I've had an occasional loud tick from the back of my motor for a while now that only seemed to happen when the car was fully warmed up and had been driven. This thread helped me diagnose: https://www.myg37.com/forums/engine-...r-driving.html

I finally got around to swapping out the EVAP purge solenoid and not only is the noise gone, throttle response is better and the car seems to have more power down low. The part is $123 from Z1 and took all of 10 minutes for me to swap. The mounting holes are slightly different on the new part, so the original rubber grommets didn't fit in the mounting holes. The bolts were too long without the grommet, so I used the grommets as spacers between the solenoid and plenum. See photos below.

I'm not a great mechanic, lol. I would have swapped this part out a long time ago had I known how easy this was and that the car would run noticeably better. So, if you have this loud tick coming from behind the plenum after driving, it may be the EVAP purge solenoid, and it is worth fixing.


Old on left, new on right. Note the difference in mounting holes.



New part installed with rubber grommets used as spacers

 

Thanks for posting this. I'm curious how much improvement you would say you noticed in throttle response/low RPM response?

I don't notice any loud ticking but definitely feel like throttle response could be improved. After replacing spark plugs, cleaning throttle bodies, MAF sensors, battery terminals I feel like response is still off. I have tried using MAF cleaner on the EVAP purge solenoid but that didn't do much.

 

The improvement is hard to quantify. It is something I noticed, but not earth shattering. Its not like the car's throttle response was abysmal before the fix.

With no CEL and no noise, it would seem unlikely to me your issue is the EVAP purge solenoid. But, I am no master mechanic. Have you had a mechanic take a look at the car and provide any advice?

 

No worries. Does your car have the 7AT or 6MT?

I haven’t had a mechanic look at the car. I’ve thought of taking it to Specialty Z to get some advice but it hasn’t been a priority and I don’t want to open a costly can of worms at the moment. I have no trouble codes so it’s hard to make out whether it’s just the nature of this drive train or if something subtle is amiss.

Just to clarify, did you have any trouble codes or was it the noise that prompted you to diagnose?

 

when you cleaned the throttle bodies, did you take off the 5mm Allen bolts to clean behind the butterfly and inside the intake plenum?

I only ask because when I first cleaned mine, I left them attached and cleaned what I could with a toothbrush & throttle body cleaner. I went back a week later to do it properly & noticed A LOT of the carbon isn’t visible until you take them off and look behind them.

If you want better throttle response, its also worth looking into cleaning the MAP sensor
(It attaches to the top right of the intake plenum & gets clogged over time)

 

7AT and no check engine light. I did not connect a OBDII scanner to see if there were any codes. The issue was obvious from where the sound was coming from.