Please Help With Engine Stall/Idle Problem

Update:
I have been able to get the car to idle, but not at 850. It wants to idle just at 1,000, might get it to 900, but wants to pretty much be at 1,000/1100 or so.

SymptoM - When driving, the car wants to idle at 1200, 2000 Rpm after I pull up to a stop light. I literally have to sit at the stop light for a few moments to wait for the RPMS to drop back to 1,000 rpm. Is this normal? Shouldn't the car go right back to 900 rpm as soon as I stop and put the car in neutral.


Things That we have done -
1.) Removed and cleaned all ports of the throttle body
2.) Installed new injectors
3.) Reset the idle according to the manual which means disconnecting and reconnecting the EACV unit and letting the car adjust (all done according to the manual)
4.) Purchased a new Optima Battery
5.) Checked for a vacuum leaks by using (probably dangerous) propane torch with the valve open (no flame just fumes) and went around every hose on top of the engine including intake while the car was running to see if I could see a blip in the RPMS to indicate the car is getting more air (sucking in fumes) from any place other than the throttle body.

Car will idle if I let it sit, but if I start the car, put it in gear and drive it, the car takes a moment to settle back in at RPM and does a slight (few hundres rpm up and down) search before it goes back to 1,000 / 950 rpm again. - don't get it.

My next steps, I need to find out if I can have the ECU checked and reprogrammed back to 1992 stock codes since the ECU drives the EACV. (again, I have no idea if the ECU is not stock, just checking) If I can have this done and it still has the issue, next will be to replace a the EACV I'm guessing.

I called SOS and left a message to see if I could use someones brain, I know they don't give things away for free, but thought that I would try. I probably sounded like an idiot on the phone, but at least I'm not afraid to ask for help.

Thanks all.:smile: - all in all, a good day of work on the car - on to the next possible cause.
 
Removing EACV Unit

To all - is there any special notes / things I should consdier before I pull my EACV unit and replace the filter and O-Rings parts?

This is the continued saga of trying to figure out why my idle will not settle in back to factory idle after i pull up to and stop my car at a stop light, driveway, sitting in the garage. it's not eratic, I just comes down from 3,2K Rpm wants to settle down slowly, but then will all of a sudden increas in rpm then try to settle down again slowly, then increase in Rpm again finally settling down to about 950 rpm -- strange to me

Things already done:
1. Pulled and cleaned the entire throttle body
2. Replace main relay with factory new unit
3. Replaced all 6 fuel injectors
4. Ran through factory manuel and reset idle speed as instructed
5. With car running, used propane gas then CARB cleaner to spray around the engine compartment to check for vacuum leak - no change in RPM
6. Replaced all 02 sensors
7. Repalced all 6 plugs
8. Proper level of coolant
9. Now ordered new filter and rings for EACV and will remove, clean and replace this saturday

Thank you all. :rolleyes:
 
Briank - thank you for the replay. below is an update. I agree, it is starting to look like a vaccum leak. below you will see what I have done so far to track this down. We were able to get the 600 rpm at idle reset. It looks like my problem is really noticable when the car is warm. I am starting to think I have a leaking Fast Idle Valve... see below.


Here is an update to my father and I’s efforts on Satruday, 1/2/10:
- We removed the EACV, replaced the O-ring and filter and reinstalled without any issue. Pretty easy job.
- As a note to your most recent post, we reset the factory idle using the manual, doing all the things necessary as indicated by the manual
- We let the car warm up at idle, sitting and running in the garage, of course, the car idles a little high when cold. With the car sitting still, running and warm, we then spray “starter fluid” all over and around the intake manifold, all hoses, leading to and from the throttle body – we got zero response. Just to make sure the starter fluid was working, I sprayed some in to the intake scoop and sure enough, the car reacted as expected. In any case, I soaked all the hoses I could around different hoses in around any part leading to some type of sensor or intake (no reaction by the car). Good news.

- Here is what doesn’t make sense. If the car is sitting still, I can manually push the throttle, take it up to about 3K rpm and let off, the idle will settle down just fine, although somewhat slowly, but still we can only seem to get the idle down to about 1100/1000. So we thought we nailed the issue, however --- If I put the car in gear and drive forward or drive backward, put it in neutral and stop, let’s say I take it to 3k rpm, just when the rpm needle is getting ready to settle down and drop it will hit about 15 to 18 hundred rpm, stop, slowly move up to about 2K or 2100 sit there for a bit then slowly drop – but wait, it then wants to go up another 200 rpm sit there and do the same thing until it decides to then drop down to about 1100/1000 rpm which is still about 150 rpm than it should be.

- Okay – considering all the other things I’ve done and test. We are now thinking two possible culprits after I’ve been reading the service manual (1) The Throttle Angle Sensor on the throttle body or (2) the Fast idle control valve near the back side of the throttle body and near the EACV.

- My thinking is that if the Fast idle control valve is bad, according to the manual, if it’s not sealing correctly, when the car is warm it is letting air leak in. And this seems to align when I have the biggest issue with this idle thing, is when the car is warm and at running temp.

- As for the throttle angle sensor, do I have to purchase an entirely new throttle body, or can I remove , purchase, and install a throttle angle sensor by itself.

- Sorry for the long email – but with me the somewhat new car guy, and my father who works on 350 small blocks and chevy’s we have a new animal on our hands, but I think we are making progress.
 
I have had exactly the same problem and have done all you have done and more.

I replaced the ECU, removed the throttle boy and did a complete clean, replaced all vacume hoses and still my idle will not drop below 1100.

I narrowed it down to the EACV, I removed the EACV and covered the 2 holes in the throttle body with rubber sheet then started the car, the vacume kept the rubber held tight and the EACV was left plugged in. Car ran at perfect idle and stopped stalling when changing gear.

I have not replaced the EACV as it is too expensive here in NZ ($1200). I have just had to make do until I can get the part cheaper. I too replaced the o-ring etc and had no luck.

I think the EACV was sending incorrect values back to ECU making this happen.

Good luck.

Regards

Gene
 
Thanks for the input. I am going to try this test as well:
Here is a URL to an Acura dealer in the U.S. The EACV is $256.00 U.S. but you may want to contact them to see if they will ship the product international.:smile:

http://www.acuraautomotiveparts.org/acura/jsp/mws/prddisplay.jsp?inputstate=5&catcgry1=NSX&catcgry2=1992&catcgry3=2DR+NSX&catcgry4=KA5MT&catcgry5=THROTTLE+BODY+(1)&ListAll=All&vinsrch=no&systemcomp=List All&vinnoT=&trim=&trans=&view=normal

This link is for a 92 - you may want to use the site to track down the part for your year NSX.
 
Update:
Can anyone inform me as to where I can get a new throttle body with throttle position/angle sensor and actuator motor?
Based on this long post, we have hunted for vacuum leaks and replaced parts. We are now at a point where we disconnected the throttle angle sensor, disconnected the throttle body actuator motor, and the idle will sit (Steady) at 2,000 rpm: no oscillation – nothing . Perfect. But yet when we hook these two items back up again, the car attempt to settle down, but just won’t. Here is what I have done so far
1. New Honda/Denso EACV Valve just installed on Jan 31st 2010
2. New Honda/Denso Fast idle control valve just installed on Jan 31st 2010
3. Reset idle according to manual – got it to idle at 500 rpm without EACV connected and reset ECU
4. Pulled and cleaned entire throttle body and all ports
5. Replaced main relay with new Honda Unit
6. Replaced all 02 sensors
7. New PCV Valve
8. Replaced all 6 spark plugs
9. Proper Level of Coolant
10. With car running, used propane gas, then CARB cleaner, then starter fluid to spray around the engine compartment and all hoses to check for vacuum leak - no change in RPM
Now. I am just looking to get an all new Throttle Body with all new sensor and actuator motor so that I can start eliminating parts and replacing with new ones.
 
Briank -

How do I check this? Do I check the / a fuel preassure regulator or do I need to check the preassure in actual lines?

The car isnt' stumbling. As posted, It will sit at 2,000 rpm to 8,000 rpm all day long, no hitch, no miss, no stumble and runs smooth at any rpm that I am at.

I am just not understanding why the car wants to run a 2,000 rpm idle or 1500 rpm idle - even after I've reset the idle according to the manual.

While setting the idle - I "Can" get the car to idel just perfect at 500 rpm with the EACV unit disconnected - just like the manual says. Why is it that I can get the car to idle and sit at thsi rpm, but when the EACV, is connected again, which feeds the throttle angles sensor and actuator motor on the throttle body - the darn car won't let it idle aat 850-

Given this, I can get the car to idle perfect and steady at 2,000 rpm once you remove the throttle body actuator motor connection and the throttle angle sensor -- but once you hook thes back up, the idle will attempt to drop slowling then slowly raise back up to 2,000 again. -- even with this issue, I've taken the car down the road and taken it to 7,000 rpom and 110 miles per hour with no hesitation - but ask the thing to idle correctly and it wont'

I just don't get it. I've done all the testing and cleaning that has been suggested on this thread (please no more post about cleaning the throttle body - anyone - thanks.
 
The service manual says you can attach a guage directly to the hole where the bolt to relieve the pressure was. Can you just buy one that screws directly into that hole and leave it there?
 
Cozmo said:
The service manual says you can attach a guage directly to the hole where the bolt to relieve the pressure was. Can you just buy one that screws directly into that hole and leave it there?
Click to expand...

Yes, just match the thread of the bolt and use a new sealing washer. Fuel pressure issues due to bad pumps often begin while the car is under heavy load (high consumption) and disappear when in neutral, so the gauge's usefulness may be somewhat limited, depending on the problem, unless you're on a dyno.
 
Daedalus said:
Yes, just match the thread of the bolt and use a new sealing washer. Fuel pressure issues due to bad pumps often begin while the car is under heavy load (high consumption) and disappear when in neutral, so the gauge's usefulness may be somewhat limited, depending on the problem, unless you're on a dyno.
Click to expand...

I have the opposite problem. It seems to run great at high RPMs but really bad at low/idle speeds.
 
Briank said:
Sounds like a vacuum leak to me. When you did the idle adjustment did you get the proper 600 rpm?
Click to expand...

Briank - To answer your question, yes. When I do the idle adjustment according to the manual, which entails disconnecting the EACV, I am able to get the car to idle at 500/600 rpm.

This is why I can't believe that it is a vacum leak. correct me if I am wrong, but if there was a vacuum leak, I should not be able to get the car to idle at 500 / 600 RPM during the "set Idle" process, correct?

I am going to get a fuel pressure gauge to check this. My theory is if the car is getting to much fuel at idle, the compute would be adjusting the rpm to compensate for the right fuel / air mixture which may be why I it wants to idel way to high.

Does anyone know what the range for fuel pressure PSI is for my 1992 at idle?
 
Has any one thought of the Fast Idle Valve? take the top 2 screws out and turn the valve till the idle retuns to the normal 850-900 Rpm works everytime,, its connected to the throttlebody,
 
shawn110975 said:
Has any one thought of the Fast Idle Valve? take the top 2 screws out and turn the valve till the idle retuns to the normal 850-900 Rpm works everytime,, its connected to the throttlebody,
Click to expand...

Yes- I have. In fact, I have replaced both the EACV valve and The Fast Idle valve with brand new factory spec Denso parts from Acura.

I thought this was it too. I then followed the NSX manual to reset the idle. Got the 500 rpm as expected, but once completed, could not get it to idle again.

I have completed a long list of things to figure out why my rpm won't settle down past 2,000 or 1500 rpm Here they are:

1. New Honda/Denso EACV Valve just installed on Jan 31st 2010
2. New Honda/Denso Fast idle control valve just installed on Jan 31st 2010
3. Reset idle according to manual – got it to idle at 500 rpm without EACV connected and reset ECU
4. Pulled and cleaned entire throttle body and all ports
5. Replaced main relay with new Honda Unit
6. Replaced all 02 sensors
7. New PCV Valve
8. Replaced all 6 spark plugs
9. Proper Level of Coolant
10. With car running, used propane gas, then CARB cleaner, then starter fluid to spray around the engine compartment and all hoses to check for vacuum leak - no change in RPM

Oh - let me also add #11 - New set of injectors too :redface:


I am left with two things to try next: Fuel pressure test and then see if my Throttle position sensor and actuator motor are bad.:smile:
 
Vandale - this is Ciphernet360 in the U.S. I have been having the same issue as you with regards to your phantom high idle. See the link below where I listed what I have done. Maybe we can exchange ideas and help one another out without us both spending money on ruling out issues.

you can also contact me at [email protected] if you want to send me emails or just P.M. me here at NSX Prime.

I hope you and I can help one another.:redface:



http://www.nsxprime.com/forums/showthread.php?p=1298878#post1298878
 
Check the air intake duct for any leak or blockage. Mine had idling problem and had to replace the intake duct together with the cleaning of the fuel injectors. No problem after that. Check the condition of the air filter paper as well.
 
I had a similar problem on my s2000 with it idling up and down and at stop lights it droping real low. I clean the throttle body and the iacv and still nothing.
I took the map sensor off and clean the ports and made sure the o-ring was good, still nothing.
I didnt throw a cel so i couldnt check the codes. I doing more routine checks i used seafoam in the fuel tank to clean the injector which helped the MPG and clean them too but still nothing.
I finally notice that my throttle cable was a little bit loose from all these years of driving they tend to stretch so i tighten it just before the revs started to rise and BAM no more idle issues. Its been 2 weeks now and it rides perfect. any questions hit me up
 
Last edited:

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