91 300zx z32 non turbo. IDLES BAD.

[juanM]

CAN ANYONE PLEASE HELP ME FIGURE THE PROBLEM WITH 91300ZX.. IT WAS OK. NOT TO LONG AGO IT GOT VANDELIZED. SO I TOOK IT TO A BODY SHOP. AND HAD IT PAINTED, AND ALL DENTS REMOVE AND BUMPER COVER AND A NEW BUMPER REINFORCEMENT... THEY STRIPPED ALL THE FRONT FENDERS AND SIDE AND REAR EVER SINCE I GOT IT BACK IT IDLES BAD.. IN THE MORNING I START IT, AND RPM GO UP TO 1400 THEN IN LESS THEN A MINUTE IS DROPS TO UNDER 500 RPMS ENGINE SHAKES BADLY AND TRYS TO COME BACK UP. DOES THAT FOR A FEW TIMES AND THEN IT DIES...

BEFORE I TOOK IT TO THE BODY SHOP IT WAS A FINE IDLE GOOD PLENTY OF POWER

NOW SOMETIMES I SMELL ALOT OF GAS. LIKE IF ITS RUNNING RICH BUT NOT ALWAYS.
SOMETIMES I SMELL OIL BUT ALSO NOT ALWAYS.

I HAVE TO REV IT FOR A FEW MINUTES WHEN I START IT ABOVE 2000RPM AND THEN DRIVE IT..\SOMETIMES IT STRUGGLES AND I LOOSE POWER IT BECOMES A TURTLE AND COMES BACK.. ON FREEWAY I CAN PUSH UP TO 80MPH. BUT DOESNT HAVE PASSING POWER EVEN IF DROP TO 4TH GEAR..
AND ALSO FEELS LIKE HESSITATING.....

I REPLACE SPARK PLUGS OLD ONE WERENT AS BAD NO SIGNS OF OIL OR FOULING...
REPLACED THE TWO SENSORS WATER TEMP AND ENGINE TEMP. PUT NEW OIL NEW FILTER..

IT FEELS LIKE ITS THE LEFT SIDE CYLINDER. THEY DONT MAKE AS MUCH NOISE AS THE ONE ON THE RIGHT PASSENGER SIDE..THERES ALOT OF DRY OIL AROUND THE BOSE TO THE PCV VALVE. I CANT FINE ANY VACUUM LEAKS. SUMTIMES I HEAR A HISSSS...... PLEASE HELP ME.. ITS DOING REAL BAD IN MILEGE TO IM GETTING LIKE 60 ON FULL TANKS......

SO ALL IVED DONE TO IT WAS CLEANED THE CONNECTORS TO TPS,
MAS AIR SENSOR, CLEANED THE SENSOR UNIT MAS CLEANER,REPLACE THE TWO TEMP SENSORS,NEW PLUGS, CLEANED THE COIL TIPS TO SPARKPLUG. HAS COLD AIR INTAKE.I TRY ADJUSTING THE TPS IT IDLES EITHER LOW OR HIGH BUT CANT GET IT TO IDLE BACK TO 800 RPM OR NORMAL....

[z32pilot62]

Check codes first and then get back to us, there are plenty of write-ups on how to do this but just in-case you are lazy and dont wanna search, i feel like bein a nice guy cuz i just got my idle issues fixed:

http://www.nicoclub.com/archives/nissan ... ostic.html

[juanM]

i check the computer for errors... none found. both light flashed 5 times each..

i ran a test for the 02 sensors. they only blinked on and off when i hit the gas.. not by the them self..
i held the engine gas down to 2000rpms and they blinked on and off but only past 2500 rpm but only when i gave it gas.

[NORCAL300ZX916]

id start with those, my car was running rich w/ bad o2s, but nothing compared to that! do a power balance test also and let us know.

[evildky]

is the car running on all 6 cylinders? vac leak? if neither of those the aicv and air regulator would be suspect

[juanM]

yes my car is runing on 6 cylinders....looks like one pcv valve on the right driver side has been replaced. its in a different rubber hose... the one on the right i hear like hizz when i squeeze the hose or wiggle it. there also oil and dirt around the pcv hose and connectors....
ever since i got it back from the body shop...

[juanM]

yes my car is runing on 6 cylinders....looks like one pcv valve on the right driver side has been replaced. its in a different rubber hose... the one on the right i hear like hizz when i squeeze the hose or wiggle it. there also oil and dirt around the pcv hose and connectors....
ever since i got it back from the body shop...

[juanM]

yes my car is runing on 6 cylinders....looks like one pcv valve on the right driver side has been replaced. its in a different rubber hose... the one on the right i hear like hizz when i squeeze the hose or wiggle it. there also oil and dirt around the pcv hose and connectors....
ever since i got it back from the body shop...

[DCaff300ZX]

I also would suspect a plugged/failing fuel injector after it sat around not being ran for a period of time at the shop.
Ohm the injectors as well during your search...

[evildky]

a bad pcv will cause smoke ti shouldn't cause idle issues unless you have worn rings and the oil cap off or some other means for unmetered air to enterthe system

[juanM]

thanks guys. im going to check the injectors by ohm them out.. around what setting should i be looking for on the meter.....

also i said about one pcv. that when i wiggle the hose on the left hand side of the engine as u face the car i hear a hizzz like air scapes or enters from there... should i replace o2 sensors? i ran diagnostic and the check engine light wouldnt blink by its self i had to reve it on an off and the light would come on but not blink status.....

[sharky]

i have a similar situation. My Z was parked for about a year, then i ran the gas through it i didn't think anything of it but i shouldn't have done that. Well anyways it has good gas now, new fuel filter but it idles rough at start 500rpm and wants to die have to keep my foot on gas to stay alive. It also back fires while its cold or and dieing out. i replaced the timing belt/components and its on the mark just haven't used the light gun for the CAS yet. Once it warms ups it's better but when i drop it in gear it drops(RPMS) again but does not die. When i put it in drive it moves very slowly even though the rpms are at 2000 to 2500 doesn't really rev higher then that when in drive. I'm thinking of a couple of thing. 1. MAS, i can start the car without an air filter which i thought wasn't possible on these cars? 2. clogged injectors-checked ohms and they are good but thinking maybe clogged from old gas. Already replaced the spark plugs as well. 3. vaccum leak- all my pcv tubes are brittle don't know what condition the valve itself is in? 4. TPS- don't think this a problem cause it reads the motor fine. just lacks alot of power when in drive. 5. PTU-would explain back fire and lack of power when in drive plus read they had a recall which i need to look into. Well aside from that i have a new fuel pump, ecu and harness so don't know what else to check. Any ideas?

[robomatic12]

NOW SOMETIMES I SMELL ALOT OF GAS. LIKE IF ITS RUNNING RICH BUT NOT ALWAYS.
SOMETIMES I SMELL OIL BUT ALSO NOT ALWAYS.

-Do you smell gas in the engine bay or in the cabin? Or are you smelling a rich gas out of the exhaust?


I REPLACE SPARK PLUGS OLD ONE WERENT AS BAD NO SIGNS OF OIL OR FOULING...
REPLACED THE TWO SENSORS WATER TEMP AND ENGINE TEMP. PUT NEW OIL NEW FILTER..

What did you replace the spark plugs with? Did you use the OEM plugs? Anything else will cause hesitation. Did you use
oem sensors?

IT FEELS LIKE ITS THE LEFT SIDE CYLINDER. THEY DONT MAKE AS MUCH NOISE AS THE ONE ON THE RIGHT PASSENGER SIDE..THERES ALOT OF DRY OIL AROUND THE BOSE TO THE PCV VALVE. I CANT FINE ANY VACUUM LEAKS. SUMTIMES I HEAR A HISSSS...... PLEASE HELP ME.. ITS DOING REAL BAD IN MILEGE TO IM GETTING LIKE 60 ON FULL TANKS......


What don't make as much noise? The injectors? A hiss is a vacuum leak btw.

SO ALL IVED DONE TO IT WAS CLEANED THE CONNECTORS TO TPS,
MAS AIR SENSOR, CLEANED THE SENSOR UNIT MAS CLEANER,REPLACE THE TWO TEMP SENSORS,NEW PLUGS, CLEANED THE COIL TIPS TO SPARKPLUG. HAS COLD AIR INTAKE.I TRY ADJUSTING THE TPS IT IDLES EITHER LOW OR HIGH BUT CANT GET IT TO IDLE BACK TO 800 RPM OR NORMAL....

You need to clean all of the injector connectors and the coil pack connectors, normally everything has green corrosion and causes rough running. Sometimes the connectors are broken and you need to replace them. You need to remove your TPS and clean it or replace it. There is also an easier way to clean it by removing a part of the TPS hose and spraying WD-40 in it with the engine running. Google "300zx tps cleaning".


You need to pull codes from the ECU first. If you do not know how to do this, google "300zx ecu codes". You need to learn to search for this stuff. Then you need to pull each coil pack connector and see if the RPM drops. If it does not drop on one cylinder, that cylinder is not firing and we can figure it out from there. I believe you are looking for 10-13 ohms for the injectors.

[juanM]

so i test the cylinders to make sure the car is running on all six... one didnt cause anything to the engine it didnt die or anything.... i ohm the injector it givest about 13.2ohms. all the other ones read about 14. 1 or 3.

and what i made about noise on the cylinder side was the ticking noise from injectors working or cylinders working properly..
i cleaned the conntectors on all injectors and re check them. same as before 14.2 for five of them. the injector on the left side wich is the the 1st firing injector wasnt reading at first when i put my meter leads, now here and there it reads 13.sum ohm.
all the other ones read fine right when i touch em with the leads of the meter.
so i figure that injector is one prob....

all my connectios on the coils are clean no sings of corrosion.
i replace the spark plugs i used ngk's.
correct oil. ived check all the hoses and dont hear no hizz noise only when i rev the engine i can hear the cold air intake make like a hizz noise as i gas it. i check the tubes and are all ok..

before the car had a weird idle up and down up and down from 1000 to 1500. it would try to die but then it would pick up.. and i had all the horses running but plenty power...

now i feel like on 3 or 4 cylinders...

when i disconnect the tps nothing happens to the car no check engine light no drop on idle. nothing at all.. connectors are clean.. but maybe inside. i moved it and engine idles high way to high like 1500 almost.car still smells rich but engine dosnt die...

[robomatic12]

when i disconnect the tps nothing happens to the car no check engine light no drop on idle. nothing at all.. connectors are clean.. but maybe inside. i moved it and engine idles high way to high like 1500 almost.car still smells rich but engine dosnt die...

First off there are two connectors on the TPS, we are gonna deal with the grey one. Leave it plugged in for now. The TPS is adjutable and you need a multimeter on the volt setting with the engine running, loosen the two bolts on the TPS body, put a little needle or wire in the back of the tps connector (white lead). Connect your multimeter positve lead to that needle and ground the negative lead to the engine block. Now you can move the TPS until you get 0.46-0.48 volts. Then shut off the car and unplug the harness. Now start the car up and adjust the idle with the IACV to the proper RPM. You can now plug the TPS connector back in.

[juanM]

ok so if i cleaned the tps and adjust it. my car idles higher but still feels crappy. and burns very rich..also i cleaned the connections to the ptu.. when i wiggle the harness it gets worst sometimes dosnt turn over.. i may have a bad ptu? the harness look ok, no broken wires.....my car is definatly running on 3 cylinders. i unpluged the coil paks but it seems like it wants to die but not really..i know my drivers side cylinders and injectors are ok cus i hear the fast slight ticking noise as they fire......and if i squeeze the hose coming from the cold air intake i hear the air being blocked and then tends to die right away, the other same hose on the left side passenger side when i pinched the hose nothing happens, no noise from the hose is heard as i squeeze it tight. car dosnt seem to die..what you guys think ptu?

[evildky]

this diagnosis is all over the place, you have conflicting statements that make troubleshooting impossible, sow abotu we start over

ecu have any codes present?
is the car running on all 6?

[juanM]

no error codes......car seems to be running on 6 cylinders...hard to tell cus it takes about 15 secs for the car to die when i unplug the coil packs.. this is too frustrating anyone in california wants to buy a 91 nissan 300zx 154k miles??dosnt idle for s**t... ima get rid of her...parts are to expensive and i cant get any help. i dont know how to be more expecific about the problem im having.......mechanics around here charge and arm and a leg for labor. and parts for this type of cars here are sky high...

[evildky]

when you pull the cop plugs one at a time, does the idle drop for each cop? you don't need to leave then off for 15 seconds just long enough to see if the idle drops

[juanM]

to be honest the car just dyes pretty quick i have to gas it from the trottle body to keep it alive. when i remove the coil packs yes the car seems like its gunna die n drops rpms but hard to tell beacuse i have to gas it if not it dyes regarless its not breathing anything at all from the passenger side theres no air going into the passenger side plenum. i disconect the hoses and dont fell any air going in at all....

[evildky]

at idle the air doe not come thought the throttle bodies, it goes thouught the aicv and the air regulator and into the back fo the plenum and into the ballance bar, if modulator the tps keep the car running then you have an idle air issue