cooch85

I have an 86 Z31 NA. I was having intermittent spark issues. Car would run for so long, then die. Id come back a few hours later, she would fire up and take off for a while and die. Well this became the norm tho it seemed to run for 10 minutes sometimes.....2 hours next time, anyway I downloaded and been reading the FSM thats downloaded on the site. I know that there is a diagnostic mode that can be turned on, on the ECCS. But I know they say to be very careful when working with this. Does anyone have any experience with this sort of thing? I have received some suggestions on other issues, but if it is not a crank angle sensor gone bad then something else is going on. I appreciate any and all help or suggestions. Thanks!

NismoPick

It's easy... with the ecu out of the kick panel, turn screw with screwdriver to diagnostic setting, and count the LED flashes, then look on the front of the ECU and read what the code means.

Easy to follow steps: XenonZcar.com Z31 ECU Diagnostics

If it dies when hot, it's most likely the ignitor module. But could also be the cas, or coil.

rogerz

don't expect a lot of enlightenment by using the diagnostic mode. It has never helped me. nismopick advice probably most likely. BAD IGNITER. buy some freeze spray. When it dies freeze the igniter. if it starts you know the problem. other wise as he said cas or coil. never hurts to put on a new dizzy cap and rotor. new plug wires and plugs don't hurt anything. may not fix the problem but insurance for a later time.

Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen. Usually on a rainy night around Oh Dark Thirty.

Clean the connectors for the maf or afm, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion. DON'T USE DIELECTRIC GREASE. more insurance for later
Z31 problems caused by poor battery/cables are common.

cooch85

Ok thank you guys. The igniter is brand new, the coil is new, the cap and rotor are all new. but I havent replaced the CAS yet. I thought i seen when reading thru the FSM that the diagnostic mode would give me a certain number of flashes for a bad crank angle sensor. ok though thanks guys. Just thought it said something about the battery cables when putting in diagnostic mode. ill re-read. K thanks tho. Hey, I have been told id be better off purchasing a used Crank Angle Sensor rather then buying new? Any truth to that? And either of you gentleman know where I can purchase parts for this car??

NismoPick

I have several spare working CAS's from newer VG33's (late 90's / early 00's). I can ship one to you USPS Priority for $25.

Pic from my 280ZXT distributor upgrade guide:

ken99

Were you actually checking for spark when the engine would not start? I've helped a lot of guys that just assumed spark was the issue without really checking. Yes, a bad crank sensor can cause this but what you describe also is symptomatic of a failing, overheating fuel pump.

cooch85

Yeah I am in need of one for a z31, a 1986 non turbo 3000 the VG30E engine. I would be very greatful to pick one up from a knowledgeable Nissan person! Message me or something so we can figure details out. Im still just getting the whole forum operation down. Thanks!!