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Curtis B.
Curtis B., service manager
Category: Heavy Equipment
Satisfied Customers: 25679
Experience:  30 years exp. with diesel engines, heavy equipment and forklifts, including lp forklifts
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95 f-superduty with a international 7.3 turbo.Really hard to start.

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I have a 95 f-superduty with a international 7.3 turbo.Really hard to start.I have to plug in the heater even in warm weather to get it to start.when its running it runs rough.can you tell me what will cause all this?

curtis b :

Welcome to JUST ANSWER heavy equipment. With many years of experience, I look forward to doing my best to help in your situation. Have you checked the glow plug system, starting at the glow plug relay on top of the engine? It looks like a starter relay, and when the key is turned on, it should click closed, turning on the glow plugs. If it doesn't close, check it for voltage coming to it. If it is closing and sending power on, the valves covers will need to be removed and each glow plug connector will need to be checked for voltage. If you have voltage, it might be a good time to replace the glow plugs, especilly if they have not been changed since new. Let me know. Thank you.


Thank you for your answer.I was thinging glow plugs but was'nt sure.I will check for voltage as you discribed.One question.How much voltage should there be?

Curtis B. and 2 other Heavy Equipment Specialists are ready to help you
Battery voltage, 12 volts.
Customer: replied 5 years ago.
Thank you,I checked voltage and have 12 volts at connectors.Replaced glow plugs,Still wont start unless the heaters pluged in.What else can it be?
Does the glow plug relay click and close when when you turn the key on and off? The glow plug system is about the only thing that would make it hard to start cold,.Did you check to be sure that you have voltage at the glow plugs?
Customer: replied 5 years ago.

Yes relay clicks and i have voltage at the glow plug connectors.


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Customer: replied 5 years ago.
Checked it.Its about fuel pressure?would that cause it?I attached a gauge and it read 50-55 when idle.
The pressure should be at least 40psi, you have that. When you try to start engine, do you get any smoke indicating that there is fuel in the cylinders? Or do you get no smoke? The high pressure oil pump has a soleonid on the inner bottom right corner of it when you are looking at the pump from the front. It is way down low in the valley, you have to almost stand on your head to see it. It has to turn the high pressure on when the key is turned on. It usually causes no starts when the solenoid does not energize the valve it goes around. But if it is slow to activate, it would cause hard starting. Check the solenoid to be sure it is getting voltage as soon as the key is turned on, You should be able to hear the valve click when the key is turned on and off.

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