EJ20T running half boost

brute · Post by **brute** » Sat Sep 05, 2009 10:13 am

Hey Guys,

EJ20T in Brumby now with recently replaced plugs and timing belt has recently started running / being limited to half boost, (5-6 PSI) unsure if the check engine light should come on if theres a fault or if I need to check fault codes to determine?. Engine is Jap import, standard ECu, etc running premium fuels with octane booster.

Any ideas appreciated.

gx_rex · Post by **gx_rex** » Sat Sep 05, 2009 6:59 pm

First question for you, have you replaced any of the vacuum hoses?
If so, does it still have the boost olive in it?

brute · Post by **brute** » Sun Sep 06, 2009 10:43 am

Vacumm hoses appear all original and just checked the boost olive which is in place. ECU reset brings up Accelerator pedal switch fault code? and know that i left the switch out when the conversion was done - any relation?

brute · Post by **brute** » Tue Sep 08, 2009 11:09 am

Took the car for a longer drive out to some open road to open her up, seems to be that 3rd gear allows boost to standard levels (11/12 PSI) and 1st and 2nd gear is reducing..? Any ideas?

Outback bloke · Post by **Outback bloke** » Tue Sep 08, 2009 11:23 am

Check to see how much pressure is on your waste gate actuator. When they get old they become soft and the waste gate can flutter or even blow open before the correct boost level.

brute · Post by **brute** » Wed Sep 09, 2009 8:25 am

Not an expert on waste gate testing procedure but rigged up a bike pump with boost guage and the waste gate aremateur is moving at just above 10 PSI and appears fully open near 15PSI. So assume all OK?

Outback bloke · Post by **Outback bloke** » Wed Sep 09, 2009 12:20 pm

That sounds like it should be fine. Next test is to trace the line that runs from the compressor housing to the boost controller. I think it is the one that comes in near the bottom of the controller at right angles to it.

Now this sounds a bit dodgy but it does work. Drill a small hole around 3-4mm in diametre in the rubber hose just before the controller. Make sure it is not on the pipe from the controller. What you are trying to do is bleed off a little air pressure before the boost control system.

Take it for a drive. If you have the correct line you should see an increase in boost. If you do get an increase and it is running how it should then your boost controller (bleed valve) is malfunctioning.

Second, if you have drilled the hole close to the controller you can now trim off the end and slide the hose on so the hole is gone.

If when you are driving it the car takes off like a rocket and then jolts it will be an over boost protection that is built in to the ecu. This will only happen if the hole you drill is too big.

Also, is your check engine light working/connected? If it is and you aren't getting any codes then it does sound like a faulty bleed valve or waste gate.

If it isn't connected it could be a number of things and you need to get it working.

steptoe · Post by **steptoe** » Wed Sep 09, 2009 1:31 pm

someone may have an answer to stop the acc pedal code coming up, like shoving a resistor on the ecu terminal to something else or simply earthing it. Find someone who knows, I don't know so don't follow my example

PeeJay · Post by **PeeJay** » Fri Sep 11, 2009 11:28 am

I've got the same boost problem with my car. I pulled all the solenoids/sensors off last weekend and checked them, all ok, put them back in and it was working. Now it's not. None of the vacuum hoses seem loose but I might try replacing them.

brute · Post by **brute** » Mon Sep 14, 2009 10:31 am

Havent had time to check mine further due to work. Not sure if it may be temperature related as we have been having considerable hotter days here in SE QLD and the factory Top Mount INtercooler needs proper scoop and better flow... Might need to take it out early morning / evening to see how she runs.

brute · Post by **brute** » Fri Oct 09, 2009 1:57 am

Still have the same issues, car running around 7psi and if I do ecu reset I get 12psi for a short time which brings a smile that disapears as soon as the boost goes... ECU reset brings up fault code accelerator pedal switch which i know is missing... any ideas on where to start?

brute · Post by **brute** » Tue Oct 13, 2009 6:29 pm

How likely would it be for the timing belt to have jumped a tooth since recent replacement? Car seems to drive fine but limited to 7/8 PSI which is damm frustrating. Noted that car also seems to have a very very minor shake to it when idling, dont really want to take the radiator out if not likely to the belt??

Any thoughts...

Outback bloke · Post by **Outback bloke** » Tue Oct 13, 2009 7:34 pm

It is a quite common problem. A lot of people put the belt on and then release the tensioner with out putting any load on the belt. Makes it very easy for it to jump initially.

Gannon · Post by **Gannon** » Tue Oct 13, 2009 8:39 pm

The fact that an ECU reset temporarily resumes the standard boost level for a short while suggests its entering 'limp mode'

Are you using 98 RON fuel?
Have you checked for codes?

It might be worth your while checking out Ozliberty.com
There are quite a few members there with turbo subes

Outback bloke · Post by **Outback bloke** » Wed Oct 14, 2009 5:14 am

Is it a twin turbo? I thought it was single.

Gannon · Post by **Gannon** » Wed Oct 14, 2009 5:17 am

Yeah sorry, my mistake

brute · Post by **brute** » Wed Oct 14, 2009 7:50 am

Single turbo. The only fault code that appears is accelerator pedal switch.
98 octane fuel.

Gannon · Post by **Gannon** » Wed Oct 14, 2009 5:28 pm

That could be you probelm

The ECU could be confused because the TPS is telling it full throttle, but it isnt getting its signal from the accelerator switch.

Find the 'accelerator switch wire, and tie it somewhere near the accelerator pedal so that when you give it full pedal, it should emulate an accelerator switch

If you want a propper switch, the kickdown switch from 3speed auto MY's will fit your brumby

brute · Post by **brute** » Mon Nov 02, 2009 12:46 pm

Hooked up the original Throttle Position Switch that i had in my shed which cleared the fault code but car still has the same problem. Installed a manual boost controller and running at 12 PSI which happy with for time being.

81GGR · Post by **81GGR** » Mon Nov 02, 2009 12:55 pm

i would try:

1. connect a hose directly from the turbo output to the wastegate. this will give you wastegate boost only. see how it goes and if it is any different to the problems you are experiencing - if it is no different - there is something wrong with the boost control solenoid/vacum lines/wiring etc.

2. if you have a manual boost tee install that (make sure you install it in the correct direction for the airflow from high pressure side of turbo to wastegate) and screw it all the way down (ie: lowest boost) go for a run and see how the boost goes - then undo it 1/2 a turn and go for a run - you should see higher boost - do this a few times until you get to target boost (say, 3rd gear) and then see how it is running in 1st/2nd. if it is all ok - same prob as above - solenoid, wiring or plumbing.

to turn off the code in your ecu, if you have an obd-II port download a program like ecu-explorer, copy the ecu rom and locate the sensor code in the rom - you can select an option to turn that code off and reflash the ecu (i think you need ecu edit or similar program for this) and then you will never see the trouble code again. i doubt it is related to your boost problem. check out some of the open source tuning forums for the exact names of the software etc but you need 2 programs to do the reflash. i did it on my forester when i kept burning the egt sensor in my up-pipe - just turned off the trouble code and everything is good now.