Hard starting diesel

john in la · Apr 24, 2022

What will make a diesel hard to start when at operating temperature ??

I have a 1959 Ford 801 diesel.
Starts well when cold as in has not run for a while.
I do not use it in the winter so I do not know about winter starting.
Runs well; idles down real low; good power.
Just do not shut it off because you will not get it started again.
Just grunts like it has a dead battery or a bad starter.
Let it sit for a while till it cools off and it will start right up.

I am thinking timing but I do not know how to check the timing on a diesel.
Thanks.

Janicholson · Apr 24, 2022

If it starts, runs well and has power it is not likely timing. Starter motors and battery connections can cause the symptom. When warm, as can the battery. Testing the voltage when cranking (or trying to crank in this case) at the ground battery terminal, and the solenoid battery connection would be a beginning of diagnosis. The voltage there should stay above 10.5 volts. A meter as shown can also indicate a bad starter motor (when warm and when cold). The meter is merely held against the battery cable and uses inductive fields to work, no wires. Simple I own 2 and use them! Jim
one example

Steve@Advance · Apr 24, 2022

I would suspect worn starter bushings first.

Could also be a weak battery, bad connection, too small cables.

M-MAN · Apr 25, 2022

There's a timing window just below the hydraulic pump. Use a wrench on the front pully hub bolt and turn it until you see 23 degrees in the center of the window. Take the timing window off the pump and line up the two marks. If you don't see them torn the engine another revolution.

It's easier to line up the pump marks first and then check the degrees.

Don't think that's your problem though.

cole in mo · Apr 25, 2022

(reply to post at 02:54:01 04/25/22)

counterclockwise · Apr 25, 2022

I agree with cole. Injection pump problem. See if dieseltech responds.

Geo-TH,In · Apr 25, 2022

John
I'm not a diesel mechanic.
If I recall to turn my dad's 1960 ford 6000 tractor you just pulled on a cable and blocked the air off.
I'm thinking if your ford is the same, while you are turning off the tractor you are still injecting fuel into the cylinders.
Compressing excess fuel in the cylinder makes it difficult to crank.

What if you idled the engine, put it in high gear and popped the clutch to kill the engine..

Just an idea. I'm not a diesel expert.

Dieseltech · Apr 25, 2022

Make sure the battery and cables are in good shape, also the starter MUST not have worn/dry bushings that cause starter drag. My 871 did not crank well hot due to the worn bushings that allowed the armature to rub the field windings when hot. Engine MUST crank over fast as possible for any diesel to start well. Lastly, the injection pump hydraulic could be worn and that will cause hard starting when hot. If tractor will not start well with starter, but will when towed that's a sign the hydraulic head is leaking internally due to wear.

showcrop · Apr 25, 2022

"grunts like it has a dead battery or a bad starter" eliminates the injection pump as a problem. The injection pump doesn't come into play unless the engine is cranking.

caterpillar guy · Apr 25, 2022

Lots of things bad battery, poor connections on cables,wear on the starter bushings letting it drag. I would start with looking at the connections and cables for corrosion and clean if good the look into starter bushings. Look for rub marks in the armature and field coil area. If so then new bushings are in order and maybe more depending on how much it rubbed and for how long. Look at switches for burned contacts or poor voltage transmission is a good indication of burned contacts. You could use a different cable from the battery to the starter to try when hot if it starts then you found the problem. Make sure it is in neutral first though. Or have a helper.

Texasmark · Apr 26, 2022

Problem is that the engine compression is at a max requiring max out of the starting loop. Problem is the starting loop has a wink link somewhere. A good place to start looking, after knowing your battery can put out 300 amperes with a 1v drop in terminal voltage, is the ground from the battery to the engine frame, and or starter to engine frame interface corroded.

A poor design, but convenient for the mfgrs, grounding the battery with a strap to the cast iron tractor housing, and expecting good coupling through the starter to housing interface gets to be more questionable as age increases. If you have 10 volts across the terminals on the starter when trying to start when hot then suspect starter. If not, walk down the starting loop with either your hand feeling for heat or a voltmeter looking for voltage at a connection.

Hard starting diesel

john in la

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Janicholson

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Steve@Advance

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M-MAN

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cole in mo

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counterclockwise

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Geo-TH,In

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Dieseltech

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showcrop

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caterpillar guy

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Texasmark

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