[arthurgoboom]

My truck for some reason always needed 1.5 or 2 full glow plug cycles from the stock controller in order to get the plugs hot enough to start, even on an 80 degree day. This winter it became almost impossible to start, and then I finally had to crank on it forever with the battery charger on boost and block heater plugged in to get it to start. Here are a couple things I learned in the process of getting it back to a normally-starting engine.

1. Do NOT try to start your engine while the battery charger is on. I learned too late that the high voltage can burn out glow plugs (mine puts out about 16 volts when connected to the leads of a voltmeter). Charge the batteries, then turn the charger off before a start attempt.

2. As part of your service, clean ALL of the connections in the glow plug system as well as all of the battery cable connections. This includes the connectors on the plugs themselves, the 8-pin junction plug that comes from the engine to the passenger fender, both posts on the glow plug relay, and the wire that comes from the battery that feeds the GPR. Scrape out crud inside the connectors, spray out with cleaner, blow dry. Wire brush the eyelet connectors on the GPR, as well as the bottom of the hold-down nuts. I even went so far as to use dielectric compound on all of the connections to avoid any future corrosion. My thought is that even though the circuit showed no appreciable resistance on the ohmmeter, they didn't have a large path when the GPs tried to pull high amperage down them, much like using too small of a cable to power the starter.

After doing this service and changing the glow plugs (since I had 4 of them burned out, presumably from the battery charger usage) it will start with a single cycle of glow plugs at 40 degrees F which is performance better than I've ever had before. Just goes to show that attention to detail pays off.

 

[Chevyboy_0]

I think I'm gonna have to try this on my 87, it's been sitting for a while and who knows what the previous owners have done, I plan on getting new GPs any way... Is there a prefered GP that people would recommend? Or ones I should stay away from?

 

[WhiteGardens]

In 87 they changed to the solid state system. In 87 a few trucks rolled out with the 6.9, and the rest the 7.3. Check behind your air cleaner, the solid state controller is a square object that has a few wires running in and out of it.

If that's the case with your truck then you'll need the motorcraft ZD-9

Pre-87 calls for the ZD-1 I do believe.

 

[01txdmax]

dielectric grease is one of the miracles of modern technology IMHO. It'll keep all connectors everywhere from getting corroded, I have applied it to every connector I have disconnected and no issues to date.

 

[Chevyboy_0]

What's the difference between the solid state and the other controller?

 

[WhiteGardens]

The old 6.9 controller is mounted in the block and measures the temp of the block and controls the glow-plugs. The controller has been an issue for many guys as it sticks open, over-heats the glow plugs, and gives you the swollen/broken glow-plug syndrome.

The solid state controller, measures the resistance in the glow plugs rather than temperature. As the glow-plug heats up, the resistance goes up, and at a certain point it shuts off.

I think I got it right.


Thanks for the info Arthur, I've been wanting to use some di-electric grease on my gp circuit, and other electrical connections. Good to know that the TLC goes a long way.

 

[Chevyboy_0]

Thanks, so it's a lil box thing that is mounted behind the throttle body right? If my truck has the solid state?

 

[arthurgoboom]

For the older 6.9 system, the proper glow plugs are Motorcraft (made by Beru) ZD-1A. I just installed the Wellman replacement for these, supposed to heat faster and self-regulate, we'll see. Wellman #G088.

Like Whitegardens said, for the solid state 7.3 type controller, Motorcraft ZD-9.

Definitely stay away from Autolite, Champion, and Bosch glowplugs.

 

[Chevyboy_0]

Alright thanks for the help and tips

 

[curinb]

Definitely stay away from Autolite, Champion, and Bosch glowplugs.

Did something go wrong with bosch in the last couple years? mine have been fine. I won't buy ford parts for an international engine. They don't put out any better than bosch but are more expensive. and i have had enough wrong parts come from the dealership to order from a company that knows the engines. but seriously if something happened to boshes quatliy i want to know before the one i put in there informs me it'self. The glow plugs shuoldn't be run more then ten seconds and thats pushing it. if the first cycle doesn't work give it a minute or two to cool the glow plugs which in turn heats the cylinder. If you know it won't start the first time run the glow plugs wait a minute or two and do it again and then try to start (remember the cycle cuts on and off the long one for the initial heat the short ones for turning over the engine. if you wait for the cycle to fully complete you are wasting power). another problem could be the starter. diesel as we knwo relies on sudden compression to create heat which in turn creates ignition. the glow plugs suplement the heat but if it doesn't turn over fast enough and if it won't start without them on an 80 degree day it's not your plugs. No speed= no heat. no heat = hard ignition. you shouldn't need the plugs on a nice warm day. imma go get me some dielectric stuff it sounds too awesome to not have! good luck with it all.

 

[cdnsarguy]

ZD1A Beru are for the 6.9 old style controller, not sure what the IH/Navistar number is for them.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
7.3 and later 87 6.9 with solid state controller use ZD9..........

Beru GPs are just packaged in the Ford plastic bag that is why we quote Beru/Motorcraft (Beru # ZD-9..... Ford part # F2TZ-12A342-A).

If you want you can go to IH/Navistar and get the Beru with a International number stamped on them...... IH 1819649C1

 

[Digitalis]

I replaced autolites with Bosch plugs about a year ago and they lasted 4 months... Wellmans have been great since then.