Car dies, no codes and then limp mode

[durangatang]

Since I bought the car it will randomly shut off under the right conditions once in a long while but for the past couple weeks the Magnum has been dying on me more and more. This is a weird one so let me try to explain.

I start the car up in the morning and pull out and idle it out to the main road. It will idle forever too because it sat in the driveway for a good 15-20 min to see if it would die. Once I get it up to speed and then slow down to a stop it dies. It does not throw a code or even the lighting bolt. It just quits for no reason. Then when I turn it back on and put it into drive it takes about 15 maybe 20 seconds for the transmission to engage. I thought it might be just be a nuisance issue before but its gone from once every few months to a couple times a week now.


Tonight it died in traffic when I was trying to merge and thats what pissed me off. Then when I the transmission engaged it wouldn't up shift or down shift. Auto stick was disabled as well. I guess this is "limp mode". Once I got it home I turned it off and turned it back on and it was fine. Still no codes, no lights, nothing.

I'm leaning to the transmission because of this, it only happens after it changes gears and its cold. When I start it back up it takes a while to actually engage in drive. Would a low fluid condition cause this? It doesn't leak though.

***Just thought of this, I'm going to try starting out in manual and manually up shifting and down shifting for the first few minutes and see if it changes. I will probably swing by the dealer for a dipstick too.

Anybody have any ideas on this let me know, thanks!

 

[Quick]

How are you checking for codes?
Scanner? which one?
Key dance?
Just looking for the MIL light?

Bad enough problem and the car will shut itself off.
Bad problem and it will do limp mode -- can't shift and won't go above about 4K rpm.

If you get a dipstick and check the trans fluid level you have to know the trans fluid temperature. Some scanners will show that (DashDaq for example), others won't. The transmission fluid temperature is only reported in reverse or any forward gear. In Neutral or Park the trans fluid PID will return the value for the engine coolant temperature.

Looks like photobucket isn't working... the dip_stick_level/trans_fluid_temp chart is on page 21-381 in the service manual. PM me your email address and I can send you a jpeg of that page.

 

[durangatang]

Checking with the key dance once I got home.

 

[Quick]

Try to check as soon as it happens. Maybe it's reset/cleared by the time you get home. It is odd you don't get a light and it's odd that you don't see a code.

 

[durangatang]

I'm gonna take it out and try and duplicate it tomorrow, I'll check right when it happens. Typically I've been stuck in traffic when it does and I just restart it and go

 

[Quick]

I'm gonna take it out and try and duplicate it tomorrow, I'll check right when it happens. Typically I've been stuck in traffic when it does and I just restart it and go

Many of the faults are single trigger (triggers the fault and action on the first occurrence/detection) and then 3 good cycles/checks/whatever to clear it. Crank position for example.

 

[Dookie]

Anytime my car dies on it's on while in gear, when i restart, it has about a 5 second delay before the tranny engages. While beginning to tune a large cam in my car, this was a very often occurrence. To keep this from happening, i upped my target idle RPM. And it is just that, a target...sometimes it overshoots, sometimes under, sometimes dead on...It's a crap shoot at best. You want to set your idle target RPM so on those instances when you target is 650, and it over shoots it by 100 RPM or so, and tries to idle at 550, you will not stall.

When mine did stall no codes, no lights, just stall out. Try bumping your idle RPM up by 50 and see if that helps.

When was last plug change?
Mods?

 

[durangatang]

Can you set the idle adjustment with the predator? All I have done is CAI, exhaust and predator.

I was thinking about changing the plugs soon, just hit 27K miles.

 

[HalV48]

Kinda sounds like what mine was doing when we 1st installed the GSM phenolic spacers and they weren't sealing.

 

[1bad4dr]

Shoot yourself. Problem solved. Wait, what?


I would agree with Kyle if you had heavy mods and it only started doing this before you got the predator, but since you have had this issue when it was bone stock, I am leaning towards the TCM??? Or even the convertor.

 

[Quick]

Can you set the idle adjustment with the predator? All I have done is CAI, exhaust and predator.

I was thinking about changing the plugs soon, just hit 27K miles.

I think you can. I don't think that's your problem. If changing your idle actually makes a difference then you will only be masking some other problem. Kyle's engine is not completely stock...

Your plugs are supposed to be good for 60K? If it's your plugs I would not expect it to just shut off completely on occassion and run fine the rest of the time.

My guess is a bad/intermittent sensor problem or something like what Ron and Hal suggested.

What exactly have you changed with the predator? over and above the canned tunes that come with it? Did you do any "modify parameters"?

Ron mentioned TCM and the "modes" thing immediately came to mind. Did you change the upshift behavior by any chance? The one where you select between mode 1 or mode 2 (and maybe 3)?

Did it ever do it before you installed your CAI? You might want to check/replace the IAT sensor and check the wire connector. Easy to damage while moving it from one CAI to another.

 

[durangatang]

Its been doing it since I bought it but only in the last few weeks has it started happening more and more. Never changed any parameters in the tune, not even the fan settings.

When I installed the CAI I got a IAT code but it reset right away and never came back.

If it could fail how would a torque converter fail? I know this probably way out there but wanted to rule it out. If the TCM is having a problem could it be troubleshot?

 

[Hemi31]

does this happen after a fill up? When the car stalls try turning the key all the way off and open and close the door,then restart.....that will reset all the trans functions and let it go right in gear.

 

[durangatang]

does this happen after a fill up? When the car stalls try turning the key all the way off and open and close the door,then restart.....that will reset all the trans functions and let it go right in gear.

Thats exactly what fixed it but I drove it home in limp mode just in case. I didn't want to stop somewhere and not be able to get it home. I haven't had a chance to take it out today but I'm hoping tomorrow.

 

[Dookie]

does this happen after a fill up?

???

I don't think a bad IAT will cause this, I drove with no IAT at all from Houston to Baton Rouge...CEL lit, but it ran and drove normal.

 

[Hemi31]

???

I don't think a bad IAT will cause this, I drove with no IAT at all from Houston to Baton Rouge...CEL lit, but it ran and drove normal.

The EVAP canister will fill with fuel if you squeeze in too much gas and the car will just die after a fillup because it cannot vent and essentially vapor locks.

 

[Quick]

???

I don't think a bad IAT will cause this, I drove with no IAT at all from Houston to Baton Rouge...CEL lit, but it ran and drove normal.

What do you mean by no IAT? Was it just hanging there or was the IAT sensor unplugged from the harness. When I swapped my CAI once I forgot to re-connect the IAT and I'm pretty sure it immediately went into limp mode. Not positive though because I never left the driveway.

 

[Hemi31]

no IAT will not cause a limp mode issue....just throw a code.

 

[durangatang]

Took it out, sitting here watching it idle at 620~630. No problems at all. Couldn't even duplicate it

 

[Dookie]

What do you mean by no IAT? Was it just hanging there or was the IAT sensor unplugged from the harness. When I swapped my CAI once I forgot to re-connect the IAT and I'm pretty sure it immediately went into limp mode. Not positive though because I never left the driveway.

As in not there at all, not even the connector, connector and sensor were cut off, only 2 wires dangled...Another one of Kelly Hammack's brilliant ideas.