A2 (M1123) Cold Starting Trouble

So my M1123 is having trouble starting when it's cold out.

I checked the cold advance circuit and everything is working the way it should. Manually hitting the throttle after the wait light goes off is done regularly to engage the cold advance plunger since apparently the electrical system isn't strong enough to do that on its own on these trucks or Hummer H1s. Almost every time I start it when it is mildly cold (50s) I have to pump the throttle to get it to start.

Now that the temperatures are in the 40s and 30s nothing gets it to start. It cranks just fine, the starter is going fast enough. White smoke is coming out of the tail pipe. The wait light stays on longer when it is colder. I narrowed it down to two areas:

- Glow plug system
- Fuel delivery

First step with the fuel delivery was to change out the fuel filter and bleed the lines. I did that and bled to the fuel filter, but haven't bled to the injectors yet. The problem remained.

Then today I started looking closer at the Glow Plug circuit. I pulled off one of the glow plug electrical connectors and hooked up a voltmeter to it. I clamped one end of the voltmeter to a bare bolt and then confirmed a good ground by testing continuity across another bare bolt in the engine compartment. After confirming a good ground I put the probe into the glow plug connector, and it beeped like it had continuity. But only for a split second. Looking at the meter, it had 90 ohms of continuity. So it appears that might glow plug circuit might be shorted.

Continuing with the rest of my test, I kept the probes connected and checked voltage. As soon as the key was on voltage popped to 24 volts like it should, but it never went off. I waited for about 15 seconds after the WAIT light went off and it still had voltage. I've got both the Protective Control Box and Glow Plug Controller logic diagrams back home drawn up with what each wire's function is. I plan on checking that again to see what is realistically happening to cause the problem.

I'm just curious if anyone has any input.

- I see there's another thread with a similar problem called "turnover trouble". 'Tis the season, I guess. Reading the G503 sticky now. -

First of all, you don't need to pump the pedal to start a Hmmwv, the Cold start advance is electrical, the CSA is 24v normally closed circuit from the right rear engine thermostatic switch, opens at 90-120 degrees and shuts off the CSA.
you need to pull all the GP's and test them, if the voltage is constant, your EESSS is toast, replace it with an S3 EESS.
white smoke is unburnt excess fuel...thus you have no gp's lighting off. If the white smoke does not go away even when warm, that could be a bad injector or even a blown head gasket, but you need to smell the white smoke and see if its fuel or coolant.

what EESS do you have installed? Hopefully not a PCB with GPC.

FYI, I wrote the sticky on G503, it's a bit outdated in regards to parts, the S3 was not out then.
but the basics still apply....

The white smoke does go away.

I will check the GP voltage on more than just the one. I did that troubleshooting on a lunch break so I was short on time.

How long would you say the glow plugs should stay on?

Being a 2005 truck, I think it's got a green label EESS already.

You need to pull the glow plugs and test them for continuity...and inspect them.
loose the green label box, they suck too, they don't use a temp sender in the water crossover, it's all encompassed into the box, the green label box Cycles the glow plugs "every time " the truck is started regardless of engine temp.
i can't stress installing an S3 anymore then I already have...

I believe you. I just have no idea what I'm talking about so I didn't know if my truck already had the S3.

I'll pull all the glow plugs when I get back from vacation. I'll likely go ahead and order new ones and look into a new EESS.

Do you know what year the S3 was standardized?

The S3 has the extra cannon port for diagnostics.

Cold start advance on a db2 pump when the solenoid is energized and it removes pressure from the head through the return line. The solenoid on the side is the throttle is the throttle kicker. Wired in conjunction with the cold advance ,it will keep idle up for a better combustion chamber burn when cold ,also helping to warm the engine faster ohm test is for glow plugs only as I remember its something like .8 to 1.3 ohms ,testing like you did does no good as all glow plugs are wired together into one 8 gauge wire going back to the relay. your short to ground was the other 7 plugs. With all plugs disconnected you should see 24 volts at any of the connectors, with all the plugs hooked up the battery voltage should drop to 12 volts. This is why some plugs swell, as you loose plugs the voltage to the remaining plugs get higher, also why some of the newer systems wont cycle unless they see the right resistance in the system, a feature to try to protect the remaining plugs. Good luck sounds like glow plugs not lighting, I would start with some new glow plugs, and the right ones for military applications. Cant remember the delco number off hand but some 12 volt 6.5's and ford diesels use a plug that looks the same as the Humvee plug

He probably wont be able to get most of the plugs out.

Don't bother checking the other plug wires for voltage. They all hook up together, unless one was cut off.

The green label boxes are older.

Thanks guys, I just ordered more plugs because I'd like to replace them anyway if I take them out to get everything on a good maintenance schedule. If that fixes it, I'll hold off and get an S3 EESS at a later date, possibly at the end of winter when glow plugs aren't needed every day. I'm already over budget on the truck, so I have to delay some costs so I can build the building to put it in!

The EESS in my truck is the green label Nartron.

Your most likely going to fry another set of glow plugs....you also need the glow plugs to start the truck any time it starts and is below a certain temp...makes no difference if it's in calif in the summer time and it's the first start of the day.
the EESS is the core of the starting system, it's the one component that needs to be working correctly, that and the glow plugs.

You are a pretty bad (good?) influence. S3 EESS kit ordered.

Thank you for your guidance!

Retiredwarhorses said:

Your most likely going to fry another set of glow plugs....you also need the glow plugs to start the truck any time it starts and is below a certain temp...makes no difference if it's in calif in the summer time and it's the first start of the day.
the EESS is the core of the starting system, it's the one component that needs to be working correctly, that and the glow plugs.

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MaverickH1 said:

You are a pretty bad (good?) influence. S3 EESS kit ordered.

Thank you for your guidance!

Click to expand...

not only will you have piece of mind knowing your box and glow plugs are new, you will no longer have the annoying after glow for 2 mins with the S3. I personally have had no issues with them....I have installed more then I can even begin to remember. Your box will come wth a new temp sending unit, make sure to install that as also in the water crossover.

Success! S3 EESS kit installed and all glow plugs replaced. The existing glow plugs exhibited all conditions. One was drooping so much that it required pliers, three were swollen up but only one of those required pliers to remove, a few had pitting and a few looked fine. None broke off in the block.

After the wait light goes out it starts up in under a half second. Thank you all!

MaverickH1 said:

Success! S3 EESS kit installed and all glow plugs replaced. The existing glow plugs exhibited all conditions. One was drooping so much that it required pliers, three were swollen up but only one of those required pliers to remove, a few had pitting and a few looked fine. None broke off in the block.

After the wait light goes out it starts up in under a half second. Thank you all!

View attachment 659062

Click to expand...

just as it should be.......and no afterglow, that surging voltage gauge and generator drives me nuts, not so much when cold, but on the nartron yellow labels it does it on every start up...hot or cold.

MaverickH1 said:

Thanks guys, I just ordered more plugs because I'd like to replace them anyway if I take them out to get everything on a good maintenance schedule. If that fixes it, I'll hold off and get an S3 EESS at a later date, possibly at the end of winter when glow plugs aren't needed every day. I'm already over budget on the truck, so I have to delay some costs so I can build the building to put it in!
The EESS in my truck is the green label Nartron.

Click to expand...

Thanks for posting this.

I'm troubleshooting the same/similar issue. Hard starting in cold weather, blows out unburnt fuel for a few seconds, warms up, very smooth running after about a minute. Remembered a "smashed switch" I glanced at in the right rear of the engine when I was putting a new gasket on the doghouse, passenger side, and was looking at how I'd wire in a ground disconnect switch using the radio wiring hole (also passenger side) right rear corner of dog house, looked at switch again, basically it's disconnected. Black plastic insert is free of body, don't see any way it could still be working. Matter of fact, from the way the beast is acting, I don't think it IS.

Also have new set of glow plugs - similar reasoning as you, I think, cheap investment for future - don't relish the thought of pulling the old ones right now, so I haven't.

I'll replace the switch first (in a couple days when it gets here), but who/where did you by the S3 EESS/temp sender units?

If it's someone on the board and it's reasonable, I might go that route. Prices I can see on the "usual sites" range from ugly to "you gotta be kidding me".

I forget what PCB I have now, ?green label nartron (no accessory port) I think. Shoulda taken a picture.

Anyway, glad you got yours fixed. I'm off to Tennessee tomorrow with my wife to look at some property we bought - "site-mapping" for our retirement home, garage, driveway, etc. Plus she's only seen photos. And the way things are going with the settlement company we might need to go "talk to them."

Norm

Retiredwarhorses said:

just as it should be.......and no afterglow, that surging voltage gauge and generator drives me nuts, not so much when cold, but on the nartron yellow labels it does it on every start up...hot or cold.

Click to expand...

Would the aftermarket ground kit help with that at all?

NormB said:

Thanks for posting this.
I'm troubleshooting the same/similar issue. Hard starting in cold weather, blows out unburnt fuel for a few seconds, warms up, very smooth running after about a minute. Remembered a "smashed switch" I glanced at in the right rear of the engine when I was putting a new gasket on the doghouse, passenger side, and was looking at how I'd wire in a ground disconnect switch using the radio wiring hole (also passenger side) right rear corner of dog house, looked at switch again, basically it's disconnected. Black plastic insert is free of body, don't see any way it could still be working. Matter of fact, from the way the beast is acting, I don't think it IS.
Also have new set of glow plugs - similar reasoning as you, I think, cheap investment for future - don't relish the thought of pulling the old ones right now, so I haven't.
I'll replace the switch first (in a couple days when it gets here), but who/where did you by the S3 EESS/temp sender units?
If it's someone on the board and it's reasonable, I might go that route. Prices I can see on the "usual sites" range from ugly to "you gotta be kidding me".
I forget what PCB I have now, ?green label nartron (no accessory port) I think. Shoulda taken a picture.
Anyway, glad you got yours fixed. I'm off to Tennessee tomorrow with my wife to look at some property we bought - "site-mapping" for our retirement home, garage, driveway, etc. Plus she's only seen photos. And the way things are going with the settlement company we might need to go "talk to them."
Norm

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You are welcome, and good luck!

I purchased the kit from HummerPartsGuy.com, item 01-542-7901.

Havok said:

Would the aftermarket ground kit help with that at all?

Click to expand...

No.....

MaverickH1 said:

You are welcome, and good luck!

I purchased the kit from HummerPartsGuy.com, item 01-542-7901.

Click to expand...

Thanks. I've got a Nartron smart start sytem, mfr-32498.

Beast started right up when temps were 50-70, now it cranks several seconds and blows white smoke briefly.


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