First off thanks in advance for everyones help. This post may be long winded so I apologize but please try to bear with me. Alright so I've been having some cold start troubles with my 2000 F250 7.3 with 247xxx miles. If the truck sits for an extended period of time (8 hours or so) it will not start unless it has been hooked up to the block heater for at least 30 minutes. 30 minutes on the block heater and the truck starts but blows out a good amount of white smoke for a couple of minutes then the smoke goes away. If it is hooked up for a couple hours or so there is no smoke at start up. If the truck is not plugged in it will crank and crank and crank and after about 10 seconds of cranking I will get white smoke out of the tailpipe (which I'm assuming means that I am getting fuel???) but no start. This has been going on for only about a month or two so I haven't had the chance to see if it will start when it is warm outside but it was around 45 one morning and still it wouldn't start until I hooked it up to the block heater. As soon as the truck starts there is no problem and it doesn't seem like it is missing on any cylinders. It does seem like it is lacking a little power once I get it started but I try not to give it much throttle until the temp gauge at least moves off the cold mark. Once I drive it for about a mile or two it runs like a scalded dog. Before anyone asks I do have a chip on the truck and I have reset the truck to the stock tune before starting cold and still nothing. Haven't actually taken the chip out of the truck yet because I'm almost positive this has nothing to do with my problem.

So heres a list of the things that I have either replaced within the last year or checked:

Replaced within the last year:

Glow plug relay (upgraded to the stancor 3 weeks ago hoping this would be the problem) I have battery + voltage to the always positive large terminal and when key is cycled I get the same voltage to the other large terminal

Valve cover gaskets and UVC wiring harness 6-8 months ago. When I did this I pulled all glow plugs thinking they would be bad but all of them ohmed out at 0.5 ohms so I did not not replace any of them.

Two new batteries and new alternator 3 weeks ago. One battery had a bad cell and the alternator had a bad diode so the batteries were being drained over night. New batteries check out at 12.5-12.7 volts in the morning and while cranking hold 10.5-11 volts.

New MAP sensor about 2 months ago. Broke the last one on accident (don't ask me how)

New Cam Sensor installed by Ford under recall close to a year ago.

New fuel filter, the last one only had 4k miles on it but I put a new one in to rule that out of the equation.

Checked:

Oil pressure (ICP) checked from oil rail plug on passenger side head when cranking cold and no start jumps straight to 600 then climbs up to 2200-2500 after about 5 to 10 seconds of cranking.

Unplugged ICP and EOT sensors individually and no start when individually unplugged or both unplugged at same time.

Contribution test and injector buzz test done probably 9 months ago and both passed with flying colors. Haven't been able to do another one yet because my mechanic is about two weeks out. I plan on getting another one done by the end of next week or as soon as he can get to me.

Pulled a code for exhaust back pressure sensor malfunction today but this shouldn't keep the truck from starting when cold right??? It also had codes for EOT and ICP sensor but I'm guessing that was just from when I unplugged the sensors and tried to start it. Cleared all the codes and the only one that came back so far was the EBPS malfunction.

This truck is really starting to **** me off and I can't figure this one out and I don't know why plugging it in is helping it start. I don't have a scan tool so I haven't been able to check IPR duty cycle yet but if that was giving me problems the truck would run rough cold or hot wouldn't it? I've thought about worn poppet valves in the injectors but it passed a buzz test 9 months ago so I would think that I'd have some signs before it gets to the point where it won't start or is that just wishful thinking? If y'all think injectors please give me any tips you have on making trucks "accidentally" explode...you know for insurance purposes. Thanks for all the help.

 

How long are you letting the glow plugs warm up before you try to crank?

 

I wait till the wait to start light goes off. I don't hear an audible click actually coming from the relay but I know the relay is good because I'm getting battery + voltage to the always hot large terminal and once I cycle the key I get the same voltage or about .1 volts less to the other large terminal of the relay. I just put a brand new stancor in less than a month ago and haven't heard it click like most people claim to. Come to think of it I don't think I've ever heard any of the 3 GPR (2 OEM ones and the new stancor) actually "click". I've tried crossing the two large terminals with a screw driver for about 10 to 15 seconds with no change at all.

 

You are getting voltage but I'm wondering if your getting amperage. If the lead to the relay is corroded it may not be providing the amperage to heat the glow plugs. You could let them heat up for about 30 or more secs. I don't think the wait to start light is directly tied to the GP system it just times out. Doesn't mean you can't let them heat longer. You could try jumping straight from the battery to the GP side of the relay for about 30 secs then try to start.

 

I cleaned all the wires going to the relay when I put the new one in and they had very little corrosion on them. I've even tried cycling the plugs 3 to 4 times before cranking and it has no effect. I can crank the ever loving **** out of it and after about 5 to 10 seconds it will act like its trying to fire but only on a couple cylinders (this is about the same time I get smoke coming out of the tailpipe) and if I keep cranking after about 5 or 6 revolutions probably 2 to 3 seconds it's like it tries to fire again but still on only a couple of cylinders and it will do this until I stop cranking. The smoke coming out of the exhaust is thick white smoke and smells like unburnt diesel so I am pretty sure I'm getting fuel, no oil or coolant smell to it. It just seems like it isn't getting enough fuel to start when its cold. I haven't had a chance to put a gauge on the fuel bowl yet but it seems like its getting good pressure because when I replaced the fuel filter I didn't get it tightened all the way and had fuel shooting out from between the bowl and filter cap at a pretty good pressure.

 

What is the Voltage Reading, When Cranking at the Batteries?

 

I was thinking corrosion in the wire under the insulation not necessarily at the terminals. That's why I was thinking direct jump to GP relay from battery to see if they will heat up. Thick white smoke sounds like plenty of fuel just not enough spark to light it off.


How long have you owned the truck? Do you know how old the GPs are?

 

10.5-11 volts I just put two brand new batteries in about 2 to 3 weeks ago since I had one with a bad cell.

 

Ill have to try that when I get a chance. Should I just hook up some jumper cables to the battery + straight to the large terminal of the GPR? I've had the truck almost 2 years now and I'm not sure how old the glow plugs are but when I pulled valve covers to replace VC gaskets and UVC harness (no melted wires or anything just replaced them since new ones came with the VC gaskets) I pulled all of the glow plugs and ohmed each one and all of them were at 0.5 ohms. Not sure I actually tested them the right way just took a volt meter and put it to the lowest ohm setting and put the hot on the top (connector) of the plug and then grounded to the body of the plug. Was that the right way to do it or is there another way to check them. All of them looked like they were the factory berus but looked too new, as in not a lot of carbon build up on the tips, to be glow plugs with 240xxx miles on them. All of them came out very easy considering all the horror stories I've heard about high mileage glow plugs breaking off in the heads.

 

I would leave the key off and eng off, hook a heavy jumper from battery positive to the GP side big terminal of the GP relay for about 30 secs, pull jumper off and start. If it starts right up then start trying to figure out why they aren't getting juice. If it doesn't break out the meter and start checking at the UVCH harness.

 

Could a completely clogged or short in the EBPS cause a no start when cold? I've unplugged both the EOT and ICP sensors when cold cranking and still it will not start. It's getting plenty of oil pressure (2200-2600 when cold cranking with ICP plugged in or unplugged) and since I've got thick white diesel smelling smoke I'm guessing plenty of fuel just no fire. Could it be injection timing? The IDM and CMP are the only ones that determine injection timing right? I didn't get a code for either when I had it scanned today. Would a failing IDM even throw a code or cause a no start when cold and run fine once warm? How would I even go about testing the IDM?

 

I'm gonna let Tom, whitetmw, or some of the smarter guys answer those questions. With the oil pressures your seeing and fuel coming out of the pipe I don't think IPR, ICP, or IDM are the problem.

 

That's what I was thinking also. With the oil pressures that I'm getting and all the smoke it doesn't seem like it could be worn poppets in the injectors since stuck or worn poppets would mean little to no fuel being injected. Thanks for all the help Paul!

 

If all that checks out, read my cold start thread. You aren't going to like where that leads you, but I think it is where you are headed.

 

Did you have smoke while cranking and no start? Sorry I didnt read the whole thing just got down to the bottom where it said 12 pages and decided to skip to the last one. Also what we're you're ICP readings while cold? The reason I ask is because if I understand correctly the poppet valve will sink down into the injector body reducing the armature gap between the spacer plate from .004" to close to 0 over time. Since the oil getting into the poppet valve is required to fire the injector, when the armature sinks closer and closer to the spacer plate cold and therefore more viscous oil is not able to sufficiently pass through to fire the injector. This is why the block heater helps trucks with worn poppet valves start since the oil is less viscous and can therefore flow more easily through the tighter gap. My thought process is if the injector is not getting enough oil to fire when cold then there would be very little to no smoke from the tailpipe what so ever and the ICP readings would be lower (lower than 2200-2600) since the high pressure oil would then just be recirculating back to the pump. I may be wrong on this but that's just my understanding on it from what I can tell. Furthermore if worn poppet valves are suspect an injector buzz test, which is essentially a continuity test between the IDM and each injector solenoid, while the motor is cold (sitting longer than 8 hours) should be able to show this since the armature is acted upon by the solenoid. A cold buzz test with worn poppet valves would likely fail unless they are right on the border line of specs (i.e. .0015"-.002" gap). This is also due to the oil being less viscous which relates to a "suction" or "stiction" effect, as some refer to it, between the poppet valve and the injector body itself making it much more difficult for the solenoid to lift the armature and poppet. Again once the motor has warmed and the oil less viscous this suction effect is less prevalant and therefore the solenoid can lift the armature and poppet more easily. I have not been able to do a cold buzz test yet since my mechanic is still about a week and a half to 2 weeks out right now. My guess is that it will pass since there is a thick white cloud of diesel smelling smoke that is coming out of the exhaust during cranking indicating fuel supply and the fact that my HPOil pressures are at 2000+ during cranking so very good atomization of the fuel being delivered. If I'm right which I'm probably not the question would be is there enough heat to ignite and is the injection timed properly (i.e. are any of the 3 wire sensors malfunctioning causing the IDM to get a false reading from the PCM resulting in improperly timed injections during cold conditions). I apologize for the novel and thank you for the help!