i just became a member and i wanted to introduce myself. i own a 1991 z32 black slicktop. i love it!! but i have a question. my car has an idle problem when i turn it on. the idle goes from 1,000 rpm down to 500 rpm or sometimes it dies. i changed the iac valve and the connector and the idle is still a problem. once its warm everything is smooth as silk. i've browsed through the different z32 threads but still not quite sure if there is something more serious going on. but i am excited to join zdriver! i will post pics later.

 

I had a 1990 and it had that problem...i think i took it to the dealer and they replaced the PTU. It was well over 10 years ago, i am not sure if it actually fixed the problem but it was done under recall. Is the alternator belt loose?

 

welcome to the site. always nice to have another slicktop owner around. these t-top guys just dont get it.

 

Hey, you never said anything about my slicktop!! Did you check BOTH the plugs at the back of the motor on the driver side? you can call the 1-800 nissan # to see if your car ever had the PTU recall work done by giving them your VIN number. I doubt it's your PTU though, and even if it is, they don't do the PTU recall warranty work anymore i don't think.

 

What about the head common '90 "soft valve"head problem?
Nissan made the valves in the head waaay too hard(funny because they called it soft", and when the valves shut on the port, they hit harder than normal valve on later models and slowly wear and creep backward into the head. Is it possible that his engines valves have creeped too far, and are creating the erratic idle?
My friend is just seeing the beginning of this in his '90 N/A.

 

i've never heard of that...

 

i appreciate all the input. i had my heads machined and all belts are new. i installed 6 new injectors installed by infinity about 9,000 miles ago, brand new alternator and belt a month ago, ( dealer install- $1,060 ouch ) new starter, new iac valve with connector a month ago. i can go on and on. i've put alot of money and time on this car.

i heard something about a recall but i havent made any history check up on that but i will look it up. but i'm beggining to wonder. i was driving home and battery light, tail light and brake lights came on and it died. i installed new alternator and right after that the idle was crappy. nissan reccomended iac valve. i got it and had a friend put it on and it was better but its still somewhat of a problem in the morning. should i take it to nissan or check for any codes? i have been trying to look for a Z shop around here ( i live in modesto, ca ) but been unsuccessful. i love this car and i dread to have something as major as taking the motor apart.

 

Welcome to Zdriver, and slicktops do rule. It looks like you covered alot of the things that might cause your idle problem. As stated, do the ecu check for codes. Double and triple check for vacuum leaks as this will be a very common cause. Additional things to check will be base ignition timing, vacuum check the fuel pressure regulator and dampener, and replace the pcv valves if they're old. I would not speculate that the ptu is your problem, or the soft valve issue that was common on the early 90'z models.

Being in Modesto, you might check out ZONC.ORG or BAYZA.ORG for some local Z shops.

 

If it started RIGHT after you put your alternator on, then hey check that again. any Z friends around that can let you borrow one to throw on real quick and check?

 

As CC mentioned, check the ecu codes, check for vacuum leaks and replace the pcv valves. I would recommend you clean your throttle bodies. If that doesn't fix it, then I would lean towards the coolant temp sensor or the AAC valve.

 

i will check the alternator again. unfortunetly none of my friends own a Z so i cant get one and test it. (for some reason they think vw and volvo are the s**t lol ) none of them want to touch my car cause they're scared of diddling with everything. i will clean the throttle bodies and check for leaks and ecu codes... ehhhh, the "soft valve" problem i dont think is the issue... 91zxtt, isnt the iac valve the same as the aac valve? its brand new so idk. but i will get this problem resolved! i will post pics. i just bought a 91 tt oem spoiler and the tt front fascia with the intercooler vents and the jdm tail lights. its going to look sweet!!! but that is the only issue with my ride. once warm, ride is awsome with smooth idling. i truely appreciate all your guys help. i feel like i'm imposing in some way. dats just me. :-)

 

Welcome. It's kinda like prison in here - Beat up the biggest guy you can find on day one and don't bend over in the showers.

Good luck.

 

Nope...

http://www.courtesyparts.com/z32/oe_IACV.html

 

i thought there were different acronyms for that specific valve. yes i know about the regulator for that valve. anyways, i called nissan and they said they will check it out for free this monday. this problem happened right after they installed the alternator. before that it had no such problem... wats da deal with the prison comment lol!! isnt it dont drop the soap or somethin. haha. helll naaaa. da last thing i want to read on here is a prison/bending over reference. i'm as straight as indian hair! i cant believe a fellow z comrad said that. makes me feel right at home. yeaa right lol. but i will keep dat in mind milo. i guess u learn from mistakes. j/k ohhh btw, is there a way u can get a spoiler template for 90-93? i have the spoiler and bolts and tape but i was wondering if i could get a template to line it up straight.

 

well i took my car in today. they said they recommend to perform ecm diagnosis, circuit testing between aac and ecm. maybe my ecm is the problem. cause it could be either the valve which is new, wires or the control, thats wat i think. any suggestions?

 

Sounds like the dealer's fishing. You didn't have the problem before, now you do. They just won't admit that they screwed something up.

Why did you replace the IACV in the 1st place?

 

i was on my way home and when i was turning left on an intersection, my car totally died. i turn the car on while its still rolling and it wouldnt stay on. i had to keep the foot on gas to prevent it from turnning off. brake, battery, tail light warning lights remained on. there was ALOT of power lagging. so the next day i took it in to nissan and they said it needed alternator. so i give the ok to put alternator. then they said there is an idle problem and that they reccomend replacing the iac valve which would of cost over $700. i said no thats ok i'll do that part myself. so i get the part from nissan myself and installed it myself and the idle was a little better. but then it got a little worst. so i take it back, which was this past monday and they said they need to check all circuits from ecu and the valve. they said valve was put on correctly and everything. i'm not going to spend $250 just to check wires and circuits. i do think something's up and theyre trying to get as much out of me as possible. if i only knew wat da hell is going on!!!! and when i got the car back on monday, my idle was wayyyyy down! now dat i think of it... i adjusted the screw on the side of valve so yes theyre f*****g with me. ahhhh, i'm such in a bad mood!!!!!! ( sorry for long read )

 

welcome, sugah--why you taking her to the stealership when there are perfectly good z shops up there?????

they don' know not'in at a stealership!!!!!

slickies are great--i have 2 ttops and a slicky--older than yours--but i keep taking out the slicky and letting the others rest.

does your car have an afm?????

try that.you are spending waaaayyytoo much tryina fix her. please tell me yyou will find a place that loves Zs and get it done right???????please?????

 

nice to meet u z-hag! is this also the mass aif flow sensor? how do i check the afm? i know i should know better than takin it to the "stealership" lol. it deserves some tlc!! it has been good to me overall. shes just a little sick but i hope she gets better or else i will have to do something and i hope it doesnt mean getting rid of it.... sometimes i wish i had some sunlight comming from top but slicktops>t-tops hands down!!

 

i got in contact with the "Z" doc and he said to clean the throttles and yes i did clean them and still the same problem. he then said to take out and clean the iac motor??? theres no one here that knows about my car other than the nissan dealership. everyone i ask tells me something different. do this do dat. and it looks like i will just take it to nissan. if i dont get this fixed soon, i will have to start thinkin of selling it. yes its a great car but the things i've done to it and wats left to be done is soooo expensive. this car is a money pit and i kinda knew dat when i got it but i never thought it was gonna be this bad. and its a freakin 1991!! i might as well buy a new 2007 car. idk, im beggining to give up on this nightmare of car.

 

You probably should have bought a 2007 model car in the first place. There are very few 16 year old cars that are going to run flawlessly for very long. You happened to choose one of the higher cost and higher maintenance cars in choosing a Z. You either need some car knowledge or some extra money to keep an old Z on the road. You can choose to learn, to pay, or to buy a new car. If you're giving up this easy then the Z wasn't for you in the first place.

Good luck.

 

It may seem harsh, but it's very true.

 

i'm not lookin at it as something harsh wat he said. like i said i knew it needed things here and there. this problem will get fixed one way or another. i'm doing so much research on it and its a learning experience obviously. i think da problem is that no one i know knows about these cars. so i kinda went in like a goldfish out in sea. its not like i cant drive it. i still drive it and love it, but i'm sooo picky its ridiculous! i was being somewat sarcastic bout getting a 2007. my z is all paid for, i have no car payments. all i need is to fix this damn problem. da fact that the car turns off when cold is kinda of a nag for me but dats bout it,its not the end of the world. i just bought a 94-96 oem spoiler and its in da body shop being painted and i got the jdm tail light kit and clear signal lights so its not like i'm giving up like " heres da car, its urs." but none da less, i welcome all criticism, good or bad, and i dont care wat negative things anyone says. besides, not alot of 2007's i like. only the infiniti g coupe and a few more. i'm more into the classic 90's and some 80's like the E 30 for example. Z was my dream car over ferrari's, lambos, lacs, etc. but yes repairs are a pain. but i take it as lesson learned. it cant hurt me, only enlighten me. when its fixed which should be sometime this week, i will post pics with the spoiler and lights and see wat y'all think. and i know i will be receiving comments like " u make ur slick look like a turbo, grrrr" or somethin like dat. hahahaha. i will take a pic after i'm done and i will post a before pic, and then an after pic wit all my accesories in bout a week. i truly appreciate all the imput that everyone mentioned. u guys are obviously knowledgable and i'm lucky and priviledged to have somethin in common in owning a Z. :-)

 

first buy a haynes then learn yo'sef how to fix it--there is a z directory for repair shops specializing in Z repair--they know your car and save you money.
and your frustration if you do not do it yourself.

sweetie, if i could fix my own and my mom's vws back in 68-72, tthen you can learn how to fix many things on your Z and save yourself time, aggravation and money.

these guyz can help you lots--they are smart. don't take anything wrong yet.

 

well i went back and checked for leaks and almost all of the fuel hoses were loose. i tightned the clamps and no more fuel leaks. i could see the fuel drip down and it was a horrifice sight! ( that explained the fuel odor comming inside thru vents ) then i did the ecu check. it showed code 34. how do i check this?