Long crank time to start, after new starter install

[Crashtest84]

Ok so here is the problem, I have a weird intermittent starting problem. All the details first 89 with 2.9 to 4.0 swap 5speed truck. when doing the swap I did not have a m5od to go with the 4.0. But I had a 2000 mile old 2.9 clutch and new starter. So I kept the 2.9 stuff flywheel back. Plan was to find a M5od. Well the clutch slipped and the throwout bearing was toast. soooo

It was time to swap in the 4.0 clutch/flywheel still using the dreaded fm146 Now It cranks for 5+ sec. will cough aka semi backfire and stop the starter. Or it will crank shudder a bit then run like normal. Fuel pressure will hold at around 40psi for over an hour so pump and reg are good. Batt checked out and I only get a volt drop to 11.2 during cranking. I have swapped the wires on the fender solenoid as noted. The motor cranks easy and fast. As I noted this one started after the clutch and starter swap. Anything you guys can think of to test or check ?

 

[Crashtest84]

lil update, seems to be worse at after sitting or cold engine.. I just went out to pull it in the garage and had 3 pretty awesome back fires... out the exhaust not intake but it also only did it right as I let off the key. Im really thinking its gotta be a spark/ ignition problem. But why after the new starter. Going to a real load test done on the battery tomorrow.

 

[Crashtest84]

Wow, nothing nobody even has input. Then again thats how I am loss for ideas.

 

[Andy D]

Just a Guess, An old starter can draw too much amperage to let a run down battery fire a worn out ignition in the cold. I would charge the battery. Meanwhile check the spark plugs, When was the last time this rig was tuned up?

 

[RonD]

Most automotive electrical systems have two separate pathways for Start and Run on the ignition switch.
When ignition switch is in Start position, only the ECU, fuel pump, coil and starter solenoid get power, this setup gives the starter motor all the power available.

In Run position ECU, coil and fuel pump have power, as well as lights and accessories.

It reads like the coil is not getting power, or enough power, in the Start position, but is in the Run position, I think that because of the backfires, fuel is building up in the cylinders so injectors are working, then when key is released to Run position coil sparks.
If you release key at just the right time engine will start.

Older engines used a ballast resistor(or wire) in the Run position, in Start position coil got full 12vDC for start up, but in Run position coil ran on a lower voltage thru the ballast resistor.
These ballasts(or wires)often failed and you would get the opposite of your symptom, engine would crank and start then die as soon as you released the key to the Run position because power to coil was cut off.
This is what made me think of your symptom.
Maybe there is a relay or power wire on the solenoid that energizes the coil when key is in the Start position, and that relay or wire is not working.

You could test voltage at coil in the Run position, and then test voltage when trying to start, you could disconnect the starter motors "+" cable so engine is not cranking for the test.

 

[Crashtest84]

Yeah, thats something I have thought about. I switched the starter wires around as explained in the Tech. guild for the 2.9-4.0 cluch swap. I might get out to the u-pull place and get a factory starter harness. See if that changes anything... Where is this ballast you talk about ?

 

[RonD]

The newer EI's(Electronic Ignitions) don't have ballasts or resistor wires, just the older cars that had 6v coils.

It was the example of two power paths needed for spark when Starting and when Running I was referring to.

I would just check the voltage at the coil when ignition switch is in Run and then in Start position to see if that is even an issue.

 

[Crashtest84]

Ok, yeah I didn't read that right. I thought you meant the older 4.0 coils. I have the same feeling its ignition related just haven't pinpointed it yet.

 

[Crashtest84]

Not much to update I did test the 12v to the coil... and It has voltage there but does drop when its cranked..... still stumped going to try a jumper to the coil and check the timing while its cranking today.

 

[Crashtest84]

Ok so Problem solved!! After almost a month of this BS!! It ended up being the starter itself. How I have no idea! I took it back for a warranty because basically I wore it out haha. With the new starter installed BAM started right up.... and installed without the shims "aka washers" I guess that should have been my first hint that it wasn't right.

 

[alwaysFlOoReD]

Glad you got it fixed! Looks like AndyD had it right.

Richard

 

[Crashtest84]

Not really... yes is was the starter.. but it was a brand new starter. just something wasn't right about it. Being new is why I didn't question it. the " made in mexico " should have helped point out the problem