High RPM, Engine Shuts Off - Should be easy fix - Tell me what it is!

[ruckdr]

Yesterday while at the track, after a couple sessions, the car started acting weird. Accelerating hard (throttle on floor), the engine shut off at 5000 +/-RPM, the Tach fell to zero. Engine probably shut off, but since I was running, probably compression started immediately and kept going. When this happened, the car of course ******, as the engine stopped. This would happen in all gears 2nd, 3rd, 4th, all at about 5000 RPM, give or take.
On the way home, entering a freeway, did the same thing while accelerating in 2nd gear at 5000 RPM +/-.
At home I checked alternator output, and battery voltage, both seem a bit erratic with accessories on/off, and battery voltage gauge seems to vary somewhat.
I suspect a low or insufficient battery voltage, possibly alternator output. Battery is 1 year old.

Your thoughts and solutions will be welcome.

Later,

 

[mad0953]

I'm no expert but you have described how a rev limiter works. Yours is probably messed up......kicks in at the wrong RPM. Just a guess though.

 

[XLR8]

It is most likley the TPS or the MAP sensor.

 

[Viper Wizard]

It is most likley the TPS or the MAP sensor.

NO WAY!! How old are you?

Mark is on the right track!!

Crank sensor, cam sensor, PCM or something in between [wiring/connector]??

 

[ruckdr]

Chuck,
Ya, not rev limiter - been there many times.

How about a battery that I just had checked , in the car via the front battery tap and a ground, that shows it is NOT taking a charge, and therefore, (my suspicion - I don't know for sure), that when the demand is full throttle, there is not enough power for the PCM ??
Your expertise please.

Thanks,

 

[Qualitywires.com]

Don, like chuck said I bet it is a cam sensor or crank sensor...easy fix. I had same sytoms in the past and it was a cam sensor.

 

[ruckdr]

Adam,
I do suspect cam, or crank sensor, but since the battery is showing not good, I have to address that also.

Wires just came, they look really, no REALLY REALLY GREAT.

Later,

 

[Joseph Dell]

Bad battery should be fixed before you try _anything_ else. I bet you a dollar that it fixes everything. this car does funny things w/ weak batteries.

Trust me. Just do it. like now.

good luck!

JD

 

[ruckdr]

Joseph,
Yes indeed, battery is the first fix.
Thanks,

 

[GTS Dean]

Don,

There were several of us track rats with '96s (using the new -for then- JTEC ECU) who had similar problems when the cars were fairly new. Some found loose crank sensors, others' cars required PCM reflash. Mine was flashed twice and still had problems. They installed a new JTEC and the malady went away for good.

 

[ruckdr]

GTS Dean,
Thanks, I will put that in my list of possibles.
Was there a diagnostic / electrical check that uncovered this problem?

The ironic thing about this is that I was at the track the Friday before (Sept. 11), and did not have this problem.

Later,

 

[ruckdr]

OK, took battery out of car and had it checked out - IT IS FINE !! It is only 1 year old, so apparently under hood check is not conclusive as with the "raw" battery.
Will this help you in the diagnosis:?
The engine will go right past 5000, clear to 6000, if the throttle is NOT on the floor; if I hit it hard down to the floor, that is when it shuts off when it gets to 5000 +/- RPM.
TPS by chance ????

Thanks,

 

[XLR8]

NO WAY!! How old are you?

Mark is on the right track!!
Yo!! Mr self proclamed Viper Wizard. My age doesnt matter.Trust me I am not your type. If you are looking for a dating web site this isnt it.The guy is looking to fix his car and I am not looking for a date.
I replaced a TPS to fix this same problem and was just trying to help. Or you could send your car and 50k to the wizard to get it fixed.
Crank sensor, cam sensor, PCM or something in between [wiring/connector]??

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

 

[ruckdr]

XLR8,
Thanks for the input. Did yours have the following characteristic, not sure if I mentioned this above, but took a while to understand exactly what was going on?
Yes I did: The engine will go right past 5000, clear to 6000, if the throttle is NOT on the floor; if I hit it hard down to the floor, that is when it shuts off when it gets to 5000 +/- RPM.

Full throttle = Open Loop mode, not sure why just
acceleration allows engine to rev well past the FULL throttle cut off of 5000 +/- RPM??

TBS ?????

Inputs welcome,
EXACT SOLUTION more than welcome.

Later,

 

[XLR8]

Sounds like the same thing that hapened to mine. Also after driving the car normal for a few days I got a check engine light. The code was for the TPS. Replaced it and problem solved. Good luck.

 

[ruckdr]

All,

OK, fixed; it was a Shorting MAP sensor; not faulty except when it was shorting, and affecting the 8 or 9 volt signal to the computer. The MAP sensor is down the chain, so to speak, and the computer would set codes for the up chain sensors on the same power - Cam, Crank,... but not the MAP because it was really not malfunctioning, except when shorting, caused by vibration, acceleration, engine movement,.... Our mechanic said he kinda had some ideas, and with the car idling (running fine), he jiggled the MAP sensor and the engine died. Repeated the process a number of times and replaced the MAP sensor and all is OK. The find was somewhat by accident,after replacing Cam and Crank sensors, and since he is such a GREAT guy, he didn't charge me 3 arms and 5 legs for the diagnostic. MAP sensor was a few $$$'s, however.


Later,

 

[KepRght]

thanks for posting the end result im sure ill need this post in a year or so

 

[ruckdr]

KepRght,
You're welcome.
So many times I see problems discussed here on the board, and I know solutions are found (or we would have a lot of parked Vipers), yet the solutions are not always posted.

Later,

 

[Jim Wilson]

So XLR8 was right all along.

 

[ruckdr]

Yes, as XLR8 said:

It is most likley the TPS or the MAP sensor.

The problem was, as I said above, no code was set for the MAP sensor, since it was truly not malfunctioning, just shorting out, disturbing, or interrupting the voltage.

All in all a very good fix, as experienced by the way the car ran at the track yesterday (9-1-06). A great track day, enough cars to have ONE run group, which meant the track was open for 6 hours, go on, come off, at your pleasure.

Later,

 

[99 R/T 10]

For future reference the MAP from a 1500 Dodge ram with a 5.9 uses the same one....40 bucks instead of 150.00 for a 'viper'. Same part number, different name. Got this from a member from the Alley!

 

[dave6666]

For future reference the MAP from a 1500 Dodge ram with a 5.9 uses the same one....40 bucks instead of 150.00 for a 'viper'. Same part number, different name. Got this from a member from the Alley!

Speaking of packaging and how it affects pricing, your u-joints on your drive shaft and half shafts.

Spicer Dana box - $37.50 with strap bolt kit

Mopar box - $125.00 no strap bolt kit

Jaguar box - $330.00 no strap bolt kit

We need a great looking volunteer to write all of these cost saving parts down and save them in one spot. Anyone have a spare ******* girl that can type too?

 

[FE 065]

Nerf..I just replaced my MAP sensor after finding this thread in January, and *** with ruckdr.

I was getting a high rpm stutter last Summer, and then this Winter I noticed a CEL at idle-which I don't think was on when I started it a few weeks before, nor when I parked it in the garage to store it.


No CEL at idle now! Hoping for the best when the weather's good enough for a road test.


Your results may vary..