M1009 Hard Start Problem

[dmilkman589]

Ive read tens of hard start threads and none of the symptoms seem to be the same as mine.
1984 m1009, or k5 blazer with a 6.2 what ever you may prefer. Totally stock other than the fact I have a manual switch for the glow plugs.

When it is about 30 or so outside it will take me 2 cycles of the plugs to get her to fire up, this morning it was 7 degs, it took about 8 cycles and then some starting fluid.

Once it was running It runs fine, drove it about 5 miles, shut if off, went into the bank to make transaction, came out, starts up instantly with no glow pugs no problem. Only about a second or two of cranking time.

When its summer time about ehh, 70 degs it will not start with no glow plugs, still need at least one 15 second cycle to get her going. And cranks for quite a while...

O and everytime no matter if its warm or cold it will blow blue smoke untill shes warm. NO signs of burning oil. Seems to make it from oil change to oil change fine without adding much.

 

[dependable]

It all sounds pretty normal to me, except I would not use starting fluid unless it was emergency with glow plugs taken off line. Most people who have to start below 20 degrees a lot install a block heater.

 

[dmilkman589]

That is not normal, Ive seen a 6.2 start instantly in summer with out plugs

 

[Warthog]

With the high compression of the 6.2L, starting assistance is normally required. Even in the summer.

Your starting issue isn't unique. I would bet that most of your glow plugs are not functioning. The blue smoke on a cold start is just unburnt fuel. If the glow plug system was functioning properly, it would be cycling the plugs on and off to help warm up the cylinders.

 

[Carlo]

Check the glow plugs but if you start changing them change them all. Never a few. Those you don't change will burn out soon after you add new ones. I learned the hard way

 

[doghead]

Check the glow plugs but if you start changing them change them all. Never a few. Those you don't change will burn out soon after you add new ones. I learned the hard way

I respectfully disagree.

I only change the ones that are bad. My system is supplied with 12v.

 

[Carlo]

I note your disagreement but my comment is based on ownership of the 5.7 olds diesel, the 6.2 , 6.5 GM, and the Isuzu designed for GM 6.6 diesel plus we in Europe and especially in Italia have been using diesel powered autos since the 60's. The electrical load going to the glow plugs must be equal and it is as long as all the plugs are working in a equal 100% capacity. If you have one working at 40% and another at 45% and others at 70% and you add a few new that work at 100% the cold injection chambers that don't preheat are dead with excess fuel and no way to ignite the fuel. This puts a drag on these cylinders that hold the cold motor back from firing as it was designed.

Experience of older men is often overlooked and seldom appreciated. Oh well....

 

[doghead]

I would say this is a case where using an ohm meter to test(rather than a test light) is the key. If they ohm within spec, they will all draw the proper load.

 

[dmilkman589]

I have new plugs in last year, I have it running through the 24v supply then the big resistor plate thing... should i take that off, what does it do?

 

[doghead]

I recommend that you resupply the GP relay with 12V, to eliminate the cascade effect of the GP failures.

As private owners, we have no need to meet NATO standards(which needed a compromise, in my opinion).

 

[dmilkman589]

Dont you get more power to the plugs running the 24 though? Would it work with 12 With the plugs I have in there if they are ment for the 24 volt hook up.

 

[SouthernSteel]

Well I have done away with the resistor off the fire wall on both my M1008's(fire hazard if you ask me my daily driver one caught fire and the other one got really hot so I presumed they were bad just saying) and both start fine now that I have run a battery cable from my GP solenoid to the 12 volt battery post it takes a little longer for a cycle but once through my m1008's crank right up no matter if its 28 degrees or 70 degrees.Oh yeah,im running the ac60's glow plugs:]Good luck got more planned for my 86 army m1008.Merry Christmas to everyone.

 

[Carlo]

Dont you get more power to the plugs running the 24 though? Would it work with 12 With the plugs I have in there if they are ment for the 24 volt hook up.

You would think it would be less power, no? Like a 24 volt bulb hooked to a 12 volt battery.

 

[doghead]

The original GP are 12V.

Please don't confuse such a simple thing.

 

[Warthog]

Dont you get more power to the plugs running the 24 though? Would it work with 12 With the plugs I have in there if they are ment for the 24 volt hook up.

The stock and replacement glowplugs are designed to work in a 12v system. The resistor pack drops the 24v down to 12v if and only IF everything is working properly. If things are not working properly then you could be sending the full 24v to the 12v plug. They do not last long like that.

Just because you put in new plugs last year means nothing. I have seen plugs go bad in just a few hours.

TEST, TEST, TEST. Never assume anything.

 

[Carlo]

The stock and replacement glowplugs are designed to work in a 12v system. The resistor pack drops the 24v down to 12v if and only IF everything is working properly. If things are not working properly then you could be sending the full 24v to the 12v plug. They do not last long like that.

Just because you put in new plugs last year means nothing. I have seen plugs go bad in just a few hours.

TEST, TEST, TEST. Never assume anything.

bravo!

 

[dmilkman589]

ahhhh ok ill check them out! First project is snowmobile though, 6 inches expected

 

[Carlo]

What kind of sled?

 

[dmilkman589]

2005 firecat 600, she needs a track. Its gonna be a project and a half im assuming.

 

[Barrman]

The stock system is designed to come on when the coolant level is below 125°. Any 6.2 you have seen start "cold" without glow plugs either had the coolant that high or had a glow plug system that wasn't working correct. Will a 6.2 start in warmer weather without glow plugs? Sure, it might take a few seconds of cranking, but it will fire up. A stock system will have the truck firing up in less than a second. If yours is taking longer, something isn't working correctly.

Since you have a manual only glow plug system. I hope you put 60G plugs in the last time you changed them out and will put 60G plugs in this time. If not, look at the threads about removing swollen glow plugs before you try changing them out.