2010 Aston Martin DBS Bizarre idle Troubleshoot with Foxwell NT530

Car model and year: 2010 Aston Martin DBS

 

Symptom:

Has been doing some bizarre idling every now.

Upon starting the car, it idles just fine. About a minute into the car idling, the car’s idle will change and it will “hunt” for idle for about 30 seconds. The rpms fluctuate up and down about 100 rpms during those 30 seconds (after the car has been started for approximately 1 minute). Once those 30 seconds or so are up, the car idles perfectly fine again until the car is shut off. Then once the car is started back up, the car does the same thing. No error codes are thrown. If I let the car idle after driving it (but without turning the car off) the idle is fine. Again it’s just on the start up. The car drives perfectly otherwise, just this strange 30 second time frame after start up.

 

It doesn’t matter if it’s a warm or cold start, this issue arises regardless.

 

Professional Advice:

I would suspect the aftermarket changes. mostly the airbox deletes. air intake is precisely designed, for volume and resistance. i would put them back on and test it. you may find the engine runs better, in general, and with more power too.

 

An OBDII reader, I have the Foxwell NT530 with Aston Martin software on board will monitor the 02 (lambda) sensors in real time. with one, one should be able to determine whether or not they are functioning properly. if one or more need to be replaced (there are four of them), aston wants about 10 times the price they are worth. most are, not surprisingly, all the same, except for the length of the wire that is attached. they shouldn’t cost more than 20-30 dollars each and are a DIY job if one cares to indulge…

I had cause to think mine were faulty due to the inability for the emissions test “drive cycle test” to succeed. apparently I wasn’t driving the car in exactly the way it needed to be driven to trigger the proper tests.

 

Good to know:

Here is the detail steps on how to download and update the Aston Martin software to Foxwell NT530 (Click on “Tech Support” column and then scroll down for the steps)

https://www.foxwelltool.com/wholesale/latest-nt530-multi-system-scanner-one-free-software-nt520-updated.html

2010 Aston Martin DBS Bizarre idle Troubleshoot with Foxwell NT530

Question: Wouldn’t a faulty o2 sensor cause an emissions light though?

From what i’ve read, it may or may not depending on the severity of the malfunction. apparently there is such a thing as a “slow” O2 sensor that will cause problems but not enough to throw an CEL. i have no idea whether or not this is apocryphal. it’s interesting how they work to detect O2 in the exhaust though…

 

in my vantage there are two on each catalytic converter, about 6-10 inches apart. they are identical except for the length of the electrical cord that attaches them to the ECU. they are, at the business end, screwed into the cats similarly to how a sparkplug is screwed into the head.

 

they all send a signal to the ECU at all times using the voltage of the signal signifying how much O2 is present.

 

because the O2 sensor in front receives the exhaust flow first and before the cat has a chance to remove O2 it will always show the most O2 present. then because the second sensor on the cat receives the flow AFTER the cat has had a chance to remove O2 it should always show a lessor amount of O2. the ECU knows to subtract the former voltage from the latter and interpret the difference into the effectiveness of the cats. the O2 sensors are assumed to be working properly. it would be difficult, but not impossible to determine whether or not a malfunction is in a sensor or in a cat.

 

by watching the voltages being sent to the ECU from each O2 sensor a human can make an educated guess as to the condition of the O2 sensors.

 

in my case, after watching the sensors in real time with the motor running, I wasn’t completely convinced i had a sensor problem, so in a last ditch effort to get my car registered for 2022, i resorted to taking it to a (may the good lord forgive me) honest-to-god Aston dealership to fix it.

 

www.foxwelltool.com

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2010 Aston Martin DBS Bizarre idle Troubleshoot with Foxwell NT530
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