EJ206 VDC Automatic idle very low and stalls

[vanislebh5]

Hi mates ,

So the car has new coils, new MAF , new tps sensor , runs very well , full 14psi boost ,

Just changed the alternator, car has good idle when cold, when warmed up idle very low , stalling the odd times ,

not sure where the issue could be , do not think it is the TPs since it is ok when cold

I wonder if I have a clogged catylitic ,

any ideas would be appreciated

[Reuben]

Alternator new, or a used unit?

If used, try running with the AC belt off to see if the idle clears up, was a common issue for old alternators to spit out tonnes of EMF which got picked up on the trigger wiring, and caused a poor idle.

TPS normally doesn't affect idle, more how the idle settles, if it lets the revs drop too far or not far enough. But doesn't affect steady state idle (unless its set so poorly that it's not regestering as "idle")(Also affects auto shift points if automatic). Do note, TPS needs to be set by multimeter, it's not something you can eyeball, there is a very specific preload that you set as a voltage, so requires multi meter while dailing it it.

[vanislebh5]

Thanks @Reuben

I did see some info on some subaru tps settings , not how to set the ej206 , do you need to unplug the ECU to do so , is it 0.45 volt ? I did not set it that way , it was eye balled

I did change the idle control valve , car runs very smooth , but did not fixe the issue , but it is not as bad

also I wonder if the catalytic converter are clogged , is there a cat after each turbo and one after the Y ?

Thanks again !

[vanislebh5]

Alternator new, or a used unit?

If used, try running with the AC belt off to see if the idle clears up, was a common issue for old alternators to spit out tonnes of EMF which got picked up on the trigger wiring, and caused a poor idle.

TPS normally doesn't affect idle, more how the idle settles, if it lets the revs drop too far or not far enough. But doesn't affect steady state idle (unless its set so poorly that it's not regestering as "idle")(Also affects auto shift points if automatic). Do note, TPS needs to be set by multimeter, it's not something you can eyeball, there is a very specific preload that you set as a voltage, so requires multi meter while dailing it it.

I just installed a new alternator , (ac delco)

[Reuben]

Setting the TPS can’t be eyeballed, cause there is a certain level or preload on the sensor, that is, it’s rotated past the point the two blades make contact.

It must be done with the ECU connected, and powered up, as the 5v sensor feed for the TPS comes from the ECU.

You need to probe the sense wire that returns to the ECU, or if OBD-II, you can just look up the live data with a tool. But in either case, you set the position based on the voltage at the sense wire (at closed throttle).

The voltage changes between generations, the voltage must be set to the generation of ECU you are using (not the generation of the sensor)(i mention this cause I run a BG sensor on my first gen, had to reverse polarity, and change the position of the sensor, but once that was done the first gen ECU was happy (had to also sort out the idle switch a different way)). The service manual also specifies the voltage value you need at wide open, so you can verify the sensor has the correct range.

In the diagnostics section of the subaru service manual (diag is in the engine section, not wiring section), you will find the specific voltage it needs to be set to at closed, and what voltage it needs to be at open.

[vanislebh5]

@Reuben

Thanks , adjusted the TPS trying to get 0.45 closed and 0.55 fully open ,

I can get the fully open at 0.55 , but closed position does not allow me to get 0.45 for some reason , at the moment it is at 0.1 closed , I wonder if the throttle cable needs to be loosen ,

I let the car idle for 10 min or so , it was already warm ,seems better , will use the car today and see

for the Catylitc converters is there one after each turbo ?

thanks again

[Reuben]

Does the service manual really say 0.55v open? This feels wrong, the volt range is normally closer to 4-5volt on older models.

You adjust by the closed voltage too, not open. The open volt is specified to verify the sensor range is good.

There is a cat in the primary downpie, amd one after the y join.

[Reuben]

Just looked up the BE/BH pre facelift TPS data.

Set volt to 0.5v closed.
Voltage should be 4.3v open

[vanislebh5]

Just looked up the BE/BH pre facelift TPS data.

Set volt to 0.5v closed.
Voltage should be 4.3v open

Mine is a 1998 facelift , I found 0.45 closed 0.55, was running good today until I gave it some stress, now it’s idleling at 1300rpm, check engine says short circuit on ISC and TPS , code 31 and 24

[vanislebh5]

sorry had that wrong , closed is 0.45 to 0.55

[vanislebh5]

sorry had that wrong , closed is 0.45 to 0.55

This doesn’t look like the proper schematic for the ej206

[Reuben]

Brother, are you looking at the USDM 98 manual for BD/BK, for a 98 JDM BE/BH? I probably should have checked, but i figured with EJ206, we are indeed talking 3rd gen.

If you want to look up data for JDM 3rd gen, a lot of US 3rd gen mamual stuff will work, but be aware of the year differences, so ya wanna be looking at MY00 USDM manuals, when you cant find JDM manuals.

Those figures I got were from the JDM BE/BH TT pinout. For Rev A-C (98-01, which is prefacelift)(Rev-D 01-03 is facelift, and uses GD style wiring).

Yeah the years are a minefield if you aren’t used to dealing with JDM, JDM is usually a year or two ahead of USDM/World markets, but with emissions specs a decade behind US/World.

[vanislebh5]

Brother, are you looking at the USDM 98 manual for BD/BK, for a 98 JDM BE/BH? I probably should have checked, but i figured with EJ206, we are indeed talking 3rd gen.

If you want to look up data for JDM 3rd gen, a lot of US 3rd gen mamual stuff will work, but be aware of the year differences, so ya wanna be looking at MY00 USDM manuals, when you cant find JDM manuals.

Those figures I got were from the JDM BE/BH TT pinout. For Rev A-C (98-01, which is prefacelift)(Rev-D 01-03 is facelift, and uses GD style wiring).

Yeah the years are a minefield if you aren’t used to dealing with JDM, JDM is usually a year or two ahead of USDM/World markets, but with emissions specs a decade behind US/World.

Thanks Mate ,

yeah it is a JDM EJ206 (98-01) I though the facelift was the headlights change from 2nd Gen , so then I can use your rating and it should work , I have a JDM app on an Android radio with a KKK cable and when the car is running i can see the voltage (it was 0.38) Ill try to get the app running with the key on and see if I can use it to set the tps ,

It is always fun to try to find all the proper service manual , parts and everything with a JDM when you are in North America

so far I have used JP-Car Parts , Yen is at par with CAD , and shipping to Brittish Columbia from Japan is cheap ,

[vanislebh5]

Thanks Mate ,

yeah it is a JDM EJ206 (98-01) I though the facelift was the headlights change from 2nd Gen , so then I can use your rating and it should work , I have a JDM app on an Android radio with a KKK cable and when the car is running i can see the voltage (it was 0.38) Ill try to get the app running with the key on and see if I can use it to set the tps ,

It is always fun to try to find all the proper service manual , parts and everything with a JDM when you are in North America

so far I have used JP-Car Parts , Yen is at par with CAD , and shipping to Brittish Columbia from Japan is cheap ,

adjusted the TPS to the specs (you have the right specs !) while playing with all of this I installed a new idle control valve , the engine died . I took the ICV out , and the spring is complete;y released . I pushed the thing back in and installed it , start the car and it did the same thing again .

I installed the old ICV and the care runs well at all throttle range , but still idles low sometimes , and will die sometimes . Not sure if the new ICV is not reusable ?

[Reuben]

Very odd. I do not know how to set phase-2 idle. Setting phase-1 is easy, you basically set it by the “fall point” for lack of a better word (im sure theres some official term). But those early phase-1 controllers, you rev the car, and if the idle falls too low, before getting brought up, you adjust up. If the idle falls too low a point too high, then you adjust it down. Basically you are trying to set the position to be as close to what the ECU is commanding.

But i dont even think phase-2 has adjustment?

Anyway. Have you replaced the o2 senor? If yes, did you use genuine? You must use genuine with BH’s.

And have you replaced the MAF sensor?

[vanislebh5]

Hey Mate,

thanks for your reply !

Setting phase-1 is easy, you basically set it by the “fall point” how do you do that ?

But i dont even think phase-2 has adjustment? same here not sure where that adjustment is ?

I was thinking on checking the cat , the 2nds one , punching out the stuff

as far as the O2 sensor , it is still the 1997 oem one , very expensive to get a new one to only find out it is not the source , but maybe I should commit to it

Thanks again !

[Reuben]

You don’t have phase-1, so little point in me explaining it for you as it will only confuse the matter. But for the sake of others with phase-1 that might need this, its pretty straightforward.

Once engine is warm, crack the two adjustment screws loose.
Manually blip the throttle by pusing on the mechanism, and listen for what the idle does as it falls back to idle from the blip.
If the RPM’s dip low, and then springs back up, it’s adjusted too low, you need to adjust the IACV cap so that it doesnt dip as low.
If the RPM’s stop and hold too high, then slowly come down to stable idle, its adjusted too high, and you need to lower it down.
Ideal is, as the RPM’s fall, they just immediately settle to the RPM the ecu is commanding, no dips and bounce back, no pausing then lowering.
When you got it to where you blip, and the revs drop straight to the idle point, you’re done, lock it off in that position. If you find that position is greatly different to the witness marks from the old position, this can indicate you have other issues.

What you are setting is the 0 point of the idle controller, the point at which the ECU starts its IACV control at. You are not setting the idle speed itself, only the ECU has control of that.


Back to your car. Yeah maybe inspect the cat. Pain in the arse, but dont forget to look at both the front side and back side.

And yeah, for 02, i can only recommend just diving in and buying new OE. The factory ones are positively ancient at this point, nearing on 30 years of service. Thats a pretty good innings by anyones standards for an o2

[vanislebh5]

You don’t have phase-1, so little point in me explaining it for you as it will only confuse the matter. But for the sake of others with phase-1 that might need this, its pretty straightforward.

Once engine is warm, crack the two adjustment screws loose.
Manually blip the throttle by pusing on the mechanism, and listen for what the idle does as it falls back to idle from the blip.
If the RPM’s dip low, and then springs back up, it’s adjusted too low, you need to adjust the IACV cap so that it doesnt dip as low.
If the RPM’s stop and hold too high, then slowly come down to stable idle, its adjusted too high, and you need to lower it down.
Ideal is, as the RPM’s fall, they just immediately settle to the RPM the ecu is commanding, no dips and bounce back, no pausing then lowering.
When you got it to where you blip, and the revs drop straight to the idle point, you’re done, lock it off in that position. If you find that position is greatly different to the witness marks from the old position, this can indicate you have other issues.

What you are setting is the 0 point of the idle controller, the point at which the ECU starts its IACV control at. You are not setting the idle speed itself, only the ECU has control of that.


Back to your car. Yeah maybe inspect the cat. Pain in the arse, but dont forget to look at both the front side and back side.

And yeah, for 02, i can only recommend just diving in and buying new OE. The factory ones are positively ancient at this point, nearing on 30 years of service. Thats a pretty good innings by anyones standards for an o2

Spent the cash on oem O2 ouch! car runs better, almost perfect,

[vanislebh5]

[QUOTE=vanislebh5;289922]Spent the cash on oem O2 ouch! car runs better, almost perfect,[/Did not go down to the top cat, like you said pain in the butt, the one thing I wondered until last weekend , was the PCV system, the plug out of the pcv has 2 ports, one goes to the pcv valve the other to the intake pipe , the nipple of the intake pipe broke , so I plugged it , that damn pipe is as you know is discontinued. So I had only the one pipe going to the pcv valve , I wonder if that added to much blow by

So this weekend . I installed out of the single pipe a tube to a catch can , then back to the pcv valve , so far seems to work.

Opinions?


Thanks