a/c man

i need help with my car it shuts down @ 4000rpm like its the traction control but its not! when it shuts down you can get out of the gas and it comes right back,also the spedo and tach go to 8000rpm and 140mph right before it shuts down but its only going about 70mph it acts like it looses power or shorts out! it also looses power to the scanner at the same time? no problems when i keep to normal driving anyone ever had this problem?

lucky131969

What is your fuel pressure gauge reading while this is happening?

a/c man

its at 60psi

lucky131969

Sucks that the scanner is shutting down....need to know if the engine is pulling timing. Had a similar situation on the dyno from the knock sensor picking up noise , and the pcm pulled timing. Had to have the KS sensitivity turned down.

a/c man

something to look at thanks! what gets me is the Gage's try to peg out! and it never kills the motor it acts like traction control no missing out or popping!it started out doing it only once in a while and just got worse and now its all the time!i thought it was fuel pump so i replaced it with no change thanks scott

lucky131969

And this only happens whey you hit 4K RPM?

a/c man

yes it runs great under 4000rpm

muncie21

When you say that the 'scanner cuts out' are you referring to a scanner hooked up to the ODBII port?

If so, I'd say something is cutting power to the PCM. There's no traction control, over rev scheme, etc. that I can think of that functions by cutting power to the PCM....

a/c man

yea odbII port it does act like its just to the pcm because the other acc still work! when it cuts out!

lucky131969

This should not be RPM related, but have you inspected the wiring in the drivers door accordian? Just thinking about a class 2 serial short possibility, but it should not only happen at a set RPM.

muncie21

Like Lucky said, there's no factory setting programmed to come on at 4K RPM, either some sort of electrical short/issue, or a related issue that just happens to occur at 4K also.

Coupled with the fact that your tack and speedo reset at the same time this occurs, I'll bet you are losing power somewhere/somehow.

a/c man

so the tack and speedo must be resetting thats why they peg out ill look at this today thanks guys!!

a/c man

yea its like you turned the key on and off but it dosent come back until i let off the gas

lucky131969

Can you reproduce the same condition with the car stationary?

a/c man

It does it on the dyno as well but not in park it's auto

muncie21

Couple of suggestions to help you narrow this down.

Try running the car up to 4000 RPM in different gears, see if the problem always occurs at the same RPM, or the same speed, or % of throttle applied. This should help shed some insight into what area the problem lies in.

Second, clear all your PCM codes and then get the car to cut out again, this time pull your codes and see what comes out.

Finally, try to see if the car will fault in both open and closed loop fueling. If you have a scanner you should be able to see the loop status. If you have a programmer, you can force open/closed loop also.

RedRiderZR1

Are you runing a MAF or are you running SD. First thing that pops in my mind is that VE turns off at 4000 RPM and you are strictly running MAF after 4000 RPM. So could be MAF related if you are running a MAF.

a/c man

yes im still running a MAF

ICUALL

Same issue on my new 427 have you found a answer. Think it might be torque management kicking in ??

GeorgeZNJ

If you can get the car up on jack stands, you might be able to replicate the problem in your driveway/garage.