7.3 hard starting
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From: New London, Mo
7.3 hard starting
Im working on an 2000 ford with a 7.3 that has a hard starting issue. The truck only has 50,000 miles. glow plug relay is new and glow plugs are new. on initial start up after truck has set i have to crank for about 30 seconds before the truck starts, the oil pressure gauge in the dash does not move until it has been cranked on. once the oil presure gauge moves it fires up. i checked the hpop pressure at the port in the top of the head where the crossove line would go. and at idle ive got 700 psi and at 1700 rpm ive got 1250 psi. is this a good test point? if not where should i be testing at? and what should pressures be? once started the truck runs great. Can anyone give me a clue as to what i should check? Thanks Justin
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What are your rpm's while cranking? The starter needs to spin the motor a minimum of 120 rpm's IIRC to get the oil pressure enough to fire the injectors. Also, the batteries while cranking should not drop below 10.7 volts or it will not fire. While cranking, are you getting ole out of the exhaust? You can move the pass. mirror down to look while cranking.
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From: New London, Mo
Cranking RPMs are fine. Battarys are new,
QUOTE=gengine;12765582]What are your rpm's while cranking? The starter needs to spin the motor a minimum of 120 rpm's IIRC to get the oil pressure enough to fire the injectors. Also, the batteries while cranking should not drop below 10.7 volts or it will not fire. While cranking, are you getting ole out of the exhaust? You can move the pass. mirror down to look while cranking.[/QUOTE]
QUOTE=gengine;12765582]What are your rpm's while cranking? The starter needs to spin the motor a minimum of 120 rpm's IIRC to get the oil pressure enough to fire the injectors. Also, the batteries while cranking should not drop below 10.7 volts or it will not fire. While cranking, are you getting ole out of the exhaust? You can move the pass. mirror down to look while cranking.[/QUOTE]
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From: New London, Mo
Ok will do that during lunch today. Could the ipr have anything to do with this. The truck is a fire truck it came out of Florida an now its in Kansas. I assumed glow plugs cuz the relay was burnt up and burnt in Florida they prolly didn't get used much. Temp has no effect on starting after it has sit for awhile.
Hotshot
Joined: Jan 2011
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From: Puget Sound
A bad IPR will have a huge effect on starting... I think that link in my sig says something about it. Are you reading the IPR with a scanner?
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From: New London, Mo
i do not have a scanner. i can test any pressures i need to test manually with gauges but thats it. i think tonight i might pull the ipr and clean it see what that does maybe swap the one out of my 7.3 and see what it does.
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From: New London, Mo
Pulled and cleaned ipr made no difference. Hpop Resivour is full. Once truck is running and shut off and it sits for prolly two min its hard to start again. What should Hpop pressures be?
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Going back to the first post, i would install an oil psi gauge and verify the lpop psi. I had a 2000 and the other a 2001. the 2001 was hard to crank when I first got it but always build psi before hand. The 2000 always cranks but sometimes has a lag before the oil psi light goes off.
What oil and oil filter does it have in it?
What oil and oil filter does it have in it?
Hotshot
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From: Puget Sound
If you can check any pressure, you might have a look at the fuel port closest to the passenger head - loacated on the back of the fuel bowl. You can drain the fuel bowl into a container and before you fire up again, watch how the fuel bowl fills with the key in "Run" and the filter top off. With the top on, you should reach at least 50 PSI within about a second or two (air purged).
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