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Assuming(I know) that only the ICV was removed(and related items) there would not be a possibility of coolant getting in the cylinders. Now not discounting a head gasket leak but you had no issues except the valve cover gasket correct? If that is the case and you have not had something damaged or broken in the process then you should be able to find your cause for the miss. Once the ICV is removed double check #5 cylinder injector clip. That should be the rear cyl on the passenger side. Also the camshaft sensor on the driver side front valve cove. No, the cover does not need to come off. Check for any obvious bent or scraped blade. On the crankshaft sensor if one blade was bent you should have 2 cylinders effected. If you are going you do it take pictures and mark things with a sharpie. There are a lot of little things that need to come off and a picture IS WORTH A THOUSAND WORDS. I also remove the windshield wiper cowl and wireing harness. It opens up the back alot.
We took it all back apart today. The plug is getting fire and we managed to get a stethacope on the injectors and it sounded like they were all firing..maybe clogged?? Put a good plug on the wire for number 5 cylinder and ran the car..the plug seemed to fire just like the other cylinders plugs did. No damaged wires that I could see. Still only number five cylinder misfiring. I was hoping to see something the previous guy missed but other that being a few screws lighter than before he got it everything seemed ok..stumped. May try to check compression tomorrow and maybe swap injectors around to see if it makes a difference.
We put a new injector in cylinder 5. car idles much better and revs up smoother. but on test drive, it backfires under a load. Sometimes it seems to run good then back to the backfire and skipping. Throwin 02 sensor 1 bank 2 no activity code and cylinder 5 misfire shortly after. May have to take it to kia on monday..was trying to avoid that but need the car fixed. Thanks again for all the help.
So after a trip to the dealership and a week later, it turns out the timing belt had jumped to teeth and was out of time. I went down to verify what they claimed to be the problem and it appeared to be true. After they put the new timing belt and tensioner on the car still missed cylinder 5 but also backfires much worse. They say taking the heads of to check for internal damage (valves) will run 2000 bucks. Compression was a little low at 140 psi in #5 cylinder. Could bent valves cause a backfire and just slightly low compression? Getting the car back home tonight and plan on taking the heads off to check for damage. Not too impressed with the local kia shop. Any thoughts on anything other than valves causing the problem. I plan to start taking it apart tomorrow. Thanks forany help
What were the other cylinders running at pressure wise? Even if they were all 140 that should be enough for a smooth running engine. If the other cylinders were 180 then I could see a slight rough running condition. With 140 in the cylinder the odds of a valve bent enough to cause a miss are pretty slim. Not saying that it is not but it only takes a tick of a bend to not seal properly. Before you remove the heads be sure to line the crank and the cams to TDC on #1. Then check the timing marks yourself. Fuel, compression and ignition. The three things you need to run an engine. Remember, there are 4 valves per cylinder.
Thanks, I definitely plan on checking all timing marks before tearing the heads off. When the car was idling, it sounded like it was firin all cyclinders then the backfire and miss. Could a valve be bent just enough to be intermittent? I will know more after I get it back tonight. I plan on figuring this thing out for her so she doesn't have to keep throwing money at it.
We got the covers off the car today. All the timing marks line up. Car was running much worse than when we took it to the dealership though. I can't help but think the previous guy that worked on it may have dropped some trash into the intake while he was working on it. I am kind of from the old school disrtibutor cars..so pardon the ignorance...Does the computer time the spart according to the signal it gets from the crank and cam sensor..or is it possible for the crank to be 360 degrees out with the timing marks lined up...exhaust instead of compression stroke? It seems as it it would fire by what these sensors tell it, but not real sure on how the computer works. I am going to remove the heads tomorrow and inspect for damage. Thanks again for all the help.
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