serious preheat/glow plug problems

[humvmech]

So i know lots of people have posted about glow plug/preheat problems on this website because i have been reading as many as i can. I have been fixing a bunch of hummers that my boss has purchased for re-sale (20 to be exact) and this one has been putting up a real fight so i will give you the full story. at first inspection I found that the wait light would only flash for a split second and then turn off. The engine would start but only with a quick squirt of starting fluid. eventually i found that the head gaskets were bad so we pulled the engine and found that the cylinder walls were beyond normal machining so we had to install oversized pistons and did a complete rebuild on the entire engine. new bearings, caps, rods, pushrods, new heads, new valves, pretty much everything that can be replaced was replaced. So with the new heads and everything else i replaced the glowplugs as well just to be safe. after finishing the install it still had the quick flash on the wait light and would start after some extended crank time. This was mid august in utah so it was 90-100 degrees most of the time so the crank time was not that bad but still longer than normal. After more investigating and opening up the originally installed Nartron box that everyone knows is a usual culprit, i found that some of the capacitors and contacts inside were pretty well fried. So assuming that the box was my problem i ordered a new one (a new KDS module with the tempeture sensor that installs in the crossover coolant pipe) after disconnecting the battery (before install) and verifiying that all the glowplugs were connected and all the grounds were attached properly, i attempted to start the engine and once again saw the quick flash on the wait light. still a long, if not longer crank time before starting occurs. I have gone through everything a few more times checking all connections and possible wiring issues i cannot find any causes to my problem. My biggest question is: are the Nartron and KDS control boxes interchangeable? The Box that i received did come with the yellow banded temp sensor/controller. any help will be greatly appreciated.

 

[Action]

does the new KDS box have a yellow label? or another color?

 

[1 Patriot-of-many]

NEVER use ether again.That virtually guarantees new glow plugs needed. I'd start by checking the glow plug harness continuity per the TM. If you used ether at all on the new plugs, check them with an ohm meter. Possible you got a bad controller or protective control box. Which glow plugs did you install?
Which alternator do you have? If it's other than the 60amp, there has to be some wiring changes done differently than the 60 AMP unit. Maybe the Army failed to do them? Just throwing stuff out there..... I had intermittent problems with my glow plug system, replaced the TSU/GPC didn't help. Bought the protective box and sensor kit, works like a charm now. I also bought a glow plug wiring harness just in case, but didn't need it.

 

[Retiredwarhorses]

Real question is, was the box you bought new? Or used take out?

 

[humvmech]

I bought the box from Eriks military surplus and it was listed as new never used matched set. It seems to be exactly what it said it was. new in box and in good condition. the temp sensor/controller had the yellow band on it but the box itself just had a white label with serial numbers on it. no colored labels. The glow plugs i used are just napa 6.2 L chevy glow plugs, not sure if there is any difference. I have not checked the continuity of the plug harness yet. Do you know what TM that would be in? The alternator in this vehicle is the 200A alt with a voltage reducer. The wiring harness appears to have been modified since the normal plug (on the 60A) for the charge wire is capped off. Not sure how exactly to tell if the harness has been moded but im assuming it has been. also where is the protective box and sensor kit located? i have not had to replace that before.

 

[Retiredwarhorses]

You have to use 24v glow plugs...military issue. Napa's are most likely 12v. Thtey should say on them what hte voltage is.

 

[humvmech]

Hopefully that is what my issue is. Any idea where to get 24 V glowplugs?

 

[humvmech]

ok, i just pulled one out and it is an autolite plug with the number 1108 on the bottom. not sure if anyone has a a part number that i could cross to see what i have here. Its been so long since i put them in that i dont remember where i got them.

 

[Wire Fox]

ok, i just pulled one out and it is an autolite plug with the number 1108 on the bottom. not sure if anyone has a a part number that i could cross to see what i have here. Its been so long since i put them in that i dont remember where i got them.

That's your problem. Took a minute to find it, but those Autolite 1108s are a 12v plug. I've heard over and over, people recommending the Wellman plugs (same as military?). Do a quick search for "Wellman 24v glow plugs" and you'll see lots of vendors listing these-I'm sure all of the usual suppliers like Erik's, Kascar, THG, and others all have them. They're good for both the 6.2 & 6.5L engine and are 24v. A 12v version of the same plugs are available, so be sure to read carefully and buy the correct version.

 

[1 Patriot-of-many]

I have Delco 15G's in mine self regulating. You need glowplugs with the bullet connectors, not spades. The box with the two big connectors is the protective control box. You have the little chain on the test port of the protective control box? That's the one I Have also from eriks. Hopefully the wrong glowplugs didn't fry anything in the box.

 

[humvmech]

Well that is good news! thanks wirefox! I was just googleing those wellman plugs and found some for a reasonable price. I will call and make sure they are 24v first. The autolites looked just like the 24 v (with bullet connectors) that others offer so i thought it would work just the same. To 1 patriot, ya it sounds like the box that i got. It has to two large connectors with the diag port on the lower portion. Im keeping my fingers crossed that nothing happened to the box with those plugs because they have been in there since august. The new box was just installed this week. I will get some new plugs and see what happens and update the post when i find out if it works. Thanks everyone.

 

[Retiredwarhorses]

I have Delco 15G's in mine self regulating. You need glowplugs with the bullet connectors, not spades. The box with the two big connectors is the protective control box. You have the little chain on the test port of the protective control box? That's the one I Have also from eriks. Hopefully the wrong glowplugs didn't fry anything in the box.

Its not a protective control box....he has an S3 EESS, using the term PCB will lead you to believe it's the old problematic PCB with glow plug controller. You don't want that old setup, unless,you like replacing glow plugs.

 

[1 Patriot-of-many]

Its not a protective control box....he has an S3 EESS, using the term PCB will lead you to believe it's the old problematic PCB with glow plug controller. You don't want that old setup, unless,you like replacing glow plugs.

Sorry. Just going by the TM lingo.... Mines the s3 EESS then too. Like it, doesn't afterglow at all.

 

[Retiredwarhorses]

Sorry. Just going by the TM lingo.... Mines the s3 EESS then too. Like it, doesn't afterglow at all.

just bustin your onions,.,LOL
yes, I don't miss the afterglow at all....so mucho better.

 

[fllaw1]

http://www.ebay.com/itm/Military-HM...ash=item1a119765ba:g:KPMAAOSwZ8ZXCZ~t&vxp=mtr

they sell Wellman

 

[humvmech]

Good news! after replacing the glow plugs with the correct wellman 24V plugs (and finding a loose connection on cyl #6) everything worked perfectly!! Thanks to everyone for their input! Im glad to have this nightmare out of my hair.

 

[snowtrac nome]

one caution to you all resistance in they gm glow plug system is critical you need to have all plugs functioning or problems will arise if yu have one of the new control boxes the light flickers if you have the old system the plugs will swell up and will be hard to remove from the head.