rpgfan

I drive a 1990 240sx. I think that the egr valve may be causing my 240 to stall when I'm in idle and when I'm going very slow. Basically whenever my rpms drop they dont stop dropping. The car will run fine untill i stop, and then it will idle very roughly until it stalls. I have been told that it could be a lot of things ranging from MAF, EGR, something involving my fuel injectors, or ECU. Before I spend $100 on a new MAF i wanna check my egr but, I dont know where to find it.

I wish I had a huge labled picture of the engine becuase this happens a lot. Please help...

Bryan

right behind your intake manifold

Cape 240

its behind the throttle body...
If you look at your exhaust manifold there is a pipe down low, it bends towards the fire wall and heads behind the block. It leads to a small-device behind the throttle body / intake manifold.

*Tx_BLooD_240*

lol yah its right behind the exhaust or intake manifold. its the tube thats connected to your header. im having trouble with that little item right now.
go to the header install guide that vinny made. that will show you where the egr is.

sularus65

go ahead and check the egr, but most likely it is not the problem. I had a similar problem. I recommend grabbing some brake cleaner and cleaning the MAF, then grabbing some seafoam and running it through the intake manifold. I bet your problem is most likely IACV(idle air control valve). With the dirty air coming back from exhaust through the EGR, and the somewhat oily air coming through the PCV system the IACV can become sticky and not want to adjust the idle properly. Running some seafoam through the intake will clean and dislodge all the crap. Don't worry, it will smoke like a frieght train when you do it, but it will help. Good luck

Jason

rpgfan

ok, I found and checked the egr and everything seemed to be fine so I'm going to try cleaning stuff out and checking the IACV like recommended.

My problem will temporarily go away if I adjust the idle with the idle screw beside the throttle body, but it always come back. I currently have my idle set very high on the screw just to keep it at a somewhat normal idle. In park its about 1,000 rpms but when I put it in drive/reverse it drops to about 600-700 rpms(Is this normal?). When checking for vacuum leaks and any clogging or whatever I found some black chunks in the air filter. I'm not sure what caused them or how long they've been there but I think that could be part of the problem. The car hasnt cut off in the last 24 hours but I'm pretty sure my problem isnt over. Like I said I'll probably look at the IACV next. Are there any tips or suggestions that I should keep in mind while doing this?

Cape 240

The idle is supposed to go up when you put it into drive.
In an automatic car, there are two "power loads"
One would be heat/AC and the other Drivetrain.

Each should cause idle to fluctuate up when turned on, and down when turned off. This is why in an automatic car, it is a good idea to go into Park at a red light, it saves on fuel and gives the engine a little extra time to cool-down.

sularus65

Cape 240 has it right about the tranny. If you have to adjust your idle that much to keep it going, you really should clean that maf and IACV. That may not completely cure it, but it will go a long way into helping. Don't forget to reset the computer.

jason

LA_phantom_240

uh.. im not quite sure you know what youre talking about cape... whenever i drive an auto, it always drops in rpms as you put it into either reverse or drive, cuz if you dont drop em, its hell on your torque converter. This is why in older cars that havent been taken the best of care of go into any gear and they vibrate the whole car realy badly... cuz the rpms drop and the car runs like ****. When it is in park it will idle higher if you dont have the a/c on, when you turn it on, it will drop the rpms as it kicks in, but then it will rise up to the point where it can drive the pump efficiently. So in a nutshell, youre idle is right in my experience.

AS for solving your problem, YES by all means seafoam that ho, cuz i swear by it... i call it automotive GOD in a can. lol. But after that if it is still doing that, check your timing. Thats a good place to start. Its one of the simplest things that can make your car go squirrely. If that doesnt work, try messing with the MAF. After that... i cant help ya much over the net.

Good luck!

rpgfan

I went to the store and they were out of the sea foam stuff so I just got some throttle body cleaner. I found the AAC ,which was right behind my TB above the egr, and took off the four screws without unplugging it from the other two connections and sprayed TB cleaner onto/in it. It was very black.In the back of the TB, where the AAC vavle was connected there was a lot of black build up. I clean it as well as I could but I doubt I got it all. After that I connected every thing back and started the car. My dad said it smoked some, but not as much as he had expected. In park, the idel was about 600-700 rpms higher(almost @ 2000) but the idle still dropped a lot (under 1000)when put into drive/reverse.

The cleaning definitely helped but I still have a problem. I'm thinking that there might be another dirty/clogged piece somewhere in the engine since the pieces I cleaned were very dirty.

I'm also curious aobut the IACV. Judging by this picture, the AAC and everything else should be below the egr, but mine was above. What does that mean?

BigVinnie

iTrader: (2)

There is a large vacuum tube that runs to the intake, and runs down to the IACV. It is the largest of three tubes before the TB, and you can see it run down the mani to the back of the IACV. You can fill the vacuum tube with CARB cleaner. You may need to do it a few times, and the engine will have a hard time turning over at first. The CARB cleaner should get rid of the stickyness to the IACV, if that doesn't work more than likely it will need to get replaced.
Cool find from Zilvia. How to clean the IACV!!!!!
http://www.zilvia.net/f/showthread.p...ght=IACV+clean

rpgfan

I tried what BigVinnie posted and I think it helped but I still have a stumbling/rough idle.

I was able to buy some sea foam and attempted to use it by pouring it down the same vacuum line off of the intake manifold. While i was doing that i noticed black smoke coming from the right side of the engine. After checking things out I noticed that the piece used to connect a vacuum line to (some random box thingy ????)[picture here] was broken so that plenty of air was being released. Can someone give me the name of that piece so that I can replace it? Do yall think that this could cause my idling problem?

here is another [picture]

BigVinnie

iTrader: (2)

That is called your AIV, but it won't cause idle problems.
Your EGR/BPT can cause a small idle problem. If you have a high mileage KA, the vacuum lines to the EGR/BPT could be burn't out, stick your hands behind the EGR and the manifold and feel the vacuum lines.. Turn on your engine while the engine is cold and feel behind the EGR/BPT and feel for air weezing through the vacuum line.
I would suggest dumping alittle more carb cleaner down the IAC vacuum line as well, I wen't through a big bottle before my idle worked right.
Replace vacuum tube to the AIV it cost like 70cents at the most.

aallbbeerrttttt

sorry to ask, but what does the AIV do?

Cape 240

It has to do with emissions and re-circulation of air.