Thread: Rpm wtf?

I am right now cruising downthe interstate and my rpm gauge went spaztic and then just stopped working. I stopped at a gas station and pulled and plugged back in some fuses and started my car back up and it worked. But after cruising for15 miles my engine studdered and it quit working again. I have an apexi afc neo spliced into my edu harness and have no idea where to start so any help will help

check your splices?

Probably your crank position sensor whatever thats called

i am with fyang did u replace your cam and crank sensors with the metal ones?

sounds like maybe a loose connection? id check all ur splices like mentioned above. could just be one moving around.....but hope u get it figured out!

My car did the same thing a little while ago and it was the crank sensor.. I would start there.

it's a crank sensor it happen to my friend before

It seems to come and go it typically works on start up then drops to zero after a while. Then it will bounce all over the place. Work properly for a bit. Then go away. So the sensor is 22 bucks so I will replace it.

I replaced the sensor it corrected the problem until today. Could the sensor possibly go ousit that fast. Throws a code crank sensor malfunction.

Was it the newer metal sensor, or was it plastic like the old one? It's a good idea to buy OEM parts when you can, it's only around $30 at the dealer.

Or you have a short in your wiring somewhere...

Did you snap the connector back in? Was it a metal sleeve sensor?

Crankshaft sensor malfunctioning. Actron lookup code.

I have replaced the sensor twice now. The second time it workeed for about 20 miles then dead rpm. The crankshaft sensor is under a lifetime warranty but i think i have a problem somewhere else. Could boost be an issue with this or is it a possible loose connection?

You didn't answer my (and Bob's) question... but it sounds like it could also be a wiring issue. Boost won't affect anything.

It was the metal one from Advanced. I plan on going to the dealership and ordering OEM. I checked my wiring in the ecu and everything checks out. I just cant fiqure out why when i installed the two new metal (advanced auto) sensors they both worked correctly at start up and cruising but didnt last 20 miles down the road.
The day this started before any problems i was cruising the interstate car spuddered for a split second and dead rpm. After a bit it literally bounced all over the place between 200- 1500rpms than grabbed back to where it needed to be. It continued doing this off and on and finally quit.

last time i seen a problem like this that wasnt the sensor, and wasnt wiring, it was because someone used the wrong flywheel with incorrect tooth count, but were assuming you havent changed the clutch/flywheel recently?

but really, your ses light it going on and the ecu is detecting that sensor as a problem. you need to check for continuity, shorts, etc. make sure you clicked the connector on, make sure you clean the surfaces for the bolt as well,, im not sure if thats a grounding bolt! and check other grounds as well, like the ones on the timing cover, and below. there is diag in the fsm for the sensor show which terminals and wires to test. i would also check the voltage with the motor on&off to check output.

It is definitly wiring then. My audio for my radio quit working and my doors look when ever they please. There is a white box under the dash i think its a door lock control box that has been clicking for God knows how long. I think i am about to run into an electrical nightmare.

electrical problems you should start by checking the battery terminals for tightness and no corrosion, check the ground has good contact. check the battery voltage with motor on&off. i would def find that clicking relay and replace it, or figure out why it keeps clicking. eventually it could drain your battery, or if its shorting could provide enough load that other sensors loose voltage, which sounds like your case.

actually shouldve read this more thouroughly, if your tach reading is going above the actual engine rpm, you have electrical issues. if your tach is just dropping to 0 then returning to actual engine speed, then its your sensor or loss of connection to the sensor.

hey i recently got a new clutch kit and my rpms wont go past 4000 every gear but idles smooth runs good lackin torque and hp please help me

I can't think of a reason why the clutch would limit your RPMs.