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Hard/no start when sitting/cold - 2000 F250 7.3

Discussion in '7.3L Powerstroke Diesels' started by Macrobb, Sep 12, 2019.

  1. Macrobb

    Macrobb Full Access Member

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    Right. So... Today I pulled the driver's valve cover off. Found that I need new CCV O-rings.
    Looks like when the CVV O-rings extruded far enough past the CVV filter piece, it left a gap for unfiltered air to get in... which is why my turbo compressor looks a bit sandblasted and worn down on the edges...
    I thought it might be the K&N filter, but I didn't see any real dust inside that part of the intake. Past where the CCV tee's in, though... lots of oily dust on the inside of the tubes.

    Also found one injector(or just the solenoid) had been replaced at some time.
    Pulled #2 glow plug. Looked and tested fine(I just tested like a IDI plug though - if the tip glows quickly it's good). Then checked the next three with a wire... all seemingly OK.
    Checked the UVCH - looks to be good? I mean, I plugged a new GP into each wire in turn(glow plug in my hand with ground wire), and it got hot when the key was cycled.
    So, I did the 50C mod on that UVCH. We shall see if there's any difference tomorrow.

    ...I probably should have just swapped out with the new set of Motorcraft GPs I have and used the old ones for spares, but I didn't...

    I might just try a spare/new GP relay, see if that makes a difference. Still need to pull the passenger's side cover off.
     
  2. greenskeeper

    greenskeeper Full Access Member

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    As 79jasper said, you can "test" the relay by jumping the large terminals, a jumper cable clamp works good for this. If it suddenly starts good you can label the relay as "toast"

    Also the entire length of the GP should glow cherry red within 10 seconds. Just the tip wouldn't pass in my book.
     
  3. Macrobb

    Macrobb Full Access Member

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    Yeah.

    I never held any GP to power that long. Because I'm used to the IDI world - if you get a current draw there and it glows red at /all/, it'll be fine.
    (I've seen *one* partially failed plug before - it wouldn't glow at all within 10 seconds, though would slowly rise in temperature and draw *some* current.)
    I *suspect* these plugs are fine - I got red tip within 3 or so seconds, and the current draw / sparks when touching the lead looked similar to the new plug.


    My current test, today, is getting the ICP PID on my phone / torque app. So, with any luck, I can crank it and see ICP pressure.
    If that doesn't work, I'll just hook up a multimeter and get it that way.
     
  4. u2slow

    u2slow Plan B

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    You can simply unplug the ICP sensor and see if it starts better. If it does, you have a bad sensor.

    The IDM uses a base value when the icp input is missing.
     
  5. Macrobb

    Macrobb Full Access Member

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    Assuming the sensor is good, though(which is what my current assumption is), it would tell me if the HPOP pressure is low. And if the pressure(relative) is much higher on a warm start than a cold one, I might need to look deeper here.
     
  6. u2slow

    u2slow Plan B

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    Sure, but disconnect and try anyway first. Might be the culprit.

    I can't remember what base value is, but ~500psi is what stick in my head for minimum starting value.

    On mine, unplugging the icp made no difference, so it was still a mystery. That's when I decided I needed hard data from a mechanical gauge.
     
  7. greenskeeper

    greenskeeper Full Access Member

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    replace the god damn glow plugs and relay already
     
    79jasper likes this.
  8. bbjordan

    bbjordan Snow Monkey

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    First off, welcome to the 7.3 PSD club. :Thumbs Up :cheers:

    LOL LOL

    I'm betting it's the Glow Plug Solenoid. I've gone thru 3 of them, and the current one still doesn't work right. I can see the voltage drop on the volt meter, but all the power isn't getting to the glow plugs. I have to cycle the plugs 2 to 3 times to get it to fire when it's cold. There must be too much of a voltage drop across the GPS. It gets hot and the wires look kinda melty. :eek:

    I've also found that the IDIs started much more easily than the PSDs...at least for me.
     
  9. u2slow

    u2slow Plan B

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    Test the ICP already. It's free and easy!
     
  10. Macrobb

    Macrobb Full Access Member

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    So, I bought Torque Pro, and installed a couple of custom PIDs for it, for ICP and IPR.
    Tried cranking, no data.
    OK, try to actually start it.
    GP relay short cycles? Like... staying on for perhaps 5-10 seconds, then cycling off and on like an IDI. Vs before, where it would stay on for 30 or so seconds.
    Maybe cleaning the connections on the passenger side bank had something to do with it?

    Either way, I jumped across it with a pair of pliers for about 12 seconds, ran inside and cranked and she fired right up... ran for perhaps 15 seconds and then died.
    I figured it might have just gotten cold...?
    I swapped out the GP relay with a random IDI GP relay I had lying about. Didn't change much - cycle time still shorter. Jumped across it, tried different things and... nothing really.
    Gave it like 5 minutes, jumped the GP relay once more, and she fired right up. Left her running at idle while I was inside playing with the torque app.
    About 3 minutes later, she just... dies. Something I've never seen before. And, after that, my OBD2 adapter won't read codes. I plugged in an old Superchips tuner and read the codes that way - nothing of interest(just codes I know I made - unplugged ICP sensor and tried to fire it up with no difference for instance).

    After that, I waited a few minutes, jumped the GP relay for 12 seconds, cranked and she fired up. And stayed running(OBD adapter not plugged in).

    So... I'm thinking A, something involving GP relay cycle time needs fixed, B, GP relay needs replaced, and C, OBD adapter (or trying those PIDs) caused the computer to just 'give up' and shut the motor down.

    As for GP relay, I ordered a cheap one to play with for now. Spares are always useful. I'll probably get a white-rodgers heavy duty one in a couple weeks, especially if I can narrow it down to the relay.
     
  11. Macrobb

    Macrobb Full Access Member

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    So... Been busy. Haven't done anything on the truck, except for plug it in one or two days this week, and drove it to work.
    I did put a small load on it - bed half full of cinder blocks(50), and half full of propane tanks(100 gallons filled!), with a smaller trailer behind it and anotjher 50 cinder blocks, engine hoist etc.

    However, I finally figured something out. This truck has a botched up air box. Bottom piece is there, with a K&N filter just jammed on top of it - a decent hot air intake.
    But, the air box that was there didn't look like anything I'd seen! Turns out it was an AIS extended-life filter setup, like this: https://www.summitracing.com/parts/mof-fa1759/
    Now, well, I only have half of it. If anyone has a kit lying around, it might be fun to use - looks like *plenty* of filter media in there. Otherwise, I'm going to have to figure something else out.
     
  12. greenskeeper

    greenskeeper Full Access Member

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    cheapest air filter setup is a 6637 with 45 degree pvc elbow right into the turbo intake piping
     
  13. 79jasper

    79jasper Chickenhawk

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    I never used a 45, just a piece of 4 inch exhaust pipe.
    I think he wants to keep the AIS though.

    Sent from my SM-N960U using Tapatalk
     
  14. Macrobb

    Macrobb Full Access Member

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    It looks interesting for a couple of reasons - One, true cold air intake. A 6637 just *there* is a hot-air intake. Also, price - looks like a 6637 is around $45?
    AIS filter element seems very close in price - $38 on Amazon right now, and should last a *lot* longer with the same dirt load, due to the tons of filter media.

    So, either I buy/make a 6637 cold-air box, or use an AIS setup.

    Also, just want to point out - on my '93, I've got a factory turbo setup. It originally comes with a hose that takes cold air from the gap right where the hood meets the grill.
    Removing that hose or reinstalling it... didn't make any notifiable difference.
    I decided to try installing the hose off a 83-87 IDI, which pulls from a hole in the core support right at the side of the grill.
    I didn't expect any difference, but I sure got one! Slightly less smoke and more power at higher speeds(as you might expect from a 'ram air' system).

    So... Kind of want to do the same thing here. I want to have a ram-air-type, cold-air intake pulling from right at the front, and a 'sealed' box/filter going into the intake.
     
    Last edited: Sep 28, 2019
  15. 79jasper

    79jasper Chickenhawk

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    Otoh, tests have been run to show once you're moving, IAT with a 6637 is very close to ambient. If running a intercooler it's a moot difference even more so.

    Sent from my SM-N960U using Tapatalk
     

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