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Discussion Starter · #1 ·
Hi folks. Sincerely needing advice on my recently acquired i20. I'm basically at the end of my tether (and two months of my life) trying to get the engine running smoothly. It's a 2012 facelift model with a G4LA engine. I bought it as a non runner and it had codes for crankshaft sensor, camshaft sensor and alternator fault. After replacing the sensors and alternator it started and idles around the 1000 revs mark, however if the throttle is used it dies like putting hand over the air intake on a carburettor engine. When running and the ignition is turned off, it continues running roughly for approximately 20 seconds before stopping with a heat shield type rattle. There is also a strong smell of petrol after. There are no codes present and the EML is not on. I have done what is below and I am waiting on a new fuel filter arriving. I've doubled the time I told the missus I'd have it sorted by so atmosphere is a bit tense as it's supposed to be hers! HELP please! I'm all out of ideas.
Timing chain kit done
New Cam adjusters
New crankshaft sensor (code shown)
New camshaft sensor (code shown)
Alternator replaced (code shown)
Plugs cleaned and within resistance spec. they were all sooty.
HT leads within resistance spec
New injectors
Coil packs replaced
MAP sensor replaced
Throttle body cleaned and checked to be working (not cable throttle) TPS reading 14.90 to 85.55 live data.
New air filter
Oil and oil filter changed
 

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2012 Civic Si Sedan
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Terrible title.
Sooty plugs implies lack of air (blockage) or seriously over-rich condition.
The run-on sounds like dieseling - timing is way off (timing chain not indexed correctly) or excessive carbon build-up in cylinders.
Both could be related.
I'd verify timing chain indexing first.
 

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Discussion Starter · #3 · (Edited)
Terrible title.
Sooty plugs implies lack of air (blockage) or seriously over-rich condition.
The run-on sounds like dieseling - timing is way off (timing chain not indexed correctly) or excessive carbon build-up in cylinders.
Both could be related.
I'd verify timing chain indexing first.
Thanks for your message. Title amended. On timing, crank was at tdc and camshaft adjusters aligned so the marks on outer edge horizontally lined up across inner center between the two and chain on links next to marks by sprockets. Also it was running like this before the timing chain was done. The run on will happen even if it has only been run 15 seconds from cold. Not enough time for any carbon to get hot enough to "Pink"
This is the procedure I used for the timing- https://kiamanual.com/kia-rio-yb/timing_chain-431
 

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Drives : Nissan NV200 Flies : Rans S6ES
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if the throttle is used it dies like putting hand over the air intake on a carburettor engine.
Perhaps there is excessive back pressure in the exhaust, usually caused by a failed catalytic converter. A quick and dirty test for that is to remove the upstream O2 sensor from the exhaust. That will leave a big hole in the exhaust upstream of the cat to allow the exhaust gas to escape. If the engine is able to rev up with the sensor removed you can feel pretty confident your dealing with a plugged exhaust.

I would also take a look at the MAP value when the engine is not running to check that it's displaying a plausible value. It should show atmospheric pressure KOEO (approx 100kpa). If that checks start the engine and see what the value drops to when the engine is at idle. It should drop to something like 40kpa at idle and increase as you open the throttle.

The other thing to look at is the fuel trims. Let the engine idle for a few minutes first though to allow the fuel system to switch into closed loop control. What are the fuel trim values with the engine at idle?

If I helped you fix it, why not...

Your support is greatly appreciated
 

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Discussion Starter · #7 ·
Perhaps there is excessive back pressure in the exhaust, usually caused by a failed catalytic converter. A quick and dirty test for that is to remove the upstream O2 sensor from the exhaust. That will leave a big hole in the exhaust upstream of the cat to allow the exhaust gas to escape. If the engine is able to rev up with the sensor removed you can feel pretty confident your dealing with a plugged exhaust.

I would also take a look at the MAP value when the engine is not running to check that it's displaying a plausible value. It should show atmospheric pressure KOEO (approx 100kpa). If that checks start the engine and see what the value drops to when the engine is at idle. It should drop to something like 40kpa at idle and increase as you open the throttle.

The other thing to look at is the fuel trims. Let the engine idle for a few minutes first though to allow the fuel system to switch into closed loop control. What are the fuel trim values with the engine at idle?

If I helped you fix it, why not...

Your support is greatly appreciated
Hi. I've not tried checking for back pressure although it had recently occurred to me. I don't know anything about fuel trim values. Is that in the live data on the code reader? What should the values be? I'm used to pre injection mechanics. Cars seem to have so many other ways to mess up these days! Timing, air, fuel, spark, it should damn well go! I'm just old and don't get complicate!.
 

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Title amended. On timing, crank was at tdc ...The run on will happen even if it has only been run 15 seconds from cold. Not enough time.. This is the procedure I used for the timing- ..
Title is good. Hopefully TDC on compression stroke - #1 cyl valves all closed. Run on from compression can occur with a cold engine - hot run-on is likely timing and a warm/hot cylinder. Procedure looks to be okay.

The clogged catalytic converter theory (post #5) is also worth pursuing.
 

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Discussion Starter · #10 ·
Title is good. Hopefully TDC on compression stroke - #1 cyl valves all closed. Run on from compression can occur with a cold engine - hot run-on is likely timing and a warm/hot cylinder. Procedure looks to be okay.

The clogged catalytic converter theory (post #5) is also worth pursuing.
Thanks for that. Going to take out o2 sensor when I get the appropriate tool and will see what sort of pressure I'm getting out of the exhaust when I put the fuel filter assembly back in. Isn't the compression stroke set by the cams? If the marks are all in the correct place and chain on correctly, how can it be 180 out? surely TDC pulley mark would be directly opposite marks on timing chain cover? As I mentioned, I'm more used to working on older basic engines.
 

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.. Isn't the compression stroke set by the cams? If the marks are all in the correct place and chain on correctly, how can it be 180 out? surely TDC pulley mark would be directly opposite marks on timing chain cover? As I mentioned, I'm more used to working on older basic engines.
I'm "old school" too. From memory TDC occurs twice in a 4-stroke motor. The correct one is with the cyl #1 valves fully closed, the other TDC for cyl #1 would have the valves open. Back "in the day" it was common to mis-position the distributor 180 degrees on V-8 motors, they would try and run but with lots of mis-fires.
 

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Discussion Starter · #13 ·
Hi. I've not tried checking for back pressure although it had recently occurred to me. I don't know anything about fuel trim values. Is that in the live data on the code reader? What should the values be? I'm used to pre injection mechanics. Cars seem to have so many other ways to mess up these days! Timing, air, fuel, spark, it should damn well go! I'm just old and don't get complicate!.
I do indeed have back pressure. Revs up just fine, if noisily and smoky, with the top O2 sensor removed. Looks like I'm getting a new cat! Thanks for your and everyone else's assistance.
 
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