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Solid State Glow Plug Conversion for 1986 6.9 IDI F250

Discussion in '6.9L IH & 7.3L IDI Diesels' started by wildman7798, Aug 19, 2013.

  1. wildman7798

    wildman7798 Full Access Member

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    So after reading as much as I could find here and fighting with a search engine that leads to frustration I am just going to post this. It seems after getting all kinds of answers or no answers here is what it comes down to.

    1) I can't establish if the newer Delphi HDC905 or the Diesel RX GP Controller that thread into rear of block are truely solid state devices or they just claim to be an improved design.

    2) Many members here suggest just wiring in a manual switch and calling it a party. I am in instrumentation and controls tech I like like things automated and pushing an extra button to start the truck is going backwards, especially if someone else wants to use my truck.

    3) It seems to me in reading, that the newer bullet style glow plugs are self protected by resistance and cannot be overheated so there is never a melting issue.

    4) There are references to this IH p/n as a complete kit to retrofit to the bullet style GP's p/n 1809443C96, is this kit still available, if so, how much and is it the way to go?

    5) Is there a paint by numbers wiring schematic or comprehensive write up on the site here to convert to solid state? If there is I haven't been able to find it.

    6) If I do convert to solid state should I sell the Beru spade connector GP's I already bought and go with the resistance protected bullet style. I have read some guys going solid state and then leaving the spade style connectors and in place. I am confused about the 6 and 12 volt issue of the plugs, when you see the specs side by side they are almost identical in resistance value. So perhaps this whole resistance limiting self sensing I hear is not true.

    7) I would like to get this sorted this week and get a plan in place to fix this once and be done with it.

    8) Thanks in advance for your help and if you find a 10.5 Sterling Trac Loc in your closet you don't need drop me a line.

    8)
     
  2. franklin2

    franklin2 Full Access Member

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    The newer style glowplugs are not self-protecting, they can burn up just as easily as the older style. I am a manual button type of guy, so I won't comment on any of your other questions. You could be done and driving your truck if you would just give up and go with a manual button. Keep researching and spending money, and you will probably get it going after awhile. Sorry, I love my manual button.
     
  3. 91idi

    91idi Fiberglass Whore

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    Its easy to do. I even took the time to make the wts light work. When sisters borrow truck asking them to the count the seconds fir the plugs. Easy to say look at light
     
  4. 91idi

    91idi Fiberglass Whore

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  5. The Warden

    The Warden MiB Impersonator Supporting Member

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    IIRC there is a solid state controller that can straight-up replace the '84-'86 controller, and I thought someone had done a write-up on it, but I couldn't find it in the tech articles. I don't have any direct experience with either of those controllers, but IMHO you'd do better to switch to the solid-state system that was stock on '87+ trucks. This way, it's easier to find replacement parts out in the middle of nowhere as opposed to needing to replace an exotic part that you can only source in a few places.

    I agree with you there; a manual switch would make for an easier installation, but especially if others use your truck, you do not want a push-button system in there...way too high of a chance of someone who doesn't know your truck holding the button too long and killing your plugs. This is a big part of why I abandoned the push-button I put in.

    I don't believe that's true; certainly, the bullet-connector glow plugs can overheat and, if a low quality plug is used (i.e. Autolite, Champion, etc) is used, you can still end up with a swelled tip and the resulting removal problems. With that said, I believe the bullet-connector plugs have different resistance values than the spade-connector plugs, and therefore you shouldn't use the spade-connector plugs with an '87+ solid state controller,

    I don't know about a retrofit kit, but you can buy an '87+ wring harness from various sources...U-Haul's eBay site might still have some available. This would certainly be the easiest way to convert to the '87+ glow plug system; it'll take a bit of splicing to work with the '86 harness, but not much. I would recommend running a heavier-duty wire between the fender-mounted solenoid and the controller; the factory wires are known to be weak.

    There was a tech article, but it was written a while ago, and the URL doesn't currently work. I can give you this, though: 7.3l Glow Plug diagram (higher quality).jpg

    I would strongly recommend straying from this as little as possible...certainly, DO NOT mess with the wires between the controller and the glow plugs themselves. I learned this one the hard way...the solid-state controller works by measuring resistance in the glow plug circuits; IIRC the lower the resistance, the warmer the controller thinks the engine and glow plugs are and won't cycle them as long. I thought that bigger wires = better current and ran individual 8-gauge wires to each plug, and my controller only cycles on for about half a second. I need to just put stock wires in, but haven't had the time.

    All OEM plugs are 6 volt plugs; Ford's idea was to use 6 volt plugs with 12 volts applied to them to get them to warm up faster...this is also why the plugs are prone to overheating; 12 volt plugs in other cars (GM, Mercedes, VW, etc) can stay on far longer before getting too hot. With that said, IMHO you should only swap to 12 volt plugs if you go the manual push-button route. All of the controllers made for these trucks were designed with 6 volt plugs in mind; they'll never keep a 12 volt plug energized long enough to fully heat up.

    I hear that!! Getting your hands on an '87+ 7.3l solid-state controller, a wiring harness, and 8 Motorcraft/Beru bullet-connector plugs will be your best bet to get it all done with. The '87+ controller's meant to bolt to the back of the intake manifold; the mounting points SHOULD be there, although you should look and see how close it gets to your turbo...you don't want the controller to be so close to the turbo that it cooks the controller :shocked:

    Hope this helps some...welcome aboard, BTW ;Sweet
     
  6. TahoeTom

    TahoeTom Supporting Member Supporting Member

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    Agnem was trying the Diesel RX. Maybe he will give us a report. I bought one for my new, yet to be completed motor, so I can't comment yet. The instructions say it is solid state and diagnostic tests for the OEM unit wont apply. If it works as advertised it would be the best solution. I have push button currently. No problems as long as I am the driver.
     
  7. Wicked97

    Wicked97 Full Access Member

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    Converting to a solid state system is easy and is way way way over engineered on here. There is no need to buy a new harness or some other fancy stuff to make the 6.9 system work.

    Parts needed.
    solid state controller and beru glow plugs
    bullet connectors for the zd9 glow plugs
    2 lengths of wire to extend your glow plug harness. I think its 10 guage but I could be wrong.
    2 lengths of 4 guage wire with appropriate sized connectors for the solenoid on the solid state controller and your battery.
    1 high amp fuse or circuit breaker
    2 5/16 10 guage ring connectors
    1 5/16 14-16 guage ring connectors
    2 number 10 14-16 ring connectors
    2 10 guage non insulated butt connectors. Solder and heat shrink those.
    heat shrink tubing
    I recommend soldering all connectors but thats up to you.

    remove the pos controller int he back of the head and plug the hole.
    remove the glow plug solenoid on the fenderwell.
    locate the two larger red or orange wires that go from the solenoid to the engine harness connector. Cut them and discard as you will be bypassing that connector.
    Cut those wires on the other side of the plastic connector and tie up. They should be orange.
    locate the black wire with the purple stripe that comes off the old solenoid on the fender well. It will have a fusable link in it about 5 inches long so you have to follow it back past the link to find the colors. Tie that up out of the way. That is your wts light.
    mount the new solid state controller where the old one was. It has a seperate ground so dont worry about mounting it to plastic.
    Now that your controller is mounted extend those two orange wires and connect to the bottom terminal of the solid state controller where the wavy resistor meets the bottom circuit board. You should only have to extend them 6-8 inches but as long as you keep it under 12 it will not effect the controller operation.
    Find a key on power source and connect it to the small terminal with the red wire on the top of the new solenoid.
    Connect the black wire coming off the bottom of the new controller to a ground
    Connect fused power direct from the battery to the large terminal on top of the new solenoid.
    Find the black wire with purple stripe that you tied up earlier and connect it to the large terminal on top of the new solenoid where the wavy resistor is. This is your wts light.
    Replace your glow plugs with zd9s
    Cut the spade connectors off your harness and replace with bullet connectors for the new plugs.

    On mine I put a toggle switch on the keyed power for the solenoid so I can just shut off the glow plug system for hot starts or ether use. I have had my truck setup this way for a couple years with no issues or ether use down to -15f.

    Check the sizes of your terminals before you start im sure I have some of the sizes wrong.

    This obviously makes your system the same as a 7.3 turn the key on wait till the light goes out and start. If you want to make it a push button your on your own.

    If you have any questions PM me your phone number and ill call you.
     
  8. 91idi

    91idi Fiberglass Whore

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    I bought a new harness because for $75 i have new wiring and way less headache. No you don't "need" one but life is easier with one.
     
  9. Agnem

    Agnem Using the Force! Staff Member Supporting Member

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    Yup. I did run the Diesel RX one and it worked great. For a while. We've since installed a Delphi unit, and it's still going strong. The weird thing is that the Moose Truck still has it's factory glow plug controller (from 1983, and it's 30 years OLD!) and never a failed start, and I think only on the second set of glow plugs (the first set were replaced preventatively. Go figure. I sell the Delphi one now, and haven't had any come back in my 10 months of doing so. LOL
     
  10. wildman7798

    wildman7798 Full Access Member

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    First off I want to post a big Thanks to 91idi, The Warden, Wicked97 and the other guys that added to this. I was beginning to think (my lack of patience) that the group here was only interested in big swaps and burning waste oil and other cool stuff - you guys were equal to the task of being technical giants. My choice for right now is to just add the manual switch and use the new spade Beru's I purchased. I'll get the truck on the road and then hunt down a good used harness and eventually move it over to the 87 and up Solid State design, as everyone has said it is so easy it doesn't make sense not to do it. I will be looking for a good harness so anyone out there shoot me a pm or email. Really, Really happy to be on board here. Thanks again guys. Wildman
     

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