1990 Z32 N/A Problem! (Help please?)

[Dima112]

so i bought a '90 z32 about 4 months ago, and right now it drives really funny. it feels as if it doesnt have enough power, feels like it drives weak from 2-2.5k RPM's, and in that range, when i Cruise the car shakes kind of, and makes a noise like (doo doo doo doo, or sometimes like Puf puf puf puf puf) sounded like the exaust?

the car has a custom Exhaust, and Intake, so its pretty loud, and i can hear the noises clearly.

i already changed my Intake Filter. and i use only Premium Unleaded Fuel.

i cant really explain this that much, but i need help! previously when i had the car, it had some problem with the fuel, (fuel lines were clogged? or dirty Injectors, and the car started when i cut the fuel off from the fuel filter to the engine it started then) so i started it once and put in Fuel Injector Cleaner, and it was perfectly fine then. that was like 3 months ago.



if someone knows that i can do to fix this, please help! im 17, and i just got into this whole JDM thing.. so i really dont understand that much about car engines. (dad does, but he doesnt know anything about Nissans!)

thank you in Advance! (:

[shippy8907]

Sounds like you have a misfire. You need to do a power balance test. Let the car idle and unplug each coil individually one at a time, and the one that doesnt make the idle get worse is the cylinder that is the culprit, whether its the injector or the coil/plug. I would do that and also check all your connections on your coil packs and injectors. Also check the PTU connection and all other connections that you can get your hands on. They usually have a bunch of green corrosion inside of them and that causes a lot of issues. There is an aerosol spray can of electrical connector cleaner you can get at your local parts stores that helps tremendously. Also before you button the connectors back up be sure to put some dielectric grease in the connection to keep the moisture out in the future. This might help solve your issue. Hope this is helpful.

[Dima112]

Also, when i drive at higher speeds, and i shift into neutral from any gear, it sometimes has the RPM's bounce up and down.. like goes up, and down constantly. and sometimes idles at 2k RPM's.

and the noise it makes, is like hearing bass just like VROOOOOOOOOOOOOOO
and in between those like gaps of air where you cant hear the noise, like theres air puffing through or something, its really hard to explain. ):
but when i accellerate, or go up hills, it seems pretty normal.

[shippy8907]

You should clean the idle air control valve and readjust the idle. Also check for a vacuum leak somewhere. Might be some vacuum lines rotted. It still sounds to me like you have a misfire somewhere. Check all the stuff that I mentioned before and clean your idle air control valve and reset your idle and see if that helps.

[Dima112]

Okay, so yesterday I actually had some time to check out what you told me above, I unplugged each coil individually, they're all fine. The ptu, one side had green stuff in it, which I cleaned out, but I noticed one of the tubes that was leading from the air intake was a bit loose. I took it out. And tried to blow air through it, every time I did. The idle got worse.. like the car almost shut off. So I thought that that was the problem, I tightened that hose up so it won't come off in the future. And thinking that would fix everything.. but it didn't, the car got worse since I did all of that. When I started it today. The rpms instead of being at 1k when the car is running just went straight down and the car shut off. The second time I started it and rev'd it a bit and put it in reverse and drove out.

When I was testing if everything is okay, the car started making more puffing noises in every gear it was in. And when I accellerate, it seems as if its hard for the car to do so, and also everytime I would take the car out of gear, the RPM's like go up and down from 1k-2k constantly and eventually stop at 2,000.. I'm pretty sure its not supposed to keep it that high.. so any more advice?

Oh and can someone please help me by putting a picture of where the idle control is? I have to also try that because it idles at really high RPM's

[nissanfreak12]

Another thing to check out is your O2 Sensors, I have heard some people having issues what your describing. You can do a ECU check on O2's, you just have to put it in mode 2 to check. Check this out.

http://www.google.com/url?sa=t&rct=j&q= ... S9aYLNc7cg

I would even check to see if you have any codes that come up in the first mode. Follow the instructions step by step. Stop blowing air into the intake, that will make the car run worse, your putting more air than what the car is metering. Do the ECU and O2 test and report back.

[Dima112]

Additional note; it runs fine when the car is cold (I.e. 6:30 am when I start it up)
it runs fine until the car warms up. Then it kicks in.

[nissanfreak12]

Coolant sensor, run the codes. Check for green corrosion on the connectors as well.

[Dima112]

So i took off my intake filter, and the car runs fine!
I put it back on and the problem is back, thats weird cause when it first started this issue, i bought a new filter hoping it would be better but it isnt.

So is the problem, in the sensor? do i need to replace the MAF sensor? Or what do i need to do?

[Dima112]

So, I need an answer before I blow off $60, do I need a new MAF sensor? Or is it adjustable?

[DCaff300ZX]

You can buy a can of MAF cleaner from the auto parts store, follow the directions and see if that helps.

[cjibs]

So Dima, did cleaning the MAF end up working for you? I've had what seems to be the same problems you're having. Let me know what else you did to get it fixed (if you did end up fixing it). Thanks!

[Dima112]

what i learned after changing all of my spark plugs, is that the wire to the first cylinder on the left was a little ripped.. apparently, and now its completely ripped.. the cylinder misfires, and i need a new wire basically