My 2000 Super duty 7.3L diesel starts hard in the A.M. White smoke comes out of the exhaust while cranking. Turns over fine but it takes about 3-5 minutes of cranking. Wait to start light goes on and off normally. Could it be a glow plug or the relay? Once it starts it runs fine and starts fine all day, just tough in the morning.

 

I have a 2000 f-350 with the 7.3 also. That is the same thing mine did and I replaced the glow plug relay last fall. Problem solved.

 

You just received the best answer from low96hb.

 

Thank you. Replaced the relay. Was 19 degrees this morning and it fired right up.

 

No problem, glad I could help...

 

hello low96hb,i have the same exact problem,but the gpr didnt fix mine.still cranking away.

 

can you tell me where this alledged module is?think they forgot to put one on my truck.

 

You're correct , there is no module there. I believe only the older 7.3 s had a glow plug controller.
The EOT (engine oil temp) sensor influences how long the glow plugs will stay on. This may be sending an incorrect reading to the PCM possibly causing a long crank time. Something to keep in mind is WAIT TO START LITE is independent from GLOW PLUG RELAY ON TIME.

 

this sensor has been a suspect.i think this is on the back of the upper resevoir?yesterday was 43 degrees in the morn,tried starting, crank,crank,crank,after 10 min of trying to start ,she fired.ck this out,today,morn temp 52 degrees.she fired up within 2 seconds,i mean instantly.it does that every time its 50 or above.i just cant believe the glow plugs THEMSELVES are causing this.im baffled.trying to hard,probably overlooking obvious.

 

The EOT is a thermistor whose resistance goes down as the temp goes up. Don't have any definite values, but there is a high resistance when cold and low resistance when warm. One of the functions that may help determine if it is at fault, at ldle when the engine temp goes down the EOT sends the info to the PCM and causes the idle speed to increase , then the engine temp gets to the programmed temp the idle speed will come down automatically. If the fault is serious enough it will cause the MIL to come on. It is usually mounted on the top of the oil reservoir and is the only thing there with wires going to it.