b18c running lean (dyno pic added)


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deb1991

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Aug 22, 2009
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hi, got my b18c eg dynod at tdi north yesterday. and the lads told me the car is running very lean. not sure on what steps to take next, any info appreciated. the engine is standard apart from intake manifold and exhaust, running on a standard jdm itr ecu.

dyno.png
 
Thats very strange.... Didnt they give you any idea's why ?
 
It doesnt look like a stock engine. Especially with that kind of power! You have nearly 20HP and a good bit of torque more over JDM spec figures! That doesnt happen only with intake/exhaust mods. It looks like there are some more changes in the engine like aftermarket cams or higher compresion ( due to aft. pistons, milled head etc..) in it. This would be a reason why the stock ECU is not delivering enough fuel. Are the HP tq values correct (where there no problems at the dyno)?? Usually if something deosnt work propperly in the PGM-fi system the ECU tends to deliver too much fuel for safety - the opposte to lean. Running lean isnt healthy for the engine as too much oxygen raises the combustion temp. so You should sort it out quickly. Think about tuning the engine with crome/hondata etc You might get better figures out of it :)
 
they just said its because i had i/h/e installed. And the standard ecu is mapped for standard intake header and exhaust.
 
i purchased the engine from a scrapyard out of a itr with the ecu, there didnt seem to be any problems at the dyno...is the car running dangerously lean? i will be looking to get a remap from Daz at DNR...how can i check if the cams are aftermarket, i know id have to take the head of to check the pistons. but im sure there will be ways to check if the cams arent standard
 
What kind of intake/exhaust do You have? The stock ECU usually has no problems with some mild modifications like sports induction kit or changed exhaust (unsless You have some kind of wonder-exhaust manifold)
 
i have a mugen twin loop, decat, rmf 4-1 manifold (meant to be really good) and a aem cai.
 
To check the cams it could be enough to take of the valve cover. To check if You have higher compresion would be more tricky but You can always chec what compression is generated at the cyinders. If You wlil drive the car gently without opening the throttle 100% there will be no harm over short period.
 
Arv said:
It doesnt look like a stock engine. Especially with that kind of power! You have nearly 20HP and a good bit of torque more over JDM spec figures! That doesnt happen only with intake/exhaust mods. It looks like there are some more changes in the engine like aftermarket cams or higher compresion ( due to aft. pistons, milled head etc..) in it. This would be a reason why the stock ECU is not delivering enough fuel. Are the HP tq values correct (where there no problems at the dyno)?? Usually if something deosnt work propperly in the PGM-fi system the ECU tends to deliver too much fuel for safety - the opposte to lean. Running lean isnt healthy for the engine as too much oxygen raises the combustion temp. so You should sort it out quickly. Think about tuning the engine with crome/hondata etc You might get better figures out of it :)
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Was just about to post the same, it's either a very "happy" Dyno or there is some internal work done to that engine.

Get a fuel gauge on there to see how the fuel pressure is, could be dirty filter or lazy pump not delivering enough fuel. If everything checks out ok with the fuel system the cheapest fix for you would be to install a adjustable fuel regulator and raise the fuel pressure, the air/fuel curve is pretty flat so the fuelling should be pretty good once you up the pressure. Reset ecu also after upping the pressure as the long term+short term fuel trims are going to need relearning. Obviously iffiumes allow a mappable ecu would be best option.
 
deb1991 said:
i have a mugen twin loop, decat, rmf 4-1 manifold (meant to be really good) and a aem cai.
Click to expand...

this might be the reason, get a remap! And check the dyno afterwards. Looks like a healty engine:D
 
yep, il be keeping the car in the garage untill i get the problem sorted, chatted to a few people and they said get a fuel pressure regulator and a vtec controller and get it sorted through that??
 
Vtec6000 said:
Get a fuel gauge on there to see how the fuel pressure is, could be dirty filter or lazy pump not delivering enough fuel.
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was thinking about this aswell. But if so there wouldnt be 216HP from it! no way
 
Arv said:
this might be the reason, get a remap! And check the dyno afterwards. Looks like a healty engine:D
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most hondas run on i/h/e..so its most likely all these hondas with bolt ons and no map will be running lean?
 
iv heard the tdi north dynos are just about right, the filter on the aem is brand new, its just been serviced aswell. i was quite shocked at the 216bhp, ive been told the power will be less when the car is fuelling correctly, will get someone to check the fuel pressure
 
maybe that combination of i/h/e is very good for air travel and filling up the cylinders and the stock ECU is not able to compensate enough, hard to say. Like said before usually there is no big deal with such mods using the stock ECU. With that kind of AFR and that kind of HP TQ figures I would think about bigger mods in the engine anyway....
 
hmm could be modified internally, the people iv taken for a spin in the eg was shocked at the performance of the car compared to a itr etc, but that could be just because of the weight
 
deb1991 said:
ive been told the power will be less when the car is fuelling correctly, will get someone to check the fuel pressure
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well, that doesnt make too much sense for me, should be the opposite in theory but I'm not an expert :)
one more thing to check would be ignition timing aswell
 
RMF 4-1 gave me huge power gains over the convention 4-1 and 4-2-1's :nice:
 
yep, i think the rmf has caused a big power gain, great manifolds. going to enquire about a remap now, any reccomendations on who to choose?
 
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