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2G code p0340 weird issue

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
so anyways my car was cranking over earlier kept stalling out unsure why then the next time i went to crank it over a P0340 code popped up and started making this odd knock noise that sounds like its coming from under my valve cover? anyone know what would be going on? It says in ecm cam angle sensor circuit malfunction. Just wonder if anyone has had a issue like this or if they know what it could possibly be before i go out and spend 200$ on a cam angle sensor.
 

motomattx

Proven Member
3,296
1,199
Dec 9, 2010
wampum, Pennsylvania
You could have crankwalk I suppose, your cam sensor should not be capable of making any noises unless something in the engine is very wrong somewhere, you should start by looking at your timing belt to make sure it hasn't jumped time or see that the timing belt is not close to jumping time from being too loose.
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
You could have crankwalk I suppose, your cam sensor should not be capable of making any noises unless something in the engine is very wrong somewhere, you should start by looking at your timing belt to make sure it hasn't jumped time or see that the timing belt is not close to jumping time from being too loose.



okay ill look into that because it wasnt knocking earlier when i started it. only once the code got thrown. and took valve cover off gave it a crank yes it spit a little oil which is whatever i knew it would but absolutley no knock at all. nothing looked messed up. no indents or anything in valve cover.
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
well i heard from other posts that its possible for it to make a knock noise if it skips a couple teeth it only did it like 3 times tops... praying my internals are fine :(
 

Kryndon

Proven Member
658
337
Jan 10, 2014
Bulgaria, Europe
If it skipped too many a teeth it would be banging valves and also completely messing with the air mixture and timing, resulting in bad starts or inability to do so. Have you since confirmed your timing?

I am currently having the same issue, cold starts take awhile to crank and it keeps fumbling. Sometimes right as it comes up to life it triggers a temporary CEL for P0340 as well, and a misfire.

Most often this is due to a bad CPS or one that is going bad (including bad connection at the plug or bad wires). Check those first, as well as your timing marks.
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
okay and whats cps if i may ask?
sry im a newbie my buddy whos pretty good with dsm's knows more than me just issue is he works a shit ton and doesnt reply all the time so its hard to get ahold of him sometimes and litterally just started banging maybe 3 times absolute tops. so im hoping it didnt cause to much damage :(

Have not confirmed timing yet it’s like 5 am will in a few hours so I’ll get back to you oil does smell little gassy in the head.

Last log I saw in ecmlink timing was up down up down up down. Which didn’t notice until I went back and looked at it
 
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ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
0298407D-8980-4DDB-9E82-18AC573CFF17.jpeg
So I’m back I posted pics of the timing marks I highlighted in red not sure if it’s on time or not Bc I can’t rotate the gears right now. Also another pic showing some slack in belt. All teeth seem to look fine though.
AD197803-3C57-4383-8383-B90CB140C0BE.jpeg
 

Kryndon

Proven Member
658
337
Jan 10, 2014
Bulgaria, Europe
CPS - Camshaft position sensor. It's a black plastic sensor bolted to the back of your intake camshaft, has a 3 pin connector to it.

Also that timing belt slack looks out of spec to me, need to confirm with the factory service manual spec.

Lastly, you can turn your wheels to the right and stick a 1/4" drive socket on the main sprocket. Rotate it slowly CLOCKWISE until you line up the two red marks you made. Then see if the lower timing mark also aligns. Right now we can't tell anything for certain.
 

dustyboner

DSM Wiseman
1,303
575
Mar 13, 2016
abq, New_Mexico
i would take the spark plugs out before you rotate it that way if you feel any resistance you stop spinning. If the plugs are in you might not be able to tell if your getting resistance from the compression or a valve contacting a piston
 

dustyboner

DSM Wiseman
1,303
575
Mar 13, 2016
abq, New_Mexico
with a bent valve, if you keep trying to start it, you ll hear like a backfire from the intake mani.
did you check to see if your timing marks line up? you don't wanna be cranking it over and bust the head off a valve. you ll really fuc shit up if you drop the valve.
make sure the timing is correct and then check the compression,
 
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ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
with a bent valve, if you keep trying to start it, you ll hear like a backfire from the intake mani.
did you check to see if your timing marks line up? you don't wanna be cranking it over and bust the head off a valve. you ll really fuc shit up if you drop the valve.
make sure the timing is correct and then check the compression,


well unfortunate news...... did compression test air is blowing out intake manifold and metal flake in my head not a lot.... but i plan to take whole head off and check pistons and investigate further my timing belt i assume jumped. could be bad tensioner im not sure but when investigating further i plan to redo pistons and rods and everything then buy a refurbished head if mine is shot so if anyone see's a 4g63t 98 gst head send them my way. thank you for all your help and boy do i gotta say starting off on my first dsm isnt so hot. but ill pull through.
 

dustyboner

DSM Wiseman
1,303
575
Mar 13, 2016
abq, New_Mexico
.... and metal flake in my head not a lot....
i was gonna say maybe you just bent a couple valves and cracked the valve guides but if have metal floating around it might be more serious than that.

FYI: you can use a head from any year 2g 4g63. the only difference is gonna be tne intake cam, gear and cam sensor/housing, so you would wanna use the ones off your current engine.
not that rebuilt heads come with that stuff anyways
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
Okay thanks for the FYI and it’s not a lot of metal flake but there is definitely some after I heard 3 knocks I shut it off n haven’t touched it since

Ok so is my timing rly off? Like what’s going on....
 

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ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
Another update, i go to manually crank the car to where the cams move well a little over half way it stops... like takes good force to turn it.

could the video i uploaded possibly be a rod knock?
 
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dustyboner

DSM Wiseman
1,303
575
Mar 13, 2016
abq, New_Mexico
your gonna have to pull the timing cover to check the timing.
when the marks on the cam gear are lined up, the one on the crank trgger plate and oil pump sprocket should also line up.
but since you already check the compression and the valves weren't sealing, your gonna need to pull the head.
since you said you saw metal flakes on the head, when you drain the oil, shine a flashlight on the oil to see if its got any metal in it.


upload_2021-3-8_23-5-8.png

upload_2021-3-8_22-59-38.png
 

delta448

DSM Wiseman
3,587
236
Jan 13, 2006
Clarksburg, West_Virginia
I'd start with simply pulling the valve cover and inspecting. There's an outside chance that you just kicked a rocker off and you're smacking it around with the cam lobe when the engine rotates. However; usually it's a symptom of a bent valve when you kick a rocker. Also make sure you pull the spark plugs before turning the engine over by hand, so you aren't fighting compression.

Not that it matters but to avoid confusion I always prefer these abbreviations:
CAS = cam angle sensor
CPS = crank position sensor
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
I'd start with simply pulling the valve cover and inspecting. There's an outside chance that you just kicked a rocker off and you're smacking it around with the cam lobe when the engine rotates. However; usually it's a symptom of a bent valve when you kick a rocker. Also make sure you pull the spark plugs before turning the engine over by hand, so you aren't fighting compression.

Not that it matters but to avoid confusion I always prefer these abbreviations:
CAS = cam angle sensor
CPS = crank position sensor

yeah i pulled valve cover off and took spark plugs out already went to turn it with a ratchet and got about 180 degrees before it locked up and couldnt turn anymore. so naturally i knew something was wrong because it wasnt turning smoothly and also all the rockers seem to be in place nothing under valve cover looks unusual i inspected it well. Next i proceeded to drain my oil pan worried of metal flakes or glitter in the oil. Found litterally 1 and only one flake or kind of like a very small chunck like the size of if u trimmed your pinky nail. *mind you im 6'3 and have big hands* but besides the point that was it no glitter no more chunks nothing. So is it safe to assume the bottom block is probably okay then? and just replace cylinder head and all the timing components? regardless once head comes off im going to examine the pistons and such. Basically what im asking by the sound of it and signs of no glitter does it seem salvageable or should i take the leap and spend the 700$ on the new entire block my buddy is willing to sell me with 170k miles on it. or just spend the 200$ on the head he is willing to sell off. *mind u again i dont have a fortune currently paying 405 a month plus rent ect on a house and 2015 civic si* so 700$ is a little steep for me but if it needs done then it needs done. ill hustle side work for it.
 

delta448

DSM Wiseman
3,587
236
Jan 13, 2006
Clarksburg, West_Virginia
If all the valvesprings are indeed sitting at the same height, you'll probably find at least 1 valve head snapped off and embedded in a piston. If you find a pair of valvesprings that sit lower than the ones on the cylinder next door, then there's a slim chance the bottom end might salvageable with minor damage and the valves are just bent and not broken off. Finding a chunk in the pan is never good, but unless you can tell what kind of metal it is, it's a sidebar. It's time to pull the head if you haven't yet.
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
If all the valvesprings are indeed sitting at the same height, you'll probably find at least 1 valve head snapped off and embedded in a piston. If you find a pair of valvesprings that sit lower than the ones on the cylinder next door, then there's a slim chance the bottom end might salvageable with minor damage and the valves are just bent and not broken off. Finding a chunk in the pan is never good, but unless you can tell what kind of metal it is, it's a sidebar. It's time to pull the head if you haven't yet.


Yeah I got a buddy that’s coming over later to help me pull the head. Fingers crossed and praying for the best.
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
Well got the new head in still working on taking my old one off only paid 200$ for this head though with 74k miles on it so fingers crossed I only need to replace head.
 

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ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
will take pics of old head as soon as its off about halfway there taking a break to eat. and id love input on the pics i will be uploading because some proffesional advice would be nice considering im still a newbie.
 

ncarson91

Proven Member
66
4
Jan 2, 2021
north olmsted, Ohio
Well gentleman here is the news...... it looks like the bottom of my block is in perfect shape so no f***ed up piston heads im able to hand crank the motor 360 degrees flawlessly and super smooth no knocks no grinding no rubbing nothing at all. Ill upload a video along with some pics anyways. But i think i got extremely lucky on this one and only have to replace all timing components water pump and the head,
 
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