1jz in MA61 making boost problem

[rxfc3s]

hi mate,
possibly map sensor issue if its not making boost properly?
I've got a spare one here for a jzz30. i know theyre not interchangeable with jza70 etc coz i tried.
Also if you wanna check for boost leaks, you need to block your airfilter (i usually just remove the pipe and slap a doubled up plastic bag over it, then fit a hose clamp around the end so it cant leak) then find a vac point on the manifold and put some compressed air in with an air blower (obviously dont go over 10psi!) Just enough so you can hear it leaking without starting the car

Andrew

[50RTD]

Regurgitated from another thread....

....but one thing i have done on every car ive ever had anything to do with, is to pressurise the entire intake system with an air compressor (need to rig up a sealed cover plate for the inlet of the turbo to allow for pressurisation) and listen for leaks/spray soapy water on hose unions, blow off valve, intake bungs/hoses etc etc.

I learnt this on one of my cars on the dyno, it wasnt quite making the sort of curry that it should. Did this, and found a bunch of small leaks around hose clamps and the bov and a few others. Gave everything a quick once over, picked up 70hp @ wheels there and then, around a 25% gain.

Since then ive seen this often overlooked check technique solve all sorts of problems, especially with airflow metered vehicles, where a leak in the intake system causes the computer to read incorrectly, run rich and generally shithouse.


-Dan

[Sideways Supraboy]

Thanks for the help guys. I put the air into it and found two vacuum lines were not connected at all. I then reconnected them and found another leak on the intake side just before the pressurized air enters the plennum. I've hopefully fixed that on too.
But yet to know because I haven't been able to give the car a quick drive to check for boost.
Hopefully can soon
Thanks for the help so far
Steve

[Sideways Supraboy]

Need help again guys.
So the running problem is fixed it runs and idles fine now.
But it still makes no boost.
It will rev up from vacuum to 0 on the boost gauge then just
Stays there. Dosent run bad or anything just runs like a non turbo car.
What else could it be?
Also what's the plug for that comes off the 1jz loom straight
After it comes out of the firewall?
It's just a small 2 pin plug with yellow and black with yellow wires?
Drift practise this Saturday night I'm praying to be out in thus rig.
Thanks
Steve

[thechuckster]

exhaust turbine(s) still attached? Wilbo had one turbo fail soon after putting the 1JZ into his MA61.

[Sideways Supraboy]

Wouldnt it be running like crap then??
Cheers
Steve

[thechuckster]

just wouldn't boost

[rxfc3s]

does the car smoke at all? Any strange noises from the turbo's?
I'd be inclined to say that maybe one of your intercooler pipes has come off or you have a split in one of your intercooler pipe joiners if it just sits at 0 under load.

Andrew

[Sideways Supraboy]

Yea that's what I though. So to test it I taped up each end of the piping and pumped some compressed air and it just blew out the tape and I couldn't hear it leaking from anywhere else.
No the car runs good and dosent smoke so thats why I thought turbos were good.
Do you think it's worth taking turbos off for inspecting?
Thanks guys
Steve

[rxfc3s]

map sensor fault?

Andrew

[CrUZida]

Map sensor fault will still boost, it will just run like shit.
The yellow and black wires on the 2 pin plug are for the JZA70's heater tap.

Pull the turbo's off and make sure all the wheels are in good condition.
It may take half a day, but it will put the mind at ease.

[Sideways Supraboy]

Thanks. The turbos will be coming off then. Yay

[thechuckster]

if you've had a CAT in there all along, have a look at the inlet side for bits of turbine wheel?

[Sideways Supraboy]

Nah no CAT. I got the turbos off.
They seem alright.
Wheels are fine and spin freely. The rear just has a bit of oil around the front wheel.
Might take them to a turbo shop tomorrow for a quick look and feel
Just incase.
Thanks

[CELICASUPRA7M]

Maybe get under the car and give the exhaust a tap with a rubber mallet, see if you hear bits of turbine wheel bouncing around