Ok, I have an interesting problem. When accelerating at about 6200 RPM I get a cut out almost like a rev limiter. The car backfires, the tach needle oscillates and no further acceleration. In other words, the car does not rev beyond 6200, 6300 RPM. When I let off the gas all is fine. Car accelerates strongly all the way to the "new" rev limit. Idles fine, no CEL, no backfire at lower RPM; all normal until I hit that RPM range. It feels very like a rev limiter. Where should I start? Fuel filter? Coils? Help! Kai
Unless someone had a similar problem and could provide you with a shortcut, I would begin my search in the fuel system. Filters, pressure regulators then pumps. Since there is not a test port provided you have to kind of make your own rig to test the system pressure.
Fuel pressure is my first inclination, although before hooking up a fuel pressure guage, I would pull the plugs just because they are easier to get a read on. Note, at the age of your car (and mine) the rubber boots in the gas tank could have colapsed from the ethanol in gasoline today. This can clog up not just the filters, but even the pick up screens. You stumble at high RPMs is indicative of the engine leaning out and then the mixture refusing to burn.
If it's consistently at 6200 rpm, maybe your chips have deteriorated and there's a glitch. Eric 3forty8 may be your new best friend. Check crank position sensors also.
Agree with Plugz, Check the crank position sensors as my car did something similiar when mine went bad, easy and inexpensive fix.
Thirding crank sensors. Had a very similar issue, which I described just like you did: See my post here, along with the rest of the thread: "... my car shuddered at about 6000 RPM. Shook like hitting the rev limiter. Made my way home, then pulled over, restarted engine and tried it again. No stutter." Easy to check, and easy and cheap to fix. http://ferrarichat.com/forum/showthread.php?t=297265
YUP. After reading through that thread I'd say my symptoms are spot on. Time to get a new crank sensor or two... Kai
Kai, check this youtube video for the location of the crank sensors (just above the horizontal oil drain plug and below the alternator belt if I am not mistaken)....looks like a fairly simple job. Also, notice the comments for this video - matches your symptom: [ame]http://www.youtube.com/watch?v=S-08jnIkGLQ[/ame]
I have a lot of oil seeping from that area ( 5 year major coming up). I wonder if the sensors got impacted by all that oil. I changed the sensors last year when I did the gold kit. Kai
Quite possible, mine where really dirty. In one of them the plastic connector was starting to crack so I changed both for peace of mind. I still got the old ones as a spare because I´m sure that they were faulty due to dirt (car had been running perfectly until the day before I cleaned the engine between the plenums, some residues and dirt fell on the sensors) but as they are quite cheap bosch sensors and my local bosch dealer stocked them, I changed them. Just clean them and give it a try.
The issue with the car's stuttering started during a group convoy trip when she was parked out in the open overnight and there was torrential rain. The next morning, she refused to rev beyond 5000 in any gear. Whenever I tried, it seemed like 1 bank was cutting in and out, you'll hear the exhaust note stuttering and if I kept the revs up at that level, the slow down 1-4 lights would flicker until I backed off. So did the rest of the trip for the next 2 days keeping to 4500rpm where she would behave and accelerate like normal from idle with no check lights. Anyway did some research here (got to love FChat) and suspected the crank angle sensors. But when plugged into the SDX, the readouts showed extremely high temp readings on the right bank. Did a swap of the temp control sensors and now the issue showed up on the left bank. So ended up replacing one of the temp control sensors and car is as good as before. As a precaution, the crank angle sensors were replaced (from Kia) which is just as well as they were cracking up. Image Unavailable, Please Login Image Unavailable, Please Login
Well dang it. Changed the crank sensors this morning and now the car is not running on bank 5-8... RPM gauge not working and the car won't rev, is barely running and the 5-8 CEL comes on. Crap. Kai
Hello. Me to had this problem with stuttering and backfires at 6200 rpm. On my car it was only when the engine bay was warm (Oil temp above 90 degrees C). After replacing most of the ignition components , I found the problem in the engine wiring. One of the two crank sensor wires was in bad condition ( I was able to pull off two out of 3 wires in the 5-8 bank wiring) and caused this problem. My fix was to cut the wiring and crimp new pins and install them in the connectors for the crank sensors. So if you just replaced the crank sensors, maybe the wiring was in so bad condition that it broke just by touching it. Best of luck to find the problem on your car.
