a time.. the other test lead to the grey wire.. then work the throttle with the key on.. see if the voltage varies from about 0.5 volts at closed throttle to just over 4.25 volts at wide open throttle...

then from the grey and red wire.. and the other to the grey and green wire.. you will have to have somebody with a vacuum hose and pulling some vacuum to see if the sensor responds..


The fuel pump and relay are in the middle of the diagram

The fuel pump relay is incorporated in the control relay. The control relay is involved in many of the circuits that the ECM uses to control the starting of the vehicle. The fuel pump circuit and the starter operation depend on the function of the control relay. The control relay powers the fuel pump during starter engagement, after which the ECM will continue operation appropriate to conditions within its parameters


THe fuel pump relay is grounded by the computer to energize the relay. THis allows voltage to pass through

black/white,blue/black & pink once the relay closes power switches from pink to pink/black fuel pump feed

black with white stripe wire should have full 12 volts with the key on. Lets check this with the key on with a voltmeter.

THe blue wire with black stripe should have battery power with key on. Lets also check this wire for full battery volts with a voltmeter.

The pink wire should be grounded by the computer to energize the relay. Lets do a voltage drop on this wire when the computer grounds the wire. Doing a voltage drop, you do not want to see more than .5 volt


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Car no start:--