Major loss of power when vtec engages

richards5445

richards5445

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So as the title says, my car seriously loses power just as vtec comes in, roughly 5500-6000 rpm. Its that bad that when your in 5th and 6th gear it wont accelerate through it and you have to drop it a gear. I have read that it can be common to lose abit of power but not as much as i am.

Heres the mods thats been done to it - gruppe m air intake, dc sports 4-2-1 mani, mugen twin loop exhaust, aem fuel rail, toda a3 cams, toda a3 valve springs, toda thinner head gasket, js racing 70mm throttle body, 440cc injectors, rbc intake manifold, k pro ecu and ported polished and skimmed head

Is it just a case that its running a dodgy map?

Got told that it may be the cams, is anyone else running toda a3 cams?

cheers
 
coyote_dc5

coyote_dc5

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Common to loose power when? These cars only make power over 6k!

Has it ever made power with this setup/map or has it happened all of a sudden started? If its since having a new map I would point figure there. Have you got a graph and does it looks apparent on there?
 
maxvr6

maxvr6

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Have you got one of those OBD dongles plugged in? I had a very similar issue a while back which just fixed itself after i unplugged it, also tried resetting the ecu, not sure if it would make any difference with the Kpro/K100?
 
richards5445

richards5445

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I done some searching about losing power when vtec is about to kick in and a few others had the same problem, my cousin had a dc5 and he said his done it. I took him out in mine and he said his was nowhere near as bad as what mine is but his was running a mugen ecu rather then k pro

I have only had the car about a month, when i test drove it i put it down to a poor map, so i dont know whether the car has been mapped to a different setup to what its currently running.

No i didnt get a power graph with the car.

Im planning on getting it to tdi north for a remap but iv got a new manifold and exhaust to go on before i take it there, just waiting for the exhaust to turn up as im getting a j's racing through injection imports and theres a 6-8 week wait
 
richards5445

richards5445

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maxvr6 said:
Have you got one of those OBD dongles plugged in? I had a very similar issue a while back which just fixed itself after i unplugged it, also tried resetting the ecu, not sure if it would make any difference with the Kpro/K100?
Click to expand...
Whats an obd dongle?
 
Benneh

Benneh

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Sounds silly, but the oil level is topped up right? Oil level and pressure are vital for VTEC!
 
D

davidpingu

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Personally I'd forget about waiting for exhausts or worrying about any other mods for that matter and take it to a garage. No point doing anything to it til it's running as it should be. I'd get it looked at sooner rather than later as driving it around like that may not be doing it any good at all.
Just a thought, does the eml illuminate in any stage of ignition before the car starts? If so I take it it goes out once the car is running?
Temp gauge reading as it should once warmed through too?
 
coyote_dc5

coyote_dc5

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So it wasn't making power when you test drove? Did the previous owner say who mapped it last? It is possible he was selling because he couldn't get to bottom of it either unless he thought it was normal too :/

Sent from my Z10 using Tapatalk 2
 
richards5445

richards5445

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41
davidpingu said:
Personally I'd forget about waiting for exhausts or worrying about any other mods for that matter and take it to a garage. No point doing anything to it til it's running as it should be. I'd get it looked at sooner rather than later as driving it around like that may not be doing it any good at all.
Just a thought, does the eml illuminate in any stage of ignition before the car starts? If so I take it it goes out once the car is running?
Temp gauge reading as it should once warmed through too?
Click to expand...
Its not my daily drive at the minute, just use it on weekend, but ill stop using it until i can get it booked in somwhere to have a look at it

emi light comes on with the ignition and goes off once the car has started

temp gauge gets to about 2/5 ( not quite half) within a couple of minutes of driving and stays there no matter how you drive it
 
richards5445

richards5445

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coyote_dc5 said:
So it wasn't making power when you test drove? Did the previous owner say who mapped it last? It is possible he was selling because he couldn't get to bottom of it either unless he thought it was normal too :/

Sent from my Z10 using Tapatalk 2
Click to expand...
It makes power, just loses it from 5500 rpm to 6000 rpm, and is fine after 6000 all the way until the limiter

He didnt mention who mapped it no, i dont think he done the work to it, it was the owner before him

Yeah it is possible he was selling it because he couldnt get to the bottom of it

Ill try and get a video of the car when im driving it to show you what its like
 
Rob.

Rob.

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Toda A3 cams wont make it do that no...

Sounds a bit like a mapping issue, probs wise to get that checked before trying anything else

Used to have similar mods to yours few years ago and also had a bit of a flat spot at VTEC point and never really got to the bottom of it but when I changed from the RBC to a RRC the problem went instantly !
Wasn't power loss just a flat spot I must add though...
 
richards5445

richards5445

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Yeah im hoping its an issue with the map

Is there much difference between the rbc and rrc?

I think i over exagerated it a little bit, think it is just a flat spot, but you can feel the car pull back quite a bit, i took some videos but cant really notice it in the video

Are you running a3 cams?
 
Rob.

Rob.

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Yep have Toda A3's

The RRC does make it much more drivable, the power an torque band is basically longer not all top end like the RBC is, although the cams do make it like that so probs not much difference with the manifolds with an engine running OEM cams

Power only went up 3 or 4bhp but is much better mid range with the RRC
 
pudski

pudski

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Will probably need to lower the vtec point on the map. If you have a copy of your map it is very easy to change.
 
Rob.

Rob.

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Was 2 years ago an now changed bits so the maps fairly different now anyway, 3" exhaust and a Toda manifold got VTEC down to 3500rpm :)
 
richards5445

richards5445

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Yeah, I'm going to wait until the exhaust turns up and take it to tdi north and see what they can do as apparently there pretty hot on the k pro

What's it like to drive with the vtec as low as that ?
 
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