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Air, fuel and spark, but won't start


Gnarlykatt

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These forums have been a huge help, but now I'm at a loss.

 

So here's the backstory. I have a 1968 Datsun Roadster 2000 that at some point prior to me getting the car had the stock U20 swapped out for a L16. The L16 has been in the car since the 80's. This past summer I started working on the car. It had problems galore, but I had it running and driving and it would fire up with the turn of a key. 

 

The roadster sat outside under a tarp up until about 2 months ago when I tired starting it to move it inside the garage. It fired up and ran with some help of starter fluid for about 5 mins then died and wouldn't start again. It would turn over, but wouldn't start. I checked for fuel (it has an inline fuel pump installed) and it's getting fuel to the carb. I checked for spark and I'm getting a white spark from the dizzy to the plugs. When I first started working on the car this past summer the coil was dead. It would turn over but wouldn't start (like it's doing now) so I recently bought a new coil and tried swapping it out and nothing changed. I rotated the crankshaft to TDC (compression stroke) and checked the timing. The dizzy rotor was pointing to #1 cylinder and plug wires from the cap are wired 1,3,4,2 (counterclockwise). I also ran a new wire from the neg. side of the coil to the dizzy where the tach connects. 

 

However, I just recently noticed that I'm getting 12 volts from the ballast resistor to the coil when the key is turned to the ON position. From what I've read I should be getting 6v at the ON position and only 12v when the key's turned to START position. I know continuous 12v to the dizzy can cause the points to burn out (I believe what's installed is the original distributor). However, I'm not sure how long this setup has been this way. I'm assuming since I got the car, cause I haven't re-wired anything from the ballast resistor to dizzy (except installing a new coil twice). 

 

I'm running out of ideas of how to get this thing running. I'm hoping someone on here might be able to help.  

Thanks in advance. 

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Hi Gnarlykatt, welcome to Ratsun.

 

Possibly a 1 ohm electronic ignition coil was used. The coil should be in the 1.5 ohm range. The ballast resister also 1.5 ohms. Combined the total resistance should be about 3 ohms. This will limit the current flowing through them and prevent the points burning out. During crank starting the ballast is bypassed for a hotter spark, but when the key is released the power from the ignition has to run through the ballast again. You should be able to produce a spark that can jump a 3/4 " gap, maybe more. If the rotor, cap or wires are old and not up to the job the spark may be 'leaking' away to ground somewhere. Have you cleaned the plugs? They may be fouled.

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Thanks Datzenmike!

 

I just checked the coil. I'm getting between 1.2-1.3 ohms from the primary side of the coil and 7,800 ohms from the secondary (tower) side of the coil. I wasn't able to check the ballast. The way the wires are connected is something strange. The connection almost looks like a pop rivet. The connection appears factory.

I believe new wires and plugs were installed about 10-12 years ago, but for much of that time the car just sat. I'm assuming the dizzy and cap are original. However, I pulled a spark plug and the end was pretty dark and fouled looking. I tried cleaning it up and reconnected it to the plug wire and then grounded the spark plug while turning the car over and got a pretty weak looking yellow/orange spark.

When I tested spark from the wires I wasn't able to get a 3/4" spark.

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I never seen a early Datsun coil go bad.

I seen the loosing the hot start 12volts or 12volt going to the coil when back is back to ON. Most time its the ballast wire loose or the connector in back by key switch.

 

You can have spark and gas but no compression it not going to start

If you dump gas in carb and then it starts it shows you have compression and spark.

So do the math. Is it means how about ck the valve lash on this L16.

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Thanks for the input so far everyone. So I bought new plugs today and installed them. I checked spark at the plug and it's a nice blue color now. I tried starting it up and still nothing. I checked the wires, they seem to still be in fairly good shape. I check the points and they're clean. The dizzy is dry inside as well. The car turns over really strong, but doesn't make the slightest sound of trying to run. I tried using a shot of starter fluid into the carb as well and still nothing.

 

I haven't checked the valve lash yet. However, how likely is it that the valves could now be gapped incorrectly to the point of it not starting if it was firing right up just a few months ago. Engine wise the car hadn't been touched since it last ran. Could it have jumped timing? I thought I read somewhere timing jumps are pretty uncommon on the L16?

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Due to the limited history I have of the engine, it's possible it could be a different firing order, but I'm almost certain its 1, 3, 4, 2.

 

I didn't get a chance to make it to auto parts store today, but I'm hoping tomorrow I'll have a chance to pick up a compression tester and see what kind of numbers I get from each cylinder. 

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So when was the last time it had fresh fuel?

I have heard of this before, Uncle Lua Lua let his 521 with an L16 sit on the side of his house for a long time(more than 6 months) and then he could not get it to run, I went over there and checked everything out, then I asked him how old the gas was, it was pump gas and it went bad, it had separated into 2 different layers in the tank, we drained the tank into a clear storage tub and it settled into 2 separate layers, the bottom layer where the pickup tube was in the tank was basically water and the L16 will not run on water.

Sometimes when the carb dries out and one starts the engine the bowl/bowls fill up with fuel that was in the fuel line coming from the tank, this fuel did not separate as it doesn't have access to air like the fuel in the tank does, so it runs for a few minutes till it burns all the fuel that was in the fuel line, but when that crap in the tank gets to the carb bowl it dies and will not run anymore.

I do not use pump gas with ethanol in anything I own that sits without running or driving for more than a couple weeks, I buy non-ethanol fuel for everything I own with a metal tank except my work truck that is a daily driver that gets fresh fuel every few days.

If you can use a gas can full of fresh fuel and run a hose to any electric fuel pump you can wire in, disconnect the hose on the carb and the power to the electric fuel pump coming from the tank and put a hose from the remote electric fuel pump coming from the fresh can of fuel on the carb, it may take a couple minutes of turning it over to get that crap fuel out of the carb, if it is the crap fuel it should start when it gets the fresh fuel.

You also could disconnect the electric fuel pump in the car from it power source, remove the hose from the carb and pour a little bit of fresh gas down the carb(I am assuming it doesn't have dual SUs), and try starting it, don't use ether, it don't always work and is hard on the engine.

If it does run then you will need to lift the back of the car up and drain the tank by removing the drain plug, if you cannot get the plug out then remove the hose going to the carb, put a longer hose on that hose and then use the electric fuel pump to empty the tank into a container.

I found if you put fresh gas into a tank with bad gas it is all bad gas after that as I used to have a second tank on my work truck that I didn't use very much, I filled it up one day and all that gas went bad, I only have one tank now because of the crap they call gas they sell at the pumps.

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We have crap gas, I thought I mentioned that a couple times.

You seen that photo I posted showing to separate layers, here are the photos again, this fuel came out of Uncle laulau's 521 that sat for 6 months???

Fuel_separated.jpg

 

fuel_separated_2.jpg

In Canada you likely have real gas. 

I wonder what gas you guys have down there. My string trimmer sits for 6 months at a time a9more actually) and the gas is 5 years old this summer. It rains a lot too.

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I bought a 620 box out of the wreckers. It sat for 5 years and 3 without a gas cap, I know 'cause I took it. Dumped the gas out and put into my 620 and away I went. It was really bright yellow but not a hint of trouble. If that shit on the bottom is water either it leaked in or the US gas companies found a way to dilute your gas with water. :lol:

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I bought a 620 box out of the wreckers. It sat for 5 years and 3 without a gas cap, I know 'cause I took it. Dumped the gas out and put into my 620 and away I went. It was really bright yellow but not a hint of trouble. If that shit on the bottom is water either it leaked in or the US gas companies found a way to dilute your gas with water. :lol:

 

It's called ethanol and it goes bad and separates if it sits too long, my machine shop guy once did a test, he sat 2 glasses on a bench in the shop, one had the pump gas they sell now and one with good fuel without ethanol, the good fuel evaporated into the air, that ethanol crap just got rancid(his word) and smelled bad, that is what he told me, he owns AC Nutter Racing(he has dropped the "Racing", a machine shop I take my stuff to, I believe him as I have had issues with it in my work truck and I removed the 2nd tank because it rusted out because of that gas, it was a perfectly good tank when I installed it.

Did you know that all gas stations in the US had to remove their underground metal tanks and replace them with plastic tanks, as far as I know all new vehicles have plastic tanks also as ethanol does't eat plastic like it does metal.

I recently in the last year was given a $3000.00 pressure washer because they could not get it started, I tried to start it at their house for them also, when I got it home I took the gas cap off and turned it upside down and emptied the tank, I removed the bowl screw and emptied that also, then I poured some good gas in the tank and let it pour out of the bowl for a couple seconds and then I put the bowl screw back in the bowl, I then poured a half gallon in the tank and it started by the 3rd pull as I recall, I use real gas in all my classic vehicles, blowers, lawn mowers, rototillers, my tractor, and any engine I test fire in my engine stands, the only rig that gets pump gas is my work truck, and that one gets fresh gas at least once every week if not more often than that.

Everyone can believe what they want, but I have heard too many stories from my customers about rototillers, blowers, and pressure washers not running anymore after they sat all winter, even my neighbor had a weed eater that would not start, it turned out to be the gas he had in his gas can as it was running before he put that gas in it, and after he bought new gas it started running again.

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Our stations all have plastic storage. Haven't seen a metal one dug up for a decade or more, though they do replace the plastic ones now and then. All regular (cheap) gas is up to 10% ethanol though Chevron and maybe others still sells high octane non ethanol fuel.

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