warm starting problem
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warm starting problem
Hello... I recently purchased an Excursion with the 7.3 turbo diesel and one week later found myself broken down. The moter cranked over at regular speed but it would not start up. I sprayed starting fluid into aircleaner and it fired and ran as long as their was fluid but would not run on its own. I allowed the moter to completley cool down and it started and ran fine. I had all systems checked and all was fine; no codes on the computer at all. It is also getting 13.5 mpg on the trip computer. I am told it should be getting 17-20 mpg. The warm start problem has since left me stranded several times but it wont break down in the shop. High pressure oil pump is working at the proper psi. I changed the cam positioning sensor and problem still exists. Is their any one who can help me? Thanks and God bless.
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I do not know the ICP presure when cranking. I was told I should replace the IPR to the HPOP the mechanic ran vehicle with the computer monitor on. he said their was no codes. If the ICP is out dosent it go to closed loop and use known oil presur readings. could a bad ICP caus my bad fuel milage. thanks for the info on the starting fluid
Last edited by roderick perkins; Jun 2, 2007 at 08:10 PM.
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From: Central, Al
3 Things (other than fuel) are needed to crank a Powerstroke
ICP > 500PSI
Voltage > 10.5 VDC
RPM > 100
With a bad ICP the PCM will assume ~700psi during cranking But if it is not really above 500 she isn't going to crank.
During cranking the PCM commands 10 -15 % duty cyclye from the IPR and steadily increases it until the truck fires. If there is an oil problem (pressure, age, ect) the pcm will increase duty cycle on the IPR but without it seeing at least 500PSI from the ICP it will not start to command the injectors to fire.
Warm no starts are usually oil related, How old is your oil and what type/weight? next is ICP or IPR mechanical problems but since it cranks fine cold ICP is doubtfull. The IPR could have a loose Tin Nut but that would also effect it cold. Some have had success removing the IPR and cleaning it.
ICP > 500PSI
Voltage > 10.5 VDC
RPM > 100
With a bad ICP the PCM will assume ~700psi during cranking But if it is not really above 500 she isn't going to crank.
During cranking the PCM commands 10 -15 % duty cyclye from the IPR and steadily increases it until the truck fires. If there is an oil problem (pressure, age, ect) the pcm will increase duty cycle on the IPR but without it seeing at least 500PSI from the ICP it will not start to command the injectors to fire.
Warm no starts are usually oil related, How old is your oil and what type/weight? next is ICP or IPR mechanical problems but since it cranks fine cold ICP is doubtfull. The IPR could have a loose Tin Nut but that would also effect it cold. Some have had success removing the IPR and cleaning it.
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Post Fiend
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From: Blairsville,Ga
depending on speed 20 could happen
over 2000 rpm mpg starts dropping
seems lots of things controll mpg
when new my F350 got 16.5 to 17 on hiway 14 in town 18 to 19 on mountain roads,at about 55000 mi decided to get 12 eo 13.5 on hiway
over 2000 rpm mpg starts dropping
seems lots of things controll mpg
when new my F350 got 16.5 to 17 on hiway 14 in town 18 to 19 on mountain roads,at about 55000 mi decided to get 12 eo 13.5 on hiway
Last edited by rbaker6336; Jun 2, 2007 at 08:24 PM.
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thanks Alan. the first thing I did was to change the oil to the Ford speck 15-40. and to make shure the oil was all the way to the top of the temp sensor housing by cracking oppen the allen bolt on top till oil came out. I will remove and clean the IPR as you sugest any thing I should look for when cleaning. Also how do I check for the 10.5 VDC. Also what do you think about reflashing the computer. Thanks
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From: Central, Al
http://cw-diesel.com/LuxSite/IPRInfo.htm
Just check at one of the batteries while someone is turning the truck over.
Just check at one of the batteries while someone is turning the truck over.
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Hello Alan I called my Mechanic and he said the duty cycle was at 11% and the ICP was mid 600psi. the vdc was over 10.5. the only test he did not run was a wiggle test what ever that is. Ray my Excurison just turned 55,000 miles and other than the starting problem is great I have 6 kids pleanty of room for all. I still need to get those MPG up I changed fuel filter and air cleaner with no change.
Last edited by roderick perkins; Jun 2, 2007 at 09:00 PM.
Post Fiend
Joined: Jun 2006
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From: Central, Al
Don't laugh the "wiggle" test is very well documented in the Service manual for finding intermittent shorts.
If that is duty cycle and pressure while idling that looks good. But you will need to catch it in a no start to actually see.
If that duty cycle and pressure are during cranking and it wont start you need to get him to plumb a 3000psi gauge into the Oil Galley plug and see what the ICP really is.
If that is duty cycle and pressure while idling that looks good. But you will need to catch it in a no start to actually see.
If that duty cycle and pressure are during cranking and it wont start you need to get him to plumb a 3000psi gauge into the Oil Galley plug and see what the ICP really is.
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From: Blairsville,Ga
I know the mpg feelin
had trans rebuilt and new torque on last trip I was up to 15.7
had new turbo and boots put on lately but don't think that will do anything
new fuel probly brought it down some
AIS filter this week probly not either
had trans rebuilt and new torque on last trip I was up to 15.7
had new turbo and boots put on lately but don't think that will do anything
new fuel probly brought it down some
AIS filter this week probly not either
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Yes test were at idling RPM. I noticed that the moter will crank a few extra times before it has a no start. I have been trying for a month to get it to break down for him. I let him take it home and It would not act up. Do you think I could set up a gauge and drive it till it has a no start and check myself.