924G runs poorly and derates

[AaronAlaska]

924G Loader derates and runs poorly. DDA03439. Very hard start. It has a 1684-8 code for erratic speed timing signal. I have replaced the fuel pump wiring harness, the pump, the ecm. Still have the same problem. I ohmed the speed sensor out fine but i will replace that next. Any ideas?

 

[thepumpguysc]

I woulda changed that 1st.. MAKE SURE it has a good fresh place to read from.. if its up in the engine don't worry about it bit if its on the flywheel or balance, MAKE SURE to use sandpaper or emory cloth FIRST.
& READ the instructions.. some have a stop built in & others screw in till it touches a "bump" & u back it out x amount..

 

[Nige]

The speed sensor just plugs into the block. See diagram. What did the condition of the nose end of the sensor appear to be like when you checked the resistance..?

 

[thepumpguysc]

Resistance is futile..

 

[Esfoder]

Get a 930 from out of the scrap bin. It will start and run forever. Mine has been since 1970 and it's never derated itself once.

 

[nzpatch]

Just had a new fuel pump put on my 924gz and had problems with it straight away
Turned out the new pump was out of timing from new ( cat reman)
Ran good some times but some times it would start but white smoke and run like sh,t!
Re timed it and goes All good now

 

[DMiller]

Sensor by basic appearance is similar to most speed and timing sensors out there. The one on my 7.3 ford is the same and just as temperamental can resistance check fine, can look Brand new and be worthless, I keep two spares as they can just Die and had one do so.

Helped a friend with one thought gone bad, had picked up a sliver of ferrous material on the tip and was driving it nuts

 

[funwithfuel]

Sensor by basic appearance is similar to most speed and timing sensors out there. The one on my 7.3 ford is the same and just as temperamental can resistance check fine, can look Brand new and be worthless, I keep two spares as they can just Die and had one do so.

Helped a friend with one thought gone bad, had picked up a sliver of ferrous material on the tip and was driving it nuts

When I worked for Navistar, I would measure cold and again after I hit the sensor and surrounding area with a heat gun, get all kinds a whacky readings like that.