Living with a Kappa

Pontiac Solstice GXP 2007

Updated: April, 2023

TO-DO List

April 23, 2023

Investigating vibrations at idle

After about a week suspecting something was off when the engine was idling (different vibrations than usual), I got a check engine light while driving to the store. My OBD-II reader reported a P0106 code (Manifold Absolute Pressure Sensor/ Barometric Pressure Sensor Circuit Range/ Performance), which suspects of a faulty MAP sensor. My car has the original GMPP tune and a trifecta tune on top of it, that means I have the 3 bar MAP and TMAP Bosch sensors and not the factory ones. 

November 7, 2022

Struggling to start after every tank fill-up

 It had been a couple of times that my car would fail to start immediately after filling up the gas tank; I ignored the issue as it would often start on the second or third crank. Recently, I took my car in a 800 mile trip and the issue worsened, but fortunately made it home in spite of it. After the last tank filling of the trip, my car wouldn't start after cranking several times, I had to press on the gas pedal a little while cranking to get it to start, and after it started, I had to keep the car revving high (2 to 3 thousand rpm), if left to idle it would stall. The car sounded like an expensive sport-scar because of the backfiring it did while revving, but after a minute or so of revving, the car was back to it's normal self (except that it would idle around 1000 RPM instead of the expected 850). Once I was home, I pulled the codes shown in the picture with my OBD-II reader. As expected, I had misfires in all cylinders, but the code that caught my attention was P0496.

This made it evident that there was an error in the vehicle's evaporative emissions (EVAP) system. The gas tank cap seal appeared to be in good condition and seated properly, so a problem with it was discarded. The EVAP system captures the fuel vapors from the gas tank and stores them in a charcoal canister until the engine can make use of them. To achieve this, the vacuum from the engine goes through a computer-controller purge valve to the gas tank and the EVAP canister. Suspecting that the purge valve might be faulty, I removed it (by undoing a single bolt and two hoses), and by blowing through it I realized the valve was stuck open, as it's supposed to be normally closed. If the purge valve is stuck open, the fuel vapors in your tank get displaced into the intake manifold while filling up, resulting a potentially too rich condition to start up the engine. Without a second thought, I replaced the part, took the car to the gas station and was able to start on the first crank. 

Oct 9, 2022

Car Grille Fix

Driving down a very busy highway I drove over a USO (unidentified stationary object) that unfortunately was tall enough to scrape against my front bumper, investigating for damage revealed that half of the bottom grille of my car was surprisingly missing! This was completely unexpected because I barely felt a thing, but oh well - things happen. I could have easily bought an OEM replacement, but decided against it for two reasons: 1) it would set me back around 130 USD, 2) I learned that this is something that could easily happen again. I guess there is a third reason, this would be a great excuse to print something big in my newly acquired Raise3D N2.

Fate would have it that I kept exactly half of the grille so that I could try and make my own. The shape of the part was actually very hard to capture; I did my best to measure and approximate the curves, and had to do several test prints of the part to compare against the actual part. Even with the big print bed of the N2, I had to slice the grille in four sections and print with a lot of support material to get the right curvature. I had to do a lot of sanding and post-processing to clean-up the surfaces that had the support material. 

By splitting the sections in an S shape between the hexagonal grills I managed to make the joints as inconspicuous as possible, and to get the mounting points just right for the bumper I made the part removable, so that I could print as many prototypes as needed to make sure the fitting was perfect. This ended up being a great idea because the installation was a hard thing to get just right. Overall, I think the part came out looking great and I couldn't be happier with the result.