Hello all, the name's Kalypso and I came across this site while doing research into some issues on my two Z's and it seemed like a good place to join. Hope my thread title is okay; wasn't sure how to preface it.

I apologize in advance for the excessively long post as well, I just want to get it all out there and get your expertise on all of the matters I'm facing.

Anyways, to get right to it:

I recently bought a 1990 300ZX N/A 5spd with 69,600 Original Miles on it. The car is in mostly mint condition except for some rust on some metal, such as the mufflers and such.

I have a few questions. Although I've owned a 1991 N/A 5spd since 2007, that car was modded heavily when I bought it (and not in a good way) so my familiarity with stock components is low.

I looked over the Z before purchasing and didn't notice anything really wrong with her, but now after a few weeks I have some issues that I can't quite figure out.

1) I think the Fuel Filler Neck has a leak in it. When I drove the car home and around the block for a few miles/days, there was no gas leak and the car was about 1/4 tank.

I went and filled the tank to the top (didn't overfill) and then drove home. I came back out a few hours later and there was a puddle of gas under the rear-left-wheel well and I could tell it was slowly dripping from the area of the Filler Neck on the Lower Section.

I took the tire off and jacked her up and after cleaning it up it didn't leak again after I test drove her gently and the tank went down and now she doesn't leak.

My Thoughts: There is a minor hole in the bottom section of the Filler Neck (It's pretty rusted) and having a full tank left some fuel in the neck and when it leaked out below the hole it stopped leaking. Make sense? PS: There was a bunch of black mud/dirt inside the Filler Neck Cover when I took it off, for what that's worth.

2) The vehicle has a notable hesitation when accelerating. It isn't anything major and there isn't any knocking or pinging noises it just feels like she's losing power on and off across all range of RPM's while accelerating. My one thought was maybe Bad Gas since it sat for so long. Could that do something? The car idles perfectly smoothly at about 650 RPM's by the way and of course if I Rev the engine in Neutral it revs fine since it's not under load.

I changed the Fuel Filter and checked ECU Codes and the codes came up 55 (Clean) and she did seem to sound different after the filter change and get a tiny bit better but the problem still persists. I checked the Air Filters (They are stock) and other than some minor dirt they look mostly new.

***SOLVED***>>>3)There is what appears to be an Electric Fan in FRONT of the Radiator in between the Radiator and the Air Filter Box (in addition to the stock Fan Clutch in between the radiator and engine) and I am confused because I don't recall that being stock and wanted to get some information on it.

4) The previous owner installed a "Viper Alarm System" as well as a 1300W Sound System with Subwoofer and Automatic Door Locks and some other power-grabbing things all connected to a standard battery (Autocraft Gold Part #24F-6 purchased 2012) that looks like it's struggling. Could power issues be a problem-causing thing due to this?

Thank you all for taking the time to read my post and I appreciate any and all help I can get. Here is a list of things I have documentation of and stats about the car:

1) The car has been driven minimally over the last 10 years. It sat in a garage for the better part of those years.

2) The Timing Belt was changed at 60k Miles but was done back in 2004 and so you can see that the car was driven only ~9,500 miles in 9 years. The documentation also includes other maintenance such as the Water Pump, Camshaft Seals, Cooling Fan and Radiator Hoses and Bypass Hoses. I don't think the Spark Plugs or Fuel Injectors were touched.

I'm going to outline below what I think might be the problem and hopefully you guys can let me know if I'm looking in the right or wrong direction so I don't waste time and that way I spend it all on the best thing.

Possible Causes (in my opinion)

1) Fuel Injectors
2) Spark Plugs
3) MAF Sensor
4) Fuel Pump
5) One or More Coil Packs

Thank you again so much in advance. I will greatly appreciate any and all advice/suggestions/help anybody can offer me .

-Kalypso

 

Hi Kalypso, does your car have AC? That's probably the fan for the AC radiator.

 

Ah okay yes it does have A/C. The 1991 I have also has AC but I guess since it was broken the guy just took it off.

Well, that explains one of those questions.

Thanks

 

Well I took my '90 Z out for a spin earlier tonight and it seems things have gotten better and worse at the same time.

I am now able to take off in first gear and rev up to 1,500-2,200 RPM's for takeoff and accelerate up to 2,000 RPM's fine but after that she's bad. If I dip below 2,000 again and try and accelerate it does the same thing; but, at least I am able to take off .

Also, it feels the Hesitation/Stuttering has gotten worse. When I rev past 2,000 as I accelerate it feels like it's bogging down and the RPM's go down and it's like the engine doesn't know if I'm still hitting the gas or not.

This is leading me to think the main culprits are the Fuel Injectors and possibly the Spark Plugs might have a hand in this ordeal as well.

Can someone please give me a link to a good guide that shows the how-to of the basics of checking Fuel Injectors? I'd really appreciate it.

EDIT: Oh, almost forgot to mention it. In my Original Post I stated I had a leak from the Fuel Filler Neck. Well, I got a stronger but not super strong smell of gas from the Filler Neck area now after driving. Is there a guide out there that can help me accomplish the task of replacing it or someone who can help me? Again, thanks so much!

 

You might want to try NICOclub.com - these type of questions are better answered there

 

300zx idle problems : 300ZX (Z32) General