Please Help With Engine Stall/Idle Problem

[TypicalNSX]

I have an engine stalling problem:

After the engine gets hot, normal warm temperature. i'll drive it and after i take it out of gear it stalls. i'll be sitting still and i'll rev it up and it will still stall. when the engine is cold, it works perfect, the idle is fine at all times except when coming down from higher rpms 2000+

96 model: i took the throttle body out and cleaned it perfectly. still stalls. changed to brand new spark plugs, still stalls. don't see any vacuum leaks. obdII doesn't have eacv or fast throttle valve so can't change those. also replaced the throttle body from a new nsx, still stalls.

thinking of changing ecu or egr valve, thats all i can think of. other than stalling from higher rev car runs fine.

any help is appreciated!!!!!!!!!!

 

[Briank]

Are you getting a check engine light?

 

[drew]

Check the idle bypass carefully--make sure there are no rips in the bellows.

Is it running rich?

I'm also wondering if your coolant temperature sender is not happy? Maybe it is not informing properly of the true temperature of the engine. There are two senders for the 1) instrument gauge and 2) ECU

 

[Daves_X]

I had this same problem before rebuilding the upper part of my engine. I know this sounds funny but when I left the sensor off to the engine that detects engine coolant temperature the car did exactly what you described. If you have access to a code reader I would see what is happening if you have a check engine light that comes on or if the light blinks at you. Just my experience with this problem.

 

[Larry Bastanza]

Please describe how you cleaned the throttle body "perfectly". This is a classic symptom of a clogged idle passage, and just spraying some cleaner in that passage will not necessarily clear it.

Regards,
LarryB

 

[SweetChuck]

Did you check the main ignition relay unit , it may not have anything to do with engine temp but rather circuit board temp causing dry joint expansion .
Just a Thought ??

 

[Zishan]

I agree, crack that Main Relay open and see if the connections are corroded.

 

[NY2NV]

If i'm not mistaken there is a recall on that. I have a 95 and had the same problem last year.Acura did diagnose on it and changed the throttlebody for free. It has something to do with emission. Just a thought.

 

[TypicalNSX]

wow thanks a lot for the responses. there is no check engine light. i took the throttle body out and sprayed carb cleaner all over it and inside. i even borrowed a friend's throttle body and it still did the same. couple days ago i tried out a new ecu from a friend too and it still did it. this weekend i'm gonna try that main ignition relay unit, don't know where it is, please help.

also gonna take the injectors out and bring them to rc. might be running rich.

that coolant temperature sender thingy sounds like it could be it possible. hope i can get to the bottom of this cuz its annoying as hell.

 

[TypicalNSX]

i do smell a distinct amount of gas lately

 

[Daedalus]

Main relay info:
http://www.nsxprime.com/forums/showthread.php?t=96630

The injectors are not the root cause of the stalling. See if you can borrow or rent a scanner that reads sensor outputs, and read the coolant temp as suggested. There are generic ones out there that cost less than $200.

 

[TypicalNSX]

ok i got the main relay cracked open. it looks pretty clean i dont see any corrosion. . . any ideas? whats a bad relay look like? i can't see anything wrong with this one.

 

[Briank]

I have not had my hands on or seen a service manual for a TBW car but I have been led to believe they do not have an EACV that controls the idle speed. With you having an idle problem looking at how the air flow is controlled is the first thing to do. When you had the throttle body off did you make any adjustments to the painted screw or the one that is sealed over?

Does anyone have a link to a service manual for a TBW car?

 

[TypicalNSX]

i didn't adjust any screws on the throttle body. trying to get a 95 service manual off ebay right now.

 

[SweetChuck]

ok i got the main relay cracked open. it looks pretty clean i dont see any corrosion. . . any ideas? whats a bad relay look like? i can't see anything wrong with this one.

Its not corrosion your looking for , the unit and relays will look very good , you need to look closely around the solder joints for cracking dry joints .

 

[TypicalNSX]

heres what the main relay board looks like. it seems kind of okay on the soldering joints. what do you think? i also took out the coolant temperature sensor and it looks okay. maybe i need to replace it and see what happens.

 

[Briank]

heres what the main relay board looks like. it seems kind of okay on the soldering joints. what do you think? i also took out the coolant temperature sensor and it looks okay. maybe i need to replace it and see what happens.

There are 2 coolant sensors, one for the gauge and one for the ECU make sure you get the right one. :wink:

 

[SweetChuck]

heres what the main relay board looks like. it seems kind of okay on the soldering joints. what do you think? i also took out the coolant temperature sensor and it looks okay. maybe i need to replace it and see what happens.

Resolder that board anyway , looks can be deceiving .

 

[Daedalus]

The ECU doesn't care how the coolant sensor looks, just that it's getting an appropriate voltage return through it . Mine looked fine too, but it wasn't. Once you get your manual test your sensor with a pot of water on a stove, thermometer and ohm-meter, and compare values to those in the manual. I would say use the on-line '91 manual, but I'm not certain the temp/resistance is the same.

 

[TypicalNSX]

i'm gonna do the test on the sensor i pulled out. its the one right beneath the throttle body. briank, what other sensor are you talking about? where is it?

thanks for the help

 

[Larry Bastanza]

Since you may be smelling extra fuel, once you complete the sensor testing, if this is not the issue, I think it is time to get a fuel pressure gauge on the car and see what the fuel delivery is.

Regards,
LarryB

 

[TypicalNSX]

here are the results from my injector cleaning from rc, turns out one injector was dripping but i'm not confident this is the culprit. getting a brand new main ignition relay tomorrow and seeing if this helps. next is checking out those coolant temperature sensors if i can find out which one goes to the ecu.

 

[comtec]

Does anyone have a link to a service manual for a TBW car?

Try This.

97-2005 Service Manual

Just click free at the bottom and type the code in the box when the timer expires.

Tip......Just open the NS9705MAINIDX.pdf in the 97-2005 manual . You can create a shortcut to this file. As long as the associated files are in the same folder you can just click the blue links or the main index buttons.




Cheers

 

[TypicalNSX]

thanks comtec!

 

[TypicalNSX]

update:
installed new main ignition relay, installed new cleaned injectors. still STALLS!!!! this is annoying. next thing to work on is coolant temperature sensor. i dont see any leaks in the vacuum lines.