Well here it is a few weeks ago I was driving my S and for some reason when am cruising in 5th or 6th gear going like 50 or 55 mph and when am slowing down to come to a stop as soon as I put my S in nuetral my car shuts off am not sure what it could be. Before this started happening it started to act like if it wanted to shut off but it wouldn't then after a week later it started shutting off on me everytime I go from cruising to a stop or when I put my car on neutral that the RPM are going down the car shuts off completely. I did a volt test and it read 14.3 to 14.5 around there. And am not sure is this is bad or not. Can you guys please help me and tell me what you think it might be. I still haven't replace my alternator cause am not sure if that's what it is or not I hate wasting money if am not sure exacly what it is. So how do I test the alternator to see if its bad or not. Thansk for all your help.

 

What ecu do u have? Any mods?

 

Am running an AEM EMS, I took it to my tuner to see if maybe needed a little retune but he hooked it up and he he says that everything on the tuning was good and that nothing has change he told me that once the ems is tuned it doesn't change like that unless himself do any changes. He says that when the car is going from high rpm to low I lose power so it turns off. Weird !!!!!

 

That is pretty damn weird. Did your tuner have any guesses?

 

This not the MAP problem?? or is this something completely different?

 

It does sound like a MAP issue. If you are turbo, what MAP are you running? Has it had the stumbling/trying to die issue since you turbo'd the car?

But I can also tell you that tip-in throttle tuning (or in your case...tip-out) takes more time for a tuner to get right.

I had a similar problem that Mase was able to fix with a little road tuning.

 

He was pretty confident on what he was telling me when he hook up the laptop to the ems and put it on the dyno he told me that the air/fuel mixture it was perfect and that for some reason when am driving the car it has a perfect voltage but when he let's go of the gas peddal and the rpm are going back down am loosing voltage the voltage drops a lot so because am loosing power the injectors stop working cause the car doesn't mantane the voltage that it should have at idle. Am goona take out today my alternator and I heard that autozone can tested for me so am gonna see if they can do that and they should be able to tell me if it is the alternator or not. Anyone has any other ideas or does it sound like the alternator that is not keeping the charge ?

 

Well...that's a lot more info than you gave before.

Does your dash flicker? That's usually a dead give away that your alternator is going out.

It does sound like a good idea to have the alternator tested. If it shows good, you might see if someone local would be willing to swap alternators for a day for some testing.

Have you changed your stereo system recently? Added an amp?

 

Ok well I just got back from testing the alternator and it checks out really good there is no problem with it at all. Now my head is spining not to sure what this could be I probably end up taking it back to my tuner to see if he can fix this problem and tell him that I believe that this is a tuning problem to see what he says. Or take it to another tuner maybe get a second opinion. I don't have a sound system on my car and my lights doesn't flicker or anything like that. Am not sure what to do next.

 

hey Guy

I don't claim to be a mechanic but a couple things to have your wrench check.
1.If you replaced the PVC vaule that may be a problem. If you haven't replaced it, that might be it.
2. Idle Air Control solenoid/valve?
3. Vacum leaks, if car runs good but wont idle I would start there. If yous got a vacum leak she aint gonin idle. But she will run fine may be lean out a bit.

But just guessing.
Good luck!