Hey guys. I've never posted on here much - I am usually in the OBS Powerstroke forum. My wife's dad has a 1993 7.3 IDI non-turbo and has been having some glow plug issues. I've been researching a lot on here, and have read the sticky, so I've got some ideas on where to start. But I didn't see anywhere where the sticky thread mentioned the voltage of the system. The Napa guy told my wife's dad that the system was a 6 volt system, which made it seem that the GP controller was actually converting the 12v from the battery to 6v. But from what I have read, the controller does not such thing. I've read that the GPs themselves are 6v and they put them in there with 12v power so they would heat up faster. I've also read that they are 9v plugs...same deal - more voltage supplied heats them up faster. So which is it?

He's also interested in bypassing all the OEM GP equipment and putting in a button (he's truly the only one that drives that truck). Are there absolute no-no's in doing this?

Generally, any help or advice is appreciated. I don't know his exact symptoms right now, other than that the WTS light has quit working to some degree. I'm not sure if that means it doesn't come on, or it comes one for a split second, or what. I'll get back after I have a chance to check it for the things I read in the sticky thread. Thanks!

 

The glow plugs them self are 6V, but it's a 12V system, this is done so the glow plugs glow red very quickly.

 

Good to know! So is it bad to bypass the relay and controller and put them on a push-button? I understand that this can create a problem if someone else uses the truck, but I can't foresee anyone else ever driving this truck.

 

I have manual plugs on my '85 (though it's not the same system as the 7.3) and I love it, no one drives my van but me however.



When you do the manual switch mod, you don't really by pass the controller, you just unhook a wire so the truck can't control them with the ignition switch.

 

there is no benefit in doing so on the 1987-1994 gp system.unless of course the controller fails,and you would rather save the $ then going push button would be ok.if it's working as it should,it's really a nice but basic system.
i wouldn't jump to conclusions and assume the controller went bad without testing anything.odds are,she just needs a set of new motorcraft/beru gp's and be good for several more years.as you plan,test the system and diagnose first,but bypassing the controller wouldn't be anything desirable if not needed (unlike the pre-87 system,as when that faulty system failed,it would often do so in the ON position and burn out the gp's.)

 

I just replaced the controller on my 91 van as it had failed, some times the controller fails in the on position and the glows won't shut off, however the system has several operation's and in most cases it fails in the default to 3 seconds of glow and off. so you have to turn the key on and of every 4 seconds or so to heat the glows to get her to start. this is what mine did. the controller I got was from O'Reilly's # GPR8 $97 direct replacement with relay, ready to install..I already have new glow plugs buru's zd9's (got at O'Reilly's) this is a heavy duty glow plug, made to work with late modle controller that senses the temp of the glows by monitoring the feedback (change in resistance of the plug when hot) to control or reduce over glow, (poping plugs,or burning out) on hot starts. she starts right up now.

 

BTW, my WTS light would only blink when key was turned, even with new glows.

 

Im with your father-in-law... not a big fan of the push button. Like F250 said, most likely a few burnt out plugs. Let us know what you find out.

 

Thanks for all the info guys. I told him we need to ohm the plugs before we do anything to see if one is bad, since I've read that one bad plug can mess up the entire system. But, he put brand new plugs in last year...the problem - they were Autolites. I know they are no-no's for my truck, and apparently they are known for being poor plugs for every year. I told him that it's likely that one could have gone out soon after putting them in, knowing their reputation.

Where is the place with the best price on the Motorcraft/Beru's? I think he's convinced to go ahead and buy a set to reduce the chances of future problems. I get mine from Riffraff Diesel, but they don't sell stuff for IDIs.

 

O'Riellys carries motorcraft, you can also get them at Ford or IH or order them from the internets.

 

Thanks. You don't happen to have a part number for them do you? I want to make sure we get the right ones for the system.

 

Are the Motorcraft ZD9's the correct ones?

 

Also check Rockauto.com if you can wait a few days. Cheaper price on the Motorcraft glow plugs then my local parts store $9.78 each plus shipping. I believe the ZD9 is correct.

 

ZD1 is for the early 6.9 (83-86), ZD9 is for the idi 7.3 (87-94), and ZD11 is for the 7.3 powerstroke.

 

Thanks. I found them on Rockauto.com, like was said, for $9.78 each. Shipping was less than $3 calculated for my area, so the total was a little over $81.00. That was the best I've found so far. I appreciate the help guys. If we end up testing some things out and running into something funky, I'll definitely be back on here.