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Discussion Starter · #1 ·
Hey guys! So my 92 bronco with a 351w and E4OD has had an intermittent issue with not wanting to start. Sometimes the key will start it and sometimes it won't. Recently replaced are the Ignition switch, Ignition Lock Cylinder, and MLPS all for different reasons outside of this one and not just because I am throwing parts at it. For a while with the key in the run position I would just go under the hood and jump the solenoid like many have in the past but that's a temp solution and I do not want to just wire up a bypass push button. First thing I did was with the ignition switch dismounted I slid the actuator rod to start position and the truck did not crank. This was just to eliminate everything mechanical in the column except the ignition switch which is brand new. I did go through the diagnostic steps found in this post here. I have no voltage at the S terminal wire while in start position on the key. Actually If I take the volt meter and go from the positive terminal on the battery and connect it to the wire going to the S terminal I get 12V... That doesn't seem correct either and makes me think there is a grounded short somewhere. Regardless I went on with the testing in that post. I went down to the trans that I just finished rebuilding and unplugged the MLPS. The MLPS is brand new with new plug because my MLPS had a crack in it. I first checked voltage at TR sensor terminal (R/LB) and had nothing. Then checked voltage at TR sensor terminal (W/PK) and still nothing. That's where the diagnostic stops for that post. It says repair open in circuit between sensor/switch and starter relay. I am guessing they mean voltage between ignition switch and the MLPS. Where do these two terminals on the MLPS get their voltage? Does anyone have any further steps for diagnostic? Potentially a wiring diagram for the whole Starter system so I can see where else to be checking voltage.
 

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Discussion Starter · #4 ·
Well I rewired the MLPS based on this diagram because mine did not match at all. Started the truck with a screwdriver and now Park acts like drive and then it spewed about 3 quarts of fluid out from the bellhousing....

Before rewiring the MLPS I started the truck with screwdriver and this did not happen.
 

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Discussion Starter · #5 ·
Now the truck won't even turn over jumping the start solenoid even though it has 12V I'm so frustrated with this truck and its years of neglect. I just spent so much money rebuilding this trans and now the truck is basically useless. I hope that the 92 being a body change year doesn't need some sort of different wiring on the MLPS and I ended up frying something or locking something up.
 

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Yo mantooth,
I was replying to your PM (CONVERSATION) , but posting it here is better for me due to easy of adding hot link diagrams , pics and vision issues.

When you turn the key to "RUN/START" and there's no spring resistance feeling it usually because the actuator inside steering column is broken or ignition switch is loose.
Accessories that fail to operate with the key in RUN, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.

Test the ignition system mechanical operation by rotating the ignition switch lock cylinder through all positions of the ignition switch. The movement should feel smooth with no sticking or binding. The ignition system should return from the START position back to the ON position without assistance (spring return). If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch

The ignition switch can be adjusted by loosening the mounting screws, and sliding it up or down.

161188
'92-up is on the RIGHT

Manual Lever Position/Transmission Range (MLP/TR) Sensor Replacement in a 92
Source: by Jeremy M (Big 92, jermil01) at FSB

MLPS Adjustment Info in a 92
Source: by Richard C (Bigric, Money Pit) at FSB
Thread includes testing

Some typical issues are re-pinning a replacement MLPS;
MLPS Wiring Diagram in 92-95 Bronco & F Series
Source: by Steve

Connector Diagram (no pin-out info) in a 92
Source: by Richard C (Bigric, Money Pit) at SuperMotors.net
Connector Pin-Out Diagrams
Source: by Steve at SuperMotors.net​

No Start; & Relay Connection pic in 92-96; "...The relay trigger wire (LG/R) comes from the ignition switch via the clutch switch or MLPS and should only be hot with the key in START and either the clutch fully depressed, OR the auto shifter in P or N. The solenoid trigger wire goes to the small terminal on the starter. If the relay fails, bridge between the 2 large studs to send power to the solenoid. If the starter still doesn't spin, crawl under the truck, remove the red plastic cover, and BRIEFLY bridge between the 2 large studs on the solenoid (using a heavy metal object with an insulated grip, like a screwdriver) to spin the starter (it won't engage the flywheel or crank the engine). If it still doesn't spin, replace the starter. 130A & heavier alternators use 2 fusible link wires. The Yellow wire goes to the stud on the side of the power distribution box, and feeds all other factory loads on the vehicle..."
Source: by Steve


MLPS Circuit in Ignition Troubleshooting & Wiring Diagrams in a 92 from Ford EVTM
161170

Source: by Ford via Seabronc (Rosie, Fred W) Rest-in-Peace my friend.
 
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Hey guys! So my 92 bronco with a 351w and E4OD has had an intermittent issue with not wanting to start. Sometimes the key will start it and sometimes it won't. Recently replaced are the Ignition switch, Ignition Lock Cylinder, and MLPS all for different reasons outside of this one and not just because I am throwing parts at it. For a while with the key in the run position I would just go under the hood and jump the solenoid like many have in the past but that's a temp solution and I do not want to just wire up a bypass push button. First thing I did was with the ignition switch dismounted I slid the actuator rod to start position and the truck did not crank. This was just to eliminate everything mechanical in the column except the ignition switch which is brand new. I did go through the diagnostic steps found in this post here. I have no voltage at the S terminal wire while in start position on the key. Actually If I take the volt meter and go from the positive terminal on the battery and connect it to the wire going to the S terminal I get 12V... That doesn't seem correct either and makes me think there is a grounded short somewhere. Regardless I went on with the testing in that post. I went down to the trans that I just finished rebuilding and unplugged the MLPS. The MLPS is brand new with new plug because my MLPS had a crack in it. I first checked voltage at TR sensor terminal (R/LB) and had nothing. Then checked voltage at TR sensor terminal (W/PK) and still nothing. That's where the diagnostic stops for that post. It says repair open in circuit between sensor/switch and starter relay. I am guessing they mean voltage between ignition switch and the MLPS. Where do these two terminals on the MLPS get their voltage? Does anyone have any further steps for diagnostic? Potentially a wiring diagram for the whole Starter system so I can see where else to be checking voltage.
Well I rewired the MLPS based on this diagram because mine did not match at all. Started the truck with a screwdriver and now Park acts like drive and then it spewed about 3 quarts of fluid out from the bellhousing....

Before rewiring the MLPS I started the truck with screwdriver and this did not happen.
Undo whatever you did. Don't rewire things unless there is clear evidence someone else fucked with it.

That whole 12v thing you found with the meter, ignore that. What you were essentially doing when you did that was testing voltage drop across the starting circuit, which will be 12v when it's off.

What you need to do is with the negtive lead attached to ground, check at multiple points along the starting circuit for voltage, starting at the ignition switch and working your way to the starter solenoid. Leave things plugged in whenever possible. You can use T Pins to backprobe connectors. Remember that just because a part is new doesn't mean it's good. There's alot of junk out there these days.
 
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