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I have a 2007 XKR with just under 40,000 miles on it that has been faultless until now. Today a CEL with P0174 "System too lean on bank 2" showed up. Just a little background, the car has been driven a total of about 700 miles over the past 2 years. I took it out for the first time in a long time this past Tuesday, Nov 12th. Since, I've have driven it back and forth to work, which is a total of about 12 miles, everyday since. The car was CEL free until today. After leaving work, I took it to a car wash and then brought it home. The car was still fault free at that point. After being home for about ten minutes, I ended up starting the car again and that's when the CEL appeared. I hope that's not too much info, but not sure what to do or where to start troubleshooting. Any advice is very much appreciated.
With that little use, the first thing I'd do is an Italian tune-up, then manually clear the OBDII codes and see if the CEL comes back on again.
(old link deleted - didn't work)
Thanks Stuart. The link you provided didn't work for me, but I'll do an Italian tune-up to see if that works. Based on my understanding of this "tine-up", it involves driving the car hard enough until the engine gets hot enough to dissolve the carbon deposits, right? I plan to use gumout or seafoam to aid in the process. Thanks for the input. I'll report back with the results.
Sorry about the link not working. I don't know what happened, so I deleted it and the new link in my Post #2, above, should work. The video in that article is worth watching.
Too lean means there's not enough fuel for the amount of air that's being pulled through the engine. That could be caused by dirty injectors, a weak fuel pump, a bad MAF sensor, a leak in the intake that is downwind from the MAF sensor... That are lots of things that can mess up the air/fuel ratio.
Basically, the Mass Airflow Sensor (MAF) reads how much air is being pulled through the intake and it gives that info to the engine computer. The computer then calculates how much fuel needs to be injected. A sensor on the exhaust measures the exhaust gasses to determine how well the gasoline was burned. It can tell if there is too much fuel (rich) or too little fuel (lean) being injected into the engine.
If I was you, I would start by popping the hood and making sure you don't have a crack somewhere in your plastic intake. Make sure the intake is fastened down good. Then get a good bottle of injector cleaner that has PEA in it. There are lots of brands of injector cleaner, just make sure the bottle says it contains PEA. https://gumout.com/our-ingredients/ Run through a tank of gas and see if it clears up. If not, reset the code and see if it comes back.
Oh yeah... when you floor it does the engine hesitate? That's the first symptom I had when my fuel pump was going bad on my 4.2 XK8. I also started getting a lean code (I forget the number).
If the vehicle is rarely driven, check the wiring loom to the injectors on Bank 2 for damage or corrosion. Lean mixture can cause misfires, so find and correct the cause.
If the MIL (Malfunction Indicator Light), begins to flash, do not continue to operate the vehicle as catalyst damage is occurring leading ultimately to DTC P0430.
Thanks for all the info! The car cleared the CEL on its own after I changed the oil. I drove it around for a total of about 60 miles while I was out running errands and the CEL didn't come back on. I'm still going to try the Italian tune up just in case it could prevent this from becoming an intermittent issue. I also plan to clean the MAFs and replace the air filters tomorrow.
I checked the intake and didn't find any cracks or anything that would seemingly cause any problems. In the event that this was caused by a vacuum leak, what is the best way of finding the leak?
Thanks for that info as well. I'll check the wires going to the injectors for both banks just to be sure. I would've never thought of that, so thanks a lot!
Thanks for all the info! The car cleared the CEL on its own after I changed the oil. I drove it around for a total of about 60 miles while I was out running errands and the CEL didn't come back on. I'm still going to try the Italian tune up just in case it could prevent this from becoming an intermittent issue. I also plan to clean the MAFs and replace the air filters tomorrow.
I checked the intake and didn't find any cracks or anything that would seemingly cause any problems. In the event that this was caused by a vacuum leak, what is the best way of finding the leak?
BEST way is to have a Smoke Generator hooked to a vacuum line and then watch for smoke coming from somewhere. Shops charge about $50 to do this.
Second best is to spray Starting Fluid on the vacuum lines with the engine running and see if the idle increases. Theory is that the leak will suck in the fluid and make the engine rev. It does work, but doesn't pinpoint, but does give a general area to search closer.
So after the car cleared the p0174 code on its own and the CEL went away, the CEL light came back on today and is showing p0171 and p0174. I began reinspecting the intake on the driver's side. When I made it close to the bottom of the intake, I looked down into the bottom section of the intake tube and noticed there is some sort of piece of paper laying against the teardrop looking sensor part of the MAF. I'm thinking this is a cause of at least one of the codes. Going to do some research and figure out the best way to get both MAFs out and clean them!
So after the car cleared the p0174 code on its own and the CEL went away, the CEL light came back on today and is showing p0171 and p0174. I began reinspecting the intake on the driver's side. When I made it close to the bottom of the intake, I looked down into the bottom section of the intake tube and noticed there is some sort of piece of paper laying against the teardrop looking sensor part of the MAF. I'm thinking this is a cause of at least one of the codes. Going to do some research and figure out the best way to get both MAFs out and clean them!
Thread has been going for 6 days now, if you had taken it to the dealer it would be fixed and running perfectly - hopefully. Running supercharged cars with a lean bank can be very bad for the engine and might even burn a hole in a piston under extreme cases.
Here is a picture of the MAF before I cleaned it. A piece of the air filter had came off and gotten stuck on the MAF. I ended up cleaning both MAFs and replacing both filters. After doing that, the CEL went away after driving the car around to a few different places with a few start ups. I only got to drive it about 30 miles or so that day and the car seemed to be running perfectly. We've been getting very heavy rain and hail here in the Phoenix area since Monday, so the car has been sitting in the garage the past few days. I plan to take it out again when the weather clears up and will report back on if the issue is resolved or not after I'm able to drive it a bit more. I'm hoping this fixes the problem. If so, a very simple fix for a guy who is a newbie to working on this car!
11-15-2019, 09:23 PM
P0174 code
