glow plug controller bad?

[chumwon]

Hello everyone! Well it's finally getting cold in my neck of the woods in michigan an have been pumped to see how my 8 new zd9s work since I put them in a couple months ago and... just my luck I get wait to start light for a second or two then I hear the controller clicking away an started terrible. My question is there anyway to test just the controller for the plugs? Thanks again everyone the 92 dually appreciates it!

 

[OLDBULL8]

Since you replaced the glow plugs they should be fine. Your problem with only a short GP cycle is probably the GP relay it self, just replace it. Make sure it's a GP relay, parts stores will try to sell you a starter relay, they look the same. Contacts in your GP relay are probably burnt and not passing enough current to the GP's. Also make sure the wire connection on the Z strip is tight and not corroded.

http://www.oreillyauto.com/site/c/d...plug+relay_5006502_-1&keyword=glow+plug+relay

 

[IDIoit]

to add what Bill has said, also check your wiring to the glow plugs, ive seen these wires riddled with butt connectors and *****'d connections to the GP's themselves

 

[chumwon]

Alrighty I'll try to expose some of the glow plug wires an double check them and I'll also go see if my parts store has a gp relay an how bad they wanna rake me across the coals for that one. Thanks gentlemen!!

 

[chumwon]

Actually just seen oldbulls link to orileys that for under 20 bones the ole girl might just have to get a new relay then!! Thanks again

 

[KZF250]

Needing a new relay might explain why mine clicks, but sometimes the WTS light does not come on, and judging by the no start...juice is not getting thru. When it clicks and the light comes on she fires right up. I have it on a manual switch.

 

[Agnem]

I've explained countless times how to test your glow plug relay, but people still want to go out and buy a new one not knowing if that is really the problem. I don't understand people. So... one more time....

Put a volt meter across the large lugs on the relay. It should show current battery voltage. No more, no less. Activate the glow plugs. If the relay won't stay closed long enough to do this test, actuate it manually, but keep in mind your glow plugs will be glowing. With the relay actuated, the volt reading should be zero or less than .1 volt. If it isn't, then it's not conducting well and should be replaced.

Keep in mind the cheap Chinese relay you buy may not be as good as the one you have from Ford. If it is not a disc type relay, you are going down a bad road and will be replacing that thing forever. They all look the same, but the insides are different, as is the quality. You want silver contacts. Not brass. And there isn't a parts counter guy in the world that is going to know what is in there.

 

[chumwon]

Well the relay wasn't the issue unfortunately I'll look over the wiring a little more just hard to get at the wires in the wire loom. Hoping it isn't the module/controller but I'll do some more digging first

 

[franklin2]

Try this; Unplug and plug back in each glowplug. Then see if the controller glows them longer. Bad connections will make the controller short cycle like it's doing.

 

[icanfixall]

Well so far everyone has not mentioned the actual main engine wire harness plug. The controller gets the power from the 2 yellow wires at the end of this retangle plug. you can't miss them. They are connected in one ring terminal to the fender mount solenoid too. That plug pins just can't handle the amps to fire the controller when they get dirty. that plug will melt as did many others. some actually had a fire under the hood that destroyed their rigs. When you open the plug and find melting or it falls apart no worries. You can see the wire colors easily. Just make them solid and be done with it. No need to open the harness either. Just cut close to the end of the harness wrap. then run new wire like i did. I used 6 gauge speaker wire found in any stereo shop that installs big amps and speakers in cars and trucks. PS>>> Get the lugs to fit the wire too. Now my controller is fed thru a huge wire that will never break down.

 

[BrianX128]

So I think I may be having the issue you just described the fix for. I have 8 new plugs and wired them to a manual push button in the cab. Yesterday I went out to start the truck and when I pushed my button my wait to start light came on like normal and yet I noticed my voltage gauge didn't move. I pushed it again and heard my relay click and my voltage gauge dipped like normal and it fired off perfectly. Today, I had to push the button a good 10 times to see the voltage gauge dip down and hear my relay click and know they were actually glowing.

I'm gonna clean all the contacts on the glow plug relay and see if my connectors look like there's bad contacts. I'm thinking it's probably something more along the lines of that, because once the relay clicks down when I push my push button to start it I tried pressing it a bunch real fast to make sure it wasn't my switch or something but it would click super fast every time like once the wires got a current going through them once that they were making good contact then.

At least I figure this is a good place for me to start. I know all the glow plugs and my manual wiring for the system are good and I know my signal from my push button is too since my wts light is coming on. Just gotta find the suspect wires I suppose.

Everything had been working perfectly with the push button and new glow plugs and whatnot for months and months so I know it's gonna be that one corroded wire that started acting up a day ago. The hunt begins. And also to make a liar out of me I just went outside and it fired the relay and the plugs 5 times consecutively for a couple of seconds as a test of my sanity. Fun.

 

[chumwon]

I do aswell think it's the wiring. May just strip the harness an try to run some fresh wiring. Haven't thought about a manual push button but that may be a possibility just to know for sure it's getting power to them

 

[franklin2]

So I think I may be having the issue you just described the fix for. I have 8 new plugs and wired them to a manual push button in the cab. Yesterday I went out to start the truck and when I pushed my button my wait to start light came on like normal and yet I noticed my voltage gauge didn't move. I pushed it again and heard my relay click and my voltage gauge dipped like normal and it fired off perfectly. Today, I had to push the button a good 10 times to see the voltage gauge dip down and hear my relay click and know they were actually glowing.

I'm gonna clean all the contacts on the glow plug relay and see if my connectors look like there's bad contacts. I'm thinking it's probably something more along the lines of that, because once the relay clicks down when I push my push button to start it I tried pressing it a bunch real fast to make sure it wasn't my switch or something but it would click super fast every time like once the wires got a current going through them once that they were making good contact then.

At least I figure this is a good place for me to start. I know all the glow plugs and my manual wiring for the system are good and I know my signal from my push button is too since my wts light is coming on. Just gotta find the suspect wires I suppose.

Everything had been working perfectly with the push button and new glow plugs and whatnot for months and months so I know it's gonna be that one corroded wire that started acting up a day ago. The hunt begins. And also to make a liar out of me I just went outside and it fired the relay and the plugs 5 times consecutively for a couple of seconds as a test of my sanity. Fun.

Since it works when it clicks, then I would think the relay is good, and your wiring to and from the relay with your manual switch may be suspect. The relay is supplied 12v from the keyswitch on one side, and your switch grounds the other side to make it click. You may want to wiggle the keyswitch and see if that makes any difference. You also want to make sure your manual switch is a decent sized switch. That relay coil is going to have a kickback voltage when you let up on the switch, which will arc at the switch contacts. If you have a dinky switch, it's not going to last long trying to handle that high voltage kickback.

P.S. Since the relay was originally controlled by the electronics of the controller, it probably has a diode somewhere to clamp down on the kickback. But I am not sure if it's built onto the relay or in the controller electronics.

 

[BrianX128]

Good point. Only thing I'm not sure about, is every time when I press my manual push button my wait to start light comes on whether the relay engages or not. So doesn't it get power from the keyswitch sending power to the glow plug relay as well? I guess my theory in my head was I had power to the relay and a bad contact was just not letting the plugs themselves cycle from the two big posts, but I should still hear the relay click if the way I was thinking was correct and just not have the plugs glow. Hmmmm.

It's worked two more times today without issue after cleaning the contacts on the gpr, so we'll see I suppose.

 

[typ4]

Its hardly ever the relay. And I don't think the 92 has the same harness connector problem.