# 1987 nissan pickup rough idle prob



## bkdbest (Dec 8, 2005)

i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies

1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses

2= is there any way to adjust the idle 

3= any help would be greatly thankful


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## gwk007 (Dec 4, 2005)

try this link. http://autozone.com/servlet/UiBroke..._us/0900823d/80/17/ae/73/0900823d8017ae73.jsp 

if your not able to link up to this try autozone.com under repairs and put in your vehicle info. then look under driveability and emission controls, then scroll down to vacuum diagrams and system components. 
hope this helps. 
gary


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## 510Mods (Feb 21, 2005)

I have the 86 Nissan 720 with the Z24 carb motor and 5 speed tranny. Do you have the Z24i which is fuel injection? If so there are alot of things to go into. If its carbed, then I have an idea on where everything is at. Does it stay running if you pump the pedal or dies no matter what? Oh I have a new group set up for early Datsun lovers and for other makes also. Its a Yahoo Group called SACPARTS, for parts and how to's on vehicles. http://autos.groups.yahoo.com/group/sacparts/


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## bkdbest (Dec 8, 2005)

*1987 nissan*

if you give it gas it reves up normal but when you let off of the peddle it idles down then dies or if you push the peddle down quick then let off quick it idles up high then idles back down then dies but when your driving at a steady pace it runs fine


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## terri goddard (Dec 10, 2005)

bkdbest said:


> if you give it gas it reves up normal but when you let off of the peddle it idles down then dies or if you push the peddle down quick then let off quick it idles up high then idles back down then dies but when your driving at a steady pace it runs fine


 i am having the same exact problem with my 1985 nissan please if you hear anything please let me know. thank you we are with out transportation!


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## bkea (Feb 4, 2005)

The engine will not run smoothly until you get the hoses back where they belong. Probably need to use new hose too. I quickly checked the link to Autozone, but didn't see the vacuum diagram. I too have been looking for it. I have a Field Sevice Manual and it doesn't have it. I'm not sure it makes any difference which nipple on the air cleaner you attach it to. I've got to run to the doc. Maybe can add more later.


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## nissannut (Jul 3, 2003)

bkdbest said:


> i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies
> 
> 1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses
> 
> ...


Plug or replace the AB valve. Those fail and cause a huge vacum leak and prevent idle. I still have a spare one. You should have a Z24i since its fuel injected. Nissan never madea FSM for the 87 only the 86.5 and 88. I have an 88 it you still need it. I remember the vacum layout after owning 720s for 10 years. :thumbup:


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## bkea (Feb 4, 2005)

Nissannut
I sure thought I had an 87 FSM. Maybe its an 88. 
If you have the vacuum diagram email it to me or post a link here please. [email protected]


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## nissannut (Jul 3, 2003)

bkea said:


> Nissannut
> I sure thought I had an 87 FSM. Maybe its an 88.
> If you have the vacuum diagram email it to me or post a link here please. [email protected]


The 88 is very similar. The only differences between the z24 and the z24i was the charcoal canister and the egr control solenoid. The z24 ha 5 hoses the z24i had 3. 

The air cleaner vacumn lines are the same in the 88 schematic. Use those first.

Did you check the AB Valve (anti backfire valve)? Just plug the huge hose and see if it idles.


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## greenbean699 (Jan 18, 2004)

Just al little bit off topic. My dads 720 pickup has the sensor light on but we replaced the o2 sensor...is there a reset like on my sentra? 

it is a carb model...with a rebult z24


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## nissannut (Jul 3, 2003)

greenbean699 said:


> Just al little bit off topic. My dads 720 pickup has the sensor light on but we replaced the o2 sensor...is there a reset like on my sentra?
> 
> it is a carb model...with a rebult z24


Only 84-86 720s have the ECU. And 83 CA models. 

Its under the drivers seat. There a toggle switch to retrieve codes. I forget how to clear.


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## greenbean699 (Jan 18, 2004)

nissannut said:


> Only 84-86 720s have the ECU. And 83 CA models.
> 
> Its under the drivers seat. There a toggle switch to retrieve codes. I forget how to clear.


Yeah its a 86.....i just realized this thread said 87.
I seen somewhere something about a o2 hold box?

If the sensor light is on, will it burn more gas and have a rough idle?
Thats what his is doing.......


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## nissannut (Jul 3, 2003)

greenbean699 said:


> Yeah its a 86.....i just realized this thread said 87.
> I seen somewhere something about a o2 hold box?
> 
> If the sensor light is on, will it burn more gas and have a rough idle?
> Thats what his is doing.......


Do not know what the symptons are I just replace when the light comes on. Then reseat the code. The haynes manual is best. Plus if you search you should be able to find it. Try 720 section on 4x4parts.com

Same engine only now injected. Z24i. 

The ECU on the D21s 86.5-97 in US is under the pass seat.


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## mtdss1 (Jan 23, 2006)

*same problem*



bkdbest said:


> i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies
> 
> 1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses
> 
> ...


if anyone has the answer please email me too


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## greenbean699 (Jan 18, 2004)

nissannut said:


> Do not know what the symptons are I just replace when the light comes on. Then reseat the code. The haynes manual is best. Plus if you search you should be able to find it. Try 720 section on 4x4parts.com
> 
> Same engine only now injected. Z24i.
> 
> The ECU on the D21s 86.5-97 in US is under the pass seat.


I got a little more info one the truck. It was built in 85. The ECU is under the driver side seat. It only has a green LED and nothing more. The green LED comes one when i turn the key over but then goes out when the truck is running. The sensor light is on, and has a rough idle and not much power.
It has a 6mo. old O2 sensor. Anyone know why the sonsor light is staying on?
How can i turn it off without unpluging the light?


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## mtdss1 (Jan 23, 2006)

*same problem here too*



bkdbest said:


> i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies
> 
> 1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses
> 
> ...


i have done the exact same thing with my 83. i did eliminate the tvv (the thing with three vacuum hoses,<because it had broken into> some sort of heat sensor attached to it) ( on the intake) and it does seem to run better but still rough idle. if anyone finds a vacuum diagram ............ that makes sense... please e mail me too.thank you thank you!!!


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## pioneerscot (Jan 13, 2006)

there is usually a vacume diagram on a sticker under the hood some times its hard to see if its covered in grime


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## rogerd (Feb 19, 2006)

nissannut said:


> Plug or replace the AB valve. Those fail and cause a huge vacum leak and prevent idle. I still have a spare one. You should have a Z24i since its fuel injected. Nissan never madea FSM for the 87 only the 86.5 and 88. I have an 88 it you still need it. I remember the vacum layout after owning 720s for 10 years. :thumbup:


 I have also been looking for the vacuum diagram for 87 p/u with Z24 engine. Do you have access to one?


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## bkea (Feb 4, 2005)

The 87 field service manual has the vacuum diagram included in with other systems and it isn't very good. There are subtle differences in some of the trucks too. Some have the TVV valve with two hoses and others have a diiferent kind with three hoses. Some also have an EGR solenoid, but mine doesn't. Boy do I wish someone would draw it out and post it for posterity.

BTW, my 1986.5 Z-24i does have a five branched gismo on the air cleaner. There is a sticker right next to it, but the hoses are labeled with colors, and guess what. The hoses have been changed and there's no colors on them now.


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## lilFlip (Nov 8, 2006)

ok, I know that this thread is pretty old...but I just found this forum and am having similar issues did anyone find the vacuum diagram?


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## nissannut (Jul 3, 2003)

lilFlip said:


> ok, I know that this thread is pretty old...but I just found this forum and am having similar issues did anyone find the vacuum diagram?



I have an 88 and a 86diagram. The vacumn is almost identical on the z24s. 

Let me try to scan it for You.

You may want to try nissanofforad.net while you wait. or 4x4parts.com. There bigger Nissan forums.


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## lilFlip (Nov 8, 2006)

Thank you nissannut...also, I'm trying to locate the idle switch...any idea on this? I'm getting the code 23 on my ecu...

Do you get different codes flashing when the engine is running and not running?


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## nissannut (Jul 3, 2003)

lilFlip said:


> Thank you nissannut...also, I'm trying to locate the idle switch...any idea on this? I'm getting the code 23 on my ecu...
> 
> Do you get different codes flashing when the engine is running and not running?


Having trouble getting my scanner working. Apparently my 20' usb cable went bad. I can scan now.

The idle switch is in the TPS (throttle position switch). If I remember correctly. Thats on the head side of the tbi.


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## lilFlip (Nov 8, 2006)

ok, when you can scan it, can you send it to me anyway? Thanks for the information. I think I need to go get a throttle position switch and see if that corrects the error code and then move from there, but I would like to double check the vacuum hoses as well...as I think that is another issue.


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## nissannut (Jul 3, 2003)

I put a link to a big jpg on the z24i conversion page. Nissan Nut 
Some other pix on that page may help you.

Make sure you open in mspaint or something. It will not be blurry. If opened in IE its all blurred. Since its a big page scan.

code 23 is not in the 88 book. I just remembered the tps is on the firewall side near the linkage. It is adjustable. Airflow is on the head side.


here is the direct link. http://nissannut.com/projects/z24i_fuel_injection/vacumn_z24i.JPG


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## lilFlip (Nov 8, 2006)

NissanNut,

I have another question for you. Do you have any other diagrams that might help me map the following correctly? It may be in the diagram you posted, but I'm having a hard time mapping them together...









Also, is there a way to test the Throttle Position Sensor, before I drop $110 on a new one?


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## nissannut (Jul 3, 2003)

That thing is just a T and a pass through. There is 5 connectors. Originally the hoses were all color coded. But that wears off. 

There is a two port manifold on the intake right in front of the tbi. 

There is a vacum source on the tbi. I just noticed the evap is not mentioned in that pic. I have another page of JUST the evap circuits. 

I just marked up that same jpg with colors. Should make more sense now. I fixed ALLOT of friends z series motors. They run bad when hooked up wrong. This chart is the same for z20, z22 and z24 and z24i.


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## lilFlip (Nov 8, 2006)

Thanks a lot for the information and going out of your way to help me out. I will check these out now that I know where they are suppossed to go!


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## 500tim500 (Apr 25, 2007)

*1987 nissan z24 rough idle*

I am having the same problem, except my will not kill all the time, it just idles up and then way down low, it will kill when placed in drive or reverse (Sometimes). It will drive fine unless you punch it then it runs like crap, missing backfiring, sounds like its only hitting on 2 of the 4. I had it in last week and there was a corroded wire that lead to the injectors which allowed it to not even start. $160 later it now runs but with the above mentioned problem. any help would be good.


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## nissannut (Jul 3, 2003)

500tim500 said:


> I am having the same problem, except my will not kill all the time, it just idles up and then way down low, it will kill when placed in drive or reverse (Sometimes). It will drive fine unless you punch it then it runs like crap, missing backfiring, sounds like its only hitting on 2 of the 4. I had it in last week and there was a corroded wire that lead to the injectors which allowed it to not even start. $160 later it now runs but with the above mentioned problem. any help would be good.


Have you tried the basics?

Check or replace cap/rotor, plugs, plug wires etc???

Yours sounds pretty serious. Do a compression test also.


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## Nissanman5.9 (Dec 18, 2008)

*How to check TPS and adjust*

I need help on checking my TPS to see if it's bad or not, and how to properly adjust it when it's back on. There are five wires in all. Three (red w/ black stripe, white, and black). And the two on the side that plug into the tps. I've looked everwhere but found no good information. Even my Nissan manual says nothing about Throttle Postion Sensors.


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## nissannut (Jul 3, 2003)

You have a z24i.

Is this the 720 (4 headlights) or D21 (2 headlights)?

I have a procedure in my FSM. Let me see if I can scan for you.


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## Nissanman5.9 (Dec 18, 2008)

It has 2 headlights. I think it's just the z24, not the i. Thank you very much for helping me out. Manual after online manual and I still can't find anything on testing them.


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## nissannut (Jul 3, 2003)

The z24 is carb. The z24i is TBI. 86+. 

If you have a d21 86.5 - 97 you basically have an early 87 or 86.5. All 86 trucks 720s. I have a wiring diagram for a 88-89. There is some differences between 86 -87 and 88-89 unfortunately. 

I have a 86 FSM also but it does not cover the z24i since it was introduced so late.

ILL add them here.

Nissan Nut


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## nissannut (Jul 3, 2003)

OK i added to that link above.

Also added some efi wiring schematics. Get emails for those all the time.


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## Nissanman5.9 (Dec 18, 2008)

Cool. Thank You nissannut. So I probably have a d21 with the z24i engine then? Didn't know that. The truck was built in late '85. One more ? So the TPS has 5 wires, 3 are tied together and 2 are together. From what I've picked up the 2 wires are the idle switch. The 3 are the potentiometer part of the tps. Now on my truck the connector is gone and spliced, just wire to wire w/o any connector. Would you know what wire is what. They are red w/ black stripe, white, and just plain black. Thanks again for posting.


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## nissannut (Jul 3, 2003)

No problem. If you have a throttle body and not a carb. Then its a z24i. The z24 was never offered in the USA in a 720 (80-86).

You really have a 87 or 86.5. All 86 720s are either z24 or z24i or sd25 diesels in the USA.

There is no such thing as a 86 d21.Nissan released the d21 truck so early it confused the industry. 

Should say electro injected on the air cleaner for the z24i motors. They almost look identical with the air cleaner on.


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## Nissanman5.9 (Dec 18, 2008)

Yep, says electro injection on the cleaner lid. I edited my last post with some more information.


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## nissannut (Jul 3, 2003)

There is a few scematics for the efi on that same page. I just added for someone else. Those should help.


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## Nissanman5.9 (Dec 18, 2008)

Alrighty, guess I didn't look close enough. Found the TPS diagram. Thanks.


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## Gcbear (Jan 23, 2021)

bkdbest said:


> i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies
> 
> 1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses
> 
> ...


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## Gcbear (Jan 23, 2021)

bkdbest said:


> i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies
> 
> 1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses
> 
> ...


Hi you will need to change you anti backfire plug. That should fix it!


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## jp2code (Jun 2, 2011)

bkdbest said:


> i have a 1987 nissan pickup with a z24 engine my truck was idling rough so i tuned it up replaced the oil,air.fule filters oil, spark plugs but it still was idling rough then i noticed that some of the vacume hoses had fell off so i tried to replace them but some of the hoses had fallen off and i do not know where they go i also adjusted the distributor right and left but it did not help with the rough idle it idles up high then idles down and dies
> 
> 1= can anyone tell me how to hook up the vacume hoses or tell me where i can find a diagram of the vacume hoses
> 
> ...


First thing that comes to mind is the service bulletin about the bad wiring connector:






FIX: erratic idle, low speed driveability, possibly more - Infamous Nissan - Hardbody / Frontier Forums


FIX: erratic idle, low speed driveability, possibly more Wiring and Electrical



www.infamousnissan.com





For the vacuum hoses, this is what I've seen others use:



http://imgur.com/XSlwN8j


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