engine skip - plugs and wires? please help.

[92z32na]

I'm a noob bought a 92 300zx for 500 dollars. The engine has a skip and has no power. Do I need new plugs and wires or could it be something else? Any help would be greatly appreciated! Thanks.

[marty1mc]

Standard thing to do is clean all connectors for MAF, CAS, PTU, coil packs, injectors, everything. There is probably a ton of green corrosion on them. Get it all off first. New plugs are a good thing if it hasn't had them in a while, but you should also read up on a 120k maintenance once you get it running. Maintenance is the key to reliability on these cars.


ETA - if you change the plugs, please buy the proper ones! A complete set of plugs can be bought for about $56. They are expensive, but the Z takes a special plug.
Here is a link: http://www.z1motorsports.com/product_in ... cts_id=636

[es.biggs]

I got a set of 9 of those plugs for $30 shipped from ebay. Check it out sometimes you can find steals on there.

Changing the plugs is a good start, also cleaning the connectors as suggested above is a must do. Wires usually aren't changed on these cars because they use "coilpacks" rather than the traditional coil, distributor, wires, plugs ignition set up. A tune up on a car that utilizes coilpacks, like ours, usually just means plugs.

Another thing that commonly causes a misfire is an injector. Common problem on this car. Could be because of a loose or corroded connector. Rule that out first, then you can test the injector and replace it if necessary.

[92z32na]

Thanks for the help. I figured out which cylinder wasn't firing and changed the plugs. Still not firing. Now should I change the connectors and coilpack?

[Rich@RDZ]

the most common reason for a misfire is injectors. Ohm test them should read about 12-15 ohms. Out of spec replace there is no quick fix. We do more injector job on the 300zx then any other job.

Yup it cost a good bit of money to do, but 18 year old parts fail.

[92z32na]

Out of spec replace there is no quick fix.

What do you mean?

[marty1mc]

Out of spec replace there is no quick fix.

What do you mean?

He means that if the injector is ohming out of that range, the only option is to replace it. It can't be repaired.

But, have you narrowed it down to spark or fuel? In other words, have you checked spark? When you pull the plug is it dry and clean? If it is dry and clean, it probably isn't getting fuel. If it is wet or black with residue, it's probably spark.

[92z32na]

Replaced all plugs. If I get no spark with a new plug would it be a coil pack? I haven't that checked yet so I'm not sure that's the case. Just a general question.

[es.biggs]

Take a coil pack from a cylinder you know is good (one that IS getting spark) and put it in the cylinder that is not getting spark. Then move the bad one to the other cylinder. Now see if you get spark.