Glow Controller Question?

[painthorsman]

My glow controller seems to have a problem that I havent been able to figure out ... maybe someone can help? Its a late model(grey) controller. Terminal locations are as follows on modular connector
A: Not Used
B: Power in Start Position
C: Power in Run Position
D: Ground
The big lugs are connected to the main glow plug cables and the other to Batt +. All conntections are clean and tight!
Problem... Turn key on and controller will fire ONE time for 4-6 seconds or so, then turns off and glow indicator light goes out. Will not cycle again at all after that, no matter how long I wait with the key off, unless I go under the hood, pull the modular plug-in off and plug it back up.... then the same scenario all over again... turn key to run, glow indicator light lights up, relay in controller clicks and turns glow plugs on... for about 6 seconds... and then goes off.
Anyone got any ideas? Controller is about a year old and worked before I rebuilt the motor and put new AC11G's in it... Any and all answers appreciated.

[Chevy4X4Van]

I dont think you have a probem at all!!!
The afterglow sequense is only activated when you cranck the engine.
The C pin on the controller must have a signal from the starter, to start the afterglow cycle.

Trond L.
Norway

[StorminN]

Just a shot in the dark, but have you verified that the grounding straps to the motor were properly reinstalled after the rebuild?

-N.

[stich54]

Check the grounds. Sometimes GM hides them in weird places like up front behind the power steering pump just look for all the black wires and wiggle them. we had the problem you have for years untill I got fed up wasting money that never fixed the issue untill I found a person who cared long enought to find the issue and he didn't charge me a dime just a thank you

[painthorsman]

Yep ! there was definatly a problem...apparantly the controllers internal timers are not functioning like its supposed to. The relay kicks in and turns the glow plugs ON... but the internal timer must not be working as the plugs STAY ON till the circuit breaker kicks them out(about 15-18 sec.) There are NO afterglow cycles after the engine starts when its cold. I found this out the hard way!!! The glow plugs stayed on too long and as a result, I burned up a Brand New set of 11G's, in a short time! Swelled them so bad, I had to take the injectors out and bust the glow plug elements off and pull the tips out the injector holes... Beats taking a head off a "new motor"...Thanks goes to Britannic for that trick!!!
(I'm using the late 80's to early 90's "all in one" controller)
I bought a new controller and a new set of 60G plugs today...to the tune of about $90 for the controller and about$100 for the glow plugs.... got tired of Mickey Mouse'n around.

[dieselmab]

Painthorseman,
What did you have to do to convert your glow system to the late model glow controller "all in one"?

I have an '84 K20 6.2 with glow system problems. Since your's is a '79 you probably don't have an ECM to contend with.

[painthorsman]

Hi,
With an 84 model you shouldnt have an ECM either, unless it came from California originally. Anyhow, you need a controller... I was encouraged to use an GM/AC Delco one but when I called for a price, they kinda "bent me over" so to speak ( GM and the word Diesel are synonymous with HIGH PRICE in the parts dept.) so, I went with NAPA / ECHLIN part number AR145, which turned out to have the same sticker and mfg etc as the AC DELCO one did... for less money!
You will also need a harness for the controller and the water outlet block off plate and studs for a late model 85 to 93 6.2D. The only place I know to get them from is either a GM dealer or try the boneyard... A good place to try is Avant Salvage (The Diesel Depot) at 800-553-8192 and talk to Benny. He can probably hook you up with those parts.
It takes the place of your current controller and relay that is located at the rear of the left cyl bank. I hope this link works for you...
http://www.thedieselpage.com/members/8593glow.htm

[rhill2901]

Converting from the pre-84 style glow plug controller to the newer style is quite easy. I purchased my post-84 style controller from autozone for less than $55 five years ago. I purchased the connector harness from the dealer for around $25. I didn't bother with removing the old glow plug controller, just left it there. In the five years of running this configuration, the only problems with glow plug operation I had was the occassional burnt glowplug. I cut the wires to the old controller and wired like this:

pin 1 of old controller to pin B of new controller (engine cranking input from alt).

pin 2 of old controller no connection.

pin 3 of old controller to pin D of new controller (key switch in start/run position). The two wire plug on the old style relay on the fender will need to be cut and the two wires twisted together.

pin 4 of old controller to pin C of new controller (glow plug voltage sense).

pin 5 and 6 of old controller are connected to each other to ground, this ground can be wired to the new controller pin E.

To identify pins if you do not have a ohmmeter, flip the round connector over from the old style glow plug controller and place the notch up. The pin opposite the notch is pin 1. If you look for pin 5 and 6 you will see a jumper between the two. This is another way to identify pins. The newer style all-in-one controller pins are labeled, so its fairly straightforwarded.

I put my new styled controller in the same location as my old relay that was mounted in the fender. The wires were long enough to run to the wiring on the old style controller and I used the existing wiring from the battery to the old relay to connect to one side of the newer styled relay and the other side of the relay goes to the glow plugs.

[dieselmab]

Thanks, guys. I just realized the previous owner has the newer controller rigged in.
BUT he did not wire it to the old controller harness and just ran his own wires to a homemade toggle switch in the dash.
If I get the harness and rewire the controller correctly the glow plugs should work off the key switch again.

[Chad 2001]

Sorry to bring up this old thread. I have a 1982 that I just changed the controller to the later version. I wired it as to Rhill's description and the plugs light up as they should. After starting the after glow sequence does not shut off. I let it idle long enough that it should have shut off. I shut off the after glow by unpluging the wires. I pluged the wires back in and the after glow continued.

What could I have done wrong? How do I check out the problem and correct it?

Thanks for any help you can give me.

Lyle

[painthorsman]

No Problem! Here's how it's supposed to be wired on the 85 to 93 modular controller
Terminal A: NOT USED

Terminal B: Power in Start Position, splice/tie into purple wire in bulkhead to starter harness... large wire.

Terminal C: Power When Glow Plugs are On. Splice/Tie into orange glow plug harness... you may want to use the inhibit switch on the top rear of the passenger side head to prevent plug operation on start up when engine is warm.You may bypass switch if needed.

Terminal D: Power in Run Position... splice/tie into large pink wire from bulkhead harness to injection pump

Terminal E: GROUND... important to have a good ground.

Large Lug Terminals:When viewing with lugs facing you...
Left Lug: Glow Plug Harness, left and right glow plug circuit feed wires (orange)
Right Lug: Battery. Important, use 10 gauge or larger wire and hook directly to battery + term or batt term on solonoid...high current draw of 60 amps or more! I used 8 gauge here

If all connections are in the locations shown and are clean and tight (my version of clean and tight is soldered with heat shrink tubing over joint), your engine to batt/frame/body grounds are good and the controller still does not function correctly, I would replace the controller.
Pretend that the original 1982 controller's wiring doesnt even exist and start over with new wires with your late model controller.
Here is an old DP troubleshooting link with photos that might help
http://www.thedieselpage.com/members/8593glow.htm

[Chad 2001]

Thanks painthorsman, I will check the wiring and make sure I have it correct.

Thanks a lot for your help.

Lyle

[dieselmab]

Through alot of trial and error I've learned a couple of things. I had the same problem as you Chad when I first modified my '84 to the '85 system.
As Paint said:
Pin A No connection
Pin B Cranking Sense (don't use the alternator connection) from the starter. purple wire in main firewall harness
Pin C Glow plug voltage sense, wired in parallel with the glow plugs. (green wire)
Pin D Ignition voltage in, 12V in "run" position
Pin E Ground

Good luck

[dieselmab]

One other thing, I've noticed the fusible links in the large orange glow plug feeder wires are not making good connection sometimes and mimicking contoller symptoms. HTH