7.3 Won't Start Cold Unless Plugged Up

[whitemomba]

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 piss 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.

 

[Magnum PD]

How long does the "What to start" light stay on?

 

[whitemomba]

On the first start in the morning it stays on for about 10 seconds and once the motor is warm it stays on for only about 3-5 seconds so I'm guessing everything is working there. I did test the voltage at the GP relay when it is cold and it was sending power to the glow plugs for about 15 to 20 seconds and air temp was in the high 20's. Does that seem long enough? I know they can stay energized for up to 2 minutes but I'm guessing this is probably only in extremely cold conditions. Also if I cycle the glow plugs 3 or 4 times it doesn't seem to make a difference. When its in a cold no start situation it will act like its going to fire but only on a couple cylinders but then nothing and then if I continue cranking about 5 or 6 more revolutions it does the same thing but still won't fire.

 

[Magnum PD]

What weight oil are you using? May need a thinner weight for cold weather. Hope you don't have low compression. A worn out engine can be hard to start.

 

[whitemomba]

I'm using the rotella 15-40 conventional oil. I usually change to the rotella T6 5-40 synthetic when it starts to get cold but I forgot to tell them that the last time I was getting my oil changed which was in December. I've never had a problem with it not starting till this winter. I had 15-40 oil in it for the first part of last winter when it got to around 5 degrees and it started first try with only one cycle of the glow plugs.

 

[bruce]

If the glow plug relay is workin then it has to be the glowplugs themselves since ICP looks alright. Go get 8 zd-11 and throw them in. Also a buzz test doesn't tell you anything about warn poppets, all it does it verify the injector solenoid is gettin energized.

 

[mandkole]

x2 -- If the plugs are of unknown age/mileage, then change them. If the compression is limp, that's a big issue also.

Since compression test and glow plug R&R go hand in hand, you'll learn a lot with one removal of the covers. When my neighbors high mile 99 wouldn't start at 35F, the GPs snapped it to attention.

 

[Charles]

My crew cab will not crank after sitting for a couple days on a real cold morning. ICP is 2500, GPR is working, glow plugs are working and it will not even smoke. It only hits on like 1 or 2 cylinders a little, not even enough to smoke.

When it finally does crank (on ether) it just kind of eaaaaaaaaaases to life, or not, mostly just rolling right back down and dying again. Pedal to the floor and it will barely run at all. Like a truck on 2 cylinders, except there is zero smoke. None, not even a wisp while it sits there hacking and bucking to the floorboard. From pedal to the floorboard all the way until you lift off the pedal completely nothing changes as the PCM already had it maxed trying to idle.

I have been told by multiple people that the injectors could be the issue. I have yet to conceptualize how since the truck drives perfect otherwise. Good balance, smooth running, so on and so forth.

I would love for someone to tell me what's going on inside the injectors to cause this.

 

[golfer]

http://swampsdiesel.com/files/7.3LInjectorDiagnostic.pdf

 

[Charles]

http://swampsdiesel.com/files/7.3LInjectorDiagnostic.pdf

If the ICP was crap I'd be on board, lol.

Send me a PCM for an 02 manual and I'll toss the 4/4's in.




I really want my sig to read intake, exhaust and 400/400's anyway...

Since stock PCM trans tuning is a sh*t show, I need a manual PCM to go PCS without a bunch of bs trying to pacify the auto PCM.

 

[golfer]

If the ICP was crap I'd be on board, lol.

Send me a PCM for an 02 manual and I'll toss the 4/4's in.




I really want my sig to read intake, exhaust and 400/400's anyway...

Since stock PCM trans tuning is a sh*t show, I need a manual PCM to go PCS without a bunch of bs trying to pacify the auto PCM.

will do.

4/4's in the works.

...oh..so you have ICP in the RAILS, that's cute. oke:

be sure to update this thread once we get that oil through the poppets.

 

[Magnum PD]

You like doing business with Charles, David???

LOL

 

[Charles]

will do.

4/4's in the works.

...oh..so you have ICP in the RAILS, that's cute. oke:

be sure to update this thread once we get that oil through the poppets.

02 PCM is what I need, I have 8 4/4's in the shop that need a new home already.

The part I'm trying to figure out is what exactly the poppet is doing that changes when warm to keep the injectors from firing. BTW, I'm not saying it isn't happening, I'm saying I don't understand what is happening.

If they weren't lifting at all that would make sense. Tons of ICP and no injection. But how would wear make them not lift? Lower seat beaten down until the over can't be pulled? If so, why would the solenoid yank that same armature when the injector was warm if the over was too great? Is the poppet physically getting "stuck" 6oh style?

When it comes to why is the injector not firing when cold I'm reminded of a movie quote:

Captain Ron: "Well diesels like their oil like a sailor likes his rum."

Mr Harvey: "And why is that Captain Ron?"

Captain Ron: "Weeeeeeell, nobody really knows...."

 

[golfer]

Have a PCM too...I'll tell Shawn to hold off on the 4/4s.

Poppet probably isn't stuck like a 6.0L spool...but increased 'over' and cold oil not flowing through the poppet (on time) just delay the event.

some guys note improved unplugged starting after installing our hvhf idm if that helps you explain it to yourself. Could try the one out of red.

 

[Charles]

Looks like I might be writing Johnny some tunes then.

 

[whitemomba]

If the glow plug relay is workin then it has to be the glowplugs themselves since ICP looks alright. Go get 8 zd-11 and throw them in. Also a buzz test doesn't tell you anything about warn poppets, all it does it verify the injector solenoid is gettin energized.

Thanks Bruce. I checked the glow plugs when I did valve cover gaskets about 6-8 months ago and they all checked out fine. Next time I get a chance I will ohm the GP pins on the UVCH connector. I have a feeling I will be pulling the VCs again. Hoping I won't have to since I have the PDP thicker wall IC boots and getting the T-clamps back on is a huge PITA. Last time we pulled VCs it took us 2 hours to get them off check all the GPs and get them back on but 4 hours to get the damn IC pipes and boots back on. I wish they still made things like they used to...you know where an adjustable crescent wrench and a BFH (big f***ing hammer) was all you needed to fix about anything.

 

[whitemomba]

Have a PCM too...I'll tell Shawn to hold off on the 4/4s.

Poppet probably isn't stuck like a 6.0L spool...but increased 'over' and cold oil not flowing through the poppet (on time) just delay the event.

some guys note improved unplugged starting after installing our hvhf idm if that helps you explain it to yourself. Could try the one out of red.

Anyway you could explain what that HVHF IDM is or does? I understand what the IDM is and what it does but would the HVHF have an effect on injection timing, mpg or drivability? Would it require custom tuning to run it? I have the PHP hydra chip and run Bill's tunes.

 

[whitemomba]

Also, getting back to the problem, I forgot to add that I did audibly hear the GPR click on yesterday but after the truck was already warmed up from running so I wasn't able to note if that helped the truck start or not. I went out this morning to see if I could audibly hear the relay click on again and cycled the plugs 5 or 6 times and never heard it click on once and of course the truck wouldn't start since I didn't have it plugged up the night before. Can't figure out why the relay decided to click on that one time but doesn't want to now. Does the relay ground itself to the mounting bracket? I don't have it firmly mounted to the bracket (there is a slight bit of play between the relay and the mounting bracket) but it is hand tight. Didn't have the right size crows foot to fit the two mounting nuts and couldn't fit a socket between the MUCH larger stancor relay and the mounting bolts. I've been meaning to get it tightened down to the bracket but have just been putting it off since I thought the relay grounded to the PCM and not the bracket itself. Am I wrong on this assumption? Does anyone know what size the two mounting nuts for the relay are? Also should I have voltage to all of the terminals once the key is on or just the two large posts? I currently have battery + (12.5-12.7 volts) to the always positive large post and same to 0.1 volts less to every other post (other large post and both of the smaller posts) of the relay when I turn the key on. Again thank you for all the help! It is greatly appreciated!

 

[whitemomba]

Alright so I went out and finally tested my plugs through the VC gaskets and it looks like I have 4 that are either unplugged or completely dead and 2 that are weak or dead. This is what I got cylinders 2 and 5 are 1.5 ohms 4 and 7 are 0.3 ohms 1, 3, 6 and 8 gave me no readings. By no readings I mean it did not move the gauge at all meaning no connection??? Does anyone know what the plugs should be reading? I thought I remembered hearing that they should be between 0.5 and 2. Is this right? Either way it sounds like I will be pulling the VCs again to at least determine why 1, 3, 6 and 8 are giving me nothing. I should have just replaced all of them when I had them out the last time since I had a brand new set of motorcrafts on hand that I got for 25% off but I guess you live and you learn right. :cursing:

 

[mandkole]

Yup, those readings were similar to the neighbors truck that didn't start. Had some that did nothing and some that had various readings. IIRC, about .3 was typical of a good one.