VIDEO LINK:

I question my Acceleration sensor, so I'm testing it out. I need some help determining if it's good or bad. I hooked my multimeter positive to backprobe pin 3. I hooked the negative wire directly to the negative battery terminal. I placed the multimeter on the windshield and duct taped it in place.

Here is a 8 minute video of a drive with the multimeter connected and a camera taped to my dashboard, Photobucket picture, Youtube hosted. Annotations added to show meter readings




HMAservice also says the computer will call a fault "When abnormal output voltage occurs at stop position of vehicle or acceleration sensor is operated beyond normal operating zone." this does not say anything about the sensor's effectiveness being reduced.

when idling:My multimeter reads 2.47VDC at all times when idling. It does not move at all.
Attempting to get a reading:I banged the sensor against the firewall, shook it, tapped it, turned it and vibrated it as much as i could and got 2.4-2.55 for a reading
While driving:It took alot to set the sensor off and I question weather or not it was just the multimeter leads loosing connection. It would really only change the value displayed on the multimeter when I shifted and engaged my stage 3 clutch very hard.

It takes an awful lot to set it off, if it is in fact being set off. The ammount of jarring required to get a response leads me to believe my multimeter may have been loosing contact. I am trying to troubleshoot a rough idle problem and I would like to know if it would be worth it to replace this acelleration sensor. Is this what the acelleration sensor should look like when tested or is it bad?

Please post your reason for yes or no.

 

My question is what is the purpose of an acceleration sensor and what does it do for the ecu?

 

Assuming the rough road condition is not set and given this description:

It's possible that my engine has learned to run with retarded ignition timing because it's reading rough road as knock.

This is simply a theory and I have no idea if that's the case.

2 people so far have stated that the video displays a bad sensor but neither have qualified or quantified it.

 

well if you think that it's retarding your timing, get a scantool that can read your ecu's ingintion timing on the fly, and drive around town. with the engine over 2k rpms at cruise you should be well over 30' advanced ignition. I have a scangauge II permantely hookd up on my dashboard and ignition timing is one of the things i constantly monitor. the highest i've ever got was 42' advanced.

 

My problem is at idle. The timing is between 9 - 13 degrees. Also, the problem is intermittent so it's difficult to get a reading. The car runs beautifully, it idles like crap sometimes. I'm getting desperate to fix this. See this thread http://www.rdtiburon.com/index.php?showtop...&pid=390985 for discussion on alternate methods.
If you know what these values are supposed to look like, then post, otherwise do not clutter this thread. I am exploring EVERY option thoroughly.

It would be helpful if someone with a good idle repeated this test.

 

Seems like a call to a good dealership service dept. is in order.

I don't know too much about the acceleration sensor itself, but, thinking about it, it is there to tell the engine something is not exploding in the engine. To make the ECM think the engine was misfiring it would take a heck of a bump, which would explain the only significant knock sensor changes happening when there is a hard jar of the car. $0.02

How much are they at a local junkyard?

 

Video was rehosted by youtube, it only took 7.5 hours to get it online because youtube has to process it. I added annotations in the video for clarity of the meter readings because youtube also reduced the quality.

 

anyone?

 

bump.

 

I have 2 hunches on this one bro:

1) you'll be doing your own primary research if you want to know how to test the acceleration sensor and

2) it's mechanical