Hello,the auto is a 2004 Chrysler Sebring Convertable 2.7 engine.I got a P0016 code and have checked harness for damage and replaced crank and cam sensors just to eliminate them.The engine will only rev. to 2250RPM and then surges just as if it had a rev. limiter.This is consistant sitting still or moving and in any gear.The engine runs fine other than this.There has been a coming and going slight rattle in engine for a while,and up until now,it didn't affect running.I have worked on cars for years,but these newer ones have too many things to go wrong.I realize this brings us to a mechanical problem between crank,and cam correlation,which I think,would narrow to chain or tensioner,or reluctor ring, and am hoping that you could simplify with the best next steps to take to pinpoint the exact problem,and any additional tips and advice to make sure I don't tear down engine for nothing,and best procedure? Thanks,Larry
Country: United StatesMake: ChryslerModel: Sebring JXi (Convertible)Year: 2004Engine: 2.7
I have written all of that in the question!
Not sure if it is a JX or JXi
Hello and welcome to JustAnswer!
What area has the rattle in the engine been coming from?
Not sure exactly,but it is in the top end,and comes and goes?
Can't pinpoint because it seems to resonate through much of the top,and I can't tell if it's around the timing chain or not,since I know that a loose chain would throw the timing off.As you know,the tech on this says that as little as 6 degrees will cause problems.I will listen again,and try to narrow down sound area! Larry
With the P0016 sets and the noise coming from the engine I'd put the most probability on a failed timing chain tensioner. It's either going to be a cracked flexplate or a timing chain issue. A cracked flexplate could make some deep knocking noise at certain times too though. A cracked flexplate alot of times will make some noise on startup, when the a/c compressor engages, things like that.
I would try to see if you can pinpoint where the noise is coming from and then go in based on your findings from that. If it sounds like the noise is coming from the top or front of the engine then it's less likely to be the flexplate, in that case I would remove the valve covers and the timing cover if necessary and get a look at the primary timing chain. It's much more likely to be a timing chain problem than a cracked flexplate, but flexplate breakage does happen too.
I will listen again and reply.I'm taking it that the possibility of a cracked flex plate is because the CSS reads from there?
Does the correlation problem cause the surging at a certain RPM,as I referred to before? Larry
Yes, the crank sensor reads off a tone wheel on the flexplate. What happens on these flexplates is they will crack around the bolt circle where it bolts to the crank. They break, shift, and stick again in a different spot and the car keeps running. This shift throws off the cam and crank sensor alignment since now the tone wheel isn't indexed to the proper spot on the crank.
On a Chrysler product if you are missing the cam signal, crank signal, either is intermittent, or there is a cam/crank misalignment then the engine controller imposes a 2,500 rev limiter. This is what you are feeling.
ASE Master & Advanced level certified, Chrysler Master Certified, Trans and Hybrid Specialist
I'm just replying because I'm an old mechanic and feel that even though I'm not highly familiar with newer autos,I am able to understand with a little help,and feel that we can communicate.I thought that I had understood the flex plate connection,and have run into cracked flex plates on older models,but rarely as you pointed out.When I did the noise was very hard to pinpoint,and if you hadn't mentioned it I probably would have failed to even check that possibility.
I thought it felt like a rev. limiter,thanks for clearing that up.
You're welcome, and good luck with it!
You don't owe me an answer,but I was curious if there was a way to get it out of the rev. limit mode without fixing the problem?At least temporarily.This thing really runs good!
No, there definitely isn't a way to defeat the rev limiter without fixing the problem. It's in the powertrain control module software, there to try to stop engine damage from occurring when the engine is out of time. Sorry!
I see that you are ASE and 100%.In the seventies when that certification started I got certified in three areas,and it was NIASE for National Institute for Automotive Service Excellance.You may already know that,but just a tidbit of trivia.Things like that interest me.
sprinkles08 is one that makes me wonder origination or reason!
The username is XXXXX XXXXX a long story really. It goes back well before my time here and is a carryover from somewhere else. At the very beginning of the story was a small gray kitten, but the name of Sprinkles. I started with JustAnswer in 2008, hence the 08 on the end.
Thanks for asking! I'm sure the username throws some people!
It got me!
Not a problem. Good luck with your car!
Have a "Merry Christmas" and a "Happy New Year"!
Merry Christmas and Happy New year to you too!