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9 replies to this topic

#1
richie k

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i recently fitted an evo 4 engine/gearbox etc to my cm5a gsr.everythings working grand except when i really drive it hard and it gets to about 4 and a half k revs,pedal to the floor...then the car shudders and jerks with no more acceleration.
first i thought it was a boost leak,then i thought the hks dump valve was upsetting the maf.
theres 2 others im more inclined to think it could be,either the fuel pump isnt able for it,(but its a new walboro) or else the boost is spiking which would tell the ecu to cut fuel i think? can anybody shed some light on what it could be? thanks in advance

#2
bazeng

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Get a fuel pressure guage and wide band to diagnose.

#3
Lister

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Plugs? coil packs? TPS?

Edited by Lister, 03 August 2011 - 08:20 AM.


#4
BMGTZ

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symptoms certainly point at boost leak......Have you tested it? leak testers off ebay are pretty good

BRIAN
Black evo 1 full road rego and done properly/legally

I have heaps of parts...but never the one I need.

 

 


#5
richie k

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dont think its a boost leak cos im able to accelerate straight away again after it jerks,would a leak be constant? couldnt spot a leak but havnt tested it.
if it was plugs or coils it would happen up through the revs at even half throttle but its only when flat out at high revs. not sure about tps tho.
hadnt thought bout fuel pressure.
im so broke after doing the conversion im goin to have to wait a bit :(
when i can afford a boost gauge and fuel pressure gauge il fit him them and see.hopefully soon.if it is spiking it could be actuator problems.

#6
TMAK

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Is it a violent jerk?
Can you reach redline with like half throttle?
TMAK - JDM Evo 6.5 TME White with stripes - burnzytuned
|MAP shortblock 2.4LR 10.5:1CR|MAP EF3|GSC S2|Ohlins coilovers|Cusco|Endless|Meek|Turbosmart|Spoolin Up|Bosch 2000|Walbro 400|Zeitronix|GM|Kumho|Stock ported intake and exhaust manifolds|
366kws (vdr) @ 2.1bar
Old setup: 280kws (vdr) @ 24psi [email protected]

Previously owned the FRONTN Cordia.

#7
richie k

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Is it a violent jerk?
Can you reach redline with like half throttle?

ya its quite violent,scared the shite out of me the first time :unsure:
i tried it there and i can reach reline at half throttle,it seems to only happen under aggressive driving

#8
Chaser

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Check the plug leads mate, good chance that 1 is earthing out. I had the same problem a few months back the leads were shorting out causing it to break down and miss fire very bad. Pull the leads out and wrap them with electrical tape and see it goes away. Also check the plugs four burn marks down the side (little black marks) that will give you a good indication if that is your problem.
slowest cc coupe in the build

#9
TMAK

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Sounds like boost cut to me.
Maybe put in an ecu from 5-8 and get it flashed. :)
TMAK - JDM Evo 6.5 TME White with stripes - burnzytuned
|MAP shortblock 2.4LR 10.5:1CR|MAP EF3|GSC S2|Ohlins coilovers|Cusco|Endless|Meek|Turbosmart|Spoolin Up|Bosch 2000|Walbro 400|Zeitronix|GM|Kumho|Stock ported intake and exhaust manifolds|
366kws (vdr) @ 2.1bar
Old setup: 280kws (vdr) @ 24psi [email protected]

Previously owned the FRONTN Cordia.

#10
richie k

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plugs only went in last week but il check the leads in awhile
trying to get my hands on boost gauge/controller so might have a better idea then. found a nice apexi avcr going cheap on ebay so just waiting and hoping to outbid.anybody know if the hks evc are any good?
thanks agin for advise lads


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