meciora said:

The biss screw is bottomed out and there is minimal difference when I mess with it

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This. I think you have already answered your own question.

If there is no change or you can't lower the idle speed by bottoming out the BISS, that indicates you have vacuum leak (somewhere between the throttle body and the cylinder head inlet ports including throttle body's internal seals/gaskets), or/and the throttle plate is open more than it should be by the fixed SAS or the throttle cable is adjusted improperly. You should start from checking for those first.

By minimal difference i mean 700rpm Throttle position is fully closed and the throttle cable is not connected.
About fiav, can I use some gasket maker rtv to successfully close tb and try other possibilities? Or maybe I should buy bypass plate and a gasket?

meciora said:

By minimal difference i mean 700rpm Throttle position is fully closed and the throttle cable is not connected.

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This means you probably have vacuum leak as I mentioned, or/and throttle plate is open more than it should be by improperly adjusted fixed SAS..
Throttle position fully closed doesn't guarantee the throttle plate is fully closed. It's actually slightly open by the fixed SAS, 1g's is the one with the IPS. You have to adjust it properly according to the FSM.

meciora said:

can I use some gasket maker rtv

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It depends, if it works it works but I recommend to replace it with a new if possible. I have used RTV on the FIAV gasket, just it was not pretty though.

meciora said:

to successfully close tb and try other possibilities?

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Check and fix all vacuum leaks. Recommend to rebuild the throttle body by replacing all seals if it's already disassembled, the FIAV gasket is not the only one you should replace in throttle body. You may also want to replace the shaft seals and BISS o-ring. And then adjust the throttle body (fixed SAS, TPS, BISS and throttle cable). You should start from there.

For now I’ve bought the oring, bypass plate and gaskets + shafts from stm tuned, we will see if that helps, when parts arrive. Will update when done. thank you

If youre resorting to a bypass plate to fix idle its a bandaid. You haven't found the root cause. As pointed out its probably leaks. You mentioned idle goes to 3000. That is not possible with a properly functioning idle position switch or on a 2g properly adjusted TPS. Find the root cause. If this happened out of the blue a vacuum leak is highly probable.

Oring gasket inside the fiav is pretty much flat and crushed on the side of coolant passage so I need to address that and I believe it could be an issue, not bandaid

pauleyman said:

If youre resorting to a bypass plate to fix idle its a bandaid. You haven't found the root cause. As pointed out its probably leaks. You mentioned idle goes to 3000. That is not possible with a properly functioning idle position switch or on a 2g properly adjusted TPS. Find the root cause. If this happened out of the blue a vacuum leak is highly probable.

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Have you verified the ISC is operational?

I know you are NT, but you should still be able to rig up some sort of Boost Leak Test.
Take off an intake pipe as close or before the MAF as you can.
Take it to Home Depot/Hardware store.

For my 3" turbo intake I found a black ABS cap that fit the coupler snug. I also bought an air hose chuck and some 2 part JB WELD epoxy. Drilled a hole and screwed the compressor chuck in with the epoxy. Let cure 30 minutes. Boom you've got a new tool.

I set the regulator on my air compressor to 20 psi, and then hook up the hose.

I was able to find out my TB shaft seals were leaking this way, and my BISS, I also had a bad Injector seal.
After fixing that my car started and idled and I was able to run through all the procedures.

Warm it up, set timing with a light, adjust the BISS for a near 750 idle and 30 position.

You always want to fix what is known to be wrong and move forward. Start with the basics and go from there 1 step at a time.

Definetely fix that gasket, then check for air leaks!
Once everything is fixed, it will work!

dwb said:

Have you verified the ISC is operational?

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Yes it’s 38ohm across the board, it’s new smp from rockauto.

93xsg said:

I know you are NT, but you should still be able to rig up some sort of Boost Leak Test.
Take off an intake pipe as close or before the MAF as you can.
Take it to Home Depot/Hardware store.

For my 3" turbo intake I found a black ABS cap that fit the coupler snug. I also bought an air hose chuck and some 2 part JB WELD epoxy. Drilled a hole and screwed the compressor chuck in with the epoxy. Let cure 30 minutes. Boom you've got a new tool.

I set the regulator on my air compressor to 20 psi, and then hook up the hose.

I was able to find out my TB shaft seals were leaking this way, and my BISS, I also had a bad Injector seal.
After fixing that my car started and idled and I was able to run through all the procedures.

Warm it up, set timing with a light, adjust the BISS for a near 750 idle and 30 position.

You always want to fix what is known to be wrong and move forward. Start with the basics and go from there 1 step at a time.

Definetely fix that gasket, then check for air leaks!
Once everything is fixed, it will work!

Click to expand...

Thank you, yes after I put throttle body together I will make some boost leak test mashine from compressor some hose and clamp btw great idea. Thank you. Parts will be shipped in next week so I will update.

meciora said:

Yes it’s 38ohm across the board, it’s new smp from rockauto.

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Not just a bench test, but if you remove it from the TB and keep the harness connected, does the pintle move in/out when the key is on?

What I'm getting at, is verifying the wiring and more commonly, ECU circuit traces, are not broken. You did mention ECU caps, but were they leaking causing corrosion on the board?

Will test that too. Thanks
This photo is before caps change. Steve give me step by step advice in ecu condition, what to check and repair, but it really wasn’t bad, only some traces from early corrosion just cleaned it with ipa, reflow put back together.

Here's my attemped repair. Might give you some ideas if the pintle doesn't move.

I think I found the problem
Dead.

What's dead?

steve said:

What's dead?

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I know you’re a guru in ecu, but is it still repairable? How? Haven’t seen that chip anywhere.

@steve I see the chip bubbling. Maybe it's only superficial?

I see the conformal coating bubbled but the eyes aren't what they used to be.
I don't see signs of heating or cracks in the package that come with letting the magic smoke out.

What I do still see is corrosion over by C19 which is the ADC reference voltage filter for the MPU.

I'd suggest trying out that new windows logger software, getting Tunerpro, of a copy of the old TMO datalogger (or even a Palm Pilot and MMCd) to see and make sure the IPS is working like it should and that the ECU is reporting sensible values.

Have you checked your O2 sensor is not dead also! It relies on that.

the FIAV can get stuck so could create issues. Bypassing the FIAV is normal for alot of people because of this.

On the TB you will want to remove the IPS till the plate is closed internally. Then with a multimeter screw it in till it grounds out. This then sets the IPS to just a touch open on the throttle plate. Then you need to reset the ecu and ISC to relearn the factory settings and idle for 5 mins.

Very well worth now to replace the TB to intake gasket as it is likely old and leaking.

After this you then need to confirm the maf, and the rest of the lines towards the intake creating the fluctuation.

steve said:

I see the conformal coating bubbled but the eyes aren't what they used to be.
I don't see signs of heating or cracks in the package that come with letting the magic smoke out.

What I do still see is corrosion over by C19 which is the ADC reference voltage filter for the MPU.

I'd suggest trying out that new windows logger software, getting Tunerpro, of a copy of the old TMO datalogger (or even a Palm Pilot and MMCd) to see and make sure the IPS is working like it should and that the ECU is reporting sensible values.

Click to expand...

Yep, I will try to make an usb to ttl cable to this system and try to run this software somehow.

FIBA M - EC17PSE said:

Have you checked your O2 sensor is not dead also! It relies on that.

the FIAV can get stuck so could create issues. Bypassing the FIAV is normal for alot of people because of this.

On the TB you will want to remove the IPS till the plate is closed internally. Then with a multimeter screw it in till it grounds out. This then sets the IPS to just a touch open on the throttle plate. Then you need to reset the ecu and ISC to relearn the factory settings and idle for 5 mins.

Very well worth now to replace the TB to intake gasket as it is likely old and leaking.

After this you then need to confirm the maf, and the rest of the lines towards the intake creating the fluctuation.

Click to expand...

Yes, the o2 sensor was shorted on the heater line and somehow burned the white wire which is for data, (maybe that’s why there is a hole in MCU) got that covered, bought a Denso o2, done new wires and plug.

meciora said:

Yes, the o2 sensor was shorted on the heater line and somehow burned the white wire which is for data, (maybe that’s why there is a hole in MCU) got that covered, bought a Denso o2, done new wires and plug.

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That can often burn up the sensor ground traces on the ECU. On a 1G those circuit traces are more difficult to see than on a 2G ECU. Often they burn up on the bottom side of the ECU.

Will update in next weekend, put back everything together with new seals and i will try to connect somehow to ecu, but i believe ecu is not even trying to boot into diagnostic ( 2 weeks ago to adjust biss i shorted pin 10 to 12 , and the plug in engine bay to ground and still no difference, still isc worked) and that hole is telling me: im tired boss meanwile im searching for spare ecu, because i think honesly its done.

Will that fit into my dsm? It has the same part number but it’s entirely different.. Is it a turbo version? @steve
Or maybe previous owner swap the internals but left the cover?

EPROM version of the same ECU. The cover doesn't match because it's the one for the non-EPROM version like you have. That's a great find.

I still don't see whatever the hole is your mentioning.