99 F350 PS Diesel cold start problem

[roccon31]

(Or you didn't use them properly. Cycle the key switch 2-3 times waiting for the glow light to go out before doing it again.)

john, please do not take offense to this, i am not singling you out.

it is a common misconception that you have to cycle the glow plugs on the powerstrokes, like you did on a poorly functioning older style system. YOU DO NOT have to cycle them several times. all this does is prematurely burn out the plugs!!!! the older 6.9 and 7.3 engines used a sensor mounted on the back of the block, determining the glow times. they were semi-reliable, as long as the plugs were all good. one plug went out, and the cycle times were affected. this is when you had to cycle them to get the truck to start. most folks dont realize they have a plug or two out until the truck no longer starts, then they realize they have 5 or more out.

the powerstroke computer is programmed so that after the dash light goes out, the plugs remain on for a certain amount of time, up to about 2 minutes with the engine off. once you crank and start the engine, the plugs will cycle on and off to reduce smoke by increasing combustion chamber temperature. this is decided by the oxygen sensor among other things (knock, etc)

the light stays on for a predetermined amount of time, depending upon engine temp and ambient air temp, all decided by the computer and glow controller.

i recently had a friend with a 99 7.3 f250 call me up complaining about his truck that it would not start below 40 degrees. it started fine above 40, no problem. first thing i did was check the plugs. ALL 8 WERE OUT!!!! i couldnt beleive it, i checked the relay, the valve cover gaskets (the wires go through the gasket under the valve cover, they do fail) i yanked the valve covers, threw 8 plugs in it and sent him home. the next week it was 14 degreesin the AM, and the truck fired right up without a block heater. moral of the story is- CHECK YOUR GLOW PLUGS!!! pm me if you need to know how. its easy.

 

[tallyho8]

When my 1995 Ford 7.3 liter wouldn't start in the cold, I bought a glow plug relay off ebay, installed it, and have had no problems since.

What I am not able to understand is: I have a voltmeter in my dash and when I turn on the key, the glow plugs make the volt meter go about halfway down the minus side showing that the plugs are using lots of juice. However, when the relay was bad, the voltmeter would still go way down when I turned the key on but the engine would not start. I thought when the voltmeter was showing a large minus that the juice was going to the glowplugs but somehow the relay must have been shorting and using the current instead.

I would always recommend that you change the relay before the glow plugs because it is cheap and easy to change and it is the most likely cause of a no-start. I bought 8 glowplugs with my relay 5 years ago and the glowplugs are still sitting on the shelf in my garage.

The motor has to run for about 1 minute before the glow plugs turn off and the voltmeter comes back up to about 14 volts.

 

[Ryan03]

Has this powerstroke ever been started with either. If so, this tends to damage {melt the tips off} the glow plugs.If so, they can be accessed by removing the valve covers, and removed with a 10 mm deep 1/4 drive thin wall socket. First, I would locate the glow plug relay, figure out which wire is the hot lead from the relay to the glow plugs, back probe that terminal at the relay, and have somebody turn the ignition switch to the on position while you are under the hood with a multi meter testing for voltage coming out of the relay and going to the glow plugs. As mentioned earlier, the correct grade [15 w 40] and CJ-4 and CI-4+ ratings. A Few examples of this are Shell Rotella T conventional base, or Rotella T full synthetic, which is 5 w 40, Mobil delvac 1300 15 w 40 and delvac 1, 5 w 40 are all suitable, there are more, but you get the idea. There are lots of reasons that your truck may be hard to start cold, but the most common ones that I have seen involve glow plug and or glow plug circuit issues, assuming the battery condition, compression, and starter condition are all acceptable.

 

[Lefty_Kubota]

first thing to do is check your glow plug relay it see if its working. "
simple to do with a test light"
Make sure its cold when you check it , cause when the EOT is 180 degrees or hotter the ECM does not cycle the glow plugs..

 

[john_bud]

john, please do not take offense to this, i am not singling you out.

No offense taken!

It's just one {more} thing I didn't know.

However, Some people {cough cough -- my wife -- cough cough) just turn the key and crank with no waiting at all. Typically it results in her tramping back in the house and giving me the "your truck won't start" speech.

jb

 

[cmuncy]

Classic!

My wife does the same " Your truck HATES me!!"

 

[Lefty_Kubota]

No offense taken!

It's just one {more} thing I didn't know.

However, Some people {cough cough -- my wife -- cough cough) just turn the key and crank with no waiting at all. Typically it results in her tramping back in the house and giving me the "your truck won't start" speech.

jb

My wife does the same thing !!!

 

[groundcover]

Can hardly get my wife in the left seat,guess that is not all bad!

Had a very strange thing happen last night. Had been plowing all afternoon,'94 F350 7.3 IDI Turbo 70,000 mi. Stopped to top off front tank,dumped in splash of power service and pumped away. Had truck running as it was about 5*out,started to run real rough then quit! I have had this since new and never anything like this before. Switched to rear tank and finaly got her going again. Went on to plow for another three hours,never skipped a beat. Dumped the rest of the Power Servive in the front tank and switched bact to the front tank after I got hame. Plowed another twenty min and all is well. Water in fuel light never came on,station moves a lot of fuel and it is stored underground. I had 1/4 tank when I started to fill,think I got a little air in the line? Was just about to do a full service /w fuel filter but got set back by weather. I asked at the station if anyone had had a problem,no one had.

 

[Lefty_Kubota]

Yes, i have seen that before... Sometimes the pickup tube in the tank breaks off or cracks down at the bottem.. Does your truck ever run out of fuel before it gets to E ?

 

[groundcover]

I never let it get that low but have never had a problem so far.