Car Won't Start

Formula 170

Formula 170

Contributing Member
Joined
21 July 2011
Messages
248
Location
Westchester, NY
Had some major problems with the NSX yesterday. I finished up some work over the last several months; spool valve gasket replacements (both) powder coated valve covers + new gaskets, new intake, exhaust and oil pan gasket. Started the car up and the idle was erratic, surging and then almost cutting off. There was a faint amount of white smoke coming from the engine bay, which I thought might be engine cleaner used when cleaning up the mess from the leaking spool valves. I Let it idle for a while then went for a short spin around the block. I pulled into traffic and hit about 5k rpm. The throttle then sticks open at 5k rpm and won’t stop, even with my foot off the gas!

I turn off the car and pull over. Try to restart and the engine goes right back to 5k. I turn it off again, wait and then restart and the engine rpms drop back to normal, then the car sputters and dies. I attempt a few restarts and it would idle very low and then die. I called for a tow and now the car won’t start at all, the starter turns but that’s it.

Any ideals? I checked for a vacuum leak and all hoses look good. Checked my battery cable, good as well. The only thing I can think of is maybe a plastic gasket or something got sucked into the intake, blocking the throttle open and then going into the engine. I’m hoping I’m wrong on this. Also, there are no error codes. Very strange!
 
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I would first look at the throttle body and all of the vacuum lines that you disconnected. It sounds like the throttle body butterfly is sticking possibly, maybe interference with the throttle body gasket. Did you do anything with the throttle position sensor(TPS)? Did you get it reconnected firmly? Check ALL electrical connections that were disconnected.
Brad
 
I checked all the lines and removed and re-installed the intake. All seems connected and good. I did not touch the TPS. Will check the electrical connections that were disconnected.
 
Checked the cable and it moves freely w/o binding. When I removed the intake, the throttle plate was closed, and it opened and closed with the cable. If I could actually start the car I could do more checking.
 
Get someone else to actuate the throttle pedal and have the intake removed between the air filter and the throttle body. Observe the butterfly valve and check for obstructions with a flashlight.

These HONDA electrical connectors sometimes are tough to reconnect due to the watertight design, double check the one at the throttle body. If the ECU doesn't get a signal from the throttle body TPS it won't let the engine run.

I would disconnect the battery (-) terminal for about 10 sec just to reset the ECU and see if that helps after checking the throttle body and electrical connector.

Something caused the throttle body to stick open if it wasn't the throttle cable. I would remove the throttle body if you don't find anything and look it over from the inside. If it never stuck before, obvisouly something happened at the reinstallation.

Brad
 
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I reset the ECU and the car will start, only it will idle low and then die. Still no codes. The TB looks OK, no obstructions or binding of the cable. The electric connector for the TPS has a good, solid connection, I guess my next step is to remove the TB and take a look. This is the first time it has stuck open, although I have had the car only a few months.
 
The engine will run only when stepping on the accelerator pedal all the way. However, the idle will be very low and as soon as I release the pedal, the engine dies. Feels like the engine is getting very little fuel, even at WOT.
 
OK, so it sounds possibly like a fuel issue. First jumper the fuel pump resistor to keep the fuel pressure at max, then try running it. Could it be bad gas? Have you replaced the fuel filter? Do you have any way to check fuel pressure? It could be a bad fuel pump. You can always disconnect the fuel return line and run it into a gallon jug and have someone momentarily (make sure they're ready to turn the key off - it comes out very fast) turn on the key to see if you have pressure.
Good Luck and be sure to post your resolution.
 
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Interesting. The fuel pump resister is circled in yellow, correct?

fuelpumprest.jpg
 
Any chance that the throttle body got dropped when it was off?

Get a fuel pressure reading to confirm or not that the fuel pump is functioning properly.

How far do you live from LarryB? He lives in lower NY state. You may need him to "Touch" your car.

It's really funny that the car was running fine before you did the work on it and now all of a sudden the fuel pump goes out and the throttle sticks wide open and then it is fine. Either something was in the way of the throttle on the outside or on the inside. I would find whatever it was, you don't want it to do it again.

Brad
 
Yes, Larry B is my next step. I'm about 50 miles from him and have already been in contact. He's given me a few places to check but so far, I'm stumped. He's booked solid for the next month or so, so I will have to keep working on it myself until that time...

One question I have is, say a plastic washer from my 'new' intake worked its way loose and jammed the throttle body before it got sucked into the engine, would the engine still start? I'm hoping this is NOT the case (the washer getting sucked in) and wondering what symptoms would the engine would exhibit.

How would you troubleshoot this? Tear down the top of the engine an see what's inside?
 
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Well.....are you missing a plastic washer? I hope that it wasn't the clamp that is missing at the intake bellows (between the aircleaner and the throttle body) where the large tube attaches (aft side) just below the strut bar.

It may be stuck somewhere in the intake or it may have gone through. Damage is really hard to tell too.

It's sounding like you may want to start back tracking what you did till you find it. Working on the intake is something that I am always very careful with.

Brad
 
Formula 170 said:
Interesting. The fuel pump resister is circled in yellow, correct?
Click to expand...

Yep, that's it.

I have had a friend use a borescope to look into my intake manifold to see if the bolts holding the butterflies were in place (they have been known to loosen and get sucked into the engine causing major damage - mine were all in place). You could get lucky and find the washer in there. It's very easy to do.
 
pgilliam1 said:
Yep, that's it.

I have had a friend use a borescope to look into my intake manifold to see if the bolts holding the butterflies were in place (they have been known to loosen and get sucked into the engine causing major damage - mine were all in place). You could get lucky and find the washer in there. It's very easy to do.
Click to expand...

I checked this thread: http://www.nsxprime.com/forum/showthread.php?t=155613&highlight=intake+manifold+bolts+loose and it got me thinking. I'm wondering if a plastic washer would have the same effect on the engine as a metal butterfly screw?
 
No way it could have the same effect, but it could create other problems (stuck valve, etc.). A leakdown test may be in order for your symptoms though.
 
How are you holding up? All these suggestions are making my head spin and yours must be too.
Sorry for your problem. Good luck with this.
 
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pbassjo said:
How are you holding up? All these suggestions are making my head spin and yours must be too.
Sorry for your problem. Good luck with this.
Click to expand...

Thanks for the support! It sucks big time to be without my car on my first summer of ownership, but I have my 300zx to keep me busy while I sort the NSX out. I've looked at everything and cannot think of anything else to check, with the exception of removing the TB. At this point I'm ready for an expert and hoping to get an appointment with Larry B soon..

Till then, keep the ideas coming :)
 
Hve you check all of your vaccum lines, making sure they are routed to the correct place? Also The vents on you valve covers that are routed to the intake are not blocked in anyway?
 
Fixed

Here's an update. Had the car towed to Larry B who lives less than 50 miles away. Seems like my timing belt skipped 6 teeth! He's thinking it was not put on correctly by the PO. He did a complete timing kit and checked out some other issues. The car is now running perfectly!!

Much love for Larry B!!
 
Not:

1) throttle body

2) Throttle position not plugged in all the way

3) Sticky butterfly

3) Vacuum lines

4) Throttle cable or plate sticking

5) Reset ECU

6) Washer ingested in engine

7) loose or missing screws from butterfly plate

No one guessed right! :biggrin: Whooda thought?

LarryB is one sharp guy.:cool:
 
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