7.3 Poor Starting in Cool Conditions - Ford Powerstroke Diesel Forum
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post #1 of 6 Old 12-23-2012, 06:27 AM Thread Starter
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7.3 Poor Starting in Cool Conditions

Hey Guys, new here. Looks like a great place!

I just recently purchased a mid 1999 F-250 7.3. The truck has 130,000 and a whole load of new parts. All new glow plugs (OEM). New Harness(OEM) Just replaced the GPR. Just did a Fuel Filter and Oil Change. Brand new batteries.

Truck is mostly stock. Running a 4 Inch Turbo back exhaust. K&N Intake. ATS Turbo Housing and Wicked Wheel. Superchips programmer on Economy tune.

The Concern:

Truck has a difficult time starting when cold. Cold can be under 50 degrees if the vehicle has been sitting. It cranks good and fast. Tach shows RPM movement during cranking. Glow plug light cycles with key properly. Starts fine when plugged in. Once it has been started for the day, as long as i dont let it cool off (sitting for anoher 8 hours) it starts right up. When running it never skips a beat. Not doggy at all once it starts even on very cold days. Normal amounts of white smoke during startup. Clears out quickly.

I'm thinking that i got a bad GPR?(AutoZone, so it's a good possibility) Injector O-Rings allowing fuel to leak down? Cam position or crank position sensor? Oil level is high. Used Motorcraft synthetic blen 15w40 oil like i do in all my diesels.

Please let me know your thoughts.

Thanks for the help,
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post #2 of 6 Old 12-23-2012, 08:46 AM
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Look at this thread, (2000 F350 7.3 4X4 No Start). It is just below your thread at the moment. See if anything sounds like it matches. I was having roughly the same problem and was able to do the seafoam and it has improved. It is still not 100% but I have a cleaner in the motor and I'm going to let it do its thing before I try any thing else.
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post #3 of 6 Old 12-23-2012, 08:51 AM
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Over 50 degrees there isn't much the GPs are doing for you. You don't need them at all in fact...

For general cold weather stuff here's a couple of things you can do though, forget about the WTS "cycling". That light is on a sort of, timer. It is no indication of how long, or even whether, the GPs are activated. Try leaving the key on for a full minute, then cranking. Also, in the cold your oil, because it's still a 15W viscosity, is adding to that effort of trying to start. In the Winter consider 5W-40 synthetic, 5W oil makes it easier.

So, you see cranking rpm on the tach and you're not having trouble with the engine quitting randomly, doesn't sound like a CPS issue. It does it at 50 degrees, I'm not thinking GPR (check though, here's a good link -> Troubleshooting GPR & GP's).

Your "leak-down" theory sounds good and would be where I would start. The first place would be to remove the little plug at the top of the HPOP reservoir (allen key) and dip the res (stick the longside of the allen) to find out how far down from the top the oil level in there is (should be @1" or so). If it's way down what can be happening is that the HPOP is draining dry overnight and you have to do a lot of cranking for the LPOP (engines oil pump) to refill first before it can produce the pressure needed to start.

After that, don't screw-around trying to guess, get it on a good scanner and monitor the sensors (ICP shows HPOP press) to figure out what's going wrong...

Also, might as well get this out of the way , you damaging your engine with that K&N AND the SuperChips isn't doing your transmission much good (if it's a Auto) nor are you getting what you should from it in programming. There are Much better choices for Both IMHO

Last edited by NoRalPh; 12-23-2012 at 08:54 AM.
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post #4 of 6 Old 12-23-2012, 09:12 AM
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if it starts up fine every morning with it plugged in, and when not plugged in, once started, runs good, i'd first be looking at the glow plug circuit.
you have a new relay, plugs and harness, but is the relay actually being commanded on? is there power to the relay?
try this; on a cold start, have someone cycle the key on while you wrap your palm around the relay. see if you can feel it click. if you can, it is at least being commanded. if it is, try jumping the relay. you can use a screw driver to jump the 2 posts together. it should spark when jumped. if it doesn't, there is a problem with either the relay power supply, or the path to the glow plugs.
if it sparks, hold it there for about 15 seconds then have someone crank. see if it fires right up then

the richest ones are not those who have the most, but those who need the least
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post #5 of 6 Old 12-23-2012, 02:44 PM Thread Starter
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Thanks for the advice everyone. I'm thinking that when the glow plugs were replaced the relay was going and may have shorted out the new goe plugs. Not sure but it is a thought. I will get the test light out tomorrow and check what has been suggested.

I understand the K&N is not a good upgrade, but i have no option until i buy a new one. I'd like something decent but inexpensive and not sure what to buy(any suggestions are welcome). I am also planning on a DP F5 Tuner in the very near future.

Once again i appreciate all of the help!
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post #6 of 6 Old 12-24-2012, 11:34 AM Thread Starter
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Did some testing today. So much for new glow plugs! 7 of them werent working. Went to the local parts store and picked up 8 ZD11's and wil install them as soon as possible. Should fix my starting concerns!
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