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Discussion Starter · #1 ·
Ok Boys….here it goes. I bought my first diesel Ford truck after many gas ones and it’s been all downhill. I got a 2006 F350, 6.0, crew cab long bed, 4wd with 200K miles, but it recently had a new crate Ford long block installed in it just before I got it. They also upgraded to ARP studs. I have the paperwork to prove the work was done. Seems the EGR or oil cooler failed and things went south. Since I got it I have installed 8 new Ford injectors with new hold downs due to potential bolt stretch if you reuse the old ones. I did this due to stiction(hard cold starts) and 3 injectors failed a cylinder contribution test at the dealer. Did the STC upgrade on the HPOP, upgraded stand pipes with Teflon washers, rebuilt the HPOP oil rails, new Ford oil cooler( Doorman crap one installed had deteriorated gasket), EGR delete (it already had this when engine was installed), blue fuel pressure regulator spring, alternator and 2 batteries, IPR, Fuel pump and water separator, SCT Livewire, and upgraded turbo oil supply line and drain. I also flushed the daylights out of it and put in a new radiator and heater core and Ford gold coolant. I only run Motorcraft oil and filters. I have done my homework. Thing runs great….when it starts. Here’s the problem. About 3 out of ten times she won’t start hot. Especially if it’s shut off just for a few minutes. I know what you’re thinking but the HPOP is great! The IPR screen is clean and the HPOP pressure is way above 500 psi when it cranks hot!! I have to either crank the heck out of it like 3 or 4 times for 20 seconds or let it sit for awhile and cool down. The compression in all 8 cylinders is 390-400 psi and it passes leak down tests with flying colors so it’s healthy internally. Also air tested through the ICP and no leaks as indicated by good HPOP pressure. FICM voltage is good, grounds and battery connections are good as well. It cranks nice and fast too. Fuel pressure tests fine. IT NEVER THROWS CODES EITHER. I’m stumped. I even threw an OEM cam sensor at it. I went out and bought a Scan Gauge II as my SCT didn’t have a prompt to monitor cam/crank sensor sync. When it’s cranking it never shows sync until it starts….is this normal with a Scan Gauge? Even when the engine fires right up in the morning or the 7 out of 10 times she starts just fine hot, the sync doesn’t change from 0 to 1 until she fires. When it’s acting up, it never shows sync until it finally starts. I’m a really good shade tree mechanic but I’m ready to drive it in a lake!! I’ve dumped a ton of money into the thing to make it dependable and I really could use any and all help. THANKS and sorry so long, but figured you guys needed good background data!!
 

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Without sync you won't be able to start either. Sync is derived from a comparison of signals from both the Cam and crank sensors.
 

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Discussion Starter · #3 ·
That's my understanding as well. Should the ScangaugeII show sync while cranking if she won't start if it does indeed has sync? Mine changes from 0 (no sync to 1 sync) when it fires up with a brief delay. When it starts it fires up almost immediately and then after a very brief time ( like a half second) the Scangague changes to 1. When it not starting, you can crank on it for 20 or more seconds starting at the Scangauge and still says 0, no sync.....
 

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if I recall mine shows sync before it starts.
 

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If I were you, I would be swapping the Crank sensor and/or checking to see if any wiring got pinched during the motor swap. Based on your info, something is up with it being able to SYNC the Cam and Crank.

I run the scangaugeII and I show SYNC going to "1" before my truck fires. The issue with mine is a long crank due to some sort of HPO leak or weak HPOP, so mine can take 5 seconds to fire in the morning. This I am sure give the scangaugeII time to update the SYNC status.
 

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Discussion Starter · #9 ·
Have RPM signal when it wont start. ICP shoots up to 750psi with only like 24% Duty cycle. FICM and other voltages look great. No fuel pulse width or sync. while cranking when it won't start. Installed new cam sensor already and just threw a OEM crank sensor in as well...What a PITA job that is as it's under the AC compressor. Tried wiggle tests and everything else I can think of....Scangauge is set to fast update...My understanding is it won't raise IPR% without Crank signal....which it does go up to around 24% and quickly rises to well over 500 PSI. Also, it's my understanding that RPM is derived from both crank and cam sensors so I guess they are working. Still no sync.....I am about to give up....
 

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Even w/o a crank signal icp will rise. I've seen where the cam position sensor ground circuit protect wire will rub into the other 2 wires and cause a ground out. Only time the code shows up is immediately on a no start. If it fires the code wipes.

Edit: also when you pulled the crank sensor out, did you look at the tone ring and make sure it was in the center of the hole?


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RPM is only derived from the crank sensor. Sync is needed from both, but intermittent Cam signals usually keep running, unless it is widely intermittent (error refresh rate). Both Jr and Rice have given you good advice.
 

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Discussion Starter · #15 ·
OK....thanks guys...JR. not sure if it was clean metal, but it wasn't crusty or corroded. How likely is it to be this? It's never thrown a code. I read in the Ford diagnostic manual it needed crank signal for ICR to rise above .14. As far as the tone ring being in the middle, I just slapped the new sensor in there. I was so happy to finally get to it!! It was a battle. Is the tone ring the crank sensor needs adjustable?? Had it at a buddy's shop last night and he has a new $10,000 snap on scanner. Of course it would only act up once or twice, but when it did: Seems like the PCM had both Cam and Crank signal, but no PCM out to FICM cam crank signal....thus no injector pulse. In the book in clearly shows two pins on the connector going out from PCM to FICM that tell it Crank and SYNC. We also tested and ohm out the harness while wiggling and as was great.
 

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That won't necessarily be accurate. As I stated above the cam sensor harness is ground circuit protected. And i have ran into this problem more than once. The ground loom is bare that goes around the cam sensor wires. Naturally over time it works its way through the coating and grounds out. Ohms will not tell you this because contact is good. I don't have pics in my phone but I'll post later from pc. I've removed the ground wire from the harness ( it goes all the way up to the pcm) and have made at least 3 trucks run that have this problem. Good luck.


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If you get this figured out let us know. Im having the same problems but i'm not getting sync after 3-4 hrs of sitting. Been to the dealer twice and each time there amazed I have good icp and its still not starting. But then again it always starts for them. Been busy here working and havent had many nice days to look over mine. I do see rpms while cranking and had them put in a new cam sensor while it was in just because it was cheap.
 

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I'm shooting in the dark, but I had this issue: bad HPO seals at the nipple cups into the injectors. I know Bostech makes the Viton o-rings to replace the old ones.
 
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