'93 6.5 Glow Plug light blinks at end with clicking noise

[trbankii]

This was posted in another thread, but I think it is different enough that I'd start its own thread.

I've read through the books of past articles and searched the forums for some information on the glow plug controller just to come up to speed on this "new to me" '93 I bought.

I turn the key to get the glow plug light, wait for it to go out, at the end of its cycle the light pulses accompanied by a "clicking" noise half a dozen to a dozen times in rapid succession and then stops and the light goes out. Turn the key the rest of the way and it starts right up.

Basically, I turn the key, light goes on. Wait for light to go off. As it goes off, light pulses and click-click-click-click... fast for about five to ten seconds. I can either wait for the clicking to stop and then turn the key the rest of the way or turn the key while it's clicking. Either way it fires right up. Of course it is currently in the 80s and 90s around here. If I don't wait for the clicking to stop it keeps clicking while it cranks and starts.

I've had it for two weeks now and have not had too much time to play around with it yet. I'm not driving it as it needs a few things before I can get it to pass inspection. Previous owner made a complete rat's nest out of the taillight wiring in trying to hook up a trailer plug - reverse lights and passenger side turn signal don't work. Also need to check out the driver's side front for some possible CV work.

Anyhow, it has been suggested that I check the batteries, glow plug controller, and glow plugs for the "clicking issue." Chances are that they are the original plugs (what, 9Gs?) and could stand to be upgraded to 60Gs (Kennedy Quick-Heats?). Any ideas on what I should be looking for when I open up the glow controller? While I'm in there, a new fuel filter is probably a good idea. I'd also like to get an EGT and boost gauge on it so that I can see those numbers.

Other than that, the engine seems to run well. To check for cracks, do I pull the oil pan and valve covers? Or is it that you have to pull the heads? The plan is to go over everything and make sure that it is all running at "base" level ok before I start into modifications.

[john8662]

The clicking that the glow plug controller is making after the initial glow isn't normal. The usual cycle is about 8 seconds for the first glow, then up to 4 after glow cycles that are about 2 seconds in length. If the controller is "chattering" after the first glow or at the end of the first glow, then it's likely the relay in the controller isn't holding contact. Do the obvious to narrow out electrical problems with a low voltage/amerage situation. Check the battery connections, check the connection on the controller itself, and grounds to the engine and to the body.

For a replacement controller you have many options, the dealer for an AC/Delco, or some aftermarket brand controllers from discount auto parts stores like Autozone. I haven't heard of any failures of aftermarket controllers that were tied to any one brand of controller. Luckily, you have the simple glow controller, the same one used on 85+ 6.2's on to the 93 6.5TD.

For replacement plugs, you can get the KD plugs or replace with the current AC60G plugs. You are right in that your truck probably has 9G plugs in it, which when they fail will swell at the tips and be difficult to remove. They can also break during removal, which will lead you to remove the injector in that cylinder to retrieve the broken glow tip. The 60G plugs won't swell when they fail, and rarely do they fail, they can take long glow times w/o failing because they are self-regulating.

Cracking... There are two main places that you could be concerned with when it comes to cracking. One, is the cylinder heads themselves, they tend to crack between the valves. The cracking between the valves is common in these engines, and rarely does it led to coolant consumption. The only way to check for these is to remove the heads, not worth the time if the engine is running good.

The other type of cracking concerns the main webbing for the main crankshaft bearings. This type of cracking is also commong, but is usually the end of the road for an engine. The cracks form on the outside bolt holes on a 4 bolt main. The cracks start and continue upward, some blocks crack and some don't, there really isn't a rhyme or reason to it. Again, if the engine is running fine, leave it alone. The only way to check for this is by removing the oil pan for an inspection, which is a lot of work. Finding and looking for cracks is usually something that we pay close attention to while considering a block to start an engine build from.

[trbankii]

Thanks for the reply, John. Have to clear out an afternoon to spend some time with my truck and go over things.

As far as checking for cracks, I'd sort of like to know where I stand with this truck before I start moving ahead with it. This is definitely a "project truck." Although it seems to be running fairly well, it was bought as a starting point and the engine will be pulled and rebuilt. Right now, I'd at least like to get everything running properly so I can get a baseline on it before tearing into it.

[cruzer]

trbankii, What you descibe sounds pretty normal.
I usually start the truck after the intial long wait then start imediately after the light goes out. I've never actually counted the # of times the light flashes after it's started, so I don't know how many flashes is too many. I have had the key on w/o starting and I do know the clicking coincides with the light and it is the controller making the normal noise.

60G glow plugs take longer to get hot. Mine would start and chug a little at start up, then would clear up, so I added a resistor to lengthen glow time. At that time, my timing was retarded, which helped cause this symptom too. You can do a "search" if you buy 60g's and have this problem.
FYI

Ken

[trbankii]

Definitely more of the "chattering" that John mentioned - quick pulsing. I understand the on-off cycles after the initial glow, but there is no way that it is anywhere close to a full two seconds per cycle. I'm sort of thinking that "normal" cycling would be more like a turn signal? Like a steady on-off cycle, I mean.

What I have, the light never fully blinks off, just sort of pulses with the "chattering" noise.

After twelve years and 131K miles, I'm sure that the glow plugs could stand to be replaced no matter what.

[Turbo Al]

The original glow plugs in mine were 9's and some were hard to get out (swollen) @ 100,000 and one had been cross threaded.
Al

[trbankii]

Have been busy with other things, so haven't had much time to "play" with the project truck. Got back to it the other evening, though.

Pulled the glow plug controller and found that the PO had RTV'ed the case back onto the mounting plate. Obviously had been into it, so I'd guess this was an ongoing problem of some sort. Cleaned things up and tried it again. Same response - glow light comes on for a period, then when it goes off it goes into a clicking (or ratcheting might be more apt) mode. Light blinks and the solenoid is clicking back and forth fairly quickly. Also, now the speedometer needle rises to about 35 mph... So it is obviously feeding back somehow. Bad ground? Fried controller? Have to get out the voltmeter and check the controller out as detailed in the Features and Articles Book.

[redbird2]

All the new controlers I have ever installed have RTV sealing the plastic part to the base mounting plate, I checked the new ones senting on my service truck they have that sealer also.
As for you clicking noise you need to check the ground wires escially the one that ground the cab to the block and the one on that back intake stud on drivers side rear take all them apart and clean them and you most likely fix your problem. Good Luck

[trbankii]

Thanks, RedBird. I'll take a look at the grounds and get them cleaned up. The RTV was pretty sloppy. Didn't look factory, so I assumed that it was the PO's work.

[BobND]

First, check to be sure all glow plugs are drawing current. (If some are burned out, the controller can get "flaky".)

Check all grounds and battery connections. If this does not help, it's time for a new controller, as chattering like that is one of their "failure modes".