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forbey
08-25-2010, 22:19
OK, I'm puzzled.

I drove to work today. Started on diesel, switched to veg, switched back 4 or 5 minutes before shutting down, purged VO lines with diesel.

Started up at 5 PM, on diesel, drove across town (5 to 10 miles) on diesel (no VO). Stopped at my usual Chinese Buffet for my usual Wednesday night, pre-bagpipe lesson dinner. Engine fired up, put it in gear, drove100 to 150 feet, engine died. Spent 4 hours trying to get it started, no fire what-so-ever!

I installed a new PMD, replaced diesel fuel filter and the fuel relay in the under-the-hood fuse box. Even tried ether. Before replacing the relay, I had to purge the filter and did so with no problem.

So...

I'm trying to walk my way through the process.

Tomorrow, first thing, I will add 5 gallons of new diesel. The guage says I have a quarter tank of fuel, but it has been know to lie to me before.

In trying to figure what else is wrong...

The idiot light on the dash says the glow plugs are working. Is it possible the light works, but the glow plugs do not? I have checked the fuel fuses, they look whole.

It might be possible for one glow plug to fail, but could they all fail at once? If the engine was already running and the glow plugs stopped working, wouldn't the engine continue to run, since the glow plugs don't stay on anyway.

The injection pump was rebuilt less than a year ago.

The diesel lift pump works because I could bypass the relay to purge the filter housing.

I'm getting stuck. First things first, we'll try diesel!

Thanks for letting me think on cyber-paper!

forbey
ToddMeister
08-26-2010, 06:15
Any smoke while cranking?

If the glow plug system fails, you should see some white/blue smoke while cranking.
forbey
08-26-2010, 07:14
No smoke, I did notice that last night. This may be the biggest indication that I was "spinning my wheels" last night. A deposit of 5 gallons of diesel at lunch time will be the biggest tell.

My luck it will be something simple like a bad reading from a fuel guage.

Jay
forbey
08-26-2010, 11:44
OK, dropped 5 gallons into the tank, reprimed the diesel filter. It made a vaccuum release sound when I opened the bleeder valve. I bled it until diesel came out. Attempted to restart again without success. However, it does appear that the batteries are now too low to start it, but I'm still not smelling fuel.

If it was a clog in the lines between the fuel filter and the injection pump, what would I do to release or investigate the clog.

And I still cannot get any fire when cranking over.
+
Jay
a5150nut
08-26-2010, 19:02
Don't see where you said what your working with. But I know my 94 has to see 100 rpm cranking before it will let the injection pump have any fun. Weak batteries can sound like its cranking fast enough, but. . . .
racer55
08-26-2010, 20:04
If you have a working lift pump I sure wouldnt expect to hear a vacume sound when opening the fuel bleed.
You could have a bad lift pump,oil pressure switch,clogged sock in the tank or a bad fuel cap on the tank.
forbey
08-26-2010, 21:04
I can't explain how it should work, just what I observe. Tonight, before I tried to start it I hooked up the jumper cables and then checked the situation in the diesel fuel filter. When I bypassed the relay it took 5 or 6 seconds for the fuel to come out the bleeder valve.

Tonight, I managed to get it started, it ran for 5 or 10 minutes, then, shortly after disconnecting the jumper cables, it died. I tried to start it again after putting the cables back on. This time, it turned over but again no fire. Unlike last night When I opened the bleeder valve diesel fuel shot up a foot. So pressure is building up, but the fuel isn't getting to the engine.

I finally called a tow truck. I will have to put the charger on it for a while. I just need to figure out how to verify if the lines to the injection pump are blocked.

Late, gotta hit the sack.

forbey
racer55
08-26-2010, 21:14
sounds like you have a restriction in the fuel supply or a leak in the lines before the lift pump.
Its strange that it would die when the jumper cables were removed.
what year is the truck
also there are 2 small screens at the IP inlet in the ds4 IP,they could be plugged if you have the electronic pump.I dont know if the mechanical pump has those screens and without the year of your truck I cant guess.
sorry about punctuation my keyboard is acting up tonite.
forbey
08-27-2010, 07:54
It's a 95.

Spoke to a friend who has worked 17 years with GMC diesels. He seems to believe it is the optic sensor in the IP.

Can I access the fuel system between the filter and the IP to clean it out? Or, am I looking at having to pull the IP?

Thanks,

forbey
forbey
08-27-2010, 07:56
Right now I'm looking at pulling the 95 6.5 in the Suburban and replacing it with a mechanical 93.

forbey
Yukon6.2
08-27-2010, 08:14
Hi
All you need to change is the injection pump if you want to change to mechanical injection.You will need a throttle cable and brackets.Then you have to address the trany if it is an auto.
I did change the optical encoder in my pump.Fairly straight forward if you have mechanical skills.There is a write up by a fellow in Norway i belive.I followed his directions and took less than an hour to take apart two pumps and switch encoders and get the truck running.
Good Luck Thomas
forbey
08-27-2010, 09:00
Hi
All you need to change is the injection pump if you want to change to mechanical injection.You will need a throttle cable and brackets.Then you have to address the trany if it is an auto.
I did change the optical encoder in my pump.Fairly straight forward if you have mechanical skills.There is a write up by a fellow in Norway i belive.I followed his directions and took less than an hour to take apart two pumps and switch encoders and get the truck running.
Good Luck Thomas

Thanks, that may be the best way to go. What needs to be addressed with the trany?

Jay
forbey
08-27-2010, 09:41
Thomas,

Do you have a link to the guy who provided the instruction to change the optic sensor?

Where do I find the specs on a mechanical IP for this rig?

Thanks,

Jay
Hooptybass
08-27-2010, 19:38
Has anyone heard of an optic sensor that will let you run off road and or veggie oil in your 6.5 ... i need one in a color other than red
Yukon6.2
08-28-2010, 09:11
Hi forbey
Here's the link of the procedure i followed when i did mine.I got my hands on a used pump that i robbed the encoder out of.
As for your trany if you were to go to mecanical injection,you would need a way to control the shifts which are controlled with the ECM.There are a couple of guys that have done the conversion.They are Dick Wells,and Bobbymartin,who also sells a book with detailed instructions and parts list.
At first it was my first instinct to switch over to mechanical,but i would like to learn the basics of the EFI for the experiance.Probly will own on with an auto tranny one day,which makes it a littel more difficult to convert.
Good Luck Thomas

http://www.mamut.net/royh/newsdet9.htm