First drive in the Z, Backfiring and sputtering.

[messenger]

I don't think these are factory Nissan or Z therapy carb lines. What do you guys think?

Looks to me that someone replaced them somewhere down the road with just regular fuel line and some hose clamps.

The nozzle on the front carb is awfully gummed up looking, when I touched it I would get ATF from the carbs all over my fingers. I guesse it is leaking.

[Zedrally]

Reading back thru the thread, you mentioned that it was plug 5 and 6 that where fouling up.

You wouldn't have the plug leads mixed up, would you?

Just a thought!!!!

[messenger]

Update, The car is still fouling plugs. I think i can rule out the vaccum advance plate since i checked it. It seems to be in working order and the car is fouling plugs at idle in under a minute.

I cleaned the carbs, synced and readjusted them, checked float levels, replaced fuel line. They also seem to be in 100% working order. FYI, I watched the ztherapy video.

I pulled a plug out the other day and the spark looked to me to be weak and erratic when i held it up to the block.

The weak spark idea seems to be the only possible answer now. Althought i have changed cap, rotor, plugs, wires, battery, plus cleaned all battery and ground connections.

I checked the base timing a while ago that seemed to be in check. I want to verify if the line i was looking at on the crank pulley is correct, just to make sure my eyes are not playing tricks on me. Does anyone know what size bolt the crank pulley is so i can line it up on TDC and make sure? I checked my manual but could not find anything.

Once again here are the stats, the car is fouling plugs in under a minute at idle, with or without the choke on. All of the plugs look to be fouled equally. And just incase you did not see in my earlier post the compression test was right on.

Thanks for any and all help.

-jared

[my_mad_z]

Not sure if you read my post or not, but if you're saying you've replace everything electrical and you're still experiencing weak spark, I'd be checking the altenator.... If the brushes are worn or the voltage reg isn't operating correctly, you're going to get a very weak spark, as a result the motor will missfire, and the plugs will foul because the spark is not detonating the mixture sufficiently. The altenator affects both electronic and points distributers, so I would recommend you check the altenator.

Another thing to check is the condensor/capacitor that is located on the dizzy. I've also experienced problems with this which causes similar problems. I know that the points dizzy has a condensor but if you're using electronic ignition, there is no condensor. Start at the condensor first as it's easier to access; if there is no change, check the alternator.

Even if the voltage output from the alternator is within specification, I would still check the brushes; the reason is that the alternator may work fine with no load, but if loaded, the output may not be enough.

Hope you get to the bottom of this problem.

Seasons Greetings.

Marc.

[messenger]

Thanks, that sounds like it may be the case.

What would be the best way to go about inspecting the brushes, do I have to remove the alternator? I tried to look with a flashlight but i could not really see anything.

[Bambikiller240]

To inspect the brushes, you'd need to remove the alternator from the car and disassemble it.

"Some" parts stores, or auto shops that specialize in electrical repairs have a machine they can use to test your alternator for proper output.

[my_mad_z]

If you have the Haynes manual, it has a description on how to dismantle and check the altenator. I can't remember off the top of my head but to access the brushes, there is a black plastic cover that you have to remove located at the rear of the alternator. Once removed, you will see the state of the brushes.... there is a minimum length that is required for the alternator to function correctly, I'm not at home so I can't check the specs.

Good luck!

[Zedrally]

Replace the capacitor before you do anything else.....

[messenger]

I ordered a pertronix electronic ignition and a pertronic flame thrower coil. Thats should increase the spark a bit.

Is the capacitor done away with when i switch to the pertronix?

[Bambikiller240]

Yess, Check the Tech articles forum for a installation instruction.

[racebird1]

I am currently working on a 76 z that had almost the identical problem. refer back to a post Fairly new member 76 z. My main problem was fuel pump was put together wrong now this is not exactly the same because you have carbs and a differant pump pressure but they affects can be the same. As refered to above you need to check your floats to make sure they are not stuck open or closed. Fuel that has sat that long will always turn into varnish which will eventually turn into a gummy paste almost like glue. All of your fuel system moving parts will need to be cleaned. Your distributor advance plate should move more than 1/8 inch. You can carefully rotate the advance plate by hand and check for free movement. Also go back and put a vaccum line on it and you should be able to suck on it and get it to rotate it that amount. It is verry possible that the plate refered to above is also gummed up and not letting it move freely. Caution if you take it apart make sure you do it over a towel so you don't loose any small parts and make sure you know how to put all the parts back together properly. Good luck