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HELP! overboost problem.. 1jz swap sc300

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Old Apr 5, 2007 | 12:30 PM
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Default HELP! overboost problem.. 1jz swap sc300

so when i hit the gas with the car cold it runs fine for a mile or so...
after it warms up, it "stutters" bad and won't get up and go.....
i took the charge pipe off and ran it like an n/a car and it accelerates smoothly up to redline...no jumping at all!!!!
i tested my vacuum pressure and it says i'm a bit low so i checked all my hoses and looked for collapses and leaks, but none found!
changed out my plugs and no difference...
my tech at my motorsports shop is even stumped...Anybody ever had this problem??
i'm running evrything stock on the engine from a soarer clip swap except for a blitz upgrade to the stock ecu...

Any ideas??? pleeeeeezzzeee?

it's not the plugs, coilpacks, fuel pump or filter.....ecu is the only logical answer because i can't test my map sensor or tps ....no one in my area knows how!!

Last edited by ttsleeper; Apr 6, 2007 at 05:27 PM. Reason: update
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Old Apr 5, 2007 | 12:32 PM
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it could be the ecu , coilpacks, spark plugs fuel pump /filter
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Old Apr 5, 2007 | 12:35 PM
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seems like everything then huh? i've checked the igniters and ohm tested them...they all checked out....
fuel / filter couldn't be the problem because it runs fine without the charge pipes on....
how do you reset the ecu?

Last edited by ttsleeper; Apr 5, 2007 at 12:40 PM.
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Old Apr 5, 2007 | 12:50 PM
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We have an engine forum, please use it.

Moved.
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Old Apr 5, 2007 | 01:00 PM
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.............

Last edited by ttsleeper; Apr 5, 2007 at 01:16 PM.
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Old Apr 5, 2007 | 02:13 PM
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Default latest on this problem

found this on another forum....great info...
i haven't fixed my problem yet, but it's the closest diagnosis i've gotten yet...
Any body got a stand alone ecm i can buy?
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Old Apr 5, 2007 | 02:15 PM
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here's the link

http://supraforums.com/forum/showthread.php?t=399069
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Old Apr 5, 2007 | 06:58 PM
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perhaps your spark plugs are not gapped correctly? Boost could be blowing out spark?
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Old Apr 6, 2007 | 05:25 PM
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bought brand new ngk plugs and checked the proper gap...already ruled that out...
thinking the ecu is bad....checked with a few of the soarer central forum guys and they say the ecu's have an internal flaw.... the drivers for the actuators go and either stick the actuators shut or closed....gives the car a "stuttery" feel under boost, but not at idle or without boost...it's almost like fuel cutoff, is what they said....
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Old Apr 6, 2007 | 06:17 PM
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overboost? i dont think it would stutters under overboosting. just go faster but itll be bad for the motor.

you dont have a boost gauge to see whats going on. hook up a wideband.

oh and running the car with the charge pipe off is bad... youll overspool the turbo and blow it.
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Old Apr 7, 2007 | 08:37 PM
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check your TPS sensor.
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Old Apr 11, 2007 | 10:48 AM
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so i opted to change out my ecu...all the boards were saying there is an ecu fault with the 1jz-engine where the banks that control the "batch-fire" portion that control the actuators for the fuel..
..seems they go out and cause a misfire.... i just put in a greddy e-manage ultimate to be a replacement and to diagnose in case something else is also the problem....tps sensor, etc...
will keep everyone posted as to the outcome....

Also, if anyone needs it, here are the jumper settings for the inside of the e-manage ultimate for a stock 1jz-gte application....

got greddy on the line.....for all of you who get the wiring done on your greddy e-manage ultimate, but wonder about the jumper settings for a 1jz-gte stock application .....I REPEAT.... stock application and setup for trim and add fuel...not just add!!

jumper settings...

J1 - OPEN
J2 - OPEN
J3 - OPEN
J4 - OPEN
J5 - OPEN
J6 - OPEN
J7 - 1-2
J8 - 2-3
J9 - OPEN
J10- 1-2
J11- OPEN
J12- OPEN
J13- OPEN
J14- 1-2
J15- 1-2
J16- OPEN
J17- 1-2
J18- OPEN
J19- 1-2
J20- 1-2
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Old Apr 11, 2007 | 10:56 PM
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so the e-manage ultimate let me read all my data.... everything was in stock parameters..all sensors including map and tps were normal....the e-manage ultimate read normal across the board.....EXCEPT it shows 100% fuel !!!!
Something is telling the ecu to do this....Any ideas what it could be??

i changed out my fuel filter to make sure it wasn't getting clogged, but no help there....
The o2 sensor is not wideband so i can't tell the measurments to see if it's bad....
the fuel pressure is gonna be checked tomorrow, but it's still only having the problem under boost!!!! Not sure if that'll even help!!

got a suggestion now?.............thanks
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