Glow Plugs

[canxj]

Hi all, need some advice on a glow plug issue. I am resurrecting a 94 Blazer with the 6.5...I am a former 6.2/6.5 owner (and TDP member) back about a decade ago. Guess you could say I got the itch again. The blazer was my dads...he got tired of changing PMDs so he got into a 12V Cummins and never looked back. The blazer has been sitting with minimal use for the last 5-6 years. Its not going to be a daily driver but more of a backup rig, occasional camping rig and for towing my small aluminum boat.

I'm battling a hard start issue the last few days. The truck has AC60g's that were replaced maybe 4 years ago. Although they don't have many miles on them they are very rusty. In fact I started poking around on the drivers side spade connectors and one of them broke right off. Spade rusted right off and stuck in the terminal connector. Tried looseing a few of the others on the drivers side and the spades all feel "soft" and like they will just break off. I don't want to get into a situation where I break them all and then can't start this sucker.

Right now I know for sure I'm down one plug on the drivers side with at least 2 other suspect spade connections; plus the #8 on the passenger side has never been replaced, so its probably the original AC9g.

Any advice on what to do next?

If I cut the connectors off can I just use standard spade connectors and crimp on to the glow plug terminal wiring (with heat shrink tubing)?

I'm going to get a new set of bosch duratherms, they are half the price of the AC60g's.

I'm sure getting the old ones out will be a challenge...maybe I should just stick to the block heater and oil pan heater to get me through the winter!!!

[BrIONwoshMunky]

If you aren't in a hurry, I'd spray them down with a penetrating oil, ATF, or other lightweight oil, a few times a week for a while. We do this regularly on 60+ year old tractor parts with great results.

I also did it for a couple of weeks to my AC-9G's I just replaced with Kennedy quick-heats, and all the plugs came out fine.

[canxj]

Ya I soaked them down pretty good with WD-40 last night...will keep the oil on them for a few days before I get the wrenches out.

Any thoughts on using regular spade connectors to repair my wiring?

[DennisG01]

Before you do to much rewiring (a regular spade connector would get the job done), have you verified how many plugs are still working? Use a test light from B+ to the spade (wire off) or an ohm meter across connector and body (look for around .8ohms (NOT "K") to 1.4ohms).

Oh, also try a penetrating fluid (WD40 is not one, fyi) like PB Blaster or as mentioned above.

[Robyn]

You can get new connectors and the nice little heat resistant covers for them at most parts stores and or a Ma General shop.

If you have to, you can use regular connctors.

Just be sure that nothing touches the terminal that could short it out.

Definately need to change the plugs out if the terminals are that bad.


Just a tid bit here

Getting to the Glow plugs on the RH side can be made a metric buuttttload easier if you jack up the rig, remove the tire/wheel (Block securely) and then remove the rubber splash apron.

Now you can sit on yer bumm and get to 3 of the 4 plugs on that side with ease

The rear one must be accessed from under the rig by reaching up around the down pipe.
The back one is not too bad but takes a little finesse.

2-4-6 are a piece of cake once you are in there.

Good luck

Missy

[canxj]

Thanks for the tips...I was planning to grab a can of PB blaster on the way home to give everything another good lube.

I have the rubber splash shield out...have a pretty good view of #2,4,6

The heat shield looks in rough shape, do I have to get that off to get the 2 middle plugs or can I just go in blind straight shot?

Gotta get at it....going down to -20 deg C tonight here in canuck land!

[canxj]

Dennis - I was hoping to try the test light trick...poking around trying to get the connectors off...but that's when one broke off the plug. So I'm not sure how many are actually good. Best case is I have 6-7 good ones right now, but based on the condition of the spades I wouldn't be surprised if I'm firing on 4.

[canxj]

Picked up 8 new bosch duratherms, thought I would try them over the AC delco's. They are half the price. Anyone have any experience with them?

Also got some insulated spade terminal connectors.

Now down to work!

[racer55]

The duratherms are the best out there.

[canxj]

Local napa wanted $31.19 for the delco plugs.

Called my go-to jobber and he got me the duratherms for less than $12 each :D:D:D

[racer55]

rockauto.com has the duratherms for less than $8 each.

[BrIONwoshMunky]

I'd use a terminal like this, if the ones on the truck went bad, they're pretty easy to come by:

http://www.allelectronics.com/mas_assets/cache/image/1/0/8/264.Jpg


http://www.allelectronics.com/make-a-store/item/6225/1/4-FULLY-INSULATED-FEMALE-BLUE/1.html

[DmaxMaverick]

The plugs are too close to the heat source. Use a thermal insulator, or none at all. The plastic insulators (or heat shrink tubing) will burn off (and usually melt into the spade, gluing it in place).

[canxj]

Dmax - would you not recommend using the connector like suggested by BrIONwoshMunky? Those are similar to the ones I have. Good thought on the heat shrink, maybe I'll skip that step. I have a good crimping tool.

[canxj]

So I go to remove front glow plug, drivers side and the hex head twisted right off. Threads still stuck in block.:mad:

What do I do now. I don't want to touch any of the others... or I'll have 8 plugs sheared off and stuck in the engine.

Now down to 2 "possibly" good glow plugs on the drivers side.

Can I run the engine with the plug like that?

Banging my head on the wall...

[DmaxMaverick]

I do not recommend using the plastic insulated connectors. You're better off with bare connectors. Same goes with the wire. If you replace the OEM plug wires with "regular" primary wire, they'll do the same.

Tough call on the broken plugs. You could try an EZ-Out, but you'd probably end up with that stuck in there, too. It won't hurt anything leaving them in (damage done, and all on the outside). Problem will be with cold starting. If you have enough plugs to get started (with some help from the block heater, which is a LOT easier to replace), leave it as-is, and hook up what you can. Then, at some time in the future when you can plan a head removal, tackle the rest of them. You might get lucky. You can get by fine with 4 or 5 working plugs, but it may be a smoky start of the day. Use the block heater when you can to ease the pain. An oil pan heater will help a lot, too.

[DennisG01]

Nothing to add on top of what DMax said. But I will second the notion for an oil pan heater - especially since you're down at least a plug. Besides, the oil pan heater is a good investment regardless of plug condition.

See the model #512 here: http://www.kennedydiesel.com/categoryresults2.cfm?Category=5&SubCategory=82

I ordered one about 2 years ago, but ended up using it for something else. Since then, I've just been lazy and haven't ordered another one for my truck. Maybe this thread will kick my butt into gear and get it done as I would like to have both a block heater and pan heater going. I installed a permanent 110v outlet in the front corner of my bumper for the block heater - I plan on simply splicing the pan heater into that circuit. That way, I only use one extension cord for both heaters.

[canxj]

I've got the magnetic style oil pan heater, have it and the block heater plugged in right now. Its -25 here today. Not sure if I should tempt fate and try a start later today...

One brainwave I had this morning - what if I rigged up some type of alligator clip to the glow plug wiring, and clamped that onto whats left of my plug/spade. The front 2 on the drivers side are now down for the count...

[DennisG01]

I'd say give it a shot. It will run rough until all the cylinders start firing off properly, and will probably kill all the mosquitoes for a 25-yard (a little less than 25 meters...;)) radius, but give it a full minute or two to clear up and see how it does.

You won't do any damage to the plug by "jump starting" it (unless maybe if you leave it "on" too long), but of course a bare, hot, lead being dragged around the engine bay isn't exactly super-safe, you know? Especially considering the fact that you probably can't get a really good bite onto the plug and the alligator clip could fall off and then short against pretty much whatever it touches. If you can figure out a way to secure it well enough, sure, go for it.

Another option... let the engine go through a full glow cycle, then turn the key off and let it sit for a minute or two. The plug, although not glowing red hot, will still have some heat to it and will warm the cylinder. Then, do another (maybe two more) cycles before starting.

[canxj]

Had the block heater on for about 4 hours...started first try. Little bit of smoke but nothing out of the ordinary.

Guess I'll leave it be for the time being, I'll keep putting the penetrating oil on the glow plugs and hopefully my remaining 6 will stay intact. Maybe try pulling one in the spring!

[DennisG01]

Had the block heater on for about 4 hours...started first try. Little bit of smoke but nothing out of the ordinary.

Guess I'll leave it be for the time being, I'll keep putting the penetrating oil on the glow plugs and hopefully my remaining 6 will stay intact. Maybe try pulling one in the spring!

Good deal. Glad to hear.

[Robyn]

If you can get 2 plugs on each side in good working order you can start the beast with minimal bother.

One thing that will help a Buttload is to get all the injectors in top condition.

I had 60G plugs in our 94 Burb with a stock glow timer and it would crack right off even in single digit temps.

As the POP pressure goes away (tired worn injectors) the spray pattern also goes south and becomes a PEEEEEEEEEEE stream instead of a fine mist.

Trying to start one of these with bad injectors can be a bitch even with 8 glow sticks that are working perfectly.

Trying to build a fire with loads of LIQUID diesel is an uphill battle to say the least.

With good squirts and a few glows to get the thing rolling faster than the starter can spin it will get the cylinder heat up pretty fast.

Once you reach about 300-400 RPM even the ones with bad plugs will light off.

I have started the 500HP Cat in the truck at very low single digits without any heat. Now granted the Cat is a direct inject engine, but with everything dead cold, it takes heat to build a fire.

The indirect 6.5 IF it has good squirts can start without the glows down to the mid 60-70 degree range with some cranking.

Compression, good cranking RPM and good squirts is the key to the whole thing.

Good luck

Missy

[canxj]

Thanks Robyn, Denis and everyone else who chimed in.

You folks and TDP community really make owning these things a little less stressful!

I must say...when these old GM diesels are running there is nothing like it. I've driven everything from jeeps to powerstrokes and everything in between. My daily driver is a 2011 F-150 (company truck) and if I had the choice...I'd be driving the 6.5 every day!!!

[canxj]

Been thinking about ways to improving my cold starts with 6 of 8 glow plugs. What about drilling and tapping a hole in the intake manifold and threading in a good glow plug, extending the high heat wiring from one of my unused seized glow plugs; and using it as an intake heater (with the stock glow plug cycle). I know the Cummins use an intake heater, I must admit I have no idea how they work...am I thinking along the same lines?

[DmaxMaverick]

Been thinking about ways to improving my cold starts with 6 of 8 glow plugs. What about drilling and tapping a hole in the intake manifold and threading in a good glow plug, extending the high heat wiring from one of my unused seized glow plugs; and using it as an intake heater (with the stock glow plug cycle). I know the Cummins use an intake heater, I must admit I have no idea how they work...am I thinking along the same lines?

An effort in futility, methinks. The late model heat coil/grid draws as much juice as a full set of working glow plugs. They make a LOT of heat, which is spread across the intake cross section. One, or even two glow plugs wouldn't do much, if anything, to improve your start. You'd be better off using a hair dryer. If it starts well using the block heater, and whatever remaining plugs, leave it at that. DO NOT be tempted to use ether (starting fluid), as this will kill the remaining plugs, and leave you with bigger problems (broken/swelled plug tips, to begin with).

If you really want an intake air heater, consider sourcing a heater designed for that purpose. New late model heaters are expensive, but you may be able to get a pull from a wrecking yard for a lot less. It could be adapted to your intake, but it will require its own relay/controller/switch (the GP relay and circuit won't carry that load). This wouldn't be a bad idea, actually. You'd have to keep your electrical system (batteries/grounds) top-notch.

[DmaxMaverick]

Also.......

If you are down only 2-3 plugs, nothing you do will improve the starting ability. It WILL start on 4-6, with only a bit more smoke, and a few seconds of rough running, compared to 8 good. The loss of 2 plugs won't diminish the start ability, unless your start quality was already marginal, which means other things to fix (injectors, fuel supply, compression, etc.).