little help please,,, need an answer
10-07-2003 | 09:10 PM
#1
Guest
Posts: n/a
little help please,,, need an answer
here is the thing ,,, while I am driving not accelerating or anything. but the car in the 4th and the 5th gear. I notice that the car seems to speed up and slow down , speed up again and slow daown in a matter of seconds , when it slows down the noise of the car gets little lawder and it seems that it looses horse power but when it kinda speed up it goes to normal. that happens on 3000 to 4000 rpm only ,
I have 90 na 5 speed
why does it do that ??????? please help me guys
I have 90 na 5 speed
why does it do that ??????? please help me guys
10-08-2003 | 02:06 PM
#2
Administrative Brown Guy
Joined: Jun 2003
Posts: 5,406
From: Ontario, Canada
Seems to me like it sounds like something might be impeding air flow. Are your air filter/s clean? Check your connections at the throttle bodies, are they tight? The throttle bodies might need to be cleaned. Or a possible vacuum leak also comes to mind.
10-08-2003 | 02:40 PM
#4
Administrative Brown Guy
Joined: Jun 2003
Posts: 5,406
From: Ontario, Canada
you might want to check your plugs and coilpacks. The plugs might be fouled or one of your coilpacks might be bad. If you have a multimeter you can check that all read similiar resistance. Could you be running lean? Did you reset your computer when you installed your K&N? Did you install it recently? If so, just disconnect your negative battery cable. Leave it that way for a few hours so that the computer resets. Drive the car hard for the first run. Afterwards the computer will adjust itself for the new airflow characteristics of the new filter.
Otherwise, I could only assume if that's not the problem, something has to be impeding your fuel. Does your fuel filter need to be changed? How about the injectors, are those reading ok? Maybe the wiring harness for the injectors isn't making contact or is making intermittent contact during your higher rpm's? I think that's all i got on that one.
Otherwise, I could only assume if that's not the problem, something has to be impeding your fuel. Does your fuel filter need to be changed? How about the injectors, are those reading ok? Maybe the wiring harness for the injectors isn't making contact or is making intermittent contact during your higher rpm's? I think that's all i got on that one.
10-08-2003 | 11:08 PM
#5
Guest
Posts: n/a
hmm I thought first of the injectors ,, I changed them .. about the k&n I didn't reset the computer. I might do it. but that thing happennd before huking up the filter. and I might do those reading of the coils ,,, what ia the best place to go ,,, nissan dealer ??? sometimes the dealer reip you off if you know what I mean ,, I will check that out anyways ,, and it might be from the injectors that was my thinking ,, but I don't wanna buy injectors if they are good , I hope it is not a big problem... thanks for the information you have been very helpful...
10-09-2003 | 06:34 AM
#6
I'm Chillin
Joined: Oct 2002
Posts: 194
From: Phoenix, AZ
Since this is happening only in the 3000-4000 rpm range it might be the VTCs (variable timing control) solenoids. First check the connections by cleaning the 2 connecters very well and see if that clears it. If not disconnect them and drive it and see if that clears it up, if so, then your VTCs need replaced or atleast one of them.
10-10-2003 | 07:14 AM
#8
I'm Chillin
Joined: Oct 2002
Posts: 194
From: Phoenix, AZ
Well, there are two of them and are at the back of the camshafts on each V. The connectors for the VTCs are located on the sides of the engine. Look here for the harness layout at the bottom of the page:
http://www.300zx-twinturbo.com/cgi-b...ault&total=190
http://www.300zx-twinturbo.com/cgi-b...ault&total=190
10-15-2003 | 05:53 AM
#12
I'm Chillin
Joined: Oct 2002
Posts: 194
From: Phoenix, AZ
Well it will not hurt it to test drive it with out he vtcs hooked up, but like I said earlier, if the problem stops after disconnecting them, have them replaced. I think it would be like $250/side. Let me know what you find out and a price, please 
10-31-2003 | 07:18 PM
#14
Registered User
Joined: Jun 2003
Posts: 83
From: Memphis, TN
RE: little help please,,, need an answer
On my '90 NA it turned out to be a defective throttle position sensor. Now the car runs like a bat out of - oops, I forgot... I already said that in an earlier post.
Johann
Johann
11-01-2003 | 09:04 PM
#16
Registered User
Joined: Jun 2003
Posts: 83
From: Memphis, TN
RE: little help please/emissions
I can't know if it's the same thing or not... you will just have to go through a process of elimination till you get it.
My '90 NA had the same problem. Here's what I did:
(1) New platinum plugs
(2) New air filters
(3) Changed the oil (Yep... that finally got it through... it gets contaminated and causes the hydrocarbon emissions to be high)
I also discovered later I had a defective throttle position sensor... which I'm sure affected the emissions too.
Keep your idle up to around 2 or 3 thousand while you're waiting to get your test... that helps keep the cylinders cleared out.
JohannB
My '90 NA had the same problem. Here's what I did:
(1) New platinum plugs
(2) New air filters
(3) Changed the oil (Yep... that finally got it through... it gets contaminated and causes the hydrocarbon emissions to be high)
I also discovered later I had a defective throttle position sensor... which I'm sure affected the emissions too.
Keep your idle up to around 2 or 3 thousand while you're waiting to get your test... that helps keep the cylinders cleared out.
JohannB
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