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Discussion Starter #1
My ep3 is down on power between 15 and 20 bhp between 7 and 8k rpm, and around 5 to 10bhp down around 4 to 5k rpm. The car is being helpful and showing no codes :rolleyes: The car is not misfiring, stuttering or feeling sluggish. It's had a new timing chain, tensioners and guides, a remap so all fueling etc should good. It doesn't use much oil, perhaps half a litre per 1k, and no regular smoke. The valve clearances I did last summer and I understand they don't need adjustment after a new chain? Checked the spark plugs which were a little white, I haven't checked coil packs or injectors. Recently changed the vtec solenoid gasket. Recent oil change too.

My thoughts are the cat could be plugged or there is some other restriction? The fact it shows no codes makes me think all sensors are fine, TPS for example.

Not sure where to go next and in which order. Is there any test I can do to check exhaust flow?
 

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Half a litre per 1000 miles seems pretty heavy oil consumption? I know these can use oil but my FN2 used about 1 litre between services and basically nothing when I switched to 5k intervals and that was doing track days too. Used 0-30. Maybe a pcv issue although I don’t imagine that would affect power?
 

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I wouldn't call it heavy oil usage, pretty normal. I changed the pcv valve last year. I'm going to check fuel trims, do a simple coil pack check (remove one at a time to check the rpm drops), check for vacuum leaks and then move onto fuel pressure.
 

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Agreed - its not heavy usage at all. I've read that 1L per 1000 miles is within tolerances, and some even use 1L to 800 miles. Mine is a bit of a burner but feels very healthy and no smoke. Hope you get the issue sorted, keep us up to date on findings?
 

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Discussion Starter #6
He said everything checked out, the cat was mentioned as a possible issue.
 

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Discussion Starter #7
Coil packs checked and fine.
Injectors screwdriver test done and fine.
Obd2 scanned, no codes.
Fuel trim around 1 to 4% on tick over.
IAT 42°C I replaced the sensor and it dropped to 32°C.
All o2 sensor and catalysts checks came back "passed".

Hmmm.
 

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Was your fuel trim the short or long term set?

Short term responds to immediate conditions, figures are usually low.

Long term corrects for a more serious issue, if present.

Both sets are added to get an overall fueling correction.

A combined figure under 10% is usually okay but higher figures suggest an underlying issue. A fault code isn't usually thrown until over 20-25%.
 

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Discussion Starter #10
Long term was 0 but might not have been applied. Intake is very tight :wink3:
Just had a thought, if the IAT is reading higher than actual temp then less fuel will be introduced, this could give a lean scenario and loss of power, backed up by my white spark plugs.
 

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my s2k sucked 1litre per 1k. ended up buying bulk oil :p 6k oil changes plus 6litres between changes got comparatively expensive buying a bottle at a time


a few things i've not seen mention;
1) got good fuel? never had it myself but seen people say a fresh tank of different fuel can help.
2) tried ECU reset and see what a 'fresh' config runs? no idea if hondata ECU's would act the same as a factory ECU in that respect.
3) fuel pump issue? high RPM = high fuel rate and if the pump is struggling your gonna see it up high. i would expect a misfire or something similar code.
4) weak spark (plugs, coil)? again, would expect knock or misfire code to be thrown.


not sure why i'm leaning towards fuel, but since you've gone through fault codes, air leaks and the usual stuff it seems like another angle to look at.
 

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Discussion Starter #14
1) shell v power or momentum
2) yep
3) could be this but it's down a bit across the rev range
4) recent ngk iridium and I did the coil pack pull test
 

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if you have white plugs after remap
then im afraid the map is **** and as you say running too weak
if the car feels ok there might not be anything wrong
some engines that are treated very civilised from new are often not as powerfull as some that are treated without respect
regardless of any faults where ever on your car remap should not make it run weak
id far rather go from the feel of how the car drives than the bhp figures
 

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Discussion Starter #16 (Edited)
I think the car was running lean before the map. Plus the pre map runs were below expectations. Another cause of high IAT is a severe exhaust restriction backing heat up :frown2:
 

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Discussion Starter #18
The diet has gone off the rails at the moment :grin2:
Iat was 29°C this morning which is a little high but the sensor is in a black silicone pipe on top of the large coolant hose.
Regarding compression....
When I did a compression test on mine I achieved 175 across all 4 cylinders, but I forgot to WOT :facepalm7: If I had wedged the TB valve open I anticipate the readings would have been higher.
 
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