Car start only with throttle pedal down

[zim]

Hello,

Last year the idle of my X was bad, going high and low. Local Honda store found it was the idle regulator valve that was dirty. They cleaned it and it was then perfect.
Now, I have another issue : my car will only start if I press the throttle pedal. If I do, it will always start. If I don't, it seems to start and immediately shuts down.
Tech has found some rubber tubes (for air, they said) with some holes and replaced them. But now? Have you got any idea?
Battery is ok and as she starts with some throttle, I don't think that it's the problem. Same for main relay?

Thank you for your feedback!

 

[Midnight_Raven]

It sounds like your not getting enough fuel or spark when you crank could be the fuel pump relay needs to be replaced or check your electrical components like the spark plugs, ignition coils, cables, etc. I'm assuming the worse case scenario is that you fuel pump needs to be replaced. I'm just guessing but Larry should be able to give you some good advice.

 

[kookoo4nsx]

Its NSX not X. Don't forget it!

Hello,

Last year the idle of my X was bad, going high and low. Local Honda store found it was the idle regulator valve that was dirty. The cleaned it and it was perfect.
Now, I have another issue : my car will only start if I press the throttle pedal. If I do, it will always start. I don't, it seems to start and immediately shuts down.
Tech has found some rubber tubes (for air, they said) with some holes and replaced them. But now? Have you got any idea?
Battery is ok and as she starts with some throttle, I don't think that it's the problem. Same for main relay?

Thank you for your feedback!

 

[Timeless1]

Appears to be similar issue to what i have but i didn't do all that you did though, i just took a flat head screw driver & adjust the idle screw. I took mine up to 980rpm(real close to 1k) & it sounds really good, a little louder but i like it. No more hesitation, fluctuation, or feels like it's about to die. Easy fix, hope this helps, if not you may have some more stuff going on here.

Also you may want to check the throttle cables, they may need adjusting too.

 

[nsx_2k]

I'm not sure that the fuel pump relay will actually resolve his matter. The OP states that without the throttle it starts then dies.

 

[zim]

Thank you for your hints.. I will check with my tech. I know that they are waiting for a call from the central, hope to tell you more really soon!

Thank you again :smile:

 

[Briank]

Appears to be similar issue to what i have but i didn't do all that you did though, i just took a flat head screw driver & adjust the idle screw. I took mine up to 980rpm(real close to 1k) & it sounds really good, a little louder but i like it. No more hesitation, fluctuation, or feels like it's about to die. Easy fix, hope this helps, if not you may have some more stuff going on here.

Also you may want to check the throttle cables, they may need adjusting too.

The idle screw is factory set and should not be adjusted. :wink:

 

[Timeless1]

The idle screw is factory set and should not be adjusted. :wink:

It shouldn't be??? But i don't like it when it is fluctuating between 800 to 500rpm. Now it is fixed, no more issues, so why not. My experience with high mileage cars idling issue is, the idle screw tend to loose it's position over time so it may be necessary to adjust the idle screw even though the factory recommends not messing with it. Plus it sounds (gurgles) better at 980rpm.
You're now probably gonna tell me i may have other problems, not really, issue is solved.

 

[Briank]

It shouldn't be??? But i don't like it when it is fluctuating between 800 to 500rpm. Now it is fixed, no more issues, so why not. My experience with high mileage cars idling issue is, the idle screw tend to loose it's position over time so it may be necessary to adjust the idle screw even though the factory recommends not messing with it. Plus it sounds (gurgles) better at 980rpm.
You're now probably gonna tell me i may have other problems, not really, issue is solved.

Whatever, you disabled the idle control system but if it works for you great. For me I like my car to operate as it was engineered to operate. A simple cleaning of the throttle body was most likely all you needed to do.

 

[Timeless1]

Whatever, you disabled the idle control system but if it works for you great. For me I like my car to operate as it was engineered to operate. A simple cleaning of the throttle body was most likely all you needed to do.

I don't see how raising the idling disables the idle control system, it's made to be adjustable, it still works & i'm having fun with it. People supercharged & turbo charged their cars, does that disable the stock horse power?..

BTW the intake manifold & throttle was clean last year & i only put 1k miles on the car so i would have to rule that out. No pun intended, & I know you're trying to help but i'm just making my point too.

 

[VampNSXX]

I think if you find a way to fix a problem you should do it. If a stock NSX and it's settings where so great then they would race stock NSX in races.

 

[charlee]

Any CEL before or after service. Had similar symptoms and cleaned up my tbody and the car performs as new. I had my son rev the motor as I spray brake cleaner into the intake box. Your car will hesitate for a few seconds as the system cycles through. Repeat this a few times. It is worth a try.

 

[zim]

So, after a few days testing the car, I can give you my feedback.

When I went back to my garage, the tech said they would need to change a few sensors.. I asked him to just clean the throttle body as you said.. and now the car starts every time and runs fine! I'm so happy! Thanks again for your tricks!

 

[zim]

Hmm... I'm afraid that my car still have the issue :frown:
Now, it won't start everytime. Could that be a sensor? or rather the main relay?

Symptoms are : when I try to start her, she nearly succeeds but immediately dies. Battery is brand new.

thank you for your help (again!) !

 

[E-Nough Logic]

Do you hear the fuel pump prime? It could definitely be the main relay, but the main relay would not relate at all to your original problem of only starting when the throttle was open. t appears you fixed that problem already though. Leave the key in accessory for a few minutes and see if you hear the pump prime.

 

[Thunder]

Other possibilities, check the vacuum tubes, after 20 years, they may be porous or pitted (I replaced mine because after all controls, 2 had holes), then replace the fuel filter, if clogged the engine starts with the fuel remaining in the pipe and stops as soon as the fuel to the injectors no longer

 

[cmthomson]

It could be the ignition switch.

I had a similar situation: it would crank and fire, but die as soon as I let the key go. Turned out to be a faulty ignition switch that worked in the crank position but not the run position.

 

[charlee]

A TPS (throttle position sensor) sounds like culprit.

 

[zim]

thanks for your answer!

It appears the fuel pump is running. All vacuum tubes have been replaced this year.
I brought her again to the garage. I'm waiting for the diagnostic.
I'll keep you informed!

 

[zim]

I finally got my car back. After one week of testing, it seems that now the issue is gone. The garage only changed the "idle regulator valve" (not sure about the technical english right term, sorry!).

So nice to have a car that is perfectly running! :smile:

Again, thank you for your help!