Boost issue

Hi everybody, hoping for some more help from the members on ere relating to my 04 R.

I have a boost issue. The turbo randomly a couple of weeks ago began only making wastegate pressure? When I disconnect the wastegate line from the TCV I get massive boost so turbo fine, re-connect it, just wastegate pressure again. Checked the flapper on the turbo moves freely and the wastegate is set correctly according to Mityvac? I have stripped out everything and very carefully checked all the vac lines and intercooler pipework, no leaks found after testing. Changed the TCV and BPS (MAF is only month old) and changed both one way check valves. Car is mapped with a Hilton stage 3 and wastegate base setting is 7psi. No EML or codes on Vida?

Anybody know the correct differential voltage between the two pins on the TCV connector plug? I have 14v and 0v at idle? Is this right? I have no idea where else to look?

Cheers

Quote:

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Originally Posted by bambamboom

Hi everybody, hoping for some more help from the members on ere relating to my 04 R.

I have a boost issue. The turbo randomly a couple of weeks ago began only making wastegate pressure? When I disconnect the wastegate line from the TCV I get massive boost so turbo fine, re-connect it, just wastegate pressure again. Checked the flapper on the turbo moves freely and the wastegate is set correctly according to Mityvac? I have stripped out everything and very carefully checked all the vac lines and intercooler pipework, no leaks found after testing. Changed the TCV and BPS (MAF is only month old) and changed both one way check valves. Car is mapped with a Hilton stage 3 and wastegate base setting is 7psi. No EML or codes on Vida?

Anybody know the correct differential voltage between the two pins on the TCV connector plug? I have 14v and 0v at idle? Is this right? I have no idea where else to look?

Cheers

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Hi matey, I tried helping you on T5D5 as I have experienced your symptoms.

By asking someone to disconnect their TCV and check voltages will obviously mean the ignition must be on. This will also mean, by disconnecting the TCV to check voltages with the ignition 'on', this will induce a fault to be stored in the ECM.
Some people won't have the diagnostics to clear the fault codes, so I urge anyone reading this to consider this before they do it!

I can check for you but you'll need to give me a day or two.

14v will be correct and I'm guessing you'll only know if 0v increases whilst performing a duty cycle on live data? Meaning, you'd need to drive the car.

Have you checked your IC isn't cracked?
They crack below the outlet side below the BPS. Evidence is usually an oily residue on the plastic. The crack, if present, will be virtually impossible to see just by looking.

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Originally Posted by LeeT5

Hi matey, I tried helping you on T5D5 as I have experienced your symptoms.

By asking someone to disconnect their TCV and check voltages will obviously mean the ignition must be on. This will also mean, by disconnecting the TCV to check voltages with the ignition 'on', this will induce a fault to be stored in the ECM.
Some people won't have the diagnostics to clear the fault codes, so I urge anyone reading this to consider this before they do it!

I can check for you but you'll need to give me a day or two.

14v will be correct and I'm guessing you'll only know if 0v increases whilst performing a duty cycle on live data? Meaning, you'd need to drive the car.

Have you checked your IC isn't cracked?
They crack below the outlet side below the BPS. Evidence is usually an oily residue on the plastic. The crack, if present, will be virtually impossible to see just by looking.

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Hi Lee, sorry I wasn't asking anybody to disconnect their TCV? I just asked if anybody knew if the voltages were correct? It hasn't created any codes when I performed the check with the engine running as I hooked Vida up afterwards and their were no codes live or stored.
I am really very grateful for your help, but it seems T5D5 isn't frequented very often by anybody these days so I posted here as it's clearly a very active and informative forum. No offence was intended I really just want to find a solution for my R.

I have thoroughly checked the intercooler, it is all good sadly so another dead end! So frustrating!

Quote:

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Originally Posted by bambamboom

Hi Lee, sorry I wasn't asking anybody to disconnect their TCV? I just asked if anybody knew if the voltages were correct? It hasn't created any codes when I performed the check with the engine running as I hooked Vida up afterwards and their were no codes live or stored.
I am really very grateful for your help, but it seems T5D5 isn't frequented very often by anybody these days so I posted here as it's clearly a very active and informative forum. No offence was intended I really just want to find a solution for my R.

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No offence taken :wink:

Hi Lee, I found a post on an American forum saying the voltage should be 14.4 and 3.5 between the pins at idle? As mine is 14 and 0, is this possibly why I am only running wastegate pressure? The TCV is not allowing boost? I am loathe to start messing with the loom where the TCV wires go but will if it looks like the culprit?

Sorry to hear of your lack of boost, just some thoughts on possible issues....Is the diaphragm in the turbo bypass valve ok ? as they do perish after time. You mentioned in the OP changing the tcv and bps, were these swapped for new or second hand items, if second hand are you sure they are good working items, you could be just swapping one duff part for another. Also if you set the actuator with a mityvac, does it open the wastegate as you increase the pressure with the mityvac. I'd be very tempted to tighten the actuator by a half or full turn and see if boost pressure increases.

As for voltage at the tcv, what Lee says is right, you will only see a change by logging live data on the road, as idling and revving up on the drive will not bring enough load demand, to give a significant change to the control voltage as far as I'm aware.

Hi, thanks for the input. I have the Forge CBV so no issues there unfortunately. I have adjusted the actuator but all it does is produce boost at the new base setting. This is why I am convinced it must be electrical. TCV and BPS sensors are brand new and OEM.
The TCV and voltage is curious as the ECU does not check it for function, I have it unplugged and nothing shows on Vida? Mechanical stuff is all good with me but electrical I am out of my depth. It does seem odd that the American R is reading 14 and 3.5 across the pins at idle and mine is 14 and 0 though? How can I read the voltage while driving? It isn't something that I can read using Vida? I am reading it via a volt meter like the American guy which I can't do while driving?

Quote:

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Originally Posted by bambamboom

Hi, thanks for the input. I have the Forge CBV so no issues there unfortunately. I have adjusted the actuator but all it does is produce boost at the new base setting. This is why I am convinced it must be electrical. TCV and BPS sensors are brand new and OEM.
The TCV and voltage is curious as the ECU does not check it for function, I have it unplugged and nothing shows on Vida? Mechanical stuff is all good with me but electrical I am out of my depth. It does seem odd that the American R is reading 14 and 3.5 across the pins at idle and mine is 14 and 0 though? How can I read the voltage while driving? It isn't something that I can read using Vida? I am reading it via a volt meter like the American guy which I can't do while driving?

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Right, the first figure of 14v is, as you probably know, alternator output voltage which is totally normal - so must be between 13.5v - 14.5v. Sometimes it can be 14.7v when cold but that's ok too, it will settle down to around 14.5 or below once warmed up.

The second voltage of 3.5v that the Yank got.....Do you know if this was with the TCV plugged in OR unplugged?
If it was unplugged, and your checking the voltage at the lume, then that is voltage from the ECM.

You have to remember that a TCV is an actuator.

Sensor = input to a system (ECU) meaning it supplies changing voltage to the ECU (or in our case ECM)
Actuator = output from a system (ECU) meaning it receives voltage from the ECU (or ECM)

So, the TCV should be getting what we call "12's and 5's" ie 12v and 5v. Obviously that's not an exact science, as if you were only getting 12v and 5v (across two different pins) then that would tell you the engine is switched off, so you'd be seeing battery voltage. Everthing powered by the vehicle recieves the same Battrey voltage 12v when switched off and charging voltage ie 14v when running.

So, the TCV should have 14v (charging/Battery voltage) on one pin if the engine is running and a voltage from the ECM...ie 3.5v (If that is correct for the ECM at idle) on the other!

(If I've got that completely wrong, then can someone please pipe up and put me straight :rolling_e, as it's 7am and I've only just woken up!)

If I remember later, I'll check my car for you when I get home from work. :wink:

I will check both with the engine switched off and running

Quote:

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Originally Posted by LeeT5

Right, the first figure of 14v is, as you probably know, alternator output voltage which is totally normal - so must be between 13.5v - 14.5v. Sometimes it can be 14.7v when cold but that's ok too, it will settle down to around 14.5 or below once warmed up.

The second voltage of 3.5v that the Yank got.....Do you know if this was with the TCV plugged in OR unplugged?
If it was unplugged, and your checking the voltage at the lume, then that is voltage from the ECM.

You have to remember that a TCV is an actuator.

Sensor = input to a system (ECU) meaning it supplies changing voltage to the ECU (or in our case ECM)
Actuator = output from a system (ECU) meaning it receives voltage from the ECU (or ECM)

So, the TCV should be getting what we call "12's and 5's" ie 12v and 5v. Obviously that's not an exact science, as if you were only getting 12v and 5v (across two different pins) then that would tell you the engine is switched off, so you'd be seeing battery voltage. Everthing powered by the vehicle recieves the same Battrey voltage 12v when switched off and charging voltage ie 14v when running.

So, the TCV should have 14v (charging/Battery voltage) on one pin if the engine is running and a voltage from the ECM...ie 3.5v (If that is correct for the ECM at idle) on the other!

(If I've got that completely wrong, then can someone please pipe up and put me straight :rolling_e, as it's 7am and I've only just woken up!)

If I remember later, I'll check my car for you when I get home from work. :wink:

I will check both with the engine switched off and running

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Hi Lee, great post thanks!
It doesn't say on the Americans post whether it was unplugged or not but I think it is safe to assume it was, otherwise he could not have measured the voltage across the pins. I am hoping that based on what you said that clearly I have wiring issue and the signal from the ECU to the TCV is missing. If you do run the test on your own R (really grateful) and get the same result as the American then happy days! :beer:

OK, So I did what I said I'd do and tested my 2004 V70R with No known boost issues.

1) Removed 3 leg plastic cover to access TCV.

(Note: There are two wires to the TCV. One coloured GREEN and the other is GREEN/GREY). The wiring colour may change on 2005> models but results should be the same.

2) TCV unplugged

Ignition 'ON' / Engine 'OFF'

Green/Grey wire = Battery voltage or 12.4v (Depends on state of charge in the battery and will differ from vehicle to vehicle)
Green wire = 3.7v

Ignition 'ON' / Engine 'ON'

Green/Grey wire = Charging voltage or 14.5v
Green wire = 3.8-3.9v (fluctuating)

Engine running / 3,000 rpm (vehicle stationary)

No change on either wire!


VERY IMPORTANT NOTE:

Do not, under any circumstances, check the voltage across the two pins of the plug that plugs into the TCV ie, the Green/Grey and Green wires. If you do this then you will short out the wiring to the ECM and highly likely cause irreversible ECM damage!!

This should only be checked by a vehicle electrician or Volvo dealer using a breakout box.
You would of cause be able to check the continuity from the ECM with the ECM disconnected. Extremely difficult and, therefore, only recommended by a Volvo Dealer IMHO. If Volvo damage the ECM then Volvo replace it! :deal:

I hope that helps you in your quest to find the boost issue.

Point to note: By disconnecting the TCV and running the engine, I had logged an ECM fault code for TCV 'open circuit', thus I required to plug in my BSR code reader just to clear the fault code.

The codes were: ECM-6806 Turbocharger (TC) control system flow fault - Flow too low
ECM-6800 Turbocharger (TC) Control valve - Signal too low

:B_thumb:

Quote:

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Originally Posted by LeeT5

OK, So I did what I said I'd do and tested my 2004 V70R with No known boost issues.

1) Removed 3 leg plastic cover to access TCV.

(Note: There are two wires to the TCV. One coloured GREEN and the other is GREEN/GREY). The wiring colour may change on 2005> models but results should be the same.

2) TCV unplugged

Ignition 'ON' / Engine 'OFF'

Green/Grey wire = Battery voltage or 12.4v (Depends on state of charge in the battery and will differ from vehicle to vehicle)
Green wire = 3.7v

Ignition 'ON' / Engine 'ON'

Green/Grey wire = Charging voltage or 14.5v
Green wire = 3.8-3.9v (fluctuating)

Engine running / 3,000 rpm (vehicle stationary)

No change on either wire!


VERY IMPORTANT NOTE:

Do not, under any circumstances, check the voltage across the two pins of the plug that plugs into the TCV ie, the Green/Grey and Green wires. If you do this then you will short out the wiring to the ECM and highly likely cause irreversible ECM damage!!

This should only be checked by a vehicle electrician or Volvo dealer using a breakout box.
You would of cause be able to check the continuity from the ECM with the ECM disconnected. Extremely difficult and, therefore, only recommended by a Volvo Dealer IMHO. If Volvo damage the ECM then Volvo replace it! :deal:

I hope that helps you in your quest to find the boost issue.

Point to note: By disconnecting the TCV and running the engine, I had logged an ECM fault code for TCV 'open circuit', thus I required to plug in my BSR code reader just to clear the fault code.

The codes were: ECM-6806 Turbocharger (TC) control system flow fault - Flow too low
ECM-6800 Turbocharger (TC) Control valve - Signal too low

:B_thumb:

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Thanks again Lee, so I definitely have an electrical fault then. Curious though as I have no fault codes at all on Vida for running with the wastegate unplugged? I am assuming thats because of the wiring fault I have. I was thinking about a main dealer to fix it, however in my experience most of the techs no less than we do and if Vida can't tell them what to do they will simply replace parts! A auto electrician maybe the safest route I think. Certainly do not want my ECU fried though!!

You should have faith in your local dealer. There not all Idiots!

It would be worth speaking to the master tech and, without insulting his intelligence, show him this thread with the results of the voltages.
Will help him in the diagnosis.

Really appreciate all you have done, I hope I can return the favour some day.
Cheers :B_thumb:

Update: Took my car to local main dealer and they told me what LeeT5 had already discovered that there is no voltage from the ECU to the TCV so the TCV is not functioning. Their solution, it's likely an ECU problem and may require replacing!!! Ye right course it is! As I need the car daily, I have today installed a manual boost controller, removed the TCV and plugged up fresh air bung. Works fine and boosts spot on up to 23psi with no issues now. I luckily already had a wideband afr gauge fitted and it shows 11.4 at wot using the the MBC and and no codes on Vida.
I am hoping for some comments about any other issues that anybody knows of that I might encounter using this ball and spring MBC until I can find a fix for the TCV. It does build boost extremely fast so being careful with the throttle at under 2500rpm as don't want bendy rods! The car is modified with stage 3 custom Hilton map, hybrid 7+7 blade Viva turbo, ported and flowed head, Feritta downpipe, custom 3" exhaust, High flow intake kit with S4 maf, uprated Aeromotive fuel pump with 650 injectors, FMIC, turbo to MAF pipe Forge CBV and actuator, and Aquamist water/meth. The block is also shimmed for those who may mention boost levels.
Cheers

Quote:

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Originally Posted by bambamboom

Update: Took my car to local main dealer and they told me what LeeT5 had already discovered that there is no voltage from the ECU to the TCV so the TCV is not functioning. Their solution, it's likely an ECU problem and may require replacing!!! Ye right course it is! As I need the car daily, I have today installed a manual boost controller, removed the TCV and plugged up fresh air bung. Works fine and boosts spot on up to 23psi with no issues now. I luckily already had a wideband afr gauge fitted and it shows 11.4 at wot using the the MBC and and no codes on Vida.
I am hoping for some comments about any other issues that anybody knows of that I might encounter using this ball and spring MBC until I can find a fix for the TCV. It does build boost extremely fast so being careful with the throttle at under 2500rpm as don't want bendy rods! The car is modified with stage 3 custom Hilton map, hybrid 7+7 blade Viva turbo, ported and flowed head, Feritta downpipe, custom 3" exhaust, High flow intake kit with S4 maf, uprated Aeromotive fuel pump with 650 injectors, FMIC, turbo to MAF pipe Forge CBV and actuator, and Aquamist water/meth. The block is also shimmed for those who may mention boost levels.
Cheers

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Hardly likely!

The more likely issue is either a dry pin in the ECM tray or mild corrosion on the pin contact.

It's worth carefully pulling the ECM out (which is very easy on a P2 using the correct ECU removal tool) and check for any signs of corrosion. If none present, check that none of the pins are bent. Then, if ok, give the pins all a good spray of contact cleaner and spray some contact cleaner onto the connecting plug attached to the bottom of the ECU tray.

Then recheck the voltage at the TCV plug.

You could, of course, refer to a wiring diagram to acertain which connection in the base of the tray supplies the TCV, then check continuity.

If all of that work's out ok, then it's worth an ECM reload before fitting a new ECM.