1990 300zx na Hesitation

[zxFarside]

http://charlotte.craigslist.or....html

I live in south Charlotte. I'm always looking at cars and car parts on Craigs list.

[mada300zx]

haha! good stuff! yea the system is sweet!

[zxFarside]

Those custom sub boxes? I need to get a better setup for my sound system. Right now I have a hippopotamus of a sub box in the back.

[mada300zx]

Those custom sub boxes? I need to get a better setup for my sound system. Right now I have a hippopotamus of a sub box in the back.

Yes sir! Got them off ebay for about 200 bucks! fit nice and snug in the back!

[zxFarside]

I'll have to start looking around for some, or make my own, I like making things lol

[es.biggs]

Haha this car is now my problem.

Hi nicoclub my name is Ethan.

[zxFarside]

Hahahahahahha welcome. I'll keep an eye out for that Z

[es.biggs]

So I'm gonna head to the dealership and the local nissan shop get some second opinions, and I'll get some info on the service bulletin about the left cylinder head on the 1990 model. Hopefully that's not the problem, but it's looking like it is.

Couple questions for you guys...if I end up replacing the left head, would it be necessary to go ahead and replace the right one too while I'm in there? Or maybe just replace the gasket/head bolts?

Also, where is a good place to get a cylinder head at a decent price? I just spent 7 grand on this car. Man I kinda f***ed myself.

Oh well. The car is mint other than this problem, which should be a fun project whenever I get some more money.

I just wish I would have seen this damn thread yesterday.

[mada300zx]

well at least I warned you of this problem before you ever looked at the car. Then you test drove it so you can't really be that dissapointed. I would do all the cheap stuff first. like cleaning the connectors. The car is 20 years old, some grime and dirt is a very good possibility on the plugs. I completed about half the check list before you bought it so at least you can narrow it down a little. But yeah if it does happen to be the head, that will suck a**! The video I posted on here suggested that you may have the wrong spark plugs. look through the receipts and make sure they are the right ones. I bought NGK but it has to be a certain NGK plug. But yea definitely do all the cheap stuff first on your own before you pay big money and find out that it wasn't even the problem in the first place! get ready to have a lot of people comment on your car though, it's pretty funny. almost everywhere I went someone said "hey dude that car is sick!" goodluck man and like i said call me if u have any questions. peace

[es.biggs]

Thanks man, no problem. Just want to say to everyone on here he did tell me there was a little hesitation and I didn't notice it much during my test drive. I was mostly listening to that sweet a** labree exhaust haha. But I know how selling a car goes you do what you gotta do...no hard feelings. It's more my fault than yours.

But shoot man the compliments have already started just messing with it in my driveway!

Any way you could post up everything you did to try and figure it out? Did you mess with the CAS at all?

I'll get to the bottom of this and maybe we could get an answer for everyone. I see tons of threads with this same type of thing going on, and a lot of people saying the head needs replacing, but nobody ever actually says whether or not that fixes it.

If I can get a good head and all the other materials at a price that won't kill me I don't mind doing it. Just give me a Saturday off of work and some cigarettes lol

[zxFarside]

Where in Charlotte are you? east west north south?

[es.biggs]

East. I live in Indian Trail, about 20-30 mins from uptown. What about yourself?

Pulled a spark plug out of the left head and got this:

It says NGK Iridium BKR5EIX-11. I think I read that the recommended plug was NGK PFR6B-11. I guess this could be my problem?

[mada300zx]

I posted everything I did on an earlier post. I haven't tried the cas. I am pretty confident its the spark plugs now that you actually pulled one out and its the wrong one. thats awesome though. Cheap fix. goodluck

[zxFarside]

East. I live in Indian Trail, about 20-30 mins from uptown. What about yourself?

I live in the Arboretum area (51 and Providence) although I have a few friends that lives in the Mathews and Indian Trail area. I'll keep an eye out for that car.

Btw those are ABSOLUTELY the wrong plugs lol Those plugs are for a '95-'99 Sentra/200sx

[z32pilot62]

Good luck to all! I found someone to buy my car for $7,000. So that's how I'm going to fix this hesitation problem!! lol.

Hey all, I just sold mine tonight for $3000 but mine wasnt in near as good of shape as Mada's. So i wont be able to comment in the future on the hesitation issue as my other 90 has a 95 motor in it To Ethan, hope you get everything figured out!

[es.biggs]

Alrriiiight. Got a little bit of a game plan...My next goal is new spark plugs. 8 or 9 bucks a pop...they aren't cheap but shoot I've noticed there is no such thing as a cheap part for this car lol.

If the spark plugs don't work, I'll be looking to buy one of the updated PTU's from a parts car or from somebody on here. New if I don't have any luck.

After that I'm thinking there is a problem with CAS, and that means it's likely that I'll need a new head

I am like 75% sure this is a timing issue. If the spark plugs don't work I will need to figure out how to check the timing/adjust CAS on this car.

I still don't know enough about this car to jump right into that though. I'm in school learning to work on BMWs and I could knock out just about any job on those engines, but believe it or not, this car seems even more crazy-engineered than most BMWs out there

[zxFarside]

You in the BMW program at CPCC?

[es.biggs]

Yeah its an awesome program

[zxFarside]

That's pretty cool. I have a few friends that go to the Levine campus so if you drive the Z to school I can guarantee that one of them is going to call me ans say "hey there's a guy with your car here" lol

I'll be going back to school in the summer of fall so I may see ya.
Modified by zxFarside at 7:16 PM 2/23/2010

[jsd300zx90]

How did the spark plugs do???

[jsd300zx90]

??????

..Can't wait to hear back from you!

[es.biggs]

Didn't get them yet, I have been crazy busy with work and school. I'm going to the Nissan dealership tomorrow probably and if they are cheap enough there I will buy them and if not, I'll wait for them to come in off the internet.

I'll be sure to post the results tho ASAP!

[zxFarside]

Didn't get them yet, I have been crazy busy with work and school. I'm going to the Nissan dealership tomorrow probably and if they are cheap enough there I will buy them and if not, I'll wait for them to come in off the internet.

I'll be sure to post the results tho ASAP!

You can get them from Z1 and you should get them in a day if your order them in the morning.

[es.biggs]

Just won an auction at ebay...

I get 9 new NGK PFR6B-11 spark plugs for just under $30

Gotta love that! Can't wait for them to come in

[zxFarside]

I hope that clears up the problem.

[mada300zx]

If that does clear up the problem. I would still clean up some of the plugs on the car.... dam i miss that thing!

[es.biggs]

Today was topless weather! haha this car is fun as hell man.

whatd you end up buying?

[es.biggs]

Just installed the new plugs...NGK PFR6B-11

There is no question the car runs a lot better now; smoother idle, better throttle response, and it seems to have gained a good bit of power back with the right plugs.

But unfortunately, the original problem is still a problem...so basically here is a recap of the big problem with the car:

At certain rpms below 3,000 the car seems to hesitate and it shakes pretty hard. It happens at about 1800, 2400, and 2700-2900. Those are just ballpark numbers to give you an idea. Once the tach passes 3000 the car takes off and feels healthy. You can physically FEEL the difference as 3000 rpm is passed, while keeping the throttle at the same level. This "hesitation" only occurs while the engine is under load. Revs in neutral are very smooth. There is an occasional backfire both during acceleration and in neutral. Sounds like it comes from the catalytic converter. When the car is cold, it accelerates smoothly at all rpms (I have never driven it past 4000 while cold though.) As the car gets warmer, the hesitation problem becomes much more apparent.

It almost seems like a predetonation/spark knock problem.

I took the car to Nissan today and spoke to a guy in the service department. I showed him a copy of the TSB regarding the early Z32s with heads that were machined wrong. After looking at my VIN, he told me that my car does fall under the early number of cars that were produced with that problem, according to the TSB. He said because of how old the car is he can't look back that far and see if the repair (new head, camshaft, CAS) was actually made back then, but he did mention that if this car was affected by the TSB then the previous owner would have had the repair done because it would have been noticed within a year of buying the car new.

I really don't know if I can believe whether or not the guy knows what he is talking about though. He seemed like he just wanted to get me out of the way so he could go make some money ripping off of some of the women in the waiting room. I hate dealerships, and I'm not going to work at one when I graduate.

My next step is going to be to check/adjust timing to 15 degrees before TDC. I might pull the CAS off and look at the teeth on it and see if they are chewed up.

Oh well. I'll keep this thread updated until the problem is solved.

[zxFarside]

Dealers are not the way to go.

There is a Nissan/Infinity shop on 74, Its past the super walmart on the right side. I personally have never been but I have been referred to them several times by a few people. It may be worth a shot to check them out to see if they can help you.

just found the site. http://www.nisstech.com/

[mada300zx]

I would definitely check the CAS before you do anything else. I read a forum that a guy cleaned his CAS and his problem instantly went away. Too bad it wasn't as simple as spark plugs huh? Anyway goodluck with it man. I'm buying a 2005 Acura TL on Friday. I have been driving my girlfriends busted ford focus all week. FML