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Reverend

It Ain't Running Right!

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I posted this pic in another thread, but it might be applicable here as well. With the tach not installed, the coil is stone cold dead. So when you were cranking the car without the tach connected, it's no surprise that it wouldn't even attempt to start. But then once you reconnected the tach, it should have taken care of that.

 

Here's the pic of the ignition system:

 

pointsignition2_zpsufjy3jrx.jpg

 

When you are cranking (Key in START) position, the ignition switch sends power directly to the tach bypassing the ballast resistor. Then once you release the key to the ON position, that connection is replaced by one where power does flow through the ballast.

 

Do you have voltage on the coil + with the key in the ON position?

Are you triple sure you've got the firing order correct?
Are you triple sure that you've got the ignition timing correct?

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Yes to all. Im taking my Z to a shop, i have tried everything in my power. Maybe they'll know more. Things like this just makes me feel so damn stupid.

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Well shooting from the hip, the behavior in the videos you posted immediately make me think you're starving for fuel.

 

There was just enough gas in the bottom of the bowls to get it to run for a few seconds, and then once that little amount was sucked dry, you might get the occasional pop when trying to start it, but there's not enough in there to sustain running.

 

All the thought so far has been focused on ignition since that's what you had been messing with, but what are the chances your carbs are empty?

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I understand the seeming contradiction. I'm not saying that's definitely the problem, I'm just tossing out ideas since the other more mainstream ideas don't seem to be panning out.

 

As a way to explain the seeming contradiction... Liquld gas isn't very flammable. The plugs could be wet, but if there's no vapor coming into the cylinders when you crank it, it probably won't fire. In other words, It may be possible that the fuel on the plugs could be the last gasp of a bowl running dry.

 

Rule it out? Have you got a simple easy to check if there's an adequate amount of fuel in the bowls?
 

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Guy from the shop said "its not getting enough spark" He could not get it started either, even he's professional mechanic and runs his own shop. He was busy as he** and thats the only reply i got from him. He did not charge me so i could not go after and yell. I checked the fuel bowls and there is enough fuel, and its dripping from the ram pipes as i try to start it. Only rational explanation he has was that distributor was somehow damaged, so I took the distributor back to the guy who modified it from points to no-points dizzy. He said either it works or it does not work at all, so it should not work with "half" power... But i insisted on checking the dizzy anyway. I wonder is there any possibility that somehow all 6 plug wires were damaged at the same time..? I bought yet another set of plugs. Lets see how this works out.

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OK, you got fuel. We can rule that out.

 

Of course it's "possible" that all six plug wires got damaged at the same time, but it's so unlikely that I'm comfortable saying it's statistically impossible. The single wire between the coil and the distributor however could simulate the same effect as all six plug wires going bad.

 

So the dizzy is at the shop that built it? He's going to check it out and let you know?

 

 

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so I took the distributor back to the guy who modified it from points to no-points dizzy. He said either it works or it does not work at all, so it should not work with "half" power...

I had thought this same thing but I had a "half-power" ignition module  I've posted about it before, recently.  I damaged it by running the engine with two plug wires off.  Not sure exactly what caused the damage.  It showed a weak orange spark and would start and run with starting fluid, but not without the fluid.  And this was on a warm engine (note - starting fluid in a warm engine will cause detonation.  I only started it a couple of times and it knocked loudly as it started).

 

What is this "no-points" system you have now?  My problem was with a GM HEI module.

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Do you have spare parts ? If so put an original distributor with points on it for now, so you can go to the car show that's coming.

 

A yellow spark is always no-go, a blue spark is good, but even then it could not be firing under load in the cylinders, i've seen that many times.

When you check for spark, it should be fat blue sparks, and the spark should stay in/around the middle of the electrode and not on the side.

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Sparks were blue, but apparently very small. My friend said that it should be at least 1 cm spark, but i saw only small ones, maybe few millimeters. But i do not remember were they in between the gap or outside of it. I truly, madly, deeply hope its the ignition module.

 

My no-points system is oem 240z distributor with custom made ignition box and interiors. Been driving with those since 2009. Too bad i dont have spare distributor, but i shall wise up and get one extra. Could coil work at "half-speed" or something? I measured ohms from coil and ballast resistor, ballast was about 1.7 ohms and coil was about the same. I dont know jack squat about electronics but those readings should be okay?

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No way your getting a 1 cm spark, maybe with msd pro mag, but not with a stock like system. The spark should be steady between the tip and the center electrode, and not interupt. Not big, but clearly visible.

Edited by bartsscooterservice

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Yeah, it was clearly visible. So then the problem has to be in the amount of current (too low?), or in the distributor distributing it unevenly somehow...?

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Its all crazy. I see spark coming from the plugs when i tested them with my old coil, and tested that the resistance was okay. I fight for weeks to get my Z running for the big car event in 1.st of may. Then, as a final resort, i went to parts shop and got a new coil, just to rule that out. And guess what....it was the goddarn coil all the time!!

 

I dont usually smoke, but i have cigarets just in case i want one. I light one just after i have finished assembling all the stuff, coil, distributor (wich was tested by the guy who built it and verified as working, i saw the testing equipment and how it produces nice blue spark) yet another set of new plugs and new coil wire. After the nerve calming cigaret, I sat in the car, pressed gas 2 times so that the carbs get enough fuel to start and left the throttle halfway open. Turned key and BRAAAAAAPPPPP. I almost $^!# myself, it was like Z was angry at me for not seeing the obvious. It idles like straight from factory line (well everything else has been tuned for DAYS so i would not excpect nothing less haha)

 

Now i have this stupid grin on my face and i can't get it off, help :D

  • Like 4

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Don't know if you're familiar with the Peanuts comic strip but Snoopy had a happy dance that is appropriate for this occasion. Congratulations.

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Yeah, it was clearly visible. So then the problem has to be in the amount of current (too low?), or in the distributor distributing it unevenly somehow...?

 

Seems my ignition guess from last wednesday was in the right direction. Looked familiar because I saw the engine shaking, and it's a sign of bad ignition. But like I said, and like you describe above: you see a spark and think it's okay. But it won't fire onder compression in the cylinders !

 

Good thing you sorted it out before the car event ! :LOL:

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Yeah, i know Snoopy :LOL:  Still not on the clear, i have to inspect the car today, have to keep fingers crossed. For now its running with ballast resistor, whats the pro's and cons running without one?

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According to what I have read in the MSD manual, the ballast resistor is only needed if you use breaker points.

 

I believe that's an oversimplification and it's not that simple. It comes down to "dwell time" and the exponential relationship between time and current which will flow in an inductor. I'll go into the details if you want, but the simple answer would be something like:

 

It all depends on what's controlling the dwell time. If the dwell time is well controlled and is short enough, then you don't need a ballast, but if the dwell time is too long, or if it's not controlled under all conditions (like in a points driven system with the engine off), then you better have a ballast in the system or you'll likely damage something.

 

The electronic ignition systems, especially the newer ones, control the dwell time electronically and can limit the coil current adequately without having to resort to using a ballast. Older systems or mechanical systems do not.

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Yeah i was in the show today, lots of fun and 2 other s30's were there too :) BUT. Its not all dandy yet. I was so happy to get it running and driving, i seem not to notice that it stutters and sneezes occasionally. Well i've been driving maybe 100 kms in two days now and been tinkering with fuel pressure. First i tought it would be good idea to dial it down a bit (i dont have gauge btw) so i did that, if that would help leaning the carbs a bit. Well it stumbled a bit more after that so i turned it up a lot. After that it stumbled even more. After adjusting it somewhat to the point where it was, i noticed that even carbs get even flow of fuel, and all the idle screws are open 1.5 turns, it still spits from rearest carb, and especially from cylinder 6. Why from that particular cylinder? Because its in the end of fuel line, might it be, that it does not get enough fuel? Because i turned it open more than others, and it pops and sneezes over 3K rpm, when main jets are kicking in. To me, that seems like fuel issue..right? Could i compensate it by raising float instead of trying to open up the idle screw as much as i can?

Edited by Reverend

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Could be dirt obstruction in #6.

 

#5 & #6 share same fuel bowl so it  should be bad on both if it was fuel rail/pressure.

 

Swap the idle and main jets from barrel #6 with barrel #1 for shitz N gigglez

Edited by Blue

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According to what I have read in the MSD manual, the ballast resistor is only needed if you use breaker points.

 

FYI. I trigger mine with points using this MSD diagram. No ballast. Now that I have the car out of winter storage

I will be changing over to a magnetic trigger and eliminate the points all together.

post-4108-0-65632100-1430519623_thumb.jp

Edited by lumens

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I've set valves last summer, but might as well check them. I swapped those jets (for shitz'n giggles) and no effect.

 

This is the current situation:

 

-Timing @ 13 degree

-Idle mixture screws 1.5 turns open

-Runs super rich and stumbles and sneezes if idle is reduced

-Consumes fuel like crazy

-Idle jets are "50/100", i think thats 50F9

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