no fuel for my 720 diesel?

moryd
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no fuel for my 720 diesel?

Postby moryd » Sun Apr 26, 2015 1:49 pm

I bought my truck about a year and a half ago and it died last summer. I had started figuring out was wrong then life happened and I couldn't work on it. Now I do. from what I can tell its the fuel pump. I did some reading and a lot of places where pointing me to the dpc. from what I can tell it working properly. I can get fuel through the pump with the primer but not when the truck is trying turn over. I replaced the filters when I got it but I only found the fuel filter in the engine bay. The glow plugs are working, I tested all 4 of them with a test light.
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draker
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Re: no fuel for my 720 diesel?

Postby draker » Sun Apr 26, 2015 1:57 pm

moryd » Sun Apr 26, 2015 2:49 pm wrote:I bought my truck about a year and a half ago and it died last summer. I had started figuring out was wrong then life happened and I couldn't work on it. Now I do. from what I can tell its the fuel pump. I did some reading and a lot of places where pointing me to the dpc. from what I can tell it working properly. I can get fuel through the pump with the primer but not when the truck is trying turn over. I replaced the filters when I got it but I only found the fuel filter in the engine bay. The glow plugs are working, I tested all 4 of them with a test light.



Welcome to NWD!

Just wait until Wayno is in, he is the diesel truck guy!
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Re: no fuel for my 720 diesel?

Postby flatcat19 » Sun Apr 26, 2015 3:32 pm

Are you getting power and ground at the pump?
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wayno
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Re: no fuel for my 720 diesel?

Postby wayno » Sun Apr 26, 2015 3:38 pm

moryd » Sun Apr 26, 2015 2:49 pm wrote:I bought my truck about a year and a half ago and it died last summer. I had started figuring out was wrong then life happened and I couldn't work on it. Now I do. from what I can tell its the fuel pump. I did some reading and a lot of places where pointing me to the dpc. from what I can tell it working properly. I can get fuel through the pump with the primer but not when the truck is trying turn over. I replaced the filters when I got it but I only found the fuel filter in the engine bay. The glow plugs are working, I tested all 4 of them with a test light.



How do you know the DPC module and injection pump controller are working, do you see the arm move when you are turning it over?
“The difference between genius and stupidly is that genius has its limits” Albert Einstein
moryd
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Cars: 81 720 diesel
94 jdm legacy gtb
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Location: Edmonton, ab

Re: no fuel for my 720 diesel?

Postby moryd » Sun Apr 26, 2015 3:41 pm

yeah that's how I'm guessing that it is working. I see the arm moving to the start, run, and off position. when some else is turning the key
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wayno
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Re: no fuel for my 720 diesel?

Postby wayno » Sun Apr 26, 2015 4:00 pm

moryd » Sun Apr 26, 2015 4:41 pm wrote:yeah that's how I'm guessing that it is working. I see the arm moving to the start, run, and off position


If you can see the arm move when it is turning over, then it can get fuel if the lift pump is good, this means someone else is turning it over or you are using a remote starter switch.
Just because the primer works doesn't mean the lift pump itself works, but let us assume it does work, so what you need to do is first check your fusible links with a volt meter, they are the 4 wires coming off the positive post that look just like the photo below, you need to check and make sure all 4 of them have power, unplug them from the harness and check each one individually, if all 4 have power then you can move on to the next thing.
Image
The next thing to do is check to make sure you have power to the glow plugs when you turn the key on, have someone turn the key on while you are watching your volt meter, it should move to a full 12 volts when the key is turned on, you cannot just assume that it works if the light comes on, the kid down the road couldn't get his engine to start, he said it had power, I tested it while he worked the key, he had no power, it will never start when cold, we jumped the glow plugs and it started.
Next you need to prime all the lines, this means you need to pump the primer while opening all the lines going to the injection pump, screw on fuel filter, all of them, you need to see fuel come out all of them before you close them back up, ALL OF THEM!!!, even the one going to the front of the injection pump, keep in mind that if the injection pump is in the off position, you will not get any fuel to come out of the injector lines or the return line as the fuel is in the off position.
I will wait for your next response before writing any more.
“The difference between genius and stupidly is that genius has its limits” Albert Einstein
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draker
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Re: no fuel for my 720 diesel?

Postby draker » Sun Apr 26, 2015 8:37 pm

Great advise wayno!!
moryd
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Re: no fuel for my 720 diesel?

Postby moryd » Mon Apr 27, 2015 10:47 am

ok I have checked the power I have 12 volts on all four of the plugs and 12 volts on the first glow plug going down to 10.7 by the last one connected. next I bled the whole system, the two bleeder screw on the pump all the bolts on the filter housing and filter and all the bolts going into the pump. all points pumped out fuel right away except for the two bleeder screws they bubbled a bit then fuel came out. still will not start.
moryd
Posts: 4
Joined: Sun Apr 26, 2015 1:18 pm
Cars: 81 720 diesel
94 jdm legacy gtb
12 g37x
Location: Edmonton, ab

Re: no fuel for my 720 diesel?

Postby moryd » Mon Apr 27, 2015 11:45 am

Good news. After I posted last I thought I'd go out and give it once last try. It did nothing then just as the battery gives up, it cough. Got the charger and with a little bit more patients it can to life. I have to give a big thanks to want for giving a great explanatio.
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wayno
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Re: no fuel for my 720 diesel?

Postby wayno » Mon Apr 27, 2015 4:51 pm

moryd » Mon Apr 27, 2015 12:45 pm wrote:Good news. After I posted last I thought I'd go out and give it once last try. It did nothing then just as the battery gives up, it cough. Got the charger and with a little bit more patients it can to life. I have to give a big thanks to want for giving a great explanatio.



Well that is good news, I am happy it started for you, when the fuel lines get air in them it causes all sorts of issues, first you have to bleed the air out of them, then you have to turn it over for a while till the air is purged out of the injector lines themselves, I especially hate it when a line/fuel hose cracks while I am driving it, when I shut it down to fix the line I lose it, and the engine at first starts, but then it dies, I bleed the system and it does it all over again, starts and then dies, so far I have been able to fix it just before the battery will not turn it over anymore, one time I called for a tow and I thought to try it one more time and it started and kept running that time, I called and cancelled the tow, the battery was basically dead, but after it sat for 10 minutes it recovered enough to turn it over a few more turns.
“The difference between genius and stupidly is that genius has its limits” Albert Einstein
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Re: no fuel for my 720 diesel?

Postby 510freak » Mon Apr 27, 2015 5:57 pm

draker » Sun Apr 26, 2015 8:37 pm wrote:Great advise wayno!!


Yes great advice wayno


Also
Welcome to NWDatsuns moryd
Taterhead » Tue Dec 08, 2015 6:35 am wrote:[quote="Taterhead » Mon Dec 07, 2015 2:41 pm


Sorry, I was channeling my inner flatcat.

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