Hard to start-any suggestions?

[Art@NissanSport]

Here's my problem. If the Z sits for a few days and hasn't been started, when I go to start her up it takes a long time. We're talking about draining the battery long time. Once I do get it running it runs fine and will start right up even if I let it sit for a few hours. Starter fluid doesn't work either. It does to an extent but not the way it should. Using the choke has no effect whatsoever. Basically, it feels and sounds like its not getting a spark. But it will eventually start so I don't think that is the problem. I usually have to use jumper cables and my other car to finally get her going. Once I do get it started I have to feather the linkage and find a spot where it will stay running until it has warmed up.

Here is a list of things that I have already checked.

1) valves, cam sprocket, and timing have all be adjusted.

2) new plugs, wires, points cap, coil, battery, battery cables are all brand new.

3) I have bypassed the ballast resistor and it still won't start quickly.

4) fuel is getting to the carbs.

5) wires to distributor and coil are correct.

If anybody has had this problem and figured out the cause I would sure like to know what you did. Any help is appreciated. I have already talked to a couple of Z gurus and we still haven't been able to figure this out.

[Mr Camouflage]

tried a new battery?

[helopilot]

Make sure you have a good battery. That is first. Get a good understanding of your carbs from the z-therapy tape.

In my experience with the z-cars and roadsters dialing in the carbs is key. You need to get the choke set right as well. If you watch the tape a few times and have some patience it's not too bad. I'm not sure where here but on 311s.org in the maint wiki there is a good narative on setting the carbs. Print it out and read it as you go. Properly set up carbs should get you a long ways.

In both my su carb cars I can reach in pull the choke and hit the key. They will fire and idle straight away at pretty much any OAT.

The other thing I have found in Datsuns is if you kinda tap the key and release they fire. If you hold the key like a Chevy and keep the starter grinding away they don't start as well. Out of the 3 Z cars and 5 Roadsters they have all been that way.

Update Link to 311s.org su section

http://www.311s.org/pmwiki-311/pmwiki.php?n=TechSection.SuTech

Good luck and don't forget to post what actually works. That is the most help.

[John Coffey]

Art,

After your description here and the need to feather the throttle to keep the car running, I'm leaning more to a fuel issue. Also, check for vacuum leaks.

[helopilot]

Found the tech article here as well.

http://www.classiczcars.com/forums/showthread.php?t=9477

Phil

[Art@NissanSport]

I actually had Steve help me out with the tuning when I first put on the new/rebuilt carbs. We got it to run really well and it was balanced. Working with him directly is much better then the video.

John. I did pull the fuel line off the rail just after the pump to see if fuel was getting to the carbs and it was.

Someone mentioned that I should get a cutoff valve and run it on the fuel line so that fuel would be trapped in the line. They thought it might be returning to the tank and that might be one of the problems. Not sure that would be it because when I checked to see if fuel was moving through the line, it started pumping as soon as I turned it over.

What should the pressure be in the fuel line? I could get a pressure gauge and check it. Like I said, when I pull the choke on, it makes no difference.

I did replace all the vacuum lines as well. What is the most common place for a vacuum leak? And with that would the vacuum change depending on if the engine is hot or cold?

Could the distributor be bad? I was thinking of putting an electronic distributor from a 280ZX on it to see if that makes a difference.

[Jehannum]

Art,

If you need, I have a known good 240 distributor, coil, and ballast resistor.

This is Geoff from the Z club, BTW. Give me a call if you want to give it a go.

[xray]

Some wise old mechanic said "If you think it's fuel, then the problem is spark. If you think it's spark, then it's fuel."

Here's some random thoughts and SWAGs...

You have to jump a new battery to get it to start? Is your alternator good? Grounds good? Have you checked to see if you're getting battery voltage to your coil? Weak voltage-> weak spark = rough/no idle

Is the primary and secondary resistance of the coil within spec?

Why did you bypass the BR? The car does that automatically on start-up so that the cold engine gets full voltage to make the biggest spark to ignite the fuel air mix. Once it's in the "RUN" position, the BR is in the circuit protecting the points (along with the condensor). It may mess with your tach some as well.

Is the center point of your cap in good proximity to the rotor (cap too loose)?

Are spark plug wires checked for correct resistance?

You can check for spark at the plug wires by using a timing light..which ones light up consistently/inconsistently or not at all?

What do your plugs look like? Are they wet with gas? Carbon-fouled? What gap are you running?

I had to tweak my float level (also ZT refurbed SUs) to keep it from being over-rich; you may have to as well. Correct fuel pressure is right around 3.5-4 psi. Choke mechanism doesn't impact fuel pressure, but does drop the nozzle in relation to the float level making all needle stations richer than when the choke is disengaged. My ZT carbs had some issues with binding of the choke mechanism, so make sure yours move smoothly with the choke linkage attached.

Is #1 TDC correct in orientation between distributor and cylinder head? Has there been any action with the front cover (new oil pump, timing chain etc?)

When it does run, is the timing correct?

Certainly not exhaustive, but this may be helpful going forward...I had a similar problem when I resurrected my car, and it ended up being a combination of all the above factors. Tweaked the float level, my oil pump drive was off a tooth, needed a new 1.5ohm coil, etc etc

Good luck!

[Art@NissanSport]

The only reason I need to jump it with my daily driver is because I spend so much time turning it over that the battery starts to get weak. The battery is brand spankin new.

Timing is correct, TDC is correct. Car would start ok in the beggining but as time as passed and it hasn't been started very often, its getting harder and harder to start. Once it has started, it runs fine. Its the getting it started thing that bugs me.

[Bruce Palmer]

Art,

Just for giggles the next time this happens, stop grinding, hop out and pull a couple of plugs. If they a way wet, you're over choking. Once they're wet, you'll spend the rest of your "natuaral born" battery trying to dry them enough to light.

[Art@NissanSport]

I think I just earned the brain fart award for 2008.

Couldn't figure out why the car was having such a hard time starting. I decided to put in a 280ZX distributor and guess what? The Z started right up. Thing is, the points dizzy was not the problem. turns out it was the plug wire that goes from the cap to the coil. The wire had slipped back so far into the wire end that it wasn't getting a solid spark from the cap to the coil and was not properly slotted into the cap. As soon as I pulled that wire I noticed black soot in the cap. Bingo, problem found. Figuring everything was brand new and I had just replaced everything during the tuneup, it never dawned on me to check and see if there was a good connection. I did push each wire down on the cap thinking that I had a good connection to start with. It always seemed to me that it wasn't getting spark. For good measure I had my wife hit me up side the head for not seeing this in the beginning. She actually thought she had done something wrong when she was helping me to get it started when it didn't want to.

[helopilot]

Art,

Thanks for posting the answer to the mystery. It helps to file these things away in the brain.

Phil