I have a 2010 RDX SH-AWD, almost 11K miles and bought new, everything is stock. This past week, when I nail the throttle, the boost goes only 3/4 of the way up and then backs down to 1/3 as the revs rise to 4K+. No stumbling or backfiring.

I reset the ECU (via pulling the battery cable) and then went on a test drive. Everything was fine, full boost where it should be. This morning on the way to work, I get on the throttle and hardly any boost again. It seems that as the revs rise the computer is pulling boost/timing.

Even though I always use top tier gas (Shell), I'm thinking that I may have gotten a load of bad gas.

Short of draining the tank, all I can think to do is use up the gas, but stay out of the boost until it's all used up.

Anyone else have this happen?

 

Something is wrong, but it is probably not bad gas.

If you live in New Jersey or Oregon you may experience what I have gone through. Here in Oregon it is unlawful to pump your own gas. As a result, about once every 3-6 months I would get a tank full of regular gas (87aki). I wouldn't notice until I got the reciept or the RDX ran like shit. I can’t really get mad and go back in to yell at the attendant, with the vast majority of cars running on the lower octane gas, it is an easy mistake. I finally started getting out of the car so I could grab their hands if they get anywhere near that “87” button.

If you are not in NJ/OR then there is very little chance you have “bad” gas, especially at Shell. That is where I fill up, and they are the most expensive gas in town for a reason. If you are a gear-head or mechanically incline (if not take it in) you might start with a battery disconnect and then drain some fuel from the fuel rail valve into an empty clear water bottle. Let it sit for a couple of hours. If there is any separation of the liquid, then you have contaminated fuel. If you have a receipt, go back to the station you bought it from, and attempt to get them to pay to clean your tank and fuel system. Usually, water contamination will cause more of a white smoke than black. Check your EGR valve for proper operation; this could also cause your problem.

 

Interesting that you mention low octane. I'm just outside of Washington DC, so we pump our own gas. Went back and looked at my gas receipt and it says I pumped 93 octane, but who knows if they had some sort of mixup.

I didn't get a chance to pull out a sample of gas for testing, but i did try something else.

Knowing that it has to be something with the timing and ECU (the turbo itself seems perfectly fine), I narrowed it down to one of a few things:

1. Water in the gas.

2. Too low of octane.

3. Combination of both.

I went out in search of dry gas with isopropyl alcohol and didn't have any luck. I have a bottle of Techron, but it doesn't really help with water in gas (moisture...yes, lots of water...no). So, knowing that Seafoam has isopropyl alcohol in it, I gave that a try.

Had 1/2 tank of gas already, added 16 oz. of Seafoam, and filled it all the way up with 93 octane at a different Shell. I then drove it gently for 10 minutes on the way back home. Let it sit for 4 hours and took it out on a test drive this evening. I purposely did not reset the ECU to see if it would adapt. Amazingly, it worked! Boost is now where it should be throughout the entire rev range. Unbelievable.

I always keep my tank above 2/3 during the winter and my RDX is always garaged so I've been trying to keep as much moisture out of the system as possible. I'll post a follow up in a few tankfulls after the Seafoam is out of the system. This is the first time I've tried Seafoam, so I'm not really an evangelist for the stuff. Anything with isopropyl alcohol it it probably would have done the trick. Also, if it did have 87 octane in it, it's now sitting at a proper 91 octane.

Lesson learned....seems that the RDX is really, really sensitive to gas quality.

In the meantime, I found some good information on dry gas if anyone is interested:
http://www.goss-garage.com/node/194

Dry gas products with isopropyl alcohol:
Iso-HEET
http://www.goldeagle.com/mobile/prod...oduct7B14.aspx

BG Fuel System Drier
http://www.bgprod.com/products/fuelair2.html

 

Excellent... Good job and keep us posted!

 

Glad you figured it out fairly simply.

My dealership actually filled my RDX with regular gas when I took delivery....I was not real happy with that. Being that I just got the car, though, I wasn't very familiar with how it would drive. However, I did notice the engine ran a bit rough and there was some noise, not to mention acceleration was not what it should have been. Upon filling with 93, everything was normal. I do not recall looking at the turbo gauge at all though, because I was driving in stop and go rush hour traffic.

I live in NY but work in NJ, and since gas is much less expensive in Jersey, I always fill up there the days I'm at the office. Once in a while, the attendant will put in regular (or try to) if I don't catch him. Very annoying but I have to stay vigilant to avoid the mix-up. I almost always get Shell, but sometimes settle for Exxon since the station is closer to work.

 

interesting post/thread. when i first drove my rdx (off the lot), i went on a 200 mile drive. now i didnt drive it like a maniac or anything like that, but when i did go uphills on decent speed (40-60 miles per hour - gradual acceleration/deceleration, etc), i did notice the turbo meter hitting only till 3/4ths too. i didnt notice noise or difficulty accelerating, however.

initially, i thought it was bec it's still on the break in and the computer adjusted it. now everything makes sense, my dealer prolly filled it up with regular gas!

rdx is now 1 yr old and >7000 miles. thankfully still going strong and so far, only 1 visit for a A1 service (dont exactly recall what it was called (A1, B1, etc): change oil and rotate tires is what was done).

at any rate, always filled up with either sunoco 94 or shell 91 here.

 

thanks for the tip re:seafoam. just a ff up question re: water in gas.

i thought that for insignificant amounts of "water" in the gasoline, the fuel filter should be able to "filter" it out? as well, how do we ensure this "water in gas" phenomenon is avoided when we gas up?

for example, whenever i remove/lift the gas nozzle from the gas pump, there's liquid coming out - i try to shake it to the ground first since im not sure whether this is condensation (eg. water) or gasoline that wasnt completely drained by the previous user. most likely it's gasoline, but still, better safe than sorry...

 

You're correct. The liquid coming out of the gas pump nozzle is most likely gas from the last person that has used the pump. They just weren't paying attention and pulled the nozzle out too quickly thereby leaving a little bit of gas behind for the next person.

Good point about the vehicle's fuel filter. I'm sure that it does a pretty good job with most of the moisture. Could be that it doesn't get quite all of it though.

Most of the moisture in your tank usually gets there from condensation. Best to keep your tank as full as possible during the winter. The less air space left in the tank, the less moisture that can form there.

I've always tried to gas up at stations that do a lot of business. That way I'm always getting the "freshest" gas as possible. I've also heard that it's not a good idea to fill up right when the tanker is at the station filling the station's tanks up. Theory being that they are stirring up the sediment at the bottom of the tanks. Although I would think that the station's filters would catch any sediment before it reaches your vehicle.

 

thanks for the clarification re: gasoline frm previous person. yes, been filling up to full again when it's 2/5ths to 1/2 tank left already during winter. myth or not, i too avoid it when tanker's in the station -- better safe than sorry . yeah fuel filter, ive seen some water sometimes in my prior cars (circa 90 corollas when i used to drive those) but these were "caught" by the filter and were harmless. thanks again