When I try to start my truck, it doesn't start. Sometimes it almost starts

To try and fix it, I changed the glow plugs, the 2 relays and both batteries with new ones. I also changed the oil and Fuel filter

Can someone diagnose what's wrong with my truck? It's a Ford F450 7.3L Diesel

Thanks.

 

Could be the CPS, crank position sensor.
Lately it seems as though a lot of ICP solenoids have been going out. either one will cause a no start situation.

 

There's usually white smoke coming out, today I smelled a lot of diesel in the exhaust.

Where is the CPS located?

 

How many miles are on the motor? Does it have a chip or tuner on it? What year is the truck? Do you get any smoke coming out the tailpipe while cranking? If so, what color smoke? Does the tach move while cranking? Does the wait to start light come on and then go off after a few seconds like normal? Do all the dash lights act normal? Does it start better if you plug it in for a few hours first?

 

220,000km / 136,000miles
Year is 2001
No chip or tuner, the truck is stock
Yes, smoke comes out when I crank. It smells like Diesel.
The smoke color is white
The tachometer does not move when I crank
The wait to start light turns off after a few seconds
The dash lights are all normal
Plugging the truck in used to work, but doesn't anymore.

 

Sounds like there may be more than one thing going on here. Let's start by testing the new glow plug relay you installed. Take a volt meter and test both large posts on the glow plug relay. With the key off, you'll see one has 12 volts and the other is dead. Put the meter on the dead large plug and turn the key on. If the engine is cold, you should see just under 12 volts on that 2nd large plug for a few seconds up to 2 minutes. If the relay never powers up the 2nd large post, you either have a bad relay or you're not getting the ground signal to activate the relay.

What brand of glow plugs did you install? (please don't say autolite)

 

Yeah the glow plugs are autolite

I'll try checking the volts on the relay tomorrow

 

As autolite glow plugs age, they have a tendency for the tips to swell up. That means when removing them down the road, there's an increased chance that at least one tip will break off in the head. You don't have to change them right away, but I would think about changing them before they get a chance to get old on you.

 

I checked all the glow plugs and relays and they're all good.

 

Do you have access to any kind of diagnostic scanner? I would start wanting to do a Buzz test. Even though you have low mileage I'm leaning towards some worn injectors possibly.

Have you tried letting the GP's warm for more than one cycle? Seeing if that will help.

 

When the truck does start, the truck runs fine, no problem with power.

Yeah 3 cycles

 

Ok, I known you said you have new GP's but have you ohmed them out? Maybe the UVCH is loose or they are not connected well?

 

We had one last week that was acting like u said....new GPR, good glow plugs, etc.....Turned out the starter was drawing 400 amps. New starter and all is good. Probably not your issue but might be worth checking.


You make take an ohm meter and check resistance on your block heater cord. Might have burned up the element which is why it does not work anymore.

 

Good thinking on the both accounts.

On the Block Heater cord, they are known to fail pretty easily, maybe not the element but the plug itself, which you could just put a new service end on.

 

I like the idea of checking voltage while cranking and checking the block heater cord. As mentioned, access to a good scanner would help, but since you probably don't have that, try unplugging the ICP sensor and see if it starts better after you watch voltage while cranking and check the heater.

The next step after that may be to pull the valve covers and watch for oil discharge while cranking from each of the injectors. You may have several that are not firing.