Don't get haynes it is very general pay for the Factory manual it will help greatly

I'm not sure what FSM you have - but Nissan issued Factory Service Bulletins which updated much of the information in the FSM's. At some point they recommended the extend tip BP6ES so that the electrodes projected farther into the combustion gases to help keep the plugs from carbon fowling.

If you are going to "read" your plugs - you have to install clean plugs and then run the car though its normal operating RPM range. A quick loop around the interstate and then home to pull the plugs. If the car has been driven around town, for short stop and go driving - you will not get much useful information from the condition of the plugs.

A choke sticking ON will give you a very rich mixture - and you will usually see carbon build up on the plugs. The FIRST thing to do is get the choke working properly so it can be full OFF...

FWIW,

Carl B.

Sorry for the thread hijack, but Carl, did the service bulletins recommend the projected tips for all models (e.g. my '78?) Thanks...

The FSM I have is copyright 1974 for the 1975 280z, and recommends b6es spark plugs. Next time I change plugs I'll get the bp6es. As for the choke, it is sticking off, so full forward, causing difficult starting but no other troubles than that, thanks! And I'll try the procedure to read the plugs since the ones I just put in are brand new and I haven't driven the car yet. Thanks for the help!

Without reading all the responces, I can tell you part of the problem is....

DO NOT Use Autolite Plugs in a Z car!!!

NGK BPR6ES

I personally use BP6ES but that's a personal choice. I also have a Mallory Promaster Coil, Unilite Dizzy and MSD 6AL. But I won't use anything but NGK plugs and wires. I've tried all the others, Autolites, Champians, Splitfires, Etc, etc. Nothing lasts as long or burns like the NGK's

Dave

Edited February 14, 201114 yr by Zs-ondabrain

I'm using ngk's now. The autolights were the previous owner, not me haha.

Ya I read that afterwards, but for anyone else who reads the thread, they'll know by reading all of our posts, that NGK is the only thing they should really use.

Glad you're getting it fixed. I think you'll be much happier with the NGK's in there. Better Gas milage and power and starting.

Dave