6.2 cranking times

[erasedhammer]

I'm not sure why this is, but my old humvee 6.2 engine would only take a bump of the key on an average temperature day to fire right up. But my cucv 6.2 takes a solid 1-1.5 seconds and then fires up.
Its a small difference, I know, but it got me interested in why there would be a difference. Battery amperage? Internal engine wear (14k miles cucv vs 85k miles humvee)? Different starter motor?

Not sure if anyone else has experienced this, or maybe I'm just loosing my mind. But if this difference is real, anyway to decrease the cranking time? Any disadvantage to having a faster starting engine?

 

[Curtisje]

My M1028A3 would do the same until 3 weeks ago when the starter quit on me. I installed another (fairly new) starter and now it starts immediately everytime.

 

[erasedhammer]

My M1028A3 would do the same until 3 weeks ago when the starter quit on me. I installed another (fairly new) starter and now it starts immediately everytime.

Makes sense. My current starter has been through a good period of mistreatment.

 

[sandcobra164]

Mine starts on about the second revolution of the engine even down to 10 degrees outside. I have AC 60G glowplugs and have done the Doghead 12V modification on the glowplug system. The Starter is the only thing on the truck that is 24 volt powered.

 

[erasedhammer]

Mine starts on about the second revolution of the engine even down to 10 degrees outside. I have AC 60G glowplugs and have done the Doghead 12V modification on the glowplug system. The Starter is the only thing on the truck that is 24 volt powered.

I have the 60g and my truck came without the resistor block.
But I also have some less than adequate batteries. Only 650cca a piece.

 

[cucvrus]

I have AC 60G glowplugs and have done the Doghead 12V modification on the glowplug system

What is this conversion? Something new in the pound?

• Animal shelter (also a "pound"), a facility that houses homeless, lost, or abandoned animals

Just asking because I never heard of the conversion on the glow plugs.

 

[Barrman]

They all should start faster than you can let go of the key after pushing it forward. Since you have consistent slower starting. I would suggest getting the batteries load tested. If they are at 800 CCA minimum each. Then check all the leads between the battery terminals, the firewall mounted Buss bars and the starter. If they all check out as clean and tight. Then a starter refresh or replacement would be next.

My first 6.2 truck was 3-4 seconds of cranking from the first time I got in it for months until a battery terminal melted off and the starter went bad. I think a bad starter caused the battery issue. But, it could have been a bad battery cause the starter to self destruct. Kind of a chicken or egg thing. Either way, start with the battery test and work your way to the starter.

 

[ken]

IP wear along with timing chain stretch can be a factor. Along with weak springs in the injectors. If the pop pressure is lower, the spray pattern will be less than ideal. Even though it may run good with no smoke, it could be time for at least some injector cleaner.

 

[sandcobra164]

cucvrus,
No new dog in the pound, I did call it FIDO instead of ROVER though. I should have stated Glow Plug Resistor Bypass which of course ensures that the system is only fed 12V. I know the stock system works great if all of the glow plugs are operational but we also know that it can have a cascading effect once the first connection gets loose or one burns out.

 

[cucvrus]

Never had any cascading glow plugs. Sounds very interesting. I have heard it said many times but never had the pleasure. Thank you and Have a Great Day.

 

[erasedhammer]

They all should start faster than you can let go of the key after pushing it forward. Since you have consistent slower starting. I would suggest getting the batteries load tested. If they are at 800 CCA minimum each. Then check all the leads between the battery terminals, the firewall mounted Buss bars and the starter. If they all check out as clean and tight. Then a starter refresh or replacement would be next.

My first 6.2 truck was 3-4 seconds of cranking from the first time I got in it for months until a battery terminal melted off and the starter went bad. I think a bad starter caused the battery issue. But, it could have been a bad battery cause the starter to self destruct. Kind of a chicken or egg thing. Either way, start with the battery test and work your way to the starter.

Vehicle only has 14k miles on it.
I would guess my situation is probably a combination of some cheap, weaker batteries (brand new, just not up to spec), and a starter that's been abused by the previous owner.

 

[sandcobra164]

Never had any cascading glow plugs. Sounds very interesting. I have heard it said many times but never had the pleasure. Thank you and Have a Great Day.

Sir,
I hate to take away from the original question and I'll state up front that I admire your expertise on the CUCV's. While there are no "cascading glow plugs", the stock system on these trucks have a cascading effect in the event that 1 glowplug fails. The resistor behind the air cleaner is designed to provide 12 volts from 24 volts to a perfectly loaded system when the glow plugs are commanded to be turned on. When one fails it places roughly 14 volts on the rest which overheats them. One quickly fails, 16 volts is applied, next one fails, 18 volts. The rest quickly fail. This causes the "cascading effect" and burns the rest out in short order. I pulled 7 of the original glowplugs out using the OTC tool, replaced them with AC60G's, removed the glowplug resistor behind the air cleaner, connected the solenoid to the 12V side and have had no further issues. You have a Great Day as well Sir.

 

[cucvrus]

I have a small booklet that was published by CUCV Electric on the CUCV Glow Plug System. I bought a circuit card from the company when it was in business and the booklet came along with it. It looks like a little TM booklet. I have read it cover to cover a thousand times and followed every detail to retain the stock system. It has been my Bible to keep and return many CUCV's to the stock glow plug system. I was poor when I was younger and I had to learn most things on my own. So now as I grow older I can do more with less. I do rely on schooling and manuals for things I don't understand. But many of the CUCV's I worked on were brand new and as I acquired my own personal CUCV I just kept them running and operational the same as I was taught and learned from the training at GM school. The first time I seen a CUCV it was a strange looking vehicle with the oddest colored interior. I do remember driving them when they were brand new. Right off the carriers. I sense when the glow plugs are failing and get right on it. I change 1 occasionally and all 8 very rarely. Thank you for your input. I still use the A C Delco 13 G.

 

[Curtisje]

Sir,
I hate to take away from the original question and I'll state up front that I admire your expertise on the CUCV's. While there are no "cascading glow plugs", the stock system on these trucks have a cascading effect in the event that 1 glowplug fails. The resistor behind the air cleaner is designed to provide 12 volts from 24 volts to a perfectly loaded system when the glow plugs are commanded to be turned on. When one fails it places roughly 14 volts on the rest which overheats them. One quickly fails, 16 volts is applied, next one fails, 18 volts. The rest quickly fail. This causes the "cascading effect" and burns the rest out in short order. I pulled 7 of the original glowplugs out using the OTC tool, replaced them with AC60G's, removed the glowplug resistor behind the air cleaner, connected the solenoid to the 12V side and have had no further issues. You have a Great Day as well Sir.

That doesn't make sense to me. The resistor drops 24 volts to 12 volts regardless of the electrical pull applied. In your example if only one glow plug was working it would receive 24 volts? If that is the case then the same logic is true for the bypass; if one glow plug fails the others will draw more current.

What makes sense to me is that if you have one or more glow plugs not working that the controller will cycle the glow plugs for a longer amount of time which will inevitably burn them out as well, thus giving you the cascading effect you are referring to.

I'm not chiming in to poo poo on your theory. I'm here to learn.

 

[richingalveston]

no, the voltage drop on the resistor is determined by the load. The lower the load, the higher the voltage goes. Thus when one plug quits working, the voltage increases to the other plugs. sandcobra is correct with his description of the cascading failure of the glow plug system.

 

[cucvrus]

https://youtu.be/MTkOl947aTk

Watch this and learn. No cascading effect going on here. The stock system protects itself. At least in 24 years mine always has. When I had hard starting and long than normal cycle times and harder starting. I was the first one to look into it and correct it. Good Luck.

 

[richingalveston]

as the video shows, when a glow plug is not working, higher voltage goes to the others. The more glow plugs that do not work, the higher the voltage goes. The card try's to protect it but does not change the fact that the plugs are getting a higher voltage and they will eventually burn out if it is not corrected.

If the card is working correctly then yes you should here the relay cycling more than normal but if you cant hear it you don't know because the cucv does not have the second volt meter that the handy simulation board has and the existing voltmeter is not adequate to read the volt change until multiple glow plugs are bad.

The glow plug cascading failure still exists. If you do not correct the bad glow plug, it will cause others to burn up even with a working glow plug card.

Thank you for the video, it is good for people to see. Once they know how to pay attention to the relay, they can know they have a glow plug issue.

 

[Curtisje]

HA! I thought for sure I was going to get home and put the volt meter to either side of my resistor and get two different readings, 24 v in and 12 v out. To my surprise it reads 25.5 volts on both ends. I learn something new every day.

I still can't say I fully understand this but I'm getting there.

 

[Curtisje]

https://youtu.be/MTkOl947aTk

Watch this and learn. No cascading effect going on here. The stock system protects itself. At least in 24 years mine always has. When I had hard starting and long than normal cycle times and harder starting. I was the first one to look into it and correct it. Good Luck.

The video doesn't address or explain anything about the 24 volt feed into the glow plug system. It does show me much more than I previously knew.

 

[Abbylind]

24 volts comes from the 2 12 volt batteries...the voltage is stepped down to 12 volts through 2 wire wound resistors located on the firewall behind the engine. The 12 volts from the resistors is sent to the glow plug relay where is used to initialize the glow plugs. The problem arises when the wire wound resistors break down and allow 24 volts to go the the relay and onto the glow plugs...resulting in burned up glow plugs...