# 1990 240sx about to die?



## eug718 (May 26, 2005)

Hey guys, here is the problem. Lately when I come to a full stop at a traffic light or stop sign, my cars RPM's drop to 200 or so and the car feels like its about to stall. I recently had my alternator replaced. After I had it replaced I experienced the same problem so I went to a local shop and they changed my spark plugs, wires, and fuel filter. Everything was fine until a month later (which is now). At highway speeds the car is doing fine. The car almost stalls at traffic lights about once in every 5 traffic lights. Could it be some sensor or could it be that the alternator i got from Autozone is garbage? I feel like the car is misfiring when I'm giving it gas after a traffic light (but no loud bang). The tailpipe looks pretty black (didnt really pay attention before). I recently ran some STP complete fuel system cleaner through also. Any ideas or help would be appreciated. BTW, I keep my car in good shape by changing all fluids and having routine maintenance done. Hopefully this wont turn into an expensive problem. Thanks again.


Eugene


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## sunnydet90 (Sep 10, 2004)

eug718 said:


> Hey guys, here is the problem. Lately when I come to a full stop at a traffic light or stop sign, my cars RPM's drop to 200 or so and the car feels like its about to stall. I recently had my alternator replaced. After I had it replaced I experienced the same problem so I went to a local shop and they changed my spark plugs, wires, and fuel filter. Everything was fine until a month later (which is now). At highway speeds the car is doing fine. The car almost stalls at traffic lights about once in every 5 traffic lights. Could it be some sensor or could it be that the alternator i got from Autozone is garbage? I feel like the car is misfiring when I'm giving it gas after a traffic light (but no loud bang). The tailpipe looks pretty black (didnt really pay attention before). I recently ran some STP complete fuel system cleaner through also. Any ideas or help would be appreciated. BTW, I keep my car in good shape by changing all fluids and having routine maintenance done. Hopefully this wont turn into an expensive problem. Thanks again.
> 
> 
> Eugene


 check the throttle body, mine had a line of carbon built up that was making the throttle plate stick when it was idleing causing it to die or idle irractically

Don


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## azRPS13 (Jun 7, 2003)

Those where the signs I had before my engine took a shit... Lets see... New Altornator, new fuel filter, new MAFS, New Injectors, new starter, new Fuel pump, New timing Chain and timing chain tensioner... Only to be about 10mins from my house and have the tensioner snap off, take part of the block with it, flood the engine with radiator fluid, and loose the chain...


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## eug718 (May 26, 2005)

sunnydet90 said:


> check the throttle body, mine had a line of carbon built up that was making the throttle plate stick when it was idleing causing it to die or idle irractically
> 
> Don


Thanks for the reply guys. If it is the throttle body as I'm starting to believe, how would I go about "fixing" it. I'm an intermediate when it comes to car repairs but got good ideas when it comes to theory. So if I go to a mechanic, what should I tell him to do. Can I do this job myself? Thanks a bunch for the responses.


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## sunnydet90 (Sep 10, 2004)

eug718 said:


> Thanks for the reply guys. If it is the throttle body as I'm starting to believe, how would I go about "fixing" it. I'm an intermediate when it comes to car repairs but got good ideas when it comes to theory. So if I go to a mechanic, what should I tell him to do. Can I do this job myself? Thanks a bunch for the responses.


 to clean the throttle body just take the intake hose off from the TB and spray some carbeurator(sp?) cleaner in it while opennig the throttle plate with your hand. if you want you can take it off and clean it better. the TB is held on by 4 allan bolts.

Don


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## eug718 (May 26, 2005)

sunnydet90 said:


> to clean the throttle body just take the intake hose off from the TB and spray some carbeurator(sp?) cleaner in it while opennig the throttle plate with your hand. if you want you can take it off and clean it better. the TB is held on by 4 allan bolts.
> 
> Don


***UPDATE***

I went to my mechanic. The car was even stumbling on the highway. At high speeds the car was driving so so but when I start to take my foot off the gas pedal, I can feel and hear the car choke a bit. I got into the shop and the mechanic sprayed some cleaning on the throttle and some other valve. The ride home was perfect. Car was racing and running smoothly.....UNTIL...i stopped off at my friends house. I came back to my car, started it up...and the problem was back again! OMG! What the hell is going on. I thought I was in heaven after the mechanic fixed it. Let me tell you some weird quirks about this problem...when the car is about to stall I usually put it in neutral and it helps out by upping the rpm's. Even in neutral sometimes the cars rpm's are so low that it causes the car to almost stall. I took some pics of the engine area and I'm going to post it here very shortly. I'll point out where the mechanic did what. Thanks again for your help guys.


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## sunnydet90 (Sep 10, 2004)

eug718 said:


> ***UPDATE***
> 
> I went to my mechanic. The car was even stumbling on the highway. At high speeds the car was driving so so but when I start to take my foot off the gas pedal, I can feel and hear the car choke a bit. I got into the shop and the mechanic sprayed some cleaning on the throttle and some other valve. The ride home was perfect. Car was racing and running smoothly.....UNTIL...i stopped off at my friends house. I came back to my car, started it up...and the problem was back again! OMG! What the hell is going on. I thought I was in heaven after the mechanic fixed it. Let me tell you some weird quirks about this problem...when the car is about to stall I usually put it in neutral and it helps out by upping the rpm's. Even in neutral sometimes the cars rpm's are so low that it causes the car to almost stall. I took some pics of the engine area and I'm going to post it here very shortly. I'll point out where the mechanic did what. Thanks again for your help guys.


 i'm almost wondering if the TPS(throttle position sensor) is bad but i cant remember when it goes out if it revs the car or it dies. gimme an update or pm when you find out what is wrong

Don


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## rogoman (Dec 16, 2004)

eug718 said:


> ***UPDATE***
> 
> I went to my mechanic. The car was even stumbling on the highway. At high speeds the car was driving so so but when I start to take my foot off the gas pedal, I can feel and hear the car choke a bit. I got into the shop and the mechanic sprayed some cleaning on the throttle and some other valve. The ride home was perfect. Car was racing and running smoothly.....UNTIL...i stopped off at my friends house. I came back to my car, started it up...and the problem was back again! OMG!


Here's several things to check:
1 - Check for dirty air filter.
2 - Check the TPS harness connector for oxidation on the pins.
3 - Check for vacuum leak; use a vacuum gauge. With the motor fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. 
If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
4 - A fuel injector(s) may be dirty; run a good injection cleaner like Techron or Redline SL-1 through the system; give the cleaner about a week or two to do it's job.


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## eug718 (May 26, 2005)

Thanks for the replies. I'm keeping all of your ideas in my head. Here is the pic of the engine area where the throttle is. I added some arrows to point out what the mechanic sprayed. Can I spray some white lithium grease where the throttle wire is...right where that yellow arrow is pointing...its that round piece where the wire is attached to? BTW, is that "crack" or separation supposed to be there where the arrow is pointing to? Tomorrow I'm gonna go out and buy some strong carb cleaner and spray the heck out of places my mechanic sprayed. He simply unscrewed 1 clamp that is near the engine and sprayed into that area. He then sprayed into a small area where some valve is. I have a clean air filter and I already ran some STP complete fuel system cleaner through. 93 octane gas is inside car (usually fill up with 87). Suggestions and types of cleaning products still welcome. thanks again.


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## eug718 (May 26, 2005)

So any suggestions about my White Lithium grease idea?


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## rogoman (Dec 16, 2004)

eug718 said:


> So any suggestions about my White Lithium grease idea?


It's OK to use the white lithium grease on the throttle wire; just make sure to remove any gunked up dirt in that assembly or else you may end up with a sticking throttle operation.

If you're going to clean the fuel injectors, use a good injection cleaner like Techron or Redline SL-1 through the system; give the cleaner about a week or two to do it's job. Many of these cheap fuel system cleaners don't do much of anything except take your money.

Check the intake system for vacuum leaks; a vacuum leak will give you the symptoms of the idle going up and down.


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## sunnydet90 (Sep 10, 2004)

rogoman said:


> It's OK to use the white lithium grease on the throttle wire; just make sure to remove any gunked up dirt in that assembly or else you may end up with a sticking throttle operation.
> 
> If you're going to clean the fuel injectors, use a good injection cleaner like Techron or Redline SL-1 through the system; give the cleaner about a week or two to do it's job. Many of these cheap fuel system cleaners don't do much of anything except take your money.
> 
> Check the intake system for vacuum leaks; a vacuum leak will give you the symptoms of the idle going up and down.


 vacuum leaks usually give that irratic idle but i've noticed on the KA that all a vacuum leak does is raise the idle not make it go up and down. did your mechanic take the intake hose off and spray carbreutor cleaner in the throttle body? because the way the engine looks it could have build up inside the TB.

Don


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## eug718 (May 26, 2005)

Thanks for the replies. Yes, the mechanic did take off the big black hose leading up to the TB (I guess the TB is that silver thing that says ECCS). He also took off some other valve further back on the side of the TB and sprayed as well. Right now I'm thinking I'll put some fuel injector cleaner (Dupont) in the car...drive to the gas station...fill it up completely and then start using carb cleaner to spray the TB again. Can I spray the throttle wire with carb cleaner and areas around the TB? I've read on the web that people spray the carb cleaner even when the engine is on. Whats the safest way? Oh yah, did anyone look at the pic where the yellow arrow is pointing to...that seperation supposed to be there?


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## sunnydet90 (Sep 10, 2004)

eug718 said:


> Thanks for the replies. Yes, the mechanic did take off the big black hose leading up to the TB (I guess the TB is that silver thing that says ECCS). He also took off some other valve further back on the side of the TB and sprayed as well. Right now I'm thinking I'll put some fuel injector cleaner (Dupont) in the car...drive to the gas station...fill it up completely and then start using carb cleaner to spray the TB again. Can I spray the throttle wire with carb cleaner and areas around the TB? I've read on the web that people spray the carb cleaner even when the engine is on. Whats the safest way? Oh yah, did anyone look at the pic where the yellow arrow is pointing to...that seperation supposed to be there?


 the throttle body is the part where that hose hooks up to. where it sez ECCS that is the intake manifold.

Don


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## eug718 (May 26, 2005)

***UPDATE***

Alright, I went to autozone and bought some STP carb cleaner. I took off the big black hose attached to the TB and sprayed inside the TB while moving the throttle wire. A lot of blackness came out. After that I started car, it ran well for about 45 seconds and then the problem started again. One guy passing buy suggested that I stop by mechanic around the corner. As I was driving there the car ran fine with no problems. The when I turned it off and back on again, the problem came back. The mechanic said that its the Mass Air Flow sensor for sure. Cost is 119 dollars (Autozone)! I told him I'll have to decide later. Could it be the MAF sensor? Maybe I should change the Throttle Positioning Sensor first? Is he bullshitting me? The car has never stalled while its RPM's are dropping dangerously low. Sometimes the rpms start bouncing up and down. Putting car in neutral helps problem out for a second or two and then problem starts again. Its probably a sensor otherwise the problem would be constantly happening? Sorry for the long windedness but its my first car and I love it. Wanna drive it till it dies.


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## 91SENTRA E (Oct 21, 2004)

*Miles*

How many miles do you have on the odometer?


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## eug718 (May 26, 2005)

91SENTRA E said:


> How many miles do you have on the odometer?


I have 92,000 miles on the car. I treat my car like its my girlfriend.

BTW, the mechanic wanted 40 bucks to install the Mass Air Flow Sensor.


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## wildmanee (Nov 21, 2004)

40 bucks? It's almost as easy as plug 'n play...


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## eug718 (May 26, 2005)

wildmane said:


> 40 bucks? It's almost as easy as plug 'n play...


Yah thats what i was thinking. But could it really be the MAF? Also, when I started the car today i saw bluish, grey smoke coming out of tailpipe.


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## zellx2004 (Sep 30, 2004)

you want a maf for a ka24E? I'll sell you mine.


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## eug718 (May 26, 2005)

zellx2004 said:


> you want a maf for a ka24E? I'll sell you mine.


Well, I'm not even sure if I need one yet. Hoping some of the guys will answer back if the MAF could possibly be the problem. BTW, how much would you want for it with shipping included. I live in NY.

**update**

Found Mass air flow sensor online for 25 bucks plus 9 dollar shipping. Should I go for it?


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## zellx2004 (Sep 30, 2004)

I wouldn't charge you a thing. Just take it. Otherwise it goes in the trash. I put in my garage somewhere, I'll have to find it.


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## eug718 (May 26, 2005)

zellx2004 said:


> I wouldn't charge you a thing. Just take it. Otherwise it goes in the trash. I put in my garage somewhere, I'll have to find it.


Wow thanks man, I'll definitely take it. I was researching some more on google and found out that I could check my ECU unit because it has flashing lights that will tell you right away if you have some problems. Hopefully some code is stored there.


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## zellx2004 (Sep 30, 2004)

Want the ecu too? I know for sure that i have that.


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## eug718 (May 26, 2005)

zellx2004 said:


> Want the ecu too? I know for sure that i have that.


Your too kind, but I only need MAF and maybe the throttle position sensor. I'm not the greatest expert on cars so I wouldnt know what other sensors i might need to replace. Today I'll go out and try to access the ECU and its codes.


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## eug718 (May 26, 2005)

***MEGA UPDATE***

So here is the run down. Today my friend and I went to check on the ECU and read out any codes it might have stored. We accessed the ECU and followed step by step instructions. The ECU reported that everything is ok (Code 55). So I started up the car to show my friend the problem and the car idled pretty good. I opened the hood and found the MAF and TPS and played with the wires, jiggled them and made sure there was good contact. The car runs great now! Here is the funny thing. When I'm driving and come to a stop, my car idles at 650 RPM. But when I put my car in PARK, it idles at 900-1000 RPM. I think my friend didnt mark the position of the ECU screw that acts as an idle control. I've been driving the car all day and no problems so far. Just for that 1000 RPM idle when in Park. I still think I need to replace the MAF cause when it idles at 650 I feel slight shaking once in a while. I would like to thank you all for helping me and reading my long posts. Hopefully I can return the favor somehow.


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## zellx2004 (Sep 30, 2004)

no thats sounds about right.


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## eug718 (May 26, 2005)

zellx2004 said:


> no thats sounds about right.


what sounds right? The idle speed in Park position?


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## zellx2004 (Sep 30, 2004)

yeah, it should idle around 1000 rpms in park. At least thats what every nissan I've driven has done.


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## zellx2004 (Sep 30, 2004)

zellx2004 said:


> yeah, it should idle around 1000 rpms in park. At least thats what every nissan I've driven has done.



About the shaking bit with the 650 rpms, please tell me, when you figured that one out. I have a 92 camaro, and it does that same damn thing! I've replaced the fuel pump, the fuel filter, Idle air control valve, only thing I can think of is the fuel pressure regulator may have a small leak in the vaccum line. However, this is just a theory.


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## SpikeMike240 (Jun 6, 2005)

Yea, I have a 91 240SX KA24DE and am experiencing the same problems with when I let off the gas the car idle rpm will go up and down untill it eventually stalls and dies, have been just heal toeing for stoping purposes while i've been trying to isolate the problem. I did have a check engine light so I ran the codes from the computer and was telling me it was the Exhaust Gas Recirculation system, I've changed out my EGR valve but it didn't change a dang thing and am still experiencing the same problems. Furthermore more going to reset the computer and wait for check engine light again the read off the codes again and see if they are the same. Yea, A vacume leak would cause those problems also but the car had that problem when I bought it and it was the gasket on the intake system, changed that out and ran fine, so i doubt its vacume leak on my car, maybe on yours. Only thing I can think of it as being if its not the EGR valve would be dirty TB or injectors. I'm currently working on it, i'll let you guys know what I find out.


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## rogoman (Dec 16, 2004)

Another thing to check is the Idle Air Adjusting unit (IAA). If it's dirty, it could cause the problem you're having. To clean the IAA, it would have to be removed from it's mounting.


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## ScottyDont (Apr 18, 2005)

*Idle Problem*

Reoccurring problem with Idle at a stop, go to depress the gas and *stall*.
Sometimes it kicks back up, orhter times engine dies completely.
ECU finally gave out a reading saying I need a new 02 sensor, getting that done and all new wires etc w/a tuneup, 90k miles.
Even still, when i got my emmissions test done, it barely passed (CA emmissions)
The guy said i needed a new EGR valve, but i sure as hell dont want that to be the real problem.
Ill let ya know if the 02 helps at all.


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## eug718 (May 26, 2005)

ScottyDont said:


> Reoccurring problem with Idle at a stop, go to depress the gas and *stall*.
> Sometimes it kicks back up, orhter times engine dies completely.
> ECU finally gave out a reading saying I need a new 02 sensor, getting that done and all new wires etc w/a tuneup, 90k miles.
> Even still, when i got my emmissions test done, it barely passed (CA emmissions)
> ...


Well, its been a month or so now after my initial post with the problem. The problem hasnt come back! Like I said before, the car seems to idle slightly rougher than before...might be my paranoia at play. Also, my car hasnt been as responsive to the throttle as it was before the problem. Transmission doesnt want to drop down a gear when I really want haul some ass. Might be cheap fuel filter or something.


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## SpikeMike240 (Jun 6, 2005)

eug718 said:


> Well, its been a month or so now after my initial post with the problem. The problem hasnt come back! Like I said before, the car seems to idle slightly rougher than before...might be my paranoia at play. Also, my car hasnt been as responsive to the throttle as it was before the problem. Transmission doesnt want to drop down a gear when I really want haul some ass. Might be cheap fuel filter or something.


When was the last time you changed your tranny fluid and filter, did you clean or replace your IAAC, O2 and EGR valve, the O2 and EGR valve are easier then hell to replace


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## Smack'snissan (Dec 10, 2005)

*Stumbling comes and goes*

I had a similar problem looked and looked , read and read . I changed my MAF sensor and the problem completely disappeared ! You may wanna test it with a multimeter , my Chilton manual told me how to do this . Hope i helped sorry if I didn't .


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## SHpaintball (Jan 30, 2006)

HOLY SHIT!! i have the same car same problem....however its a fuel problem im sure of it ok if you know of a place that does full fuel system clean up take it there and then do some of the things people are saying to do in this forum!! i thnk i will to shit my car keeps acting like this its the damn 02 sensor and exhaust


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## SHpaintball (Jan 30, 2006)

how old is your "catback exhaust " my car problem is solved in 3 simple steps if it doesnt work....your cars probably dead....mine isnt and it has 222,034 miles 
step 1 : clean TB, MAF ,IAA
step 2 : get your fuel system cleaned
step 3 : if your exhaust is shot get new catback ** 02 sensor is a must to replace!
thats it ....make sure of that and it should work great

hit me up and let me know if that fixes it!!


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## Trippen (Feb 21, 2006)

THE EGR would cause the O2 sensor to throw a code....Since the valve should never open unless at higher speeds...If it is open at lower speeds it mixes the exhaust with the reg air choking your car and making it stumble...Easy way is throw a nickle(yes a 5 cent coin it is the perfect fit for this pipe at the header) in the EGR tube at the header and call it a day. This will block exhaust gas from entering the system and make your car run 1000 times better if it is the EGR messing up.


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## SHpaintball (Jan 30, 2006)

anyone have any pictures of the EGR i wanna take mine off but need to figure out just how to..


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## rogoman (Dec 16, 2004)

SHpaintball said:


> anyone have any pictures of the EGR i wanna take mine off but need to figure out just how to..


It's located under the back of the intake manifold.


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## Trippen (Feb 21, 2006)

rogoman said:


> It's located under the back of the intake manifold.



This is the DOCH EGR SOCH is different and in a different location.. On the dirvers side of the car...there is a pipe 1" extending from the exhaust to the wheel well. I will post a pic once i find one


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## SHpaintball (Jan 30, 2006)

yea i know its that little black box....i took the hose off of it and sealed the holes where the hose was its that it ? i cant take that box off or is that all you do ....?


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## Trippen (Feb 21, 2006)

http://www.nissanforums.com/s13-240sx-1989-1994/117931-what-called-emissions-controls.html

Check this thread out...was one that helped me understand the system and fix it. I am having problems with my Acrobat reader when i get it fixed ill post some diagrams


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## surfer240sx (Dec 15, 2005)

i think the black box is a muffler system for it... not sure tho


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## SHpaintball (Jan 30, 2006)

nice thanks...so i can take that box off and leave it off and just plug the EGR?


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## Trippen (Feb 21, 2006)

surfer240sx said:


> i think the black box is a muffler system for it... not sure tho



It is the problem was solved but the pics should of helped you....the egr is the silver disk with a metal strap and 2 screws...


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## rogoman (Dec 16, 2004)

SHpaintball said:


> nice thanks...so i can take that box off and leave it off and just plug the EGR?


The black box that's located on the driver's just behind the air filter box is an air damper that's part of the Pulsed Secondary Air Injection (PAIR) system. It has nothing to do with the EGR system.


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## Trippen (Feb 21, 2006)

*I GAVE SOME MISS INFO I AM SORRY*


***********This is true the black box has nothing to do with the EGR but is part of the entire EGR flow path... *I appoligize Rogoman* is Correct...the EGR is on the back side of the intake...But the AIV valve is the one that goes bad...I got those flippin things confused...

Even with the Vacuume lines plugged the AIV if leaking will cause problems...Here is another thread dealing with blocking that connection

I took the whole thing off and blocked the input to the air cleaner from the PAIR system (thanks Rogoman couldnt remember the name)and placed a nickle in the AIV hard line from the Exhaust header. The second thread it has a great diagram of the entire system...

http://www.bbs.240sx.net/showthread.php?t=1635


http://www.ka-t.org/forums/viewtopic.php?t=10789&postdays=0&postorder=asc&start=30


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## surfer240sx (Dec 15, 2005)

Trippen said:


> *I GAVE SOME MISS INFO I AM SORRY*
> 
> 
> ***********This is true the black box has nothing to do with the EGR but is part of the entire EGR flow path... *I appoligize Rogoman* is Correct...the EGR is on the back side of the intake...But the AIV valve is the one that goes bad...I got those flippin things confused...
> ...


u just placed a nickel on the line or welded it? ive heard about it...


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## Trippen (Feb 21, 2006)

surfer240sx said:


> u just placed a nickel on the line or welded it? ive heard about it...


I used Hght temp exhaust gasket stuff to hold it in while i screwed it back in...Didnt want to mess it up. for later use so i didnt weld it...works like a charm...You dont have to use gasket stuff on it...I needed too it was roasting hot and i needed to get it fixed...my PAIR box was cracked and fumes were comming in the car and running like crap....lol..


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## surfer240sx (Dec 15, 2005)

i need to get that lower line completely off cuz i just got my header on and my steering rack is catching on the line darn pacesetter not fitting rite... any suggestions?


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## Trippen (Feb 21, 2006)

Maybe take it off and cut the tube to allow th nut to be loose and then do the nickle trick??? If you havent figured this out yet.


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## 180typeX (Jun 25, 2006)

You should check your injectors. I am a nissan tech and I have seen this problem before. The pindle inside the injector grounds itself to the injector housing. One way to check for sure is to ohm test the injector, spec is 14-16 ohms, if you have OL on any injector, its pretty much toast. The problem is usually more apparent when the car is warmed up. I just had this problem with my car about a week ago. The injectors are a little pricey but it only takes a few minutes to install. Good luck man.


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