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Hesitation / fuel cut 3k rpm

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Old 04 August 2015, 02:10 PM
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charlesm17x
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Default Hesitation / fuel cut 3k rpm

Hey guys

I have a 2000 turbo impreza that I picked up a few weeks ago finally got it through not after spending 1800 on it.

Anyway the guys I picked it up from bolted on loads of mods fmic, MBC, full decat 3inch exhaust and loads more probably.

My issue is that it had a massive hesitation at 3k rpm I changed out the maf and this made it better but not fixed, I also no its running very rich and will be changing the o2 sensor this week to help save the engine as this thing has never to my.knowledge seen a remap have bypassed the MBC and so is running off waste gate pressure 7psi it has helped the hesitation but really has just moved it round to 4-5k rpm as the boost comes in as the boost comes anything above 5psi and it feela like the car has it a brick wall.......before the gauge showed anything up to 22 psi!!!

Remap will happen down the line but is there anything else I can do to fix the hesitation / move closer to standard in the mean time.

Any advice is greatly appreciated

Last edited by charlesm17x; 04 August 2015 at 02:33 PM.
Old 04 August 2015, 03:21 PM
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kevo10
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First thing id do is connect the green connectors under the dash and see if any error codes pop up. Next is check the maf and its condition. May just need cleaning or , more likely , replacement. Try resetting the system by disconnecting the negative on the battery
Old 04 August 2015, 03:35 PM
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charlesm17x
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I've replaced the maf and seems fine now, wouldn't idle on old one.

Ecu has obd2 port scanned it today but showed no errors will try green connector method later
Old 04 August 2015, 03:42 PM
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Tidgy
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wind the boost controller right back, drive it like miss daisy and hope you don't blow up the engine and no damage has been done already.

Its pretty obvious its a map issue and there is only one solution for that, well two but do you really want to return it to stock?

When it comes to map time sack the mbc, let the ecu do its job and a proper map
Old 04 August 2015, 03:54 PM
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charlesm17x
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No no don't want to go standard just want it to be as safe as possibly until I can get it mapped, I've even fitted a full standard exhaust.

I've disconnected the MBC and connected turbo straight to waste gate should I leave like that for time being or should I connect up to something else?
Old 04 August 2015, 04:23 PM
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kevo10
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If you can get an oem solenoid , id stick that on. Its very hard to stay off boost on these , its just too tempting !!lol.If you cant get one easily, just take it easy until you can fit one or map it
Old 04 August 2015, 04:58 PM
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charlesm17x
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As far as I can see the standard map sensor and solenoid are all still there will have another gander tomorrow.
Old 04 August 2015, 05:05 PM
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Tidgy
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Keep it below 3000rpm and drive off boost, make sure you run it on 99 ron and should be ok.

no gaurenty though because it may well borewash.

need to get the remap done asap
Old 04 August 2015, 06:02 PM
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charlesm17x
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Hoping that with new lamba it won't over fuel
Old 05 August 2015, 08:41 AM
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kevo10
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Just make sure its a decent genuine one
Old 05 August 2015, 09:10 AM
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Tidgy
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will prob make sod all difference tbh, I would stop spending money untill the map is looked at, find a decent place and they can fault find and sort anything that needs sorting when its mapped, the sensors may well be perfectly fine
Old 05 August 2015, 12:52 PM
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charlesm17x
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I know o2 sensor is broken so I'll deof replace it anyway
Old 05 August 2015, 05:39 PM
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kevo10
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A good place to start if its broke!!! lol
Old 06 August 2015, 11:21 AM
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Went down to the car today so change a battery terminal and even though the garage said no error codes were on the ecu I decided to connect up the old fashion way and what do you know code 45 map sensor!

Does anyone have a diagram of how this needs to be plumbed in once I replace it, prevos owner has hacked all the vac Lines up.
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