Power cutting off at 4,000 rpm?

My wife normally drives our 06 obxt (stage 1), yesterday she said the battery died in the middle of the day so I took it to work this morning (started ok, battery a bit weak). After it was warmed up I stomped it in 2nd gear and the power shut off like a light at 4,000 rpm, scared the s*&^ out of me. Car drives fine under 4,000 but in any gear it won't accelerate past that mark. The car doesn't die but its like the fuel or spark is shut off completely. I'm not sure if it has to do with the battery being dead or possibly an alternator issue?

Any check engine lights?

Any check engine lights?

 

No cels

That's weird, if it was fuel cut or overboosting you should see a CEL. Does your check engine light illuminate when you turn the key on? Do you have a laptop and OBDII cable?

I was going to say that it sounded like a fuel cut caused by overboosting. Same thing happened to me at 4000 rpms, but I definitely got a CEL.

The CEL comes on as normal when turning the key and then goes off. I just tested and the cut off is happening even while revving in neutral! Is there some kind of valet/safety mode that could have been triggered by the battery going dead or weak alternator output? I haven't so much as plugged in my AP in 3 yrs so I know I didn't change any maps....

Last time it happened to me it was my ABS sensor. The cel doesnt come on tho, just the ABS light. No lights are on the dash at all?

no lights on the dash at all, very strange.

very very strange. Usually it cuts the power at 4000rpm when theres an error, i call it "safe mode". Stops you from damaging anything. Well it started with the battery, so get the battery fully charged and see what happens,and check the alternator as well

^this. you're limping from the earlier low volts -- car on wg pressure i bet, as well. same thing happened to me on a weak battery. it should clear up on its own rather quickly (assuming the battery isn't hopeless). probably time for a new unit, though.

I'm going to have the battery replaced today, will see if that makes a difference. I just drove it again and it feels exactly as if the rev limiter was moved to 4,000, no check engine lights, no other issues just an abrupt loss of power which feels exactly like when you hit the limiter normally.

I'm going to have the battery replaced today, will see if that makes a difference. I just drove it again and it feels exactly as if the rev limiter was moved to 4,000, no check engine lights, no other issues just an abrupt loss of power which feels exactly like when you hit the limiter normally.

 

It sounds like it hit some limit in the system - boost spike, etc. - enough for the ECU to put it in limp home mode. But not enough to give a CEL, or at least, not one that is displayed on the instrument cluster. It probably has one stored in the ECU that can be called up.

 

If that's the case, the limp mode will clear up on it's own after enough restarts, or you could just reset the ecu by disconnecting the battery and pumping the brakes 4 times.

 

Regards,

 

Paul Hansen

http://www.avoturboworld.com

the electronic operated systems (ecu, injectors etc) probably cant keep up with the demands ona dead battery. the higher the RPM goes the more juice theyll need and if their not getting it ityll just cut out to avoid frying anything.

ok, just put in a brand new battery and checked the alternator (14 volts at idle). Same problem. :confused:

when this happened to me, it took some driving time to resolve the ecu's apparent reluctance to dole out the happy.

Not what's happening in your case, but a friend had an aftermarket tune and lots of mods on his car... it was set to go to valet mode if the power was cut.... well, he was at the dragstrip and they made him test his power cut switch in tech... he forget it put the car in valet mode... his normal 12 sec car ran something like 24 sec at 50mph, redline at something like 3500rpm..

I'm hoping the drive home and a couple of more ignition cycles will clear this up. I'm going to try to see if my AP pulls any codes tonight.

Plugged in the AP, no codes, same map (TDC stage 1 91 octane), still with the problem. since my wife drives the car most of the time and she doesn't go over 4,000 rpm the problem may have started some time ago.

this may sound silly, but is there proper octane fuel in the car? give it a top off with some good known 93, flash the RT, and give that a go.

I was thinking about octane, I haven't done anything different fueling wise, using 92 or 93 octane and its a 91 octane map. Anyone know if its normal for a aftermarket (TDC stage 1 91 octane map) to cut off power at 4k rpm if it doesn't like the octane level?

Maybe your key is busto? I remember the salesman telling me that the difference between the valet key and the regular key was a chip - if the car didn't see the chip it went into valet mode. Perhaps the 'chip' in your ignition key, or the sensor itself is having issues?

*accidental*

The symptoms are that of limp mode. Does your radiator fan run continuously when the key is in the "on" position? Are you getting an ER SS message on the info display? Is the ABS light on? Is the cruise light flashing?

 

Car will not rev beyond 4000rpm when in limp mode.

No error messages at all on dash, no flashing lights, radiator fan not coming on. I didn't know there was a chip in the key but we are using the same one we always do, I'll try the spare key to see if that makes a difference. Appreciate all the help - frustrating!