conman577

First post and its sadly a cry for help
I'm not the greatest around cars, but I'm currently working on that, and going to school next semester for Auto mechanics. I have a little knowledge, but in terms of help, talk to me like I'm an idiot, lol.

I have my Z31, best car I've owned yet. Currently she's having some really odd issues. I was driving on the freeway home, and it started to just slow down, and lose any sort of power at all. I turned off cruise and tried to give it gas, and it just sputtered, and wouldn't go. Thankfully I was right by an off-ramp as this happened, and I managed to get it off the freeway, but as soon as I took it out of gear, she just died. Every attempt to start her after that would go as such; Turn the key, engine starts, sputters, dies. I managed to eventually hobble her into a gas station nearby, where it died and did not start again, till I went out the next evening to get her towed back in.
This time, she started, and idled very low and poorly, and was trying to stay on. She did, but I felt in no way safe taking it back on the freeway, so I got it towed back. The next day I went outside to diagnose and see if I could narrow it down, and it started right up, like nothing was wrong. As it warmed up, the idle dropped down lower until it sat at around 600RPM. I went out about two days later, just to start her up as its been pretty cold. Started fine, I even was able to run it around the apartment complex without any issue. I reparked, and let it idle, and amazingly there wasn't a single problem this time. Literally nothing seemed out of the ordinary. I didn't want to push my luck so I left it at that, but today I went out and initially there wasn't an issue, but I noticed that around 2k RPM she would just not rev past that point without a lot of sputter, but after 2.6-8k it would straighten out, but it didn't sound very happy about it(sadly though I had to cut short my observing as I forgot to completely tighten the anti-freeze cap, oops).
I've checked all the connections I saw out in the open, all but one were good, the one that was leading to what I think is the MAF was corroded, so I need to clean it up. All my hoses look in good shape, none that need immediate changing, or related to the issue.

Its a long read, but hopefully I gave enough info to help.

shogunb

My two cents, seems fuel related. Filter, pump, regulator. . check out your fuel system and let me know, Im curious, any trouble codes on your ECU?

Good luck
Shogunb

conman577

The filter is pretty new, I changed it back in june or so, only put around 1k on the car since. The rest I'm not sure. I was afraid it was the pump initially, just from how it was acting, but the fact that it works now is what throws that out the window. Tomorrow I'll go back out and mess with the ECU, and see what it throws at me, it was way to cold to keep messing today after my mishap. :P

conman577

Ran out and looked, I got no codes back, no blinking or anything, but the lights came on at least.. I have no idea what that signals.

rogerz

forget the codes they are usually useless. check the fuel pressure. check the chts. get the fsm from xenon. do the below listed as a start.
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.

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.

conman577

Its too dark now, but I'll take a look tomorrow and see what I find, thank you.

I wanted to add a note I forgot to mention, I had cruise on as I was driving home. Could that have had any catastrophic effect on the engine if it suddenly acted up? Surprisingly enough, almost 2 weeks later, my car isn't acting up anymore, as I was able to drive it around the neighborhood with no issues at all. I'm still suspicious and untrusting of this, as even the noticeable rattle my exhaust gives off at around 1900rpms or so has stopped. Why its stopped, I don't know, but it was really nice to not hear it for once, lol. I'm still going to keep poking around and being cautious though.

conman577

Well, I took it to a buddy's shop today, and aside from guessing the ignition coil was bad, we couldn't find any logical explanation for what happened to my car, or why its magically running fine again. I sprayed cleaner into two corroded connections, added fluid for the gearbox, brakes and power steering, and we replaced my distributor, as well as cleaning up the battery terminals. I personally think my cruise control tweaked out and made my car take a crap, so we just disabled that too to be sure(the switch was broke when I got the car, and the light recently started staying on and wouldn't turn off, thanks to the switch being busted).

On a side note, raising my car up let me see underneath, which showed me leaks from the power steering on both sides of the car, and 3 different spots on the transmission. They're not huge, they look like they've been there a while, and are very gradual, small leaks, which I think means the seals are going bad, and will cost me out the rear to fix. At least there's hardly any rust on the underbody, which was a great positive.