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Engine dies on hot start


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Okay so I’ve been living with this for a couple years..and am finally deciding to try again to figure it out. This is on a 2003 R50 with the electronic throttle body (drive by wire), auto trans. It will always start flawlessly when cold, but when hot it has a stumble for the first 2-3 seconds. If I just start it normally, it will start but then the idle will immediately dip way down to around 100-200 rpm. This only lasts about 2 seconds. If it doesn’t stall out, then the idle will pick up to normal range (about 750-850) and everything will be fine after that. Or, if I give it a little gas for the first couple of seconds after starting it to keep the idle from dipping down, then I can release the throttle and it will idle fine after that. Basically, I just have to get it through the first 2-3 seconds when the idle tries to drop, and after that all is good. It has absolutely zero drive-ability problems after that. I’ve performed the throttle position and idle air relearn procedures several times, and that doesn’t help. There are no trouble codes. Again this only happens on a hot start. I’ve gotten used to just blipping the throttle a little every time I start it, but I’d like to finally figure out what’s actually going on. If anyone else with the drive by wire system has experienced this I welcome the input.

 

thanks!

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I had this problem but cold, here’s the video.


Have you checked your mass airflow sensor? Or your throttle body to make sure they’re clean? My mass airflow sensor was making the engine run rich and it fouled up all of the plugs and injectors.
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Okay so I’ve been living with this for a couple years..and am finally deciding to try again to figure it out. This is on a 2003 R50 with the electronic throttle body (drive by wire), auto trans. It will always start flawlessly when cold, but when hot it has a stumble for the first 2-3 seconds. If I just start it normally, it will start but then the idle will immediately dip way down to around 100-200 rpm. This only lasts about 2 seconds. If it doesn’t stall out, then the idle will pick up to normal range (about 750-850) and everything will be fine after that. Or, if I give it a little gas for the first couple of seconds after starting it to keep the idle from dipping down, then I can release the throttle and it will idle fine after that. Basically, I just have to get it through the first 2-3 seconds when the idle tries to drop, and after that all is good. It has absolutely zero drive-ability problems after that. I’ve performed the throttle position and idle air relearn procedures several times, and that doesn’t help. There are no trouble codes. Again this only happens on a hot start. I’ve gotten used to just blipping the throttle a little every time I start it, but I’d like to finally figure out what’s actually going on. If anyone else with the drive by wire system has experienced this I welcome the input.
 
thanks!

Have you tried cleaning the throttle body? It could also be the CPS


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https://maxima.org/forums/5th-generation-maxima-2000-2003/619021-hot-start-issue-start-car-when-engine-hot-will-stall.html

Found this on a Maxima forum sounds like it is common. Their solution appeared to be cleaning the TB. I wish I had a cable controlled throttle .


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12 minutes ago, JackFletcher said:

https://maxima.org/forums/5th-generation-maxima-2000-2003/619021-hot-start-issue-start-car-when-engine-hot-will-stall.html

Found this on a Maxima forum sounds like it is common. Their solution appeared to be cleaning the TB. I wish I had a cable controlled throttle emoji24.png.


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Sounds like exactly my issue. The electronic throttle bodies are weird since the idle air control valve is built in and not a separate unit. Now that I think about it, there was a time when it had improved a bit which was after I had changed the spark plugs and also did a half assed throttle body cleaning at the same time. I think I’m going to try a legit throttle body cleaning tonight and see what happens. 

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Sounds like exactly my issue. The electronic throttle bodies are weird since the idle air control valve is built in and not a separate unit. Now that I think about it, there was a time when it had improved a bit which was after I had changed the spark plugs and also did a half assed throttle body cleaning at the same time. I think I’m going to try a legit throttle body cleaning tonight and see what happens. 

I did a throttle body clean a few months ago. tripped codes cuz the computer doesn’t understand that you are getting more air than you were after cleaning it. Simply just do a idle relearn and the code cleared itself. P0507


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I’ll echo the suggestions to clean the throttle body. I had the same problem a few years ago, and I think the only thing I did in regards was cleaning it. Haven’t had that problem since.

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Success! I pulled the throttle body off after work, cleaned the crap out of it with b-12 chem tool (was careful not to move the throttle plate at all by hand). I also cleaned the maf while I was at it. Put it all back together and went through the relearn procedures, then got it fully warmed up and tested it several times shutting it off and back on and it idles great! It’s starting smoother now than it ever has. I didn’t realize the throttle body cleaning made such a difference on these things. Thanks for the input!

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Update. I’ve put about 300 miles on it since cleaning the throttle body and so far not one single problem with start up! Lesson learned, if you have a VQ with the drive by wire throttle, they really don’t like being dirty. 

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