litzdog911

Our RX400h (delivered in November) is currently in the shop with a "check engine" problem. They've had it for a day now and are not yet sure what's wrong.

The "check engine" light came on a few days ago with no obvious drivability issues. Of course we checked the gas cap Called the local dealer and arranged for service and a loaner. During the drive yesterday to the dealer, the "check engine" light began blinking and the gas engine was stuttering and misfiring. Several technicians greeted us upon arrival and seemed eager to diagnose the problem. Talked to the Service Manager this afternoon and he said they think it's a fuel-related problem and that they were still working with the "experts" in California for a final diagnosis and repair.

Any ideas folks? I'll keep you posted when the dealer solves the problem. In the mean time we'll get by with a loaner RX330.

Barefoot B

Just curious if they told you what code stored setting off the check engine light

Lexmex

First impression to me is that sounds like an ignition coil if it was stuttering and misfiring. Now a fuel delivery problem would also cause that, but injectors screwing up seems unlikely.

Would be interesting to know the OBDII code for future reference.

litzdog911

I'll post the OBD code once I have it.

litzdog911

Service advisor tells me that it was an "engine misfire" diagnostic trouble code. Additionally he told me that they are currently leaning in the direction of fuel contaminarion, which restricts the injectors and causes check engine light and driveability concerns. They will be checking further Monday (today is Friday). If it's fuel contamination it very well maybe necessary to replace the injectors.

I would be surprised if it turns out to be fuel contamination because we only use name brand (76 Union) premium gas.

I'll keep you all posted.

JZA80MHU38

It may sound weird but my wife used to have a 97 A4 and when we first owned it the check engine light came on from time to time, even though the car drives normally. We took it in to the shop and one of the very early question the technician asked us is if we use BP gas. There's a BP gas station near our home back then that we used very often.

From then on, we hadn't put BP gas into the A4 anymore and that check engine light problem never comes back. It's weird as we don't have problem using BP with our other cars.

Booyah

After you get it back I would lean towards using Chevron or Shell V-Power from now on! I have never related Union 76 as "good" gas

Lexmex

I would be glad to take Union 76 down here in Mexico, Pemex, which is much, much higher in sulfur than U.S. gas.

mink92890

eek. It looks like the 400h is very "picky" on fuel, etc.
I hope this doesnt happen to me.. I fill up QuikTrip gasoline, has anyone experinced problems with this gas?

Mink92890

VVT-i

Yes, the 400h is very picky in gas. I got one customer with the P0300 multiple misfire code( that's it) about 3 month ago. After talked to the owner and he said that the CEL came on after 50 miles of fueling the gas. I was weird that no another code was in the system. Usually when the P0300 comes on, it will set another code from the P0301-P0308( the # 1-8 are designated to each cylinder). I've asked him to change to another brand and never heard any problem from him again.

It's really weird, but may be after the Katrina the gas company put some kind of additive in their gas or speed up their production to meet the demand...

litzdog911

Update 2/13/06:

Well, the Service Advisor called today and they're convinced the problem was indeed bad gas. His theory is that "suspended polymers" clogged the fuel injectors, although there was some disagreement with the "experts" in California who initially thought it was an electrical problem. So now they've ordered new fuel injectors and filters and will clean the tank and fuel pump. Hopefully we'll have our RX400h back by Friday this week.

My Service Advisor also told me that the RX fuel injectors are especially sensitive to fuel contamination problems .... something about the "unique design" of the RX injectors. Obviously this is a bit worrisome, especially when we've only bought name brand premium fuel. How does one prevent it from happening again? I wonder if using an additive like RedLine SI-1 Fuel Treatment regularly would help?

Lil4X

If the problem is particulate matter suspended in the fuel, you might ask about installing another fuel filter in the line. This is common practice in marine and industrial applications where the quality of the fuel might be questionable. I put a pair of large marine filters on a Suburban when 40 gallons of bad fuel put about a half-pound of fine black sand in my tank. Cleaning the tank didn't seem to help, so I got mad after being stranded a few times. The stock filter - about the size of a cigarette filter - would clog in about 4-5 weeks. After installing two 2" dia, 8" long filters upstream, no further problems for over 100,000 miles. Overkill? Probably. Satisfaction?

Here's a more reasonable spin-on filter, normally used in marine (gasoline) applications. It's about fist sized, or about the size of a small 4-cyl oil filter. Coast Guard approved, it is not a potential leak source or fire hazard. Change the filter yearly if your local gas is REALLY dirty - otherwise 4 or 5 years is probably typical service - depending on mileage..


Photo courtesy of www.maesco.com

For more info see http://www.maesco.com/products/racor/r_gas/r_gas.html . These filters will take out particulates down to 10 microns - which should easily take out solids clogging your injectors. For chemical contaminants, Lexmex seems to have found the solution!

Lexmex

Run your RX on Pemex gas here in Mexico for awhile without fuel injector cleaners (they even sell Restore fuel injector cleaner at the stations now and dangle it in front of you) and you will feel something similar. What I do is mix Restore fuel injector cleaner and Techron together and that gives my injectors such a nice feeling afterwards.

Gibster

I avoid filling up when the tanker truck is present at the station. This can stir up sediment in the storage tanks.

litzdog911

Update 2/18/06:

Got our RX400h back today and it seems to be all better. They replaced all 6 fuel injectors, pulled and cleaned the fuel tank, and replaced the fuel filter. They still think it was a bad batch of gas. Our service advisor said that the RX engines have especially sensitive fuel injectors. He suggested adding a bottle of Redline SI1 or Techron fuel cleaner additive every 3 months or so to help keep them clean.

Here are the details from the work order of what they diagnosed and performed ....

Check engine light on, flashing then solid. Find codes P0300, P0304 & P0305. Misfires on cylinders. Clear codes and inspect data while engine under load. Noted misfires in excess of 50% at #5 cylinder only. Find misfire not always current. Find fuel trims well above normal. Also above normal for code stored data for "P0304". Contacted "TAS" for concern. Find no pending codes other than noted above. Perform misfire isolation diagnoses. Swapped ignition coils and spark plugs with #5 and #6 cylinders. Recheck for misfire. Find misfire still within #5 cylinder. Inspect fuel quality = unknown. Misfire caused from lean burn at #5 injector. Also pending codes P0300, P0302 & P0305. Perform A/F control active test. Set A/F to "+25%". Noted large improvement with no misfire felt. Remove & renew all fuel injectors. Remove fuel tank and renew filter/suction sock. Reinstall tank and check for leaks. Extensive drive test. No misfire noted. Recheck engine control and values are well within normal ranges. Clear codes and test drive second day with cold start. All good.