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521 fuel issues


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Hey guys, I’m sure this is covered somewhere and I’ve researched a bunch, just nothing that is solving my issue. I have an L16 in 521 and a couple days ago the idle seemed a tad rough, then it wouldn’t start after shutting it off.
I narrowed it down to fuel. I connected a fuel line to pump inlet and the other end was put into a gas can. Turned it over and no gas coming out of pump outlet. 
So, I replaced the pump and cleaned the fuel filter (which wasn’t too bad). 

Then I blew high pressure air backwards thru the line and heard it bubbling in the tank so no clogs there. 
I’ve been turning it over and over but no gas is getting pulled into the fuel filter. I even used some starting fluid and got the engine to run for a couple seconds but still no fuel being pulled. 
any ideas? 
thabks 

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 STOP! DON'T RUN ENGINE

 

Take the valve cover off and check out the eccentric in front of the cam sprocket.  If the head has been off and the sprocket bolt wasn't tightened enough and has come loose the eccentric will slip. Find out before you run the engine again. If that bolt backs out from running it and falls out the cam sprocket will fall off the cam and the timing chain tensioner will fall out. The damage could be bent valves and chewed up timing cover and more.

 

 

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Sudden loss of fuel.

Filter and pump replaced and line blown out

Still no fuel.

 

Check the eccentric ! 

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take the pump than pump the arm by hand!!!!!!!!!!!!!!!!!!!!!!

take off the gas cap

 

idle rough could just need a timing light and set that to say 10deg btdc

 

maybe idel jet is getting plugged

 

cut open the fuel filter and see how dirty and rusty it is. 521s esp in wet and dirty areas need to be swapped out more often

 

dirt get down fuel neck in tank

 

 

 

 

 

Edited by banzai510(hainz)
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Posted (edited)

Thanks everyone for your help. So I figured out my issue was that the pump arm was not sitting on the eccentric, but below it. From turning it over so many times, the arm kinda gouged the eccentric, but not too bad. I hooked it back up and it started up and ran no problem. 
THEN, while driving to work, I suddenly lost power and bogged down. I pulled the hose off the pump outlet and turned the motor over and no fuel pumped out. Is it possible the arm slipped off somehow? I never took the head off so i don’t think the eccentric is loose and my fuel looks super clean in my fuel filter (I have one of those glass ones with replaceable filters). I don’t have tools on me right now so I can’t do anything until later tonight or tomorrow. Thanks 

Edited by Primerdimer
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 Question. Is your pump bolted directly to the head? or is there a 1/4" plastic pacer between? The pump arm does not usually come off the eccentric like that ever.

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The original pump didn't pump either. Also if the spacer is left off a factory pump the arm is gouged by the eccentric.

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49 minutes ago, datzenmike said:

The original pump didn't pump either. Also if the spacer is left off a factory pump the arm is gouged by the eccentric.

Well, that could have been the old pump failed

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14 hours ago, datzenmike said:

 Question. Is your pump bolted directly to the head? or is there a 1/4" plastic pacer between? The pump arm does not usually come off the eccentric like that ever.

The spacer is there. I’m not sure that the arm came off, I was just speculating since I don’t have fuel pumping again..

 

12 hours ago, thisismatt said:

Could be the wrong pump. Did you carefully compare the arm and pivot location to the old one?

I did compare them, but prob not careful enough. I know the arms didn’t have identical shapes but seemed to end up in the same location as far as the eccentric goes. When I get off work today I’m gonna pull the valve cover and check it out. Thanks again  

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14 hours ago, Primerdimer said:

Thanks everyone for your help. So I figured out my issue was that the pump arm was not sitting on the eccentric, but below it. From turning it over so many times, the arm kinda gouged the eccentric, but not too bad. I hooked it back up and it started up and ran no problem. 
THEN, while driving to work, I suddenly lost power and bogged down. I pulled the hose off the pump outlet and turned the motor over and no fuel pumped out. Is it possible the arm slipped off somehow? I never took the head off so i don’t think the eccentric is loose and my fuel looks super clean in my fuel filter (I have one of those glass ones with replaceable filters). I don’t have tools on me right now so I can’t do anything until later tonight or tomorrow. Thanks 

 

Why would you need to take the head off to see if the eccentric was loose?  Simply taking the valve cover off would tell you that.  If it were me I would just buy a new fuel pump and eliminate it as the cause.  

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Like I said before pull the pump and pump it by hand. If it works there then its a gap or eccentic issue.

this is a simple fix. Im not getting it.

 

fuel pumps has a spacer inbetween.

 

does this do this when full tank or does this at a lower level?

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7 hours ago, d.p said:

 

Why would you need to take the head off to see if the eccentric was loose?  Simply taking the valve cover off would tell you that.  If it were me I would just buy a new fuel pump and eliminate it as the cause.  


I understand that, I was saying that because someone said that it might be loose if I removed the head at some point. And this is a new pump. 
 

6 hours ago, banzai510(hainz) said:

Like I said before pull the pump and pump it by hand. If it works there then its a gap or eccentic issue.

this is a simple fix. Im not getting it.

 

fuel pumps has a spacer inbetween.

 

does this do this when full tank or does this at a lower level?

 

ok so I just went over to the truck (across town where it broke down) and pulled the valve cover. The fuel pump arm came completely disconnected and fell down by the timing chain. The spring too. I’m gonna go over with a retractable magnet and fish them out. Wondering what may have caused this? I’ll have to compare the arms, and maybe just use the arm off my old pump. Do you think the gouge in the eccentric could have pushed the arm around enough to knock it off the pump?

42A89C44-E2DE-4DD5-AAF3-E799C324CCCB.jpeg

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Stock original Hitachi pumps don't fall apart like that. Maybe the first one was a replacement too???

 

I doubt that the replacement pump is an original Hitachi. Was the original pump like this?.... You should still have it. Never throw away stuff and never an original part.

 

OUT OF BOX Original Kyosan Denki Mechanical Fuel Pump For Datsun L20B 2.0L  NEW Car & Truck Air Intake & Fuel Delivery Parts Car & Truck Parts

 

Look like this?...

 

1340 Airtex Fuel Pump Gas New For Pickup Datsun 620 1976 610 | eBay

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5 minutes ago, datzenmike said:

Stock original Hitachi pumps don't fall apart like that. Maybe the first one was a replacement too???

 

I doubt that the replacement pump is an original Hitachi. Was the original pump like this?.... You should still have it. Never throw away stuff and never an original part.

 

Engine Fuel Pump New Fit For 1976-1979 Nissan 620 720 Datsun 411 510 520 521

Pretty sure it wasn’t original. 

709473D1-7CE8-4B7C-A1C6-BA965A1B32A9.jpeg

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What about the firsat one that stopped pumping???

 

Is that the one that just fell apart? If so these are obviously crap and the second one followed the first.

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Posted (edited)
16 minutes ago, datzenmike said:

What about the firsat one that stopped pumping???

 

Is that the one that just fell apart? If so these are obviously crap and the second one followed the first.

The first one just stopped pumping and that is the one in the pic I posted... 

The second one fell apart and looked like the pump in the upper-most picture you posted.(with the bolts holding it together). 
Is there somewhere that sells hitachi ones?

Edited by Primerdimer
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