New startup problem J13

[XXL]

Here is a 520 Wiring diagram. PM me your email address and I will send you the original PDF Wiring Diagram.

 

 

 

 

 

Thanks.  I have a 24" x 36" printout of the diagram hanging on the wall.

[DanielC]

If the above diagram is correct, and there are only three wires on the ignition switch, the meter, and the OIL, and IGN lights have to stay on during cranking.  

Unfused power from the battery goes to the ignition switch on a white wire.  Ignition current returns to the fuse block, on a black wire, with a white stripe, and that powers two fuses.   The black with a white stripe wire then continues to the ignition coil.

Black with yellow stripe wire goes to the starter.

[XXL]

Update is there's no solution on this yet.  I'm back to thinking it's a fuel startup issue because it's no longer hot around here and it's still going on.  First startup of the day, if I hit the starter for about 3 seconds, it will light up, then die (prior to my starting this thread, it would almost always light up like that and keep running... like you'd expect a well running car to do).  If, instead of 3 seconds, I just keep the key twisted for another 15-20 seconds, it will start up and run normally.  It will hit that kickover point I describe above, but I keep letting the starter do the turning, and voila... it starts.  It's really not a big deal except 1) it didn't used to do this, and 2) if I ultimately tear up the starter over time because of the prolonged spinning, it looks like I'll be in trouble trying to find a replacement.  

 

Having said all that, my gut tells me it's a lack of fuel coming up from the tank... so it wants to kick over with what's in the bowl, but that's not enough to sustain it for the extra seconds it takes to get fresh fuel.  One of the PO's (a board member) indicated he replaced the fuel pump, and it looks newish, so I don't want to immediately expect it.  But...

[difrangia]

Update is there's no solution on this yet.  I'm back to thinking it's a fuel startup issue because it's no longer hot around here and it's still going on.  First startup of the day, if I hit the starter for about 3 seconds, it will light up, then die (prior to my starting this thread, it would almost always light up like that and keep running... like you'd expect a well running car to do).  If, instead of 3 seconds, I just keep the key twisted for another 15-20 seconds, it will start up and run normally.  It will hit that kickover point I describe above, but I keep letting the starter do the turning, and voila... it starts.  It's really not a big deal except 1) it didn't used to do this, and 2) if I ultimately tear up the starter over time because of the prolonged spinning, it looks like I'll be in trouble trying to find a replacement.  

 

Having said all that, my gut tells me it's a lack of fuel coming up from the tank... so it wants to kick over with what's in the bowl, but that's not enough to sustain it for the extra seconds it takes to get fresh fuel.  One of the PO's (a board member) indicated he replaced the fuel pump, and it looks newish, so I don't want to immediately expect it.  But...

What kind of fuel filters have you got between the tank and carb? What about the screen in the carb inlet if it has one. Check all the filters between tank & carb. Iad a VW single-carb Squareback once that picked up a little piece of crap from the carb, lines, or tank that got in one of the jets. It would get enough fuel to just start and then would crap-out. Take the carb off and wash and blow it out real good.

 

Steve

[XXL]

What kind of fuel filters have you got between the tank and carb? What about the screen in the carb inlet if it has one. 

 

I have the factory style filter on the fender, which feeds the glass reservoir bowl on the fender.  I don't know if the carb inlet has a built in filter or screen, or if the pickup tube in the tank has anything there.  Anyone???

 

I like the suggestion though, and if I get un-lazy, I will dig into it a little... but it seems that if I had filter blockage, the problem would get worse at speed.  I can drive down the highway at 70 without issue... that's a lot of fuel that needs to get past a blocked filter or screen.  Just brainstorming.

[wayno]

OK, there are a couple things I will suggest looking into, number one is since you have the stock type fuel filter I might suggest that the top of that filter is bowed, it's made of pot metal, and they deform over time, so what happens is that it gets an air leak, then the fuel slowly goes backwards into the tank.

Now one would expect that the fuel in the bowl would be enough to get the fuel back to the carb before it died, but that is not how it worked out for my NL320, it would not start until I poured a little fuel down the carb to get it going until the fuel pump could out suck the air leak, and it didn't effect the starting of the car the next day, only after it set a week.

I put a normal plastic fuel filter where the stock filter was supposed to be, no more issues.

 

The other thing you should look at is the start mode power supply, so what you do is un-plug the wire going to the starter(start wire/exciter wire), then have someone turn the key to the start position, now check for power to the coil, does it have power?

I had an issue several years ago, somehow I had disconnected the power wire to the coil for when I started the engine, now I had no issues starting the truck when warm, I would just hit the starter and let off right away and it would run, well when it got cold it got a little harder to start it, then after a long period of time when all my ign. parts were dirty and wore out, it would not start at all the way I normally did it.

So one day I decided to help it a little, I have no idea why I did this, but it worked, I made a hot wire, every morning when it was cold, I put the hot wire on it from the positive side of the coil to the positive side of the battery, and it would start right up every time, this is how I found out that my hot wire for starting it had been disconnected.

So I found the disconnected wire eventually and have not had this issue since.

The reason it always started in the past was that I would hit the starter and let off, but the engine was still turning briefly, and it would get far enough after I let off the key to hit because the key was in the run position, and the coil had power.

 

First I would check for power to the coil with the key in the start position, if it has power, then I would bypass the stock fuel filter with a cheap plastic inline filter, and see if that fixes the issue.

 

There now, you have my 250 cents :lol:

[XXL]

Thanks, wayno.  Here's the filter setup I have now.  I ASSumed it was stock since both are mounted to factory tabs on the inner fender.  I figured the front one was just a reservoir, and of course, the rear one is the filter.  Seems odd to me... since GM used to combine the glass bowl reservoir and filter into one piece... that Datsun would keep them separate.  Maybe this isn't stock???  As you can see in the second pic, the bowl is full to the top with fuel.  I did just drive it, but I've also checked it first thing in the morning when the startup delay happens and it's also full then.  The "specks" in the photo aren't inside the bowl.  They are just amplified by the glass from the dirt on the inside of the fenderwell, plus some specks of dirt on the outside of the glass bowl itself.

 

[wayno]

That bowl is always going to be full, as the fuel is not pulled off the bottom and it is supposed to have a filter inside it with a spring.

You can have a air leak that you cannot even see, that is the type of fuel filter that failed on my 320, once I got rid of it, I had no more issues, it would start without pouring fuel down the carb after removing it from the system, all I have to do now is pump the pedal quite a few times as I let it sit to long all the time.

 

That second filter is a 521 filter on it's side.

 

I don't know, I was just suggesting that the stock glass bowl filter might be the issue, not saying it is, it might be.

[zed1]

There may be air being drawn in at the point where the glass bowl meets the housing. Try replacing the gasket with Tisco Gasket & Screen Kit, 70245941 9http://www.tractorsupply.com/en/store/screen-amp%3B-gasket-kit-allis-chalmers-case-john-deere)

Keith

[XXL]

There may be air being drawn in at the point where the glass bowl meets the housing. Try replacing the gasket with Tisco Gasket & Screen Kit, 70245941 9http://www.tractorsupply.com/en/store/screen-amp%3B-gasket-kit-allis-chalmers-case-john-deere)

Keith

 

Denton TSC has one in stock so I'll pick up tomorrow morning and see what happens.  Thanks!

[Charlie69]

Here is what I run.

 

Malpassi Filter King Fuel Filter & Pressure Regulator these are for carburetored engines

 

http://www.fuelpumpsonline.co.uk/malpassi-filter-king-fuel-pressure-regulator-85mm-clear-or-alloy-36-p.asp

 

 

 

[difrangia]

Bypass the original filter & see if the problem stays or goes away.

 

Steve

[XXL]

Follow-up to this issue... zed1's pointer led me to what I believe was the problem.  It turned out not to be in the glass bowl gasket, but rather in the sight window on the carburetor itself.  I noticed a tiny bit of weeping along the bottom edge of the window... not enough to cause even a drip, but just enough for there to be an almost-drop hanging from the bottom.  I gave the 4 flat head screws a very slight tightening (I know how weak carburetor metal can be) and the problem immediately went away.  So... that's fixed for now, but I suspect that, since that gasket was allowing the weeping, it's probably so fuel-logged that it may need to be replaced at some point.

[jalexquijano]

Isnt this Malpassi Fuel Pressure regulator and filter bowl to big?? I have a Datsun 240z and have seen there are two bowl sizes : 67mm and 85mm as the one you show. Shouldnt we use the 67mm?

[datzenmike]

From a purist's point of view...perhaps.

 

From common sense view....

 

I had a Dodge Omni and it had a tiny 3" spin on oil filter about $6. As it was a FWD and tons of room I slipped a chevy 305 filter on that was almost twice as long. More oil reserve and more filter material about $3. I've run Chev or Ford 4.9 liter I6 spin ons on my Datsuns for years. Same maker just larger and cheaper.

[Charlie69]

I have the 85 mm filters.

 

Here is a picture comparing the 85 to the stock 520 filter.

 

 

Here are a couple pictures of it mounted in my 520 using the original fuel line hole in the inner fender.

 

 

 

If you are looking for an 85mm glass bowl filter contact me I have 2 left.

[FunkyFresh520]

Wow so after all this time it was because the carb. Window part was loose??

[Charlie69]

I am happy you figured it out.  Enjoy!