Mr.Woof's72z Posted September 15, 2009 Share Posted September 15, 2009 I haven't posted on here much, but I've been driving my '72 240Z for almost 3 years now. Until recently she didn't have any mechanical woes besides a point replacement or valve adjustment here or there. And then... I was cleaning up the engine bay, getting the last bits of crud and accumulated gunk from 40+ years, and all around just getting her looking nice (wash, wax, polish). When I went to start the car up...nothing. Turned over, but wasn't getting a spark at all. A friend and I tried to figure out what went wrong, traced back through the wiring harness to see if there was any damage or a wire that was pulled loose. The only way we could get the car to fire was to bypass the resistor. Since it was an old coil/resistor I decided to pick up a new MSD Blaster II and matching resistor and throw it in. I was still getting full voltage from my wires so I wired up the new resistor and coil and the car started right up. About 20 seconds into it's idle it started lagging, and eventually died. The wiring on the original distributor has two black and white wires and a green and white wire, black and white coming from the "start" position and green and white coming from the "run" position from what I remember from looking at a wiring diagram. After it died again, I just wired up a 12v wire to one side of the resistor and the other side of the resistor to the coil with the included jumper from the MSD resistor. Had the same problems, started up GREAT, idled well for 15-20 seconds, then slowly died. I have asked a few knowledgeable people here and there, most have said that something is getting too hot in the wiring/distributor, causing things to overheat and go down. A few other people have said that the fuel pump/lines are the root of all this evil. I know very little on the fuel pump for these cars, so it could be something along those lines that I have completely missed, but it was running so perfectly for so long right before I decided to clean up the engine bay, which makes me think that the fuel system is not the issue at hand. I consider myself a weekend mechanic who is terrible at troubleshooting, so I'm looking to you guys for some help/hinters or just some ideas that I have blanked on, any help is greatly appreciated! Car set-up: L24 w/ E88 head Mild cam (unknown duration, etc) Weber 40DCOE's 6 into 2 headers Monza exhaust MSD Blaster II coil w/ resistor Aside from some Tokico springs, some body mods, and what is listed above everything is stock. This car is too much fun to let it sit! Please help! Quote Link to comment Share on other sites More sharing options...
zuum Posted September 16, 2009 Share Posted September 16, 2009 sounds like you uncovered a vacuum leak, maybe you dislodged some "crud" that was sealing it, and now its leaking? Get some carb cleaner or brake cleaner, and start spraying around all vacuum fittings and anywhere theres a gasket on the intake manifold, listen for a rise in idle speed, it may be very slight. Also if there is "crud" in the tank it may be getting sucked into the fuel outlet of the tank blocking it, and then settling back in the tank when shut off... Quote Link to comment Share on other sites More sharing options...
Mr.Woof's72z Posted September 17, 2009 Author Share Posted September 17, 2009 Decided to run new wires to the distributor, cutting out the extra "run" and "start" wires. Started right up and kept going strong. Drove around for most of the day today, no problems yet. Have an E12-80 and a new Autometer tach on the way, decided enough was enough with points... Zuum - hopefully fuel issues don't pop up, but I think I have fixed the problem, thanks for the heads up though Quote Link to comment Share on other sites More sharing options...
zuum Posted September 17, 2009 Share Posted September 17, 2009 Decided to run new wires to the distributor, cutting out the extra "run" and "start" wires. Started right up and kept going strong. Drove around for most of the day today, no problems yet. Have an E12-80 and a new Autometer tach on the way, decided enough was enough with points... Zuum - hopefully fuel issues don't pop up, but I think I have fixed the problem, thanks for the heads up though I hope you did not bypass the resistor... it will burn up your points rather quickly if you did. Also it could cause the coil to blow up (not like explosion, and shrapnel, but bad news for sure). Quote Link to comment Share on other sites More sharing options...
Mr.Woof's72z Posted September 17, 2009 Author Share Posted September 17, 2009 Did not bypass the resistor, set it up right. I've heard stories of coils catching fire, not fun. Quote Link to comment Share on other sites More sharing options...
zuum Posted September 18, 2009 Share Posted September 18, 2009 Good job then! Quote Link to comment Share on other sites More sharing options...
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