m1008 starts under throttle, dies at idle

[jam]

Hey guys,
I've been following the threads on this site for the better part of the last six months, and it has been amazingly helpful! I have been applying advice from the site and have finally gotten to the point to try to get my m1008 project running. Let me run through a quick recap of what I've tried so far:

1) 12v roscommon conversion
2) doghead relay conversion
3) airtex electric fuel pump with spin on fuel filter (before pump and below fuel tank, mech pump gone)
4) push button manual gp override
5) ac60g's
6) drained fuel tank and put in new diesel
7) new 800cca batteries

I started by running the electric pump, doing a 6 second manual warm of the gp's and turned her over with no luck.
I then cracked the fuel line to make sure I was getting diesel to the pump, which I was.
Then I pulled the glowplugs and put a piece of cardboard in front of the holes and only one was getting anything out of it.
So I cracked the injectors and turned over the truck, they started weeping fuel.
Closed them back up again.
Still no luck...
Read some more... realized I needed to depress the throttle to halfway according to the service manuals, and as per recommendations fully until the lines were bled.
Also read that the ac60g's heat up more slowly and are safe to cycle in larger increments...
Held down the throttle to the floor and ran the gp's for 7 seconds, wait 5 seconds, then another 5. Turned the key and she would catch but not stay running.
Slept on it, read some more about replacing the return line with clear line (done) and pulling the top of the injector pump off to see if there is an obstruction....
Did this... there was no obstruction and fuel flows fine... more on this in a second. Not sure exactly what I was looking at nor that I put the top on correctly... looks like its supposed to go towards the radiator before pushing down towards the cab...
Put back together and no leaks... not sure the cold advance solenoid is working, and not sure there is a glass ball in the return line...
There is _no_ cold throttle advance solenoid... not sure if the 84 m1008 came with them?
At any rate, jumped in the cab, ran the ac60's for 10 seconds, let cool for 5 then 5 more seconds. Pushed throttle halfway to the floor and she runs.... kind of.
If I let off the throttle she dies.
If I move the throttle forward... she dies.
I don't have a tach on her, but it sounds like shes running 1500 or higher rpms...
Held her in the magic spot once long enough to get the engine somewhat warm and she sounded like she wanted to idle down... but died.
When running in the higher rpm state if I step on the throttle she does not accelerate.

You guys have been amazingly helpful from all the previous posts I have read and hopefully somebody has an idea.
The stuff I have in mind right now includes:
1) is the cold advance solenoid getting power?
2) if not is the thermostat sensor dead?
3) how about the position of the injector pump top... are their teeth that engage for the advance that I didn't get in right?
4) The timing marks are dead on... should I advance it slightly to the drivers side?... about 1mm from what Ive read

Dont know if there could be something else horribly wrong or not... now that I've got the starting process I can barely touch the key and it will try to catch and run... 7-10 seconds, let rest 5 seconds, then apply another 5 seconds of heat (only do this once...) then half gas and touch the key... vroom... just too much vroom.... and no control. Injectors? IP? Lines? Will keep working it, but if anybody has tips please let me know!

 

[Hasdrubal]

In regards to the AC60's and a manual push button. You can keep them engaged for 20 seconds or longer, no problem. They are self-limiting, but do take longer than the original AC-13's or Wellman's to get to full temps. I have the time-temp comparison graphs if you would like to see them.

You do not have to turn them on or off. I always give it twice the time that the wait light shows. In cold weather that's about 17-20 seconds, then I after glow for 10 seconds followed by 8 second pauses and several glows for 8 seconds at a time. If I get back in my truck after a few hours I'll glow for 5 seconds so it fires right away, otherwise it would need several seconds of cranking to catch. Always think about reducing the wear on the starter.

 

[jam]

Hasdrubal, Thats really helpful to know and I'm always happy to read anything shared! After reading on the different plugs I like the safety of the ac60's but never had a clear picture of how long was safe to run them manually.

One question on the afterglow though... is that something I would do with the engine running? Or is that between starts?

Thanks for the info too, I really appreciate the help and have been trying to not bother you guys with the common stuff. I've been pouring through the manuals and I think my current problem may be the cold advance solenoid not pushing the timing up appropriately... going to pop the cover tomorrow morning and see if its engaging and smooth. Also read the little lever inside the injection pump could be sticking... but the manuals seem to point to the cold advance so I'll try that first.

 

[Chaski]

You should advance the timing. I'd advance it twards the drivers side 2mm ish. Cold starting with retarded injection timing results in no starting.

Also, how much pressure is your lift pump putting out? Is your return line unobstructed and intact?

 

[jam]

Will try advancing the timing... the lift pump is an airtex E8153 pulling through a Baldwin BF1212 Heavy Duty Diesel Fuel Spin-On Filter. Used the airtex after reading h76287-Electric-fuel-pump-recommendation and 48444-Electric-fuel-Pump-install... seems to have worked for some folks. Not sure of the exact pressure though, maybe I need to put a pressure gauge on it just to be safe...

The return lines are.... not? clogged.... I'm actually not entirely sure they are in good condition though... the clear return line I put on the injector pump seems to fill up each time I start the truck (after just installing it, or pulling the cover). Once the truck stops I get a single air bubble that floats to the top of the bend from the nozzle side towards the IP... not sure this is a problem or not. When I run the electric pump and pop the cap on the gas tank I can hear fuel pouring bank into the tank too.

Its possible the solenoid for the cold start is dead though, going to check this morning to see if its working or not.

Thanks for the info on the advance!

 

[Chaski]

Looks like that pump is a 10-14 psi output. It should work fine. How you put the lid on doesn't affect the cold advance. Lid instill should always be done with the throttle shaft in the idle position. Put the lid on the pump as far twards the front of the engine as possible, then slide it rearward. The whole point of that is to make sure you don't stick the shutoff solenoid arm behind the linkage and create a full throttle runaway engune. The cold advance solenoid just regulates the pressure inside the case. The pressure change will move the advance piston (it is that thing on the bottom of your pump that is perpendicular to the main body)

If for some reason your return line is impeded or clogged it will kill the engine. If the case pressure isn't relieved it will climb to the point where the little pistons in the injection pump rotor won't return on every stroke, and if they don't return they are not pumping any fuel. Try using a length of hose connected to the top of your pump out to a bucket to see if it runs better.

 

[jam]

Pulled the top off the IP and pulled the primary fuel solenoid... applied power to both posts and it actuated. Clamped the ground to the body of the lid and touched hot to the post for the cold advance solenoid and nothing happened. Also tried applying power from the engine shutoff lead to the lead for the cold advance solendoid and got no clicking.
Pulled the nozzle off that returns the fuel and I don't see any glass ball:


Would think that shouldn't be possible....

Checked the power coming to the cold advance terminal and there was nothing at the lead. So I pulled the leads from the coolant temperature sensor at the back of the engine and checked for power... which came back at 12v, then attached the lead harness and stuck my probe in the green side and it came back positive... so that seemed to indicate that the sensor was getting power and passing it through. But when I checked at the solenoid end again I had nothing. Went back to the sensor and checked and no power to the sensor or out of it. Very confusing... is there another sensor inline with it that could be cutting the power? A timer or something? Or can I just run a hot fused lead to the sensor and count on it to shut off when it heats up?

Also don't entirely understand how the cold advance solenoid pushes up the timing... body pressure from holding back the overflow I guess....? There is a big vacuum thing on the side right next to the cold advance arm... does that have anything to do with it? Replaced a bunch of cracked and crumbling vacuum lines today too...

Again, thanks for all the help guys!

 

[jam]

Ah vacuum is for transmission shifting... that makes sense.

 

[Hasdrubal]

One question on the afterglow though... is that something I would do with the engine running? Or is that between starts?

That's with the engine running, cold start. Glow once and start once. When its slightly warm, you only need one 5 second glow for quick fire up. Here's a great vid explaining stock card operated glow times, courtesy of member Antennaclimber ; http://www.youtube.com/watch?v=MTkOl947aTk

 

[jam]

WOW, that was awesome, that explains so much! Going to give that a go... thinking I need to get the new solenoid and find the glass ball check valve (no idea where to get this, doesnt seem to show up on google, going to dig for a part number in the manuals) for the injector pump first though so the cold advance will kick in, but I can bet the afterglow will help and seeing exactly how the card works is incredibly useful.

It looks like the card is directly involved with the temperature sensor from the graphic above... which would indicate that my attempts at subverting the card might not be worthwhile afterall. Would explain why the power isn't showing to the temperature switch after some time sitting in the on position. Will try it again cold tomorrow and see if it gives voltage again...

 

[Chaski]

Hopefully the picture works. It is actually a regulator, there should be a spring and ball inside. The part # is 14067420 or Stanadyne 23183. You can get them new from your local injection shop, or from eBay or other sources. If you live near a pick-n-pull wrecking yard there are often a 6.2 powered rigs to harvest parts from cheap if you want to go with used parts, or are in a hurry.

 

[jam]

So after digging into the ball valve it looks like its pushed into the open state by the solenoid... which would reduce backpressure by 10psi and increase the advance by approx 4 degrees. So in my case, since it appears the ball is in fact missing, then am I right to assume the engine should be operating as if the cold advance solenoid is actually activating as expected for the cold start? If so then I guess I am barking up the wrong tree and there must be something else going on. Perhaps tomorrow I'll hook up a compression tester to all the cylinders to ensure I have good pressure.... not sure what else could be causing this weird condition...

 

[Chaski]

Your injection pump may need some work. If your compression checks out ok, and everything else checks out it may be time to get comfortable in the engine compartment and pull your injection pump.

 

[jam]

Right on, thanks again for the help! I'll post back the compression pressures in case its useful for somebody else in the future.

 

[jam]

So an update... I ordered a new cold idle advance solenoid, and the little glass ball valve to go with it.
I also ran checks on the power line going from the thermostat to the solenoid and wasn't getting power.
So... ran a new wire from the thermostat, replaced the solenoid and glass ball.
Then as per the advice provided above I loosened up the injector pump body and advanced the dash mark about 2mm and tightened it back up.
I ran the glowplugs as suggested above for about 15 seconds (ac60G's) and then once the engine caught kicked them on and off a few times for a second or so each.
After a little bit of adjustment it kept running and idled down!
Got out, looked under the hood and started making a list of everything else I need to replace now, but at least I've got a running 6.2!

Thanks so much for the help guys, couldn't have done it without the help!