Help, drove through water now rough idle

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thebaum

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I have an 02 V8. Yall have helped me fix a lot of the common problems so far. I recently drove through some water, which at the time I didnt feel was too high as several other sedans were driving through. When I drove through, the car died. I started it up and drove a few miles home and it was running very, very rough. I figured I had killed the motor. Fast forward a couple months and I have some time to look at it. I had a mechanic friend take a look and he was able to get some codes (even though there was no CEL). The codes were 1507 and 0103 which pointed to the MAF sensor and the IAC valve. Those were replaced. The car started and continues to idle rough (although not near as bad as initially). I have read a lot of forums on here. I replaced the coils about 7k miles ago. Any ideas on what this could be and if it is fixable? I dont want to spend any more money if we dont think that it is repairable.

Thanks for any help. And I accept any criticism for both driving through the water and then driving home (it was kinda an emergency).
 
Hey sorry to hear about your dilemma, if you have an aftermarket (or even stock) airbox check to see if water may have been sucked up into the filter. When I had my LS I was forced to drive in 1 1/2ft water on a highway during a rainstorm and had no problems other than overheating because the belt wouldn't make good contact with the water pump. Also my airbox was replaced with a cone filter which sits higher than the stock box. My theory is that keeping a constant pace on the accelerator while driving through high water would keep water from being sucked up the exhaust and into the engine; and heck i never had problems.

Try a compression test, perhaps you cracked one or more cylinders?
 
Thanks for the tip. Hopefully I can get around to performing a compression test this weekend. I already have all the plugs out so it shouldnt be too much work.
 
do you run accel coils and have the valve cover lids removed? its possible water got in the plug wells.. Could be from drviing through high water or if it was raining your wiper cowl gaskets could need to be replaced
 
MysticMac said:
do you run accel coils and have the valve cover lids removed? its possible water got in the plug wells.. Could be from drviing through high water or if it was raining your wiper cowl gaskets could need to be replaced
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Thanks for the tip. I dont have accel coils but did notice that a couple screws were missing from the covers so I went ahead and replaced all 8 coils and plugs. No change. I guess im at the end of my abilities! Unfortunately, I dont trust anyone to know whats going on with this car, other than those on this site

Thanks all for your help
 
Do a compression test. That will determine if this is probably minor, or probably major.

Do note that P1507 only indicates that the engine could not maintain proper idle. The IAC is only one of dozens of possible causes for that. If the engine was running badly at all speeds (not just idle), then the IAC was never your problem.
 
will do. thanks. Yeah the idle was bad at all speeds. Im sure i damaged it beyond repair. Thanks for the input
 
Another question while I wait to do the compression test (Im waiting for a ride to the autoparts store). I just started it up to move it out of the rain. It runs rough (of course) but I found that the brakes were very, very stiff. What could this be from?
 
joegr said:
Do a compression test. That will determine if this is probably minor, or probably major.

Do note that P1507 only indicates that the engine could not maintain proper idle. The IAC is only one of dozens of possible causes for that. If the engine was running badly at all speeds (not just idle), then the IAC was never your problem.
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Joegr, I just cam across a thread where you discuss the exhaust cam and timing chain. This sounds like it could be my issue. If so, what am I looking at to fix this, price wise?

Thanks again
 
Hard brakes + rough engine = major vacuum leak.

The price to fix a jumped secondary chain depends on how much you can do yourself, and if any valve damage occurred.
 
joegr said:
Hard brakes + rough engine = major vacuum leak.

The price to fix a jumped secondary chain depends on how much you can do yourself, and if any valve damage occurred.
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Okay thanks, any common culprits for a vacuum leak I should be looking at? I checked anything within view and i couldn't visually see any.
 
thebaum said:
Okay thanks, any common culprits for a vacuum leak I should be looking at? I checked anything within view and i couldn't visually see any.
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Ahh... Chasing for vacuum leaks, it brings back so many memories. If you don't smoke, find a buddy who does. Buy a cheap cigar and puff away into the brake booster hose or any other vacuum hose while someone else looks for smoke coming out anywhere else.
 
joegr said:
Hard brakes + rough engine = major vacuum leak.

The price to fix a jumped secondary chain depends on how much you can do yourself, and if any valve damage occurred.
Click to expand...

Can't seem to pinpoint vacuum leak. Could a jumped secondary timing chain cause these same symptoms or do I need to continue to hunt down a separate vacuum leak?

Thanks for your help. Sorry for my ignorance
 
thebaum said:
Can't seem to pinpoint vacuum leak. Could a jumped secondary timing chain cause these same symptoms or do I need to continue to hunt down a separate vacuum leak?

Thanks for your help. Sorry for my ignorance
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Yes, I think that it can.
 
IMG_20160825_192603.jpgIMG_20160825_192612.jpg

So I got around to taking the valve cover off today. Here is what I see. Honestly, I was expecting to see a broken chain or something obvious. This is beyond my current knowledge/skills. What am I looking for to tell if the chain has jumped? Thanks for helping, I enjoy learning and trying to figure this stuff out.

IMG_20160825_192603.jpg


IMG_20160825_192612.jpg
 
Why no compression test?
You turn the crankshaft till the flats at the front of the cams are facing up. They should both line up exactly when you place a straight edge over them.

It's interesting that there is something written on the exhaust cam. Whatever oil was used for most of its life wasn't very good, or the change interval was over extended (or both).
 
joegr said:
Why no compression test?
You turn the crankshaft till the flats at the front of the cams are facing up. They should both line up exactly when you place a straight edge over them.

It's interesting that there is something written on the exhaust cam. Whatever oil was used for most of its life wasn't very good, or the change interval was over extended (or both).
Click to expand...

Oh yeah, sorry I forgot to report that. Had a buddy do a compression test. Don't remember the exact numbers but he said it was fine. I'll try to get the numbers from him. And I use the word buddy lightly.

A far as oil goes. Only Mobil one for me and about every 7000 miles
 
Interesting, looks very different. I took the cover of because I have a brand new gasket kit that I've had laying around. Figured this was as good a time as any to put it in.

Thanks for your help. I think I'm in over my head at this point. Probably time to bite the bullet and take it to a professional. I'd love to be able to figure this out on my own but it didn't look like that is going to happen
 
As far as the compression test goes, I'll probably try to do my own. Not sure how good the guy was. I have newborn twins at home so time is hard to come by!
 
thanks for the patience. Today I was tinkering around with it, putting things back together when I noticed this. It looks like where the intake manifold gasket would be. It looks like a pad that has absorbed a bunch of water and is swollen. It looks the same on both sides. Could this be a bad gasket? Its that golden brown thing in the picture.
ATTACH=CONFIG]828476432[/ATTACH]

IMG_20160826_200658.jpg
 
thebaum said:
thanks for the patience. Today I was tinkering around with it, putting things back together when I noticed this. It looks like where the intake manifold gasket would be. It looks like a pad that has absorbed a bunch of water and is swollen. It looks the same on both sides. Could this be a bad gasket? Its that golden brown thing in the picture.
ATTACH=CONFIG]828476432[/ATTACH]
Click to expand...

The big foam pad under the engine cover is for sound deadening.
 
So I finally was able to do my own compression test. No compression in cylinder 4. I guess its toast. Thanks for all of your help, this is why you do your own tests!
 
Well I was able to pick up an 02 LSE for dirt cheap, hopefully I can salvage my good parts and have a nice running LSE. I'm sure Ill have a whole bunch of new problems with the new car. Pretty excited to have the LSE edition
 
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