Flat spots low down rev range?


A

Aerodeckb18

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Recently rebuild my B18c6 engine,With oversized .5 pistons now. Since rebuilding it I have noticed between 3-5k RPM theres like a hesitation/flat spot which I thought was a miss so i changed the distributor,plugs and leads. It is still having the same issue,However it didnt do this before the rebuild.I'm also running a p30 ecu which is standard which i'm thinking isn't helping,Although it ran with no issues prior to the rebuild.Car will be mapped next month but any help to rectify this will be greatly appreciated!
 
It's probably running too lean. A p30 ecu is for b16a, you need a p73 ecu, but even with that fuelling won't be right as you have gone oversized pistons.
 
Vtec6000 said:
It's probably running too lean. A p30 ecu is for b16a, you need a p73 ecu, but even with that fuelling won't be right as you have gone oversized pistons.
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Thanks, What's the best way to rectify this short term before mapping? As im currently saving to have it mapped by yourself funnily enough. If I have say a base map installed by H-tune in the meantime would that maybe help? I'm clueless when it comes to ECU's as you can see. Thanks.
 
With the P30 ECU you`re running to lean which can`t be good. Do you hear knock? Flat spots could be faulty/wrongly adjusted TPS, fuel filter, bad fuel injectors... Best get a P73 ecu untill you map.
 
What do you mean do I hear knock? Its when I put the foot down low down,It goes then like a miss/flat spot then it goes fine in vtec. With a p73 will it not be immobilised etc and the car wont run?
 
Knock as in detonating. I don`t remember exactly about immobilisers and ecu`s in the uk, but if you use a jdm ecu (which don`t have immobiliser) then you`ll be fine? Someone correct me if i`m wrong.
 
pateras_vtec said:
Knock as in detonating. I don`t remember exactly about immobilisers and ecu`s in the uk, but if you use a jdm ecu (which don`t have immobiliser) then you`ll be fine? Someone correct me if i`m wrong.
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Yes I know that mate,I thought the name of the JDM ecu's was different than p73. Hopefully I can source a jdm one in the meantime or VTEC6000 will clear up if a basemap will help.
 
A basemap will definitely help. Won`t be much, but will be safe. Hope you get this sorted quick.Until then avoid driving it past 3000 rpm`s and in general drive like a old folk!!

edit:come to think of it a while back, when i plugged a P30 ECU on my car (b18c) and went out to test if the ecu was working i had a flat spot around 3000 rpms as well.
 
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pateras_vtec said:
A basemap will definitely help. Won`t be much, but will be safe. Hope you get this sorted quick.Until then avoid driving it past 3000 rpm`s and in general drive like a old folk!!
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Have been doing so running it in anyway's mate,Started raising the RPM after 6/700 miles and noticed this. Thanks alot so do I.
 
Options are drive it easy and avoid loading the engine up too much or buy a ecu with safe basemap to run it on till you get it mapped. I can sort you out with a ecu and safe map if you want to run it around on in the mean time
 
Vtec6000 said:
Options are drive it easy and avoid loading the engine up too much or buy a ecu with safe basemap to run it on till you get it mapped. I can sort you out with a ecu and safe map if you want to run it around on in the mean time
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Ok thanks,Please PM me details and price,If this rectifys the issue it would be great!
 
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