BaldRald90

I believe I've solved an issue I've had with an 08 and wanted to share my experience because I haven't read of anything similar to this online in regards to the first gen rdx. About 1 year ago I bought an rdx that wouldn't pass emissions so I assumed the catalytic converter and possibly the turbo were bad (car had 203k when I bought it, it had 207k currently). Car was parked for about 6 months, I would drive it around the neighborhood to keep the "battery charged". I would usually hop on the highway and hit WOT, when I did this I would very rarely hear what I would describe as a " rhythmic slapping" (very important later on). I was stumped, it would happen so rarely and be so quiet my girlfriend would sometimes not even notice it if she was in the car. When the noise would happen I would get a check engine light (Overboost) as well as a Sh-awd warning that would disable awd. As time went on the noise became more apparent, it would only happen at WOT in a straight line and for some reason if you were turning and giving it a 50% or more throttle (weird coincidence?) I assumed it was the waste gate on the turbo and that replacing my turbo would solve the issue.

So I parked the car to replace the turbo, upstream catalytic converter and intercooler hoses (this was planned when I bought the car). I also replaced the transmission fluid because I changed the front axles months before all of this and lost an unknown amount of transmission fluid in the process and this always worried me. I followed the trans flush procedure posted on this forum exactly (except the part about adding the exact amount of fluid you remove) Went to drive the car and it wouldn't go past 15 mph, shift out of 1st, or make any boost at all. It felt like the car was in limp mode ("fail safe mode" as Acura calls it, I'm used to bmw's breaking down lol) I assumed that I had fudged something up with the turbo or transmission fluid change.

I bought a scanner that reads live data (creader elite for Honda/Acura, worked well for me) and downloaded the factory service manual (super helpful information) this allowed me to see the fail safe mode relay was off, and I had no transmission related codes. I had the following codes: P0238, P1157, P0556, AWD 41, VSA 86, VSA 83, AWD? 77 (Communication error with PCM), TPMS 85. The factory service manual showed most of these codes were related to each other, this information was found in the dtc troubleshooting index (sounds like one triggered another one? kinda confusing). The live data also showed the car was running very lean and slightly misfiring on all cylinders. One small issue was a cracked connector on my upstream o2 sensor that was causing my AWD? 77 (comm. with PCM) and p1157 codes. Replaced with a denso sensor and those two codes went away but car still had issues.

Started reading online and somehow found a post on a 2008 accord with a k24 that had skipped one tooth on the timing. I set my motor to TDC and removed the Valve cover enough to peek at the cam gears so I wouldn't have to remove the wiring harness that goes over it. I could see that the arrows on the inside of the cam gears were off by one tooth and the timing chain has some slack in it! (I pushed it with a flat head and it moved about 1/4" inwards) I was honestly super stoked when I saw this lol luckily no damage was done and the car is staying parked until I receive all of the parts in the mail (still waiting). The total for the OEM Honda timing chain, guides, tensioners, and o ring for the chain case was about $270, the scanner was $150, and the factory service manual can be found on google in pdf. I would also recommend anyone doing this repair to buy the Lisle 19mm harmonic balancer socket ($30), this along with my 1/2" dewalt impact with a flex bolt battery was the only way I was able to remove the harmonic balancer bolt. I also bought a set of k series cam locks off eBay for $13 and a billet lower timing chain guide for $13. I know allen keys can be used in place of the cam locks, I'm just a sucker for specialty tools. I am curious if it was a stretched chain or tensioner failure on my end (they lose tension under low oil conditions), when I get the new chain I'll compare the new with the old chain and report back. Hopefully my experience is able to assist someone else with their issues, this forum has helped me pinpoint my many issues with this rdx and I wanted to give back.

TLDR: Acura wouldn't pass emissions so I assumed it was turbo/cat, it wasn't. The car drove worst after turbo replacement. Had a lot of weird codes (and some odd noises as well) I believe they were related to one another. Set motor to TDC and saw the cam timing marks didn't line up. Timing had skipped 1 tooth. It was either tensioner failure on my end (low oil) or the chain had stretched.