# 1979 Datsun 310 starts then dies



## dudleydoitright (Nov 12, 2011)

It starts fine and runs good for about 5 seconds although at a high idle, then trails off and dies. Carburetor kit was recently put in it, but it was doing the same thing before. I also put a new fuel pump on it, a new clear gas filter matching the original, new air filter matching original, and new pcv valve all from advance auto. Wasn't having any luck finding parts from Oreillys or Autozone.

I've had the carb apart 3 times now adjusting the float and finally got that right since I can see gas halfway up in the sight glass, but it still seems like a fuel problem. The gas filter is half full, and sometimes I don't see gas in the sight glass.

I can keep the car running if I hit the accelerator pedal a few times right before it starts to die, but it's only temporary.

One thing else I noticed, when I take off the fuel tank line at the carbon canister, gas pressure is released and it doesn't gurgle out when i take off the fuel line at the carburetor.

It's quite a mystery to me. Any suggestions would be helpful. I have a shop manual so I can eventually figure it out if I get on the right path.


----------



## kelliann (Nov 7, 2011)

Did you try replacing the accelerator pump and rubber boot? Replaced mine and now it idles, doesn't stutter when taking off and no more feathering the pedal to keep it running.


----------



## dudleydoitright (Nov 12, 2011)

Good suggestion. I assumed the guy who put the carb kit in it replaced the accelerator pump, but I do remember the rubber boot still looking old and worn out. I'm thinking the rubber boot is only to keep dirt out and it's not airtight but I might silicon it down and around the cracks to see what it does.

I just got through sanding down and painting my wheels. Gray is the wrong color for an off white car. Metallic or silver looks much better. 2 coats 30 minutes apart, and a clear coat after that, and the wheels look better than the car.


----------



## kelliann (Nov 7, 2011)

If the boot is bad then chances are the pump plinger is bad as well.
When I removed mine tonight and compared the plungers, they were identical. The only difference was the boot on the old one was torn. The plungers both seemed to have the same amount of spring in them but I replaced it anyway. I have a 78 510 wagon. Not as cool as yours but still a neat old car. My engine is an L20B with the stock carb. I found an accelerator pump and boot through Fort Dalles Nissan in The Dalles Oregon and they ordered it in from Tennessee. That night I found a complete rebuild kit on E-bay for $15 and free shipping so now I have a spare. Now if I could only get the kickdown switch to work so I would have passing gear again! aahh the joys of owning a 33 year old car.


----------



## kelliann (Nov 7, 2011)

Oops. Pays to proof read. duh, Plunger not plinger


----------



## smj999smj (Jan 1, 2006)

When it was apart, were the jets and passages cleaned out? Afterwards, was the idle mixture adjusted?


----------



## SPEEDO (Jun 9, 2003)

there is a fuel inlet filter, replaced ?
also, there is a ficd (fast idle control devise) that screws in, sometimes the plunger will stick, has it been checked/cleaned/replaced ?


----------



## dudleydoitright (Nov 12, 2011)

Supposedly the guy cleaned the carb when he put the new kit in it. I verified the fuel mixture setting is correct by screwing it out, then screwing it back in to where the color changes on the screw so that should be close to where it was before. The fuel inlet filter on the carb appeared clean and I could blow through it. 

I'll check my shop manual for that fast idle device you mentioned.


----------



## smj999smj (Jan 1, 2006)

Simply screwing in the idle mixture screw to approximately where it was before is not adjusting the idle mixture.


----------



## dudleydoitright (Nov 12, 2011)

Well my dad came down for the holiday and had me slaving away on it. He's a retired ford mechanic. After concentrating on the carb for hours, he finally whittled it down to somewhere behind the gas filter to the tank, by putting the fuel pump intake line into a portable gas tank, and it ran forever.

I did think it was strange that the transparent gas filter was always showing half full, but I just thought a check valve was allowing the supply line to drain back into the tank after shutting off.

My original theory always was that the intake screen inside the tank was clogged, but my brother supposedly dropped the tank to investigate that while he was driving it. I'm thinking now, he may have dropped the tank, but maybe he gave up on trying to get to the intake screen. I even suggested he use an air compressor to blow out the gas line but I guess that check valve would have prevented that anyway. So here goes dropping the tank next.


----------



## dudleydoitright (Nov 12, 2011)

I took off the fuel tank and discovered there were some pieces of a black plastic flange off what I have no idea. I had to shake it upside down for 30 minutes to get it all to come out the fuel guage opening. I'm thinking smaller pieces may have gotton into the metal fuel line. There is no intake screen on the inside that you can see, remove or even get to. I doubt it has one. The only thing that comes out is the fuel guage and nothing really to check there. I did use a rubber fuel line hose and blow through the supply and return lines on the tank, they seemed fine.

Then my brother came over and we used an air tank to blow through the metal lines that run the length of the car. The return line blew like Hurrican Katrina, the supply line barely trickled out. So it's looking like I need to clean out the metal fuel line that runs the length of the car.

If you ever determine that the car runs fine out of a portable gas tank, but won't out of it's own tank, I recommend you just disconnect the rubber fuel lines at the gas tank, point them into a portable gas tank, and have someone blow air through them. Once all the gas is blown out, you may able to tell if one is clogged up in comparison to the other one.

Drain your tank first though, because the supply and return lines are towards the bottom.


----------



## dudleydoitright (Nov 12, 2011)

Finally got the metal fuel line cleaned out. That was a nightmare. It would have been a lot easier if I had checked for clogged lines before I went to the trouble of taking off the tank. The lesson to be learned here is use a portable gas tank sitting right next to the car gas tank in order to determine if the tank needs to come off or the metal fuel line needs to be cleaned. 

First, I took off the rubber fuel line in between the car gas tank and the metal fuel line and i went down to Ace Hardware and got 12 ft of that clear poly hose and got 2 brass couplers that fit both the clear hose and my rubber fuel line. Turns out I only needed one brass coupler though. Then I found a neighbor who's always working on cars, and asked him if he had a used fuel pump he could sell me. He did, and it was only $10. He showed me it probably worked by connecting it to the battery charger. Then I already had a regular can of carburetor cleaner, but eventually i needed 2 more full size cans. That was barely enough. After hooking everything up, I found that it was moving the cleaner through the line about an inch every 30 seconds. I knew that was bad, but at least it was moving it. When I decided to pump it through from the engine side, I got into even more trouble. Apparently, if you don't use water when you connect these rubber fuel lines, sometimes the inner lining can dislodge. Sure enough, when I ran some kind of metal wire through it, the liner had clogged the rubber fuel line completely up. 

Then I started making some progress. I was using a low pressure fuel pump 3 to 5 psi, which is probably your best choice for a small engine that has smaller fuel lines. I would be afraid to use an old crown vic fuel pump that supposedly has 30 some pounds of pressure. You have to strap that down, and hope it doesn't blow apart your entire metal line. Patience is a virtue. I figured putting the pump in the engine compartment would be more effective in dislodging the gum deposits since they were smoothed out from the rear.

I also started unplugging the battery charger, and raising the hose to get it to flow in reverse a bit, then plugging it back in to sort of give it a punch. Eventually it started moving through the clear line about a foot in 5 seconds. It was pretty cold so I also used a hair dryer on low setting to keep the cleaner warm in the small relish jar. I had to periodically refill it with carb cleaner.

The poly line will have a larger internal diameter than the metal and rubber fuel lines, so it won't be gushing out when it returns to the jar or can. You should be able to tell the difference though. To begin with it will only trickle out, and when it's clean it will shoot out from the tube slightly.

You can use one of those portable tire pumps to blow the lines out that most people keep in their trunk if it's got one of those 3 plastic adapters. I had no idea what some of those were for, but it worked like a charm. Just had to pick the right adaptor and stick it in the rubber fuel line, flip the lever down, and hold it with my hand so it wouldn't come loose. You don't want more than 30 pounds in the line that's for sure, so have your other hand on the lever to turn it off if it goes above 30. I also made one big mistake when i was finished, and I decided I was going to blow out the carb cleaner from the metal fuel line. I had 5 feet of poly hose with nothing in it, but as soon as I turned on my air pump, it shot it out quicker than I knew what was happening. Don't make that mistake. I was lucky it didn't get it in my eyes. I never did find any of those loose pieces i found in the tank. It seemed like I had gotton them all since I could pretty much piece it back to its original shape, but I wasn't sure. Turns out it was just gummed up.

If I had to do it over again, I would also use kerosene instead of carb cleaner, and I would use a larger glass jar, with a lid on it, and holes drilled to put the fuel pump sump line and the return poly line into. My booster battery came in handy to run the air pump too.

Remember, this can be extremely dangerous if you don't do this outside. If you're like me, I was concerned if I pushed it outside and put it on jacks, it may end up staying outside all winter long, so I did it all in my garage. You have to have good ventilation, and I did that by raising the 2 car garage door, and the side door while working and leaving them cracked open all night. There was always a little breeze. Flash explosions can occur due to the furnace or water heater igniting the vapors.


----------



## dudleydoitright (Nov 12, 2011)

If you do use kerosene, I'm thinking you definitely need to have it outside. It seems to me that kerosene would be much more explosive than carb cleaner. I also wore my weedeater safety glasses at first but they were shaded and I quit. Not smart especially when I went to blow out the carb cleaner with the air pump. Btw, that poly tubing is called vinyl tubing on the receipt. It was 5/16 i think and you will need a minimum of 11 ft for a 2 door 310 hatchback. If you put it directly on the supply side line then you will have to place the hose clamp on the knob to prevent leaks. It's not as tight as a rubber fuel line is.


----------



## dudleydoitright (Nov 12, 2011)

I decided to try kerosene out on the return line. I didnt have much luck since I couldn't get it airtight with no drips by the return line at the gas tank. Now I'm thinking 1/4" i.d. clear vinyl hose might be the best choice. The best I could do was get the line full of kerosene by priming the pump with a restaurant catchup container of kersoene, let it soak a few minutes then blow it out with my air pump. Once again, the main problem with that is even if you have 5 feet of clear hose, it only takes 2 seconds for the air pump to blow it all over the car. less with a smaller diameter hose. You really need two people for this job so one person can hold the hose away from the car or into a sealed jar. At any rate it blew pretty good so I think i'm good there. Btw, always bypass the fuel filter when doing this to make sure it gets full pressure. I'm also thinking a 10 to 20 psi electric pump might be ideal.

I also checked the check valve in the rear hatch area. Tricky to get the panel off and you can really only pull it out halfway without breaking the panel, just enough to get the check valve loose. it has 3 vents. The one on bottom goes to the outside right next to to the filler opening. The one in the middle goes to the fuel tank, and the one on top goes to the carbon canister in the engine compartment and is labeled fuel on the canister. To check the valve, disconnect it and blow through the middle vent. You should feel complete resistance until you blow a little bit harder then it will open up. Next, blow through the top vent and it should blow freely continously. 

I also went ahead and ran water from the carbon canister to the check valve area just to make sure it was clean too. Since this is just a vent line, I didn't figure i needed to do any more. Then I blew it out with air.

Next, I investigated the return metal line that runs from the carb. It seemed like it was completely clogged when i tried to put thin weed eater line in it, it wouldn't go, but after removing it I discovered the end is a nipple with a very small hole. I did find some extremely thin wire later after I took it off to run through it. I also put a little kerosene in it too then blew it out to make sure.

Well I guess that covers the whole process. Maybe I saved you from taking the tank off and the metal line from the carb.


----------



## dudleydoitright (Nov 12, 2011)

I'm looking to replace my accelerator pump boot too now that she mentioned it. Don't know why the guy who rebuilt the carb didn't put a new one on. Maybe the kit didn't come with one. Here's the info you will need 


California Type DCH306-75
Non California Type DCH306-76

Canada Type DCH306-74

I believe it's an Hitachi Carb, and I was told by my brother who had the rebuild kit put in, that he got it at Oreilly's.

http://www.tomco-inc.com/carblookup.aspx


----------



## dudleydoitright (Nov 12, 2011)

Just finished replacing accelerator pump and boot with a fuel system repair kit from Oreilly's made by Walker fuel systems Part# 15712A. It didn't solve my problem. Still starts and runs strong and smooth for about a minute then as the idle goes down, it tries to die. 

I read about a technique for holding a lint free rag over the carb opening, and if the rpm's increase it means you have an intake manifold leak. It appears that I do. It worked like a charm. As the car started to die, i could increase the rpms at will simply by holding the rag over the butterfly opening.

Does anyone know if I have to drain the radiator fluid first before I take this intake manifold off?


----------



## dudleydoitright (Nov 12, 2011)

Instead of taking the Intake manifold off, I think maybe the carb was just missing a gasket on the baffle. I noticed that it only had one gasket for the baffle plate a long time ago, so now I have a gasket under and on top of the baffle plate. Hopefully, that solved that problem.

Unfortunately, I detected another problem with the automatic choke relay located next to the battery on the fender wall. I would occasionally hear it clicking multiple times even when i had the battery charger hooked up. Battery is only a yr old too. Replacing that tomorrow.

This car acts like it wants to give up the ghost, but as far as I'm concerned, if the motor and transmission is still good which it is, I'm not gonna let it.


----------



## dudleydoitright (Nov 12, 2011)

Well I installed the relay and fixed that problem, but it's still not running quite right. I can drive it around the block, but the idle is too high, then when I lower the idle it won't stay running. Any other ideas? The idle seems to slightly fluctuate too.

By the way, I got that relay at Advance Auto. They seem to carry a lot of old datsun parts. All I probably needed to do was clean the prongs of the old one though. I didn't realize that until after I pulled it apart, and then I already broke the voltage wires to the coil on both sides. If you want to inspect one, leave the screw in and just pry the entire cap off. I made my mistake when I undid the screw, then pried it off. The copper wires running from the prongs to the coil are extremely fragile, and I broke both sides. If I had left the screw in, it would have all come out in one piece by prying the entire cap off with monkey pliers.

Anyway, on the other relay i just used white vinegar and salt, and soaked the prongs in a small yogurt container. Then neutralized the chemical reaction with distilled water and baking soda. I could have saved myself $17.


----------



## dudleydoitright (Nov 12, 2011)

Well son of a gun you won't believe this. I think I figured out the timing chain skipped a tooth now. I finally painted the timing mark, and no matter how far i turn the distributor, I can only get it to about 30 degrees.

I'm thinking it did it recently, because if you remember, when my dad (the real ford mechanic) was down here, it was running smooth out of the portable gas tank. That's when I started cleaning out the fuel lines.

Well today, I tried the portable gas tank again, and it barely stayed running long enough for me to check the ignition timing. 

Stay tuned.


----------



## dudleydoitright (Nov 12, 2011)

I'm running into problems replacing the timing chain of course. Here's what I've learned so far. You might as well take the alternator out, the brackets that hold it, and the water pump off. It's gonna leak about half an ice cream container full. Put a lid on it and clean up the mess so your pets don't lick it up. Some grease balls will fall into it, but I plan on filtering it with a coffee filter before I put it back in the car.

Now when it comes to getting the crankshaft pulley off, after 30 years it seems everything has melted together. It was extremely difficult. I had to use a heavy duty 3/4 in ratchet with 27 mm socket. I didn't have a breaker bar so I used an old fashioned bumper jack about 4 feet long for leverage. My brother gave me 2 good tips. Heat the crank shaft pulley bolt for 10 minutes with a cheap propane torch you can find at any hardware store. I tried 5 minutes to begin with but the flame was a little bit angled on the bolt. so it was still stuck. I finally figured out that I could put the propane out an angle outside the frame area and it would heat the bolt directly. Btw, it may look like there's a plastic center in it, but it's not, it's just a depression area in the center.

Also put the car in 4th gear with the emergency brake on, but even that won't prevent slippage. My brother figured out to use a medium sized pipe wrench, fit it into the bottom of the pulley area, and brace it against the car frame. After 10 minutes of heating the bolt again this time directly, it broke free. Supposedly they put 200 lbs of torque on these bolts from the factory.

The water pump and timing cover are all one piece so you'll have to take all the bolts out and nuts off all around the whole thing. Even the 2 bottom nuts on the corners. Then you can use something small and sharp, maybe even a nail to break the seal. 

Now here's where I'm running into problems. At first I thought the oil pan was preventing the cover from releasing, but then I realized I need to take out the outer crankshaft seal and work on removing the woodruff key to remove the inner plate. There's also a circular metal stretchy piece that is in there somewhere. Mine came out in one piece. Not sure if it's part of the outer seal or what. Anyway, my key has apparently bonded with the crankshaft. I tried everything possible even using a 2 ft long crowbar that has sharp ends for pulling nails and hammering it from the front and both sides. Even hammered down on it at an angle later. After hrs of working on it, I saw no alternative but to try and drill it out right down the middle without damaging the sides. 

This may take a while but if I get it, then the cover should pull off.


----------

