Engine Nearly Shuts Down

[smockers83]

This has happened to me twice so far. What happens is when the car is at idle, it'll stall or something and come back to life all on it's own. It's done it once about 30 seconds after starting up and earlier today while sitting at a light.

Any ideas?

[pfarmer]

This has happened to me twice so far. What happens is when the car is at idle, it'll stall or something and come back to life all on it's own. It's done it once about 30 seconds after starting up and earlier today while sitting at a light.

Any ideas?

No mis-firing etc., just a big drop in rpm followed by operating normally?

Is the ambient temperature up?

Perry

[Poyzinous]

I saw that once in an FX, threw a throttle code, new throttle chamber, good as new. But it could also be something simpler. between maf and throttle is where i'd look for something as a first step.

[smockers83]

No mis-firing etc., just a big drop in rpm followed by operating normally?

Exactly. It just drops RPM and essentially restarts itself. All the lights on the dash come on as if you just started it and then go off. No SES light or anything afterwards.

Temperatures are actually cooler than previous summers, it hasn't been too hot, and it's only done this once back in June and just the other day.

I haven't done anything to the car lately. Airfilter was cleaned and reoiled back in early April. Only things that have been done is an oil change and new tires.

I saw that once in an FX, threw a throttle code, new throttle chamber, good as new. But it could also be something simpler. between maf and throttle is where i'd look for something as a first step.

Vaccum leak or something? What do I need to be looking at?

[pfarmer]

Exactly. It just drops RPM and essentially restarts itself. All the lights on the dash come on as if you just started it and then go off. No SES light or anything afterwards.

Temperatures are actually cooler than previous summers, it hasn't been too hot, and it's only done this once back in June and just the other day.

I haven't done anything to the car lately. Airfilter was cleaned and reoiled back in early April. Only things that have been done is an oil change and new tires.

Vaccum leak or something? What do I need to be looking at?

Well I was going towards a fuel issue until you stated it acts like it restarted itself, lights come on and go off, etc. This to me is starting to sound more electrical.

What lights come on, everything or just some selective lights. Probably hard to grab now as it must be sort of startling when it occurs.

To me if something comes on that is not directly engine related then it starts to sounds like a BCM issue. If only engine related items then maybe it maybe something simple related to ignition, fuel pump, etc. See if you have any DTCs.

Perry

[smockers83]

What lights come on, everything or just some selective lights. Probably hard to grab now as it must be sort of startling when it occurs.

After being startled that it happened, all I noticed was it seemed all the lights that come on when you start it came on and they shut off like they normally would after starting.

If I went to have a code pulled, would it still be logged or no?

[Poyzinous]

yes. codes won't clear until you've completed 40 trip cycles without fault.

[tollboothwilley]

I'd bet money on the Throttle Body. Sounds like it is dirty. This is what the symptoms are for people. Be careful when/if you clean it.

This can also happen from a plenum leak. Idle drops with an intake leak.

[pfarmer]

After being startled that it happened, all I noticed was it seemed all the lights that come on when you start it came on and they shut off like they normally would after starting.

If I went to have a code pulled, would it still be logged or no?

Twice during my failure to start issues the car started in a real strange way. Both times everything indicated that the car should start only it did not (no crank) and then a second or so after I removed my finger from the button and my foot off the brake it appeared like a new start procedure had been initiated and the car started normally - on its own.

Now what would it had looked like if the car was running and lost whatever allowed it to continue to do so and then cleared? Could it be the same thing only occurring in different states of operation?

Perry

[smockers83]

What's the procedure for checking the TB for dirtiness and how would I go about cleaning it without screwing it up?

[Poyzinous]

What I do is just remove the intake tube, and with a lint free cloth, rub off all the dirt and crap molecules inside of it. You can manually lift the valve and peek inside. Just don't do this with the engine running. Careful with cleaners as they usually cause damage and make your engine explode. Maybe.

[smockers83]

So I can move the butterfly with the engine off without having catastrophic TB failure? I just want to double check that because I've heard of people screwing it up somehow. Just as long as I use something like my microfiber to wipe it down, right?

[Poyzinous]

photosynthesis.

[SteveTheTech]

What I do is just remove the intake tube, and with a lint free cloth, rub off all the dirt and crap molecules inside of it. You can manually lift the valve and peek inside. Just don't do this with the engine running. Careful with cleaners as they usually cause damage and make your engine explode. Maybe.

Sorry Gabe but;

You should never move the throttle plate while attempting to clean it or inspect the intake.

I am guilty of this I know may other too who are, but it is just not a safe practice, but I have since learned.

There are two microswitches and two extremely sensitive potentiometers inside the little black case. Although you may be able to do this without issue this is tempting fate and if the ECM looses it's closed throttle learning due to a fault in the TB assembly there is no repair that can fix that short of component replacement.

Instead of touching the plate I usually remove the assembly (actually takes about 10minutes with the right tools). In lue of touching the plate it is easy to clean both sides of the throttle. Although this may not resolve your specific issue it might help. This will also give you complete access to the top part of the intake. If you don't need to drive for a few hours spray some cleaner in the intake and let it dry either with time or the assistance of compressed air. (This will prevent a potential misfire due to an extremely rich mixture and potential fouling of spark plugs and AF ratio sensors). The car still may hesitate and sputter when you initially start it, but it should go away. When you restart it be sure to let it reach operating temperature once it is started. This will burn off any remaining residue.

Twice during my failure to start issues the car started in a real strange way. Both times everything indicated that the car should start only it did not (no crank) and then a second or so after I removed my finger from the button and my foot off the brake it appeared like a new start procedure had been initiated and the car started normally - on its own.

The V35 (although in this case Smockers has an 06) and V36 are light years apart electronically although the some units are there the wiring and ignition components are all different. With the I-Key system in the V36 there are a good dozen parameters that need to be met. If something is askew even slightly the car may not start. If it comes back up and starts again with no ill effects there is a good chance that it will not get fixed until it breaks more frequently, sorry.

[Poyzinous]

Never do that? You and James both told me to clean it like that some 4 years ago... lolWell I'll remember that

[SteveTheTech]

I know and I was wrong.

[smockers83]

What if there was something wrong with my A/C, like it needed to be relubed or something, could that be a culprit? My A/C has been kind of loud, or at least it seems like it. The first time it happened, it seemed to coincide with the A/C starting. The 2nd time though, I don't think I had it on (may have had the windows down), but it's possible, it was hot that day.

Good thing I haven't had time to clean it yet.

[pfarmer]

The V35 (although in this case Smockers has an 06) and V36 are light years apart electronically although the some units are there the wiring and ignition components are all different. With the I-Key system in the V36 there are a good dozen parameters that need to be met. If something is askew even slightly the car may not start. If it comes back up and starts again with no ill effects there is a good chance that it will not get fixed until it breaks more frequently, sorry.

What was puzzling in this case was that parts of the criteria to start the car was removed and then the car started acting like a new start had been initiated. Basically I was getting at is what would it act like if a running parameter was removed and then reestablished. In my case it appears that at least parts of the start cycle are (for lack of a better term flip-flop, latched) stored in memory for a period of time and once established can be removed (ie pushbutton and brake). The result looked like a new start sequence was initiated and these parts were no longer needed.

If you were traveling down the road and lets say lost a running parameter and then it was reestablished does the car go through what looks like a start procedure?

Personally I would think that the brake has to be kepted on for a set period of time after the starter is powered but this sure doesn't seem to have been the case here.

Perry

[pfarmer]

What if there was something wrong with my A/C, like it needed to be relubed or something, could that be a culprit? My A/C has been kind of loud, or at least it seems like it. The first time it happened, it seemed to coincide with the A/C starting. The 2nd time though, I don't think I had it on (may have had the windows down), but it's possible, it was hot that day.

Good thing I haven't had time to clean it yet.

Check your battery. After rereading this and another thread something just came to mind with what occurred with my Jeep. I drove to pick up my sister at the airport when Mom died. Just leaving the airport the a/c started and the Jeep died. Got a jump from AAA and as soon as the a/c kicked on it started to die again and I shut it off before it died all the way. Got a new battery the next day and all was good (except the situation).

So I am wondering if you may have a bad battery or could your charging circuit be charging a little bit short. A large load pulls it down just enough to cause one or more modules to not function properly.

Perry
Modified by pfarmer at 12:26 AM 7/25/2009

[smockers83]

Here's something new that has popped up.

I was in a construction zone with slow moving traffic. While I was moving, much of my electronics would go off for a split second and come back on. The only light that lit up was my ABS light, but the radio and HVAC system shut down, too. Looks like when I get back home, I'm going to have to have it looked at (it is due for 30,000 service).

My volt light hasn't been on at all.

[pfarmer]

Here's something new that has popped up.

I was in a construction zone with slow moving traffic. While I was moving, much of my electronics would go off for a split second and come back on. The only light that lit up was my ABS light, but the radio and HVAC system shut down, too. Looks like when I get back home, I'm going to have to have it looked at (it is due for 30,000 service).

My volt light hasn't been on at all.

Not sure on the 06 but the charging light sort of has a different meaning on my 08 then I am used to:-----------------The IC regulator warning function activates to illuminate thecharge warning lamp, if any of the following symptoms occur whilealternator is operating:• Excessive voltage is produced.• No voltage is produced.

------------------

I need to look at this again as it seems to lack 'low voltage'.

pERRY

[Sentientbydesign]

Sorry Gabe but;

You should never move the throttle plate while attempting to clean it or inspect the intake.

I am guilty of this I know may other too who are, but it is just not a safe practice, but I have since learned.

There are two microswitches and two extremely sensitive potentiometers inside the little black case. Although you may be able to do this without issue this is tempting fate and if the ECM looses it's closed throttle learning due to a fault in the TB assembly there is no repair that can fix that short of component replacement.

Instead of touching the plate I usually remove the assembly (actually takes about 10minutes with the right tools). In lue of touching the plate it is easy to clean both sides of the throttle. Although this may not resolve your specific issue it might help. This will also give you complete access to the top part of the intake. If you don't need to drive for a few hours spray some cleaner in the intake and let it dry either with time or the assistance of compressed air. (This will prevent a potential misfire due to an extremely rich mixture and potential fouling of spark plugs and AF ratio sensors). The car still may hesitate and sputter when you initially start it, but it should go away. When you restart it be sure to let it reach operating temperature once it is started. This will burn off any remaining residue.

The V35 (although in this case Smockers has an 06) and V36 are light years apart electronically although the some units are there the wiring and ignition components are all different. With the I-Key system in the V36 there are a good dozen parameters that need to be met. If something is askew even slightly the car may not start. If it comes back up and starts again with no ill effects there is a good chance that it will not get fixed until it breaks more frequently, sorry.

Are you at will to describe the procedure for having the car open the throttle plate on it's own?

Jacko could have been just a wacko, but he once said that his technician was able to have the throttle plate open on its own and cleaned the throttle body while it was open.

[Sentientbydesign]

I believe 4drmadness had similar symptoms with his 04 and it turned out being the throttle body.

[SteveTheTech]

As with many of the things Jacko claimed there seems to be very little truth to that. For DIY maintenance removal is the best option.

I was in a construction zone with slow moving traffic. While I was moving, much of my electronics would go off for a split second and come back on. The only light that lit up was my ABS light, but the radio and HVAC system shut down, too.

That's an interesting one. Technically those things should stay off if they go off unless there is an issue in the IPDM or something somewhere in the power leg of the circuit.