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Misfiring before and after repair/tune-up


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kmgainey
User

Aug 2, 2017, 2:47 PM

Post #1 of 25 (1754 views)
Misfiring before and after repair/tune-up Sign In

I have a 2010 Hyundai Santa Fe, 3.5L V6, 150k mi. It suddenly started misfiring last Friday. I had the codes read and had a p0018/p0300/p0302/p0306. I then took it to a mechanic who said he would change the camshaft position sensor and see how it goes after that. He called back saying he also did an engine flush because I had a lot of sludge. At that point I asked him to do a tune-up too. He said it ran great afterward, but when I picked it up, it started misfiring again about a mile away from the garage. I had the a/c running, whereas he didn't. He asked me to drive it without a/c a few miles, and after doing so, it seemed okay again. But again, on the way home it started misfiring again without the a/c this time. He said that after a week to get the oil changed again and maybe that would clear it up. I have my doubts now after driving it for two days with constant misfires. So, is the approach wrong? Was the engine flush a mistake, and likely new culprit for the problems? Maybe he didn't do what he said he did? Any info/advice on this problem is appreciated.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 3, 2017, 4:55 AM

Post #2 of 25 (1732 views)
Re: Misfiring before and after repair/tune-up Sign In

Oh boy: A sludged up engine and what to do is subject to what is seen and what to do. It's my opinion to just change oil super frequently and hope it cleans out slowly as too fast can throw chunks and make the problem worse if not fatal - all depends how bad or what was really done and how.
Codes (the mechanic should know this) don't tell you to replace anything just which circuit is showing a fault. How you interpret that is diagnosing it more.
I don't question needing a tune up which could be very telling when some parts come out what the situation is.


Just at a glance at what you said: It's sludged, now about 18 years old, enough miles for a load of things to do but clearly sludge means neglect of oil changing or a problem neglected that caused it. Some of those all depending you can turn around for a good time still some you really can't.


You can't back step neglect. Suggest you get a better diagnosis of engine condition in general and decide from that what to do next,


T



kmgainey
User

Aug 3, 2017, 5:08 AM

Post #3 of 25 (1723 views)
Re: Misfiring before and after repair/tune-up Sign In

Thank you Tom for the reply.

To clear up a few points, the car is 7.5 years old, not 18. Regarding sludge, I have followed the manufacturers recommendation of changing the oil every 6500 miles, and with a synth blend the whole time. I've been told now that following the manufacturers recommendation isn't always wise, and maybe that is the source of my sludge (which I am taking the mechanics word for).

My immediate problem is the misfiring. I can change my oil more often, but not sure how that helps with the misfiring now. Anyway, I agree that a better diagnosis of the engine is needed.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 3, 2017, 5:26 AM

Post #4 of 25 (1721 views)
Re: Misfiring before and after repair/tune-up Sign In

Sorry for the age mistake but it still stands. Something is wrong to have the sludge. True - synthetics are much less apt to sludge up but may have not used that for the common warranty time the vehicle had new many 100K if you keep up strictly to the letter with everything on the list provided in most owner's manuals and info on what means what that will void warranties.


Note almost no vehicle is used such that you can really go 6,500 miles on oil - any type. Why - the manual will call most "severe use" meaning such things as a lot of stop and go driving, short distance driving, hot or cold weather exposure and dusty conditions to name some. About everything fit into that so both miles and months are cut in 1/2 or so synthetics or not which I do exclusively use when at all possible and still change it out.


150K counts. Lack of lubrication because of sludge and subsequent wear with could be zero lubrication of some items or a lot is serious trouble. Fast flushing isn't recommended but must be running totally properly.


Oil get contaminated so doesn't much matter what you use. It's get wrecked lots faster if you drive on an engine that isn't running well, overheating or misfiring for any reason up to plain harsh use?
It may not have good compression anymore - I don't know that but all that should be known and checked along with other reasons it's not behaving and find a real good reason why sludged at all. You can just look at dipsticks and oil filler caps for evidence there should be none.


Coolant! It really doesn't go over five years and harmful up to overheating slowly in areas, reducing effectiveness of radiator even if not leaking, corrosion of gaskets and more and is easily neglected also.


Same suggestion is to really find out mechanical condition of this engine and make decisions on the fix from that,


T



kmgainey
User

Aug 3, 2017, 5:31 AM

Post #5 of 25 (1715 views)
Re: Misfiring before and after repair/tune-up Sign In

Thanks Tom for taking the time for the detailed response.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 3, 2017, 5:45 AM

Post #6 of 25 (1713 views)
Re: Misfiring before and after repair/tune-up Sign In

Good luck. Let me/us know what you find out,


Tom


Discretesignals
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Discretesignals profile image

Aug 3, 2017, 6:11 AM

Post #7 of 25 (1704 views)
Re: Misfiring before and after repair/tune-up Sign In

Not a good idea to drive it around with misfires going on. If they are ignition related, you'll probably end up burning out your catalytic converters.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


kmgainey
User

Aug 3, 2017, 6:16 AM

Post #8 of 25 (1700 views)
Re: Misfiring before and after repair/tune-up Sign In

DS, I was wondering about that. Thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 3, 2017, 7:06 AM

Post #9 of 25 (1695 views)
Re: Misfiring before and after repair/tune-up Sign In

My bad - that should be noticed if checked out and highly suspect it's junk now and a reason to cause problems alone but would be the result of problems this way.


By checked out I mean ask for an hourly rate by the right pro tech for a written diagnosis to put this back in order engine wise to run well for a good long time or many more miles or find out not. Knowing is value,


Tom


kmgainey
User

Aug 3, 2017, 7:56 AM

Post #10 of 25 (1686 views)
Re: Misfiring before and after repair/tune-up Sign In

"the right pro tech" is the tricky part of that task. Not sure if I should return to the last mechanic, or try to find a new one.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 3, 2017, 8:20 AM

Post #11 of 25 (1682 views)
Re: Misfiring before and after repair/tune-up Sign In

If you don't know anyone else you can check rating of a shop on the web but you really want to know which tech. ASE certified is one way to mostly know the tech at least bothered and passed the tests for engine and engine performance should be posted it's bragging rights if nothing else.


Nothing is going to verify you get the right attention no different than any other thing. If you make it personal and meet the tech just agree to evaluate it's real condition and ask up front how long at what rate so you know.


The last place might be fine but you still have the problem if really behaving and no recurrent codes when done a tech might think it's good to go and just guess on that and be wrong?


That part is up to you. Ask for the exact tech that can handle this and meet them,


Tom



kmgainey
User

Aug 4, 2017, 5:09 AM

Post #12 of 25 (1661 views)
Re: Misfiring before and after repair/tune-up Sign In

Tom, I appreciate all of your answers.

The shop is a very small shop, and is ASE certified. I talked to the owner/primary mechanic and he said he still prefers that I drive my car a few more days before looking at it. I asked about compression testing, and he replied that since I can drive at speeds above 20 mph without any apparent misfiring, it isn't compression. He also claimed my coils were fine. He is still convinced it is the sludge. I am torn on whether I should drive it or not. The misfiring at stops and slow speeds are still noticeable, it seems a little less severe. However, during each cold start, the is a rattle/clicking/knocking that seems to be getting worse, which worries me.

Now I more lost than ever on how to proceed. The KBB value without these problems is about $6k, and I am afraid to sink too much money into a car that may need the engine changed.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 4, 2017, 5:56 AM

Post #13 of 25 (1655 views)
Re: Misfiring before and after repair/tune-up Sign In

You so called mechanic, and I use that term loosely, appears to be an idiot and I suggest you get a second opinion.

Sludge is not causing your misfire and if he continues adding chemicals to loosen it up he will create even worse problems when that stuff loosens up and restricts oil flow.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kmgainey
User

Aug 4, 2017, 6:00 AM

Post #14 of 25 (1651 views)
Re: Misfiring before and after repair/tune-up Sign In

Thanks Sir Paul. I'm beginning to think the same.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 4, 2017, 6:34 AM

Post #15 of 25 (1647 views)
Re: Misfiring before and after repair/tune-up Sign In

? Doesn't seem like they/tech is very interested for some reason? ASE or not doesn't mean necessarily there aren't other reasons to allow or suggest you keep driving this. It sure doesn't help to both end up needing an engine and probably already do need a catalytic converter. The original sludge noticed, subsequent flush unknown just how aggressive that was is possibly the reason for noises now. Question remains if the damage was already there or getting worse by the minute - having real clicking, knocking and rattles while starting up can be the engine self destructing now!


It has you play a go between from a forum, my/our ideas and experiences with what YOU say is one sided when as a customer complaining or asking for help shouldn't really need to be here at all you are paying for experience and they alone see what you are relaying or that's exaggerated or something missing about it?


That cold sound thing you may notice oil pressure if you have a gauge or light is slow from a cold start to read OK either way.


The part novel on lubrication: Engines really don't use a bearing that rolls rather surfaces of round shells on a round shaft with oil pressure in between is the lube and what takes the pressure of it running or would be metal on metal not meant to roll rather slips on a film of oil. Sludge can easily like a fudge move too fast as that oil first picked up in oil pan sent instantly on thru small drilled holes to pressure up the most stressed parts and what is left on to the next, the next on up to valves thru all those passages. One stopped up port the following don't get lubed and all hell break loose with wear. The pistons also require that film of oil or wear the cylinder walls, piston skirts themselves and will not created enough compression to fire properly if so in short order if not already which is why finding out now is important as I see it.


Back to my opinion on flushing oil because of sludge: Some flushes are just too fast and the chunks of sludge can block even oil pick up screen or the ports that carry oil all over up to the passive draining of oil back to pan to do it all over again and again if it can't do that it's a whole lot of trouble.


They had plugs out and I didn't hear if the old ones were oil fouled or what condition. Even older all things right they should be even looking . Fuel issues leave evidence and oil another type of evidence it's not right but it was misfiring before they would be different but now which ones probably shown by the codes.


Understand that fuel is only useful to "combust" when fully evaporated AND compressed as a vapor no liquid fuel. If without compression it might just catch fire not "combustion" doesn't make power nor burn totally, feels like the misfire and raw fuel on to converter and out tailpipe. You would even smell it or just wipe tailpipe with a clean paper towel it really shouldn't be oily at all just some dust if all was well. Right now bet you can feel tail pipe exhaust putting with the misfire and it stinks of either unburned fuel or strong odor of oil maybe even see it.


So - no adequate compression is going to lead on to cause other problems. All these problems are like a domino effect harming the items next in line till the engine is no longer worth redoing which isn't IMO as good if so as another whole engine rebuilt or well checked used that is a perfect match.


None of just that addresses the damage to sensors, converter and more either and it alone is costly enough. You priced value of whole vehicle without this problem and are probably faced with a break even for fix or bail out if this bad but we/you don't know this so far and told to keep driving it will probably remove all doubt soon if not bad already.


Even if you repaired or replaced whole mechanical engine you still have the whole rest of this vehicle to consider has the use and miles on it so it doesn't make the thing all new again at all.


Tough situation to be in and losing time fast using it at all. If it can be saved the chances of that by driving it with these noises now noticed are quickly becoming engine fatal cost wise.


It shouldn't be up to you already said that. I still suggest you check appearance under oil filler cap for what you can see, oil dipstick and the tailpipe. If not right with now the noises it shouldn't be driven.


Right now it's all second hand info even suggestions by me. From my understanding you've reported this needs attention now just to know where you stand with this vehicle so you can make choices the suit you.


It probably does mean another shop and tech (not bashing anyone I'm not there watching all this) but guessing the crank sensor back when, the flush I don't ever suggest (IMO) and continued driving with some expectation this will heal itself doesn't add up to my expectations of an experienced tech. Reasons why could vary.


Again - you need to know where you stand as IMO you are about to lose a vehicle over this!


Tom



kmgainey
User

Aug 4, 2017, 8:02 AM

Post #16 of 25 (1637 views)
Re: Misfiring before and after repair/tune-up Sign In

Thanks Tom. I just left a different shop, and yes, they concluded the engine is beyond working on from a cost and logistical perspective. I'm in a no win situation with this car. It's new car time for me, and without decent trade in value (if any), it'll be painful. Thanks again for the time you spent responding to my posts.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 4, 2017, 8:56 AM

Post #17 of 25 (1635 views)
Re: Misfiring before and after repair/tune-up Sign In

Why have you already ruled out replacing the engine with a good used one?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kmgainey
User

Aug 4, 2017, 8:59 AM

Post #18 of 25 (1631 views)
Re: Misfiring before and after repair/tune-up Sign In

The problem is cost vs value. I got a quote for $4k to replace the engine. The KBB trade in is only about $5.5k, and I will be trading it in. So I am working to find out what I can get for it as-is as a trade in.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 4, 2017, 9:14 AM

Post #19 of 25 (1621 views)
Re: Misfiring before and after repair/tune-up Sign In

Watch out for real trade-in values - totally depends on what you are buying what they offer you.
OK - you know now - that much great even though bad news. Now how is the rest of the car overall. If this is an outstanding vehicle, not damaged, fixed up, interior all great, already done tires, battery, brake work all fine no other serious issues you are buying this car over again actually so think outside the box. Would you purchase this vehicle with a known perfectly good engine now? Has transmission service been done or an overhaul already done on this one? Things like that.


You know this car so unless trading for new think as if you are buying it with that cost coming and known. Did you like this thing? OMG - I'd freak if I personally bought something even if perfect in every way and hated it AFTER test drives and all that find out it isn't comfortable for me and just don't like it would be a mess to change out again over!


Tom



Hammer Time
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Aug 4, 2017, 9:15 AM

Post #20 of 25 (1619 views)
Re: Misfiring before and after repair/tune-up Sign In

A good used engine should cost more around the $2500-$3000 range, not $4K

The car will be worth almost nothing with a bad engine unless you can somehow hide that fact from the dealer.

It really depends on the condition of the rest of the car and if it is worth repairing. You have a car with a bad motor so there is no question you will take some sort of financial hit in this.

I found the trade in value only $3500 with that mileage and a good engine. It's worth $6100 in a private party sale.

With a bad engine I would expect around $1500



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Hammer Time
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Hammer Time profile image

Aug 4, 2017, 9:20 AM

Post #21 of 25 (1613 views)
Re: Misfiring before and after repair/tune-up Sign In





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kmgainey
User

Aug 4, 2017, 9:28 AM

Post #22 of 25 (1611 views)
Re: Misfiring before and after repair/tune-up Sign In

Two different places have said about $4k now, but that includes labor too. Doing such a thing is not an option for me.

I know I will take a hit financially. At this point, I would accept $1500 for a trade-in.


kmgainey
User

Aug 4, 2017, 9:36 AM

Post #23 of 25 (1607 views)
Re: Misfiring before and after repair/tune-up Sign In

I was planning on buying a new car anyway... if only I'd have done it beforehand.

As for the car overall, it isn't an outstanding vehicle. The body is in good shape except a broken mirror case. The interior is good, and has relatively new tires, brakes, water pump, struts, shocks, but never had transmission service, and there is some minor rattling somewhere in the suspension.

I've definitely put money into it the past year or so, and I didn't want to do so anymore.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 4, 2017, 9:36 AM

Post #24 of 25 (1607 views)
Re: Misfiring before and after repair/tune-up Sign In

If that works for you, then that is the way to go.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 4, 2017, 10:04 AM

Post #25 of 25 (1593 views)
Re: Misfiring before and after repair/tune-up Sign In

Can't argue that - good luck on getting a fair trade for it and move on. With your description of the rest of it I probably would as well just get over it on a 150K vehicle overall,


T







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