CX-7 makes noise in the middle of the night.

J

Johann

Member
The noise occurs when the vehicle has been turned off for several hours.
Noise can be described as an electrical buzzing which originates from the rear of the vehicle. The duration lasts about a minute.
This has been observed twice at one week intervals. Since it's an intermittent problem, I suspect it occurs much more often.
I'm guessing the sound is from the electric fuel pump within the gas tank.
Question: Why would the fuel pump turn-on in the middle of the night with the car off?

(Wife's '08 GT, purchased 6 weeks ago, built 10/07)
 
were you sleeping in the garage? or did you park in the bedroom? (scratch)

did you check the rear cargo area for electronic devices?
 
Midnight is about the time I retire and let the cat out.
As far as I know, it may occur all through the night. But I don't plan on camping out in the garage to find out. BTW, I've asked the cat to keep an ear open and alert me the next time it happens.
 
You sure it's the car and not something else making the buzzing noise?
If the fuel pump ran all night you would have a dead battery.
 
I'm almost positive it's the fuel pump. It only runs like for a minute and shuts off. Not really enough time to drain the battery.
The last time it happened I was able to crawl under the gas tank and the noise was quite distinct.
Besides that, the car has no other symptoms that I know of.
 
Do these trucks have a seperate water pumps for the inner-cooler?Well I also have an X-runner and TRD uses sep. water pump for the cooler and it does engage every so often to assure theres adequate water in tha system
 
Maybe the wife has a hidden web cam to check your sneaking out at night. The newer models are very small and are triggered by footsteps. Joking Maybe it is the security system recycling & reseting.
 
Last edited:
Hey Guys,

pay attention! This may be normal.

I've also owned a 2008 corolla and in I've read in the user manual that 5-6 hours after the car stays you may hear some curious noises. This is (For corollas) the fuel(or exauts; Don't remember well) system performing some self test. This may be normal.

Now the matter is how loud are the noises?
 
It's been two years since I posted this thread and the car still experiences the noise. I'm 99% sure it's the fuel pump in the gas tank however this hasn't caused any ill effects.

The noise isn't loud, it just buzzes like an electric motor running. Duration is 45 seconds or so...I haven't timed it.
Mazda scanned the computer and found nothing.
The only service work done on the car was a battery replacement at 24 months.
 
My Impala used to make something like 8 knocking sounds 45 minutes after shutting down. It sounds like most newer cars do some sort of self diag. after shutting down.
 
I've searched the Net and have found no one else with this issue.
Other than that the car has been trouble free.

This is the wife's car and she never exceeds 2500 rpms. Gas mileage was 22mpg in the city. But Texas has completely converted to 10% methanol and now she gets only 20mpg.
 
Hey,

Wife bought me a new CX-7 while I am on a forced vacation in a lovely Southwest Asian country. I can't stand it, so I spend some of my free time browsing through the CX-7 forums and stumbled on this thread.

My guess is your evaporative emissions control system is purging. You may want to check the car talk website (cartalk.com), search for EVAP and see if some of the posts there don't sound like what is happeneing with your car.
 
I have the same thing on my '07 Speed3, I think that its the fuel pump. My wife has a cx-7 and I haven't heard her car make the noise yet.
 
Its your evap system running self test.. the buzzing noises and such are from your tank/canister checking pressures. in my ten years of the automotive world ive had maybe 2 ppl say something about it but its been there since they have had the vsv's
 
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