1994 Mazda B4000 Timing issue


mattcarlson7

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1994 Mazda B4000 Timing issue (california Model) 95 Ranger 4.0 Motor

Hello,

I am having a huge issue timing my engine on this vehicle. It is actually a 1994 Mazda B4000...but its the same as the 95 ranger 4.0. We have gone through and gotten the engine to TDC according to the books multiple times. When I check the wiring on the plug I have a solid ground, and also am running 13v on the hot wire. When I try to time it I get hot 13v+ full time. It never drops to 0/increases or anything. What can I do.

Thank you
 
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RonD

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Welcome to TRS :)

There is no spark timing adjustment on the 4.0l OHV
1990 to 1994 used EDIS-6 spark module and the EEC-IV Computer, 1995 and up used newer EEC-V computer with built-in spark module.

Either used a Crank Position(CKP) sensor to set base spark and fuel injector timing
CKP sensor outputs AC Voltage, it is a Variable Reluctance(VR) sensor.
Should see about .5-.8 voltsAC when cranking engine over


If you are working on the Cam Position(CMP) Sensor then that is a Hall Effect sensor prior to 1999, VR sensor 1999 and up.
You don't time this sensor electrically, not sure you even could without frequency meter and running engine.
You need to find #1 TDC COMPRESSION STROKE, not #1 TDC exhaust stroke
Then follow the instructions to point the cam synchro tower and sensor in the correct direction
Directions here: http://www.therangerstation.com/tech_library/camshaft_position_sensor_cmp.shtml

The Cam sensor is used to fine tune sequential fuel injection and some spark advance/******, it wasn't used on 4.0l engines until 1995, except in Calif.
The Computer will adjust CAM sensor pulse for best power and fuel economy internally, so all you need to do is to get it Close to correct location.
i.e. you can't rotate CAM synchro to fine tune for better power or fuel economy like you could a distributor, because computer will change any adjustment you make back to what it wants.
But you do need to get it close so computer can fine tune it.
 
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mattcarlson7

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It is a 1994 Mazda, but has the 4.0 with the CMP. My understanding is they did not put them into the rangers until 95. According to everything I am reading you turn the key on, and check the middle wire on the CMP. You turn it counter clockwise until 12V+ then clockwise until 0, then back counter until voltage shows.
 

RonD

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They were used in Calif models prior to 1995, B4000 is Ranger 4.0l, only badges and some exterior differences

Do it the way it is shown here: http://www.therangerstation.com/tech_library/camshaft_position_sensor_cmp.shtml

If you are just testing the sensor you can crank engine(coil unplugged) and test that it is sending a 12v pulse to computer every 2 RPM(one rotation of Cam sensor), but won't tell you much(more like a 9-10volt pulse with starter motor active).
Cam synchro with sensor is not all that expensive, and they do wear out, so if you get intermittent or high or low CMP codes then just replace it.
If you get Circuit codes, it could be wiring or sensor
 

mattcarlson7

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I do not have the same CMP that you showed in those directions.
 

RonD

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Then you do not have a 4.0l OHV engine, 3.0l Vulcan and 4.0l OHV both used same setup for Cam Sensor.
1991-1998 used 3 wire Hall effect, 1999 and up used 2 wire Variable Reluctance, but same setup using cam synchro tower and same method of timing when installing new unit

Ford's 4.0l SOHC engines(1997-2012) used a cam sensor located on drivers side valve cover, but no adjustment was needed or possible.

Crank sensor is on the front of the engine down behind Crank pulley, no adjustment is needed or possible.

2.3l or 2.5l Lima 4cyl engines had crank sensor on drivers side behind timing belt cover, it reads Oil Pump Gear rotation, and no adjustment of sensor is needed or possible
 


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