Hi all,

1993 F-150 with 4.9 RWD I've run into a wall and wanted to look outside for some help.

Currently, I have the front belt removed, all of the spark plugs out, and rocker arms loose (new head gasket). The engine turns freely by hand on the harmonic balancer, but the starter will only slowly turn over the engine. I've checked the engagement of the starter below, and it meshes with the flexplate perfectly. I removed the transmission to replace the torque converter, and it also spun freely by hand before I bolted it to the flexplate.

I've also run the power leads directly to the starter, and I am using a remote starter trigger switch to jump the solenoid to confirm it wasn't a relay issue. New battery, battery cables, and starter. All were checked to make sure they aren't the culprit. The engine will slowly turn, but starts overheating the wires. I even went to the length of getting a 0ga positive lead made, but of course, the negative continues to get hot.

Does anyone have any other suggestions?

 

You did say "New Starter", but does that mean you tried two different starters and both of them turned over slowly?

 

I’m on the 3rd starter now. Original, AutoZone, and a high dollar Bosch from Napa. I also had them bench test the last 2.

 

Does this mean that the only thing that has not been updated is the ground cable from the battery?
I'm assuming it goes directly from the battery to the block somewhere close to the starter?

 

“New battery, battery cables, and starter.”

Negative goes from battery to frame to starter. I also added a ground strap from the starter mount bolt to the frame.

 

Is there a place where you can run the negative battery cable directly to the engine block just for the sake of troubleshooting?

 

FActory is like he has it, battery to frame> top starter bolt.
This way the starter has a direct connection to the battery.
There should also be a ground from the motor to the firewall to ground the cab.

Now you are only looking at 1 side of the electrical path you still have the positive side of the system.
I know you said you replaced the cables but you still have a solenoid on this side.
If and when you replace it DO NOT go cheap as they will fail and when they do it will keep the starter spinning even when the motor is running.
As for bench testing starters other than see if they spin does not prove anything as it is not under a load like turning a motor over.

I have been running a NAPA top of the line solenoid for six years now. The old one acted like a bad battery connection, it would click, do it 3 or 4 times and then it would turn over and I knew all the cables were new and starter was fine as it turned the motor over just fine. But just to make sure it was not a connection I cleaned them all and don't you know it was worst as it clicked before I put my tools away

If you really want to know where this slow motor turning over cause is do a voltage drop test.
It will test every part of the starting system and show where the bad part or parts are as you may find 1 part bad before testing the whole system.
Do a Goole search how to do the voltage drop test.
Dave ----

 

Here is a short cut to the voltage drop test in the 80-86 truck area How To's
https://www.ford-trucks.com/forums/1...w-starter.html
Dave ----

 

https://www.oreillyauto.com/shop/b/a...993-ford-f-150

Are you using the newer style PMGR Starter. How is it wired, on the positive side.
You can use jumper cables to add an extra ground for troubleshooting.

From the web....
For a 1993 Ford 4.9L (300ci) engine with an automatic transmission, the starter is a Permanent Magnet Gear Reduction (PMGR) unit. It typically has 10 teeth, clockwise rotation, and mounts with two unthreaded bolts.

Jim

 

Information and photos here regarding wiring.


https://www.garysgaragemahal.com/pmg...er-wiring.html

Jim