I'm going to be replacing a few glow plugs sometime soon, and I was thinking that while I'm in there I could convert over to a manually operated system via some kind of switch or button in the cab (I've seen this in a few youtube videos and the like). I was wondering what it would take or if there are some serious reasons not to do this.

Thanks.

 

7.3L has a much better GP controller than the 6.9L in my opinion. If you are not having issues with it then replace the GPs and be done with it. I installed a push button years ago on my 6.9L because the controller would stay on and burn out all of my GPs.

 

agreed. if it ain't broke, don't "fix it"
put a set of motorcraft ZD-9 glow plugs in it and call it good.

 

I just went manual on my 7.3 with a momentary button because I have a fuel drain back issue and an electric pump. I dont wanna sit there with the plugs glowing for an unnecessary amount of time not to mention you do not always need to heat them up.

 

a properly working glow plug system shuts off once the engine hits around 110 degrees with the 87 and newer solid state controller.

 

and IF you use the wrong Plugs with them the PTC value will be incorrect and you will fry plugs right and left.

there is nothing wrong with a Manual GP system other than using Cheap Parts and the Loose nut behind the wheel.

The Thermistor that senses the Glow Plug Controller Temperature is Located about center of the PCB of the controller itself so you cannot Relocate the controller to a Cooler area as this will cause premature Plug Failure if you do.... current sensing is done by reading Voltage across the Shunt.... the Buss Bar looking thing and using wrong Plugs will change the Current readings and the controller will fail and destroy Plugs.

IF you want to keep the Controller always use the proper Plugs.... IF you go a Manual System then use 12 Volt Plugs. and not the 6 volt Fast Glow plugs.

TJC is correct... IF it ain't broke then don't fix it, I have repaired many of these controllers and 90% of the time the failure is the drive transistors for the Relay because the Relay does not have a Flyback/Freewheeling Diode.(aka the internal Flyback has failed)


I guess I should mention here that folks that use Cheap Push buttons run the risk of that switch contacts sticking and keeping the relay Closed and consequently frying the Glow Plugs a good quality Spring loaded Toggle with a Switch guard is a much better option. IMHO and always put a Freewheeling diode across the Relay to prevent Inductive kickback that can fry the points of the switch.

I've seen many Glow Plugs costing 100 bux a set be fried by a Cheap @ZZ horn button that sticks

 

Interesting. My controller and relay were already moved to the driver fender shroud due to the aftermarket turbo install. Easy to switch back to auto control if I can solve the fuel drain back. I am using MC plugs. It had 2 or 3 bad plugs in it when I got it and at least 2 plugs were not MC but they all came out fine.

 

I've had Autolite 12V plugs installed since 2010 and I pull them every couple years to inspect them and I have no deformation of the electrodes ... I use a Manual Glow system and never use more than a 3 second count for a Quick Start. OF course I'm in the south Texas area.so I don't have the Freezing weather like others do in the North.... the only time I need Glow is in the morning, unless during in our Coff Coff winter months where it might be required a bit more often.

contrary to what folks say I have even seen MC plugs Blister, they do that when they get over heated.

putting the Controller on the fender changes the Temps that the controller can detect... have you ever disassembled a controller and figured out how it actually works ?
I have. I'm not saying that Moving it will cause Instant Disaster but it does remove Design Safety.

Drain Back should be a Non Issue ..... unless you have Air leaks... what year vehicle are you speaking of that has Drain Back issues ? couple check valves can solve all your drain back issues IF you really have them.

 

This is my first diesel so I had no real understanding of GPS or starting a diesel. It came with a elec fuel pump under the hood and a host of fuel leaks on the return circuit in addition to wiring fukery mainly from the reloaction of the GP system. Motor is dry now after replacing GPS, injectors, and return system. The PO put a toggle on the pump so it appears he was priming the system or using it to clear any bad fuel. I could immediately see air in the system. I have not checked recently after all of my work but starting remains hard and it appears that pump is working hard at every start. I want to avoid long cranking for obvious reasons. It is time I check compression. Motor sounds great once started so I never felt compression was a problem. I have fresh fuel in the tank and additives but I suspect there was some older fuel in the tank as well but that should be long burnt by now. GP system worked great once I replaced all of the plugs. I just do not want long cranking sessions to burn out the plugs or do other damage.

 

when my banks turbo was installed, the glow plug controller was moved forward over the passenger side valve cover/intake area about middle of the engine to clear the turbo.
it still works as intended after 495,000 miles.
if you still have start issues after e-fuel, check to see if the pump is even working. the cheap electric pumps do not last very long with diesel.
the facet duralift in my 88 has been on it for over 300,000 miles.

 

yeah that Location still gives enough heat for the Thermistor in the Controller to work


I'm not trying to say you cannot mount the controller on a fender well... you can mount it any place you want, I'm just saying the reason it was mounted on the engine is to detect engine Temperature.

here is one I have repaired in the past.... the Thermistor is circled in Red......

 

I recently replaced the glow plug controller and plugs in my 89 7.3. I did however change how they are triggered. The ignition and a rocker switch has to be on for them to work like normal. Any time I need to spin it over for whatever (bleeding lines/other work), I can keep them from unnecessarily heating up and drawing a ton of amps. Keep it on and it starts like a new truck.

 

My 1991 had off and on air leaks to injectors causing hard starts for years. Changing injector return lines and sleeves several times over the years helped when it got really bad but never completely fixed. Was always worse in winter or when truck sat several weeks. On day I had the electrical connector to fuel heater in top of fuel filter housing off and saw diesel down inside it. Figure if fuel could leak up air could also leak in at the filter. Replaced the expensive little heater that is in the top of the housing the filter screws onto and issue was fixed after years of cussing. I would try to get the hard starting problem tracked down before messing with the glow plug controller if it is working ok. Don't do what I did once messing around with the wiring and activate the glow plugs with half of them disconnected, it melted down the harness. You tube has got me in big trouble a few times trying stuff on it, use a lot of caution!

 

I fixed the leaking fuel heater with a bolt and blob of jb weld about 20 years ago.