Issue is on my other car a 300M special not the lambo (thanks God!) Car run a little without oil. The Oil filter O ring failed while my wife was driving and she lost all oil sudently. Car stopped and was knocking when tried to start. Bottom pulley jumped to the right 3 teeth (facing the engine). My mechanic changed all timing stuff and ajusted timing, TDC etc... Put oil back and pointed to me the FRAM filter failure. Engine knocked a bit when restarted properly but went away as the oil pressure built up again. Car is now driving fine, no noise, except a slight shake at idle. Very slight. After 50 miles got a "bank 2 too rich" code. Car driving fine with code. Back to mechanic again, change 1 oxygen sensor that was doubtful. But mechanic cannot find obvious issue. What could have happend to the engine that would cause a bank to run too rich?
Ouch. Jumped teeth after something like that can imho only point to one thing, a cam bearing that briefly seized in the ordeal. Did they do a compression and bearing check at all? If not then your mechanic/garage is not the best. It could be either of the following: the timing was off enough during the problem that a valve got bent and one cylinder is now losing compression, or it briefly seized again after the fix, and the cam timing is off again. Both compression loss through a valve on one cylinder or a jumped cam can cause the rough running at idle and running rich. After such an event I would personally tear the engine down and have all the bearings (including the crank bearings) checked. An event such as this is the auto-equivalent of a heart attack and often very impairing for longevity. From the outside it's impossible to tell what was damaged and what not. Have the compression, cam timing and bearings checked asap would be my advice. Depending on how far you're willing to go and take the risk of an expensive engine problem probably sooner than later, do at the very least the compression check. Or it's just coincidence and you just had a bad sensor. But the fact that it (still?) runs different from before is a sign all is not well.
It's a 6 to 8 year old Chrysler so I wouldn't just jump at an expensive teardown yet. A compression check and a test of oil pressure (using a mechanical gauge) will give you a pretty good idea if you have big trouble.
I agree economics play a role. For the same reason of economics if I had to fix a compression issue on an engine with such a history, I would want to make sure I am putting in that effort for a known result. A.k.a: I would do a teardown of the bottom end next to the valve job, and at least inspect the rod bearings. Reliability comes at a price. In my experience an oil pressure check is not very useful on an engine with such a history. The damage can be very localised and not show up with an oil pressure measurement. I once worked on an Alfa Nord engine that had rod knock. When removing the pan one of the rod bearings surely was broken but it turned out one of the five mains had also completely spun. Melted the bearing, the cap came loose and was in the pan! Two bearings gone and the oil pressure was still over 1 bar at idle. Last, there is always the option to drive on with the compression issue even if found, and just see how far she goes. Ignorance is bliss.
i will get the compression tests and the oil pressure. I cant see putting the money in a tear down for that car. I love the car but not to spend more than it is worth. An engine replacement is about $7K, about the car value
I'm not sure if it's even feasible to look at bearings without committing to a big bill. If it has oil pressure and decent compression it makes sense to just drive it. If the motor's shot it might make more sense to buy a short-block from a rebuilder or even a good-used engine from a wrecked car. I don't think "matching numbers" are ever going to be important here.
Looking at the bearings (or at least a high percentage of them) without pulling the engine is possible with a lot of cars. If the engine needs to come out for this the bill could be high though. A good mechanic knowing the model will know. On the upside, once it's out it can be easily fixed and put back. Indeed run the compression or leakdown test (should have been done in the first place) and then see. I was just advising against investing money in what would be the logical next step if a problem shows up in that test (a valve job or head replacement) without looking properly at the rest of the engine. The option of just driving it 'as is' will probably leave you stranded one day somewhere where it'll be most inconvenient to you or your wife. When assessing the economics of the repair, do not look at what the car is worth, but look at what it will cost to replace the car for something similar. You can of course contemplate to trade it in now, while it still runs, but that would not be nice now would it. This is by no means whatsoever a suggestion to take it to a stealer for a trade-in. Do not take this as advice.
Compression test done came out good. So no bent valves. If compression is good then no need for a leakdown to pin point the specific issue. <<Both compression loss through a valve on one cylinder or a jumped cam can cause the rough running at idle and running rich.>> Well i am not sure how a bent valve leading that would give bad compressions would make the car running too rich. The valve does not control the intake mixture right? And again a bad valve WOULD give a bad compression. <<Sticky injectors>> Yes but not the whole bank would get rich. We would have an error code pointing to the bad cylinder I believe << oil pressure test>> This would not help for that problem. What we have here is a rich running car. The oil pressure would have no affect. I have to note that when idling, the computer tries for a while to manage the mixture and does the best job it can. then after a while it gives up realizing it can get it right and goes open loop to let the standard mixture ratio. At this point the car stalls because the mixture is way out of wack. My mechanic does not quite know how to take it from here. Something is affecting the whole bank. Timing was perfect when the car was put back after the timing belt job was done. That leaves the bearing but I fait to see how this again would affect the fuel mixture. I mean given the compressions are good and we have no engine noise at all and the car does not misfire, hickups and run ver smooth on hiway with good acceleration, a significant engine issue is probably not the cause.
Assuming you don't have an injector problem, I'm not aware of anything other than cam timing that would affect only one side of the engine.
Ok, officially surprised here. Assuming everything is correctly timed and put together after the first repair, it must then either be cam timing or injection causing it. Rich running can be caused by a bad MAF sensor or a coolant sensor going open loop, but I would assume this car does not have coolant sensors for each bank, and a broken MAF would be pretty coincidental. I am still puzzled why the timing was off after the event. Have the cams themselves been checked? The rear cam bearings are generally the first to be starved of oil and something could be hiding under the cam covers.
