M1008 cranks but won't start unless I ...

[warwick]

Back ground :
govliq auction truck and is in stock condition , every thing under the hood. The only thing not stock is a length of wire added by the motor pool before I bought it from auction. Wire runs from 24v bus output to resistor input. It was hooked up to the back battery negative post when I got the truck and the truck wouldn't start, moved the wire and it fired right up.

Possible problem :
Truck has been running great, no known problems. I let my brother borrow the truck and when he was done he parked it in my back yard. I went to start it the next morning for work and it would crank but not start. Brother said it drove fine and he couldn't remember doing anything wrong to cause the problem. Later said he may have gotten in the truck and cranked like you would a gas engine. He cranked right away with out waiting for the wait light, realized it after a few seconds and turned the back to run position. The wait light went out and he cranked it and the truck fired up.

What I've tried :
> checked fuel at filter bleed valve - it pumped fuel but I didn't measure output
> checked fuel at engine -pulled #1 glow plug and cranked engine and got a good mist of fuel
> batteries - new Interstate Battery 31P-MHD amps 1190 cca 950
> glow plug relay - I thought this was the problem 'cause I was getting different readings from the top(input) and bottom(output), so replaced the relay with a napa st-85 this didn't solve starting problem
> glow plugs - new acdelco 60g

I got a little frustrated and started jumping back and forth taking volt readings and trying different things, mostly just chasing my tail.

I removed the 24v to 12v resistor and pulled power for the glow plugs from the bus bar right above the gp relay.

I installed a push button switch for gp relay when I first got the truck for back up. I pulled my control card and have been using the button while trying to sort out what is wrong.

What happens now:
I turn key to run and hold the gp button for 15-20 secs, throttle half way to floor. If its cold and has sat for a day it will start and run for about 5 seconds then die. Then if I crank it for 30-45 secs with throttle to the floor wait a minute and crank 30-45 secs pedal to floor repeat one or two times and it will eventually start up. I have to feather throttle for a minute or two until it warms up. Then it will act like normal fast idle until gets up to temp. and the volt gauge climbs up to the middle of the green.

I can drive it like normal no indication of anything wrong. If I stop, the truck will fire right up while its still warm. Let it sit over night and I'm back to having to crank and crank to get it to start.

I've been pulling my hair over the glow plug system thinking that is where my problem is

Questions :
> where are the grounds on the engine block? I could only find the ground on intake to firewall near the fuel filter.
>could it be sucking air from bad hoses or another source causing the hard starting?
>other than bleeding the injectors or pulling every glow plug is there any way of check if the IP is good or not?


Thanks for any help and sorry for the long write up.

 

[Shankem-Deep]

If your starter is not cranking the engine fast enough you will be chasing your tail from now on. It could be several things but your starter should spin the engine over really fast. I thought mine was turning the engine over fine until I had it rebuilt just to cross that off my list. Now it spins the engine really fast! All my hard start problems went away.

 

[dependable]

Sounds like symptoms of air getting into fuel line. Check filter base first. Lots of threads on that topic.

 

[chesapeake]

Mine would fire up for about 5 seconds and then die. Then like you said it would take 30-40 sec to get it to fire off. Then everything was fine. I put a spin on filter on mine and haven't had a problem since

 

[doghead]

Is your fuel filter base completely dry(at the bottom)?

 

[Warthog]

Is your cold advance getting 12v?

 

[Hasdrubal]

Sounds like your fuel pressure sensor on the back of the fuel filter base drawing air. After you shut it down, crack the fuel cap to release vacuum. In the morning it will fire right back up. I drilled a tiny hole so I wouldn't have to remember to do this every time. Ran for a couple of years until I finally sourced a OEM filter base that omitted the pressure sensor.

 

[warwick]

... I had it rebuilt ...

how much did it cost to rebuild your starter?

Is your fuel filter base completely dry(at the bottom)?

filter and base are dry on all sides


I just realized i have not changed my filter in 2.5 to 3 years.


Is it possible that a clogged filter is the source of my problem?

Is your cold advance getting 12v?

when I force the truck to start it will fast idle until it warms up


I have not checked for volts at cold advance, I will check the TMs and figure out how and report back

 

[Shankem-Deep]

I have the 27MT direct drive starter on my MV's. The one I recently had rebuilt was pricey, somewhere around $150 for the rebuild. I could have got a new import gear reduction for less but decided to stick with the direct drive. According to the the starter shop owner, in his opinion the direct drive starter is more reliable but won't spin the engine over as fast as the gear reduction. Since I had a direct drive rebuilt there before I knew it would spin the engine plenty fast. Neither of the 27MT starters left me standed when a rebuild was needed. They just wouldn't spin the engine fast enough without a glow plug assisted start. That's another good reason to add the manual glow plug switch as a back up.

 

[Barrman]

The theory is that gasoline engines need around 60 rpm to start and diesels need around 180-200 rpm to start. Good load tested batteries and a good starter are essensial.

The direct drive starter is super easy to rebuild yourself. You build your M715 all those years ago, you can do the starter. The -30 talks you through how to do it, what to measure and everything. Several places on the internet sell 27MT starter rebuild parts. The only difference between a 24 V and a 12 V unit is the brushes. Make sure they send you the 24 volt stuff. Plus, of course the 24 volt solenoid.

There is a cold advance solenoid inside the lid of the IP which gets power from the green wire. The green wire also gives power to the fast idle solenoid. They turn off and on together obviously. However, just because one is working doesn't mean the other is.

A new filter would be a great idea. Your choice on keeping the square leak prone stock filter set up or going to spin on. Spin on seems to be where most of the problems end however. All of my trucks are switched over and they start every time and have for years.

While you are cranking, do you get a white/blue have out the exhaust pipe? If so, you have fuel but no heat. Check glow plugs. If nothing is coming out the pipe then it is a fuel related issue.

 

[warwick]

... You build your M715 all those years ago ...

Ya, It was ten years ago this summer that I bought that M715 [ the one in my avatar pic, my first M715]


I need to check in on the 'Zone more often, thought about posting this problem over there as well


if I remember right there are some cucv owners over there

... The direct drive starter is super easy to rebuild yourself ...

I'm going to check some of the other stuff first, maybe rebuild the starter in Jan./Feb. and instal new cables


never had a problem before my brother borrowed the truck barely turn the key and it would kick over only in the dead of winter would take and extra second or two

... There is a cold advance solenoid inside the lid of the IP which gets power from the green wire. The green wire also gives power to the fast idle solenoid. They turn off and on together obviously ...

If I read the wire diagrams right - cold advance(CA)/fast idle(FI) temp switch - lt. green wire to CA control - lt. green to FI solenoid


If FI is getting 12v then CA should have it as well. After verifing this with a meter should I open the cover and see if it actually moves? or just listen for a click/clunk when someone turns the key?

... A new filter would be a great idea. ...stock filter set up or going to spin on...

I have a new napa stock filter in the garage [somewhere] gonna put that on first and see if it helps. I'm gonna call Chris and get a spin on filter from him [ http://www.steelsoldiers.com/showthread.php?103941-Stanadyne-FM100-and-Napa-3546 ]


If I read the ad right you can get a filter base and a 6 pack of filters for $50 and a 6 pack case of filters for $25

... While you are cranking, do you get a white/blue have out the exhaust pipe? ...

from what I can tell sitting in the driver seat it starts off with little to no W/B haze and will build up during the crank 30-45/wait 60 cycles until it kicks over


I should be able work on the M1008 this sunday and will verify the suggestions and report back. Also my brother will be able to help so first thing when its cold I'll have him crank/wait/repeat while I watch the tail pipes








Thanks again you all for the help, I'm the only "mechanic" in my family and group of freinds so when I get stumped there's really no one to ask for advice, if I do talk to someone I get a blank stare and a sort of slow blink .. lol ... at which piont I pivot to "how 'bout those Eagles/Phillies/Flyers"


Anyway I'm off to help my uncle build a hunting blind, then over to my moms to do some yard work, then babysit my nephew ... hopefully this sunday I'll get it sorted


Take care you all

 

[warwick]

cranked the truck when it was cold and had no white/blue haze, crank/wait/repeat it started to increase the haze till it kicked over.

pulled the stock filter and the pressure sensor was wet from fuel as well as the bottom half of the base. put a new filter back on, primed it and started the truck up and let it idle. And it was dripping fuel from the base.

I didn't put a meter on the cold advance

After putting on the new filter and the truck idling it started leaking from the fuel pump.

I'm going to get a spin on filter from Chris and an ACDelco fuel pump from atozone

 

[top_prop]

You can also put a clear line on the top of the IP to the return system... it will help emensly with noting and diagnosing air in fuel problems.

good fuel filter mod thread: http://www.steelsoldiers.com/showthread.php?36435-My-CUCV-spin-on-fuel-filter-mod/page5

electric fuel pump: http://www.steelsoldiers.com/showthread.php?48444-Electric-fuel-Pump-install

 

[GPrez]

I know you say it has new glow plugs, but if you had a glow plug system problem you could have burned them up even though new. I mention this because that is exactly what happened to me and I was pulling my hair out trying to figure it out. If yours runs fine once it's warmed up it certainly sounds like a glow plug problem.

Mine was keeping the glow plugs energized all the time and burned up my new plugs. You can easily check it by turning the key on and put a test light on a glow plug and see if it goes out once it runs the cycle. I, like you ended up installing a momentary switch to manually energize the glow plugs and have not had an issue since. Good luck, I hope you get it figured out.

 

[BobM]

I know you say it has new glow plugs, but if you had a glow plug system problem you could have burned them up even though new. I mention this because that is exactly what happened to me and I was pulling my hair out trying to figure it out. If yours runs fine once it's warmed up it certainly sounds like a glow plug problem.

Mine was keeping the glow plugs energized all the time and burned up my new plugs. You can easily check it by turning the key on and put a test light on a glow plug and see if it goes out once it runs the cycle. I, like you ended up installing a momentary switch to manually energize the glow plugs and have not had an issue since. Good luck, I hope you get it figured out.

I had some of your same problems with a civilian version of the 6.2. The previous owner had installed new glow plugs and they were shiny new. I tested the circuit like GPrez suggests and it tested fine. So I replaced the starter, all new battery cables filter ( a couple of times, just in case!) put an electric fuel pump on, replaced the injectors, replaced the IP .....And nothing! Getting frustrated, I started over in my testing. Instead of testing the glow plug CIRCUIT like GPrez suggests, I unplugged each glow plug and, hooking my test light to the positive battery cable, I tested each glow plug individually by touching the lead on the plug. Two worked, the other six were burned out. After removing the plugs and inspecting them, I believe the PO had "tested" the glow plugs before installation which burned them out. It seems that there have been several "new to diesel" people who believe that you should hook a power and ground to the glow plugs to make sure that they heat up. This often causes the glow plugs to burn themselves up and making them useless.
I replaced all 8 plugs and the truck, with it's new injectors, IP, wires, etc started better than any other 6.2 I have had. So I would suggest testing each plug individually ( and not by taking them out and energizing them!!).

 

[warwick]

... put a clear line on the top of the IP to the return system ...

thanks for the tip I plan on replacing the fuel hoses when I change the pump and switch to a spin-on filter.


I may add the clear line as well, not sure where to get diesel rated clear hose

I know you say it has new glow plugs, but ...

thanks for the advice, my glow plugs are working the way they are supposed too


thanks for the tip about the 12v test light I'll keep it in mind for future repairs

... I believe the PO had "tested" the glow plugs before installation which burned them out. It seems that there have been several "new to diesel" people who believe that you should hook a power and ground to the glow plugs to make sure that they heat up. This often causes the glow plugs to burn themselves up and making them useless ...

I have checked my glow plugs this way with no ill effect. did I just get lucky or is a matter of how long you leave them energized.


-> to be clear I checked an old set of glow plugs this way, the new ACDelco 60s I installed straight out of the box

 

[warwick]

I got most of the parts to do the spin-on filter and a new fuel pump.

I have to get the fittings for the filter base and I should be able to work on the M1008 friday afternoon and saturday mid morning

I'll let you all know if it solves the hard starting

 

[BobM]

I have checked my glow plugs this way with no ill effect. did I just get lucky or is a matter of how long you leave them energized.


-> to be clear I checked an old set of glow plugs this way, the new ACDelco 60s I installed straight out of the box[/QUOTE]

NEVER ( IMHO ) check new glow plugs in this manner. I wouldn't ever energize glow plugs in the open if I were going to install them later. There is just too much chance that you will stress the plugs. If you over heat them and weaken the shell, then you risk the plug (s) coming apart in the cylinder. And random pieces of glow plugs rattling around in the cylinder is never good!

 

[top_prop]

The clear hose is the standard stuff you an buy a Lowes or homedepot. Not diesel rated but works. I replace mine every year or two.

 

[Ackevor]

What ended up fixing the problem? I am having the same issue now. Last week I used the truck daily for work, it always seemed to need a few seconds longer than normal to start the last few times I used it but in the end it would and ran fine. Before its always started easily, although I figured if the plugs where new it should perhaps have less of that rough idle and cackle but goes away with a little throttle. Today it started and ran for a few seconds with its typical cold cackling and rough start then died. I didn't have time to do much but I tried pedal to the floor and cranked twice for about 10 second restarting the GP cycle each time. It sputtered weakly like it wanted to start but never would. At this point I just hopped in my car and drove to work. I will have to go through all of these ideas today if its not raining.

Fuel filter and 60g plugs were installed less than 1200 miles or 15 E-hours ago. Resistor bypass, 1 year old glow plug card, new GP relay, and using a gear reduction starter which spins engine nice and quick.

My guess is burnt out plugs/bad plug wires (If so I need to find the cause), Injection Pump decided to go on me (71500 miles on truck), or sending unit isnt doing so hot.