car dies when coming to idle
 

yesterday i tried starting my car for the first time in over 3 weeks. the battery was completely drained. luckily i had my yellow top that i charged before i left. put it in and the car started up and i let it idle in the driveway until it warmed up. tried to go out to dinner later on and it started fine again. got down the street and stopped at the stop sign and my car just died. it was then hard to get started, i had to give a little gas and keep the motor revved up to keep it going. had to rev it every time i came to a stop. i was able to get it to advanced where they checked the battery and alternator. they said they were both running fine.

so my questions are, why does my car keep dying when it comes to idle? why would it idle earlier in the day and then all of a sudden stop later that night?

disclaimer: my 8 is an AT so i am not stalling it.

Not sure, I had a similar problem, I went through everything only to find out my engine was toast. It was running fine one day for me and then all of the sudden this shit happened. This was on my second engine. On my first engine, I had stalling issues but it was only when I came off throttle quickly. It eventually failed at 22,000.

I would clean you MAF, check to make sure there are no vacuum leaks and go from there.

thanks. i will check for leaks later today. i don't know what else it could be. i thought it was either a battery or alternator issue but they checked out fine.

well i checked a couple of things. the vacuum lines under the UIM and my BOV recirc line. the vacuum lines had a crimp in them so i fixed that. the recirc line was a little loose on the BOV flange so i tightened that up too.

started the car up and thought it was fine. then i took it around the block for a test drive and the same thing happened as last night. it will stall out at a stop. then when i try and restart it, i have to give it gas to keep it running.

any more ideas?

sure the ecu is not just re-learning the trims after disconnecting the battery ?

Tip for after disconnecting the battery :
Warm up engine .
Bring revs down to idle VERY slowly with the accelerator .
If you can get it to idle , leave it idling for a couple of minutes to relearn its trims .....


This works a lot quicker than normal driving ,stalling ,restarting etc etc

i let it idle for a few to warm it up before i took it for a test drive. how long should it take?

When you swapped out the batteries, the PCM volatile memory probably was erased. Could just be that the PCM is re-learning your driving style. But then again, I'm a "glass half full" kinda guy. Drive it for awile and see if it corrects itself.

Also, if the battery you swapped out was fully charged and it died in 3 weeks you probably have excessive dark current drain. With the engine and all electrics off, connect an amp meter in series with the positive battery terminal. Should be around 50 ma or so drain. If it is significantly more than that, you need to track down the cause or you may continue to experience dead batteries.

my best guess is MAF...

Not sure if disconnecting the battery resets the ECU (I forgot) but try to reset your ECU with the 20 brake pedal method then let the ECU relearn the trims...

My car used to die when I had installed my K&N Drop in Filter/ RB exhaust on my Auto 8 before I reset the ECU...

I don't think the warmup cycle resets the trims so engine needs to be at normal operating temp then do as above .
I think it helps to (after doing the above)turn it off wait a few seconds then restart and you should be good to go .

If not it is probably something else .

The trick is modulating the throttle to keep it running and keep easing it back to idle which it will do eventually (if this is the issue) .
Best done in your driveway - not on the road .

I dunno man, the crimps in the vacuum could have been and issue but what I noticed when mine was acting up is that when it was cold, it idled fine and did not stall, it was only after it was fully warmed up and driven for a mile or two they it would start stalling.And at first it was intermittent but slowly started happening all the time.

The reason it took me so long to figure out was because it started happening coincidentally at the same time I accidentally broke my VFAD solenoid so I was trouble shooting that thinking it was the problem but actually breaking that solenoid was meaningless.

I don't think it's the ECU, that doesn't sound right.

yes, i think its only when it is warmed up.

Brettus i cannot get it to come to idle at all once it was warmed up. i tried holing it close but it just wants to cut off. i was able to log a start and die cycle but i'm having issues with my AP. it won't connect to my computer.

I know you don't have a lot of miles on the car, but. Thought about doing a compression test?

/\ ok then it is something else . Just seemed to coincide with battery replacement that's the only reason I mentioned it ...

that's probably not a bad idea. how would i be able to get it checked? is a dealer the only way?

Dealer is an option. Unless someone over there on that end of the country has a compression tester.

Sucks, dude but what you describe is exactly what I experienced when my engine died. Once it was warmed up I would have to put it in neutral and hold the revs at like 800-1000RPM's so it wouldn't stall.

/\ Easy fix then - increase the idle speed



JK

any possibility it could be this?

https://www.rx8club.com/showthread.p...+control+valve

Typically with that problem you will see a loping idle not usually stalling each and every time. i used to be heavy in to Honda's and when the IAC valve got clogged the loping idle was a common issue.

the idle was "hunting" before it sat.

Hmm, well can't hurt to take your throttle body apart and clean it. How many miles do you have on your car?

do the fuel trim resistors go bad? i removed my air pump system a while back. i plugged that resistor back in and taped it to the firewall.

got my car running again last night. let it warm up for a while this time. it started to drop down below 750rpm and then go back up and stable out at around 1000rpm. then i took a test drive. at some stops it would drop really low, below 750rpm and then come back up but it did not stall. i then drove to a couple places and shut it off. it started up every time.

remember guys, i just got my car running a couple weeks ago after a long down time from my turbo install. now it seems to be running like it did before i let it sit again for the last few weeks. i think it might be fixed for now. i wish i knew why the rpm drops so low when i stop and why it bounces around at idle.

i would still run a compression test one of these day with a local rotary shop to be on the safe side.