Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
No, apart from metered air which at idle should be around 16.0 g/s at idle.
At 2500 rpm it should be 77.0 g/s, 56 g/s at 2000 rpm, and 40 g/s at 1590 rpm
(g/s = grammes per second)
Manifold pressure at idle should be around 100 kPa.
Boost pressure adjustment 86% at idle dropping to around 34%ish on hard acceleration to 3000rpm
You could use a multimeter to see what signal values are present at the MAF with the ignition on or engine running.yµ (idµ - eAµ) ψ=mψ
11th May 2021 12:07 am
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
Thanks have just found a link for the signal values, so will check those too.
11th May 2021 12:25 am
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
These are the engine fault codes recorded today: -
Engine TDV6
P023D-22 (68) Manifold absolute pressure - turbocharger/supercharger boost sensor A correlation - General signal failure - signal amplitude>maximum
P0113-17 (2C) Intake air temperature sensor 1 - circuit high input - General electrical failure - circuit voltage above threshold
So same ones again.
I took some readings on the four MAF wires as follows: -
Red/Blue - 12v with engine off, 14.4v at idle.
Red/Grey? - 5.03v with engine off, 4.07 at idle.
Yellow/White - 5.03v with engine off, 3.02v at idle.
In addition I obtained this information using the IID tool: -
All were with the vehicle stationary. Should I do the same under load?
12th May 2021 12:45 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
Yes, the last one needs to be under load, the others look OK and there is nothing jumping out from your DMM tests. Except for this dtc, P0113-17 (2C). Isn't that new? The intake air temp sensor is in the MAF meter itself but that's new right?
When you do the load test include the battery voltage to see if there's anything funny going on with voltage fluctuation! yµ (idµ - eAµ) ψ=mψ
12th May 2021 1:14 am
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
You're absolutely right. I saw the -17 at the end and thought it was the same one again. Yes, the MAF was new only a couple of months ago.
Will do the load test and report back.
12th May 2021 7:12 pm
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
Here are some live values under load in 6th gear.
14th May 2021 10:04 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
I can't see much wrong there tbh, was the fault triggered?yµ (idµ - eAµ) ψ=mψ
14th May 2021 11:05 pm
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
No it wasn't this time. No engine codes after a 30 mile round trip but still down on power at low revs..
14th May 2021 11:56 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
Plug in the iid and set up a log, but include a few other sensors such as MAP.
Leave it plugged in and keep logging until the fault reoccurs. Unplug it overnight though.
See what that brings yµ (idµ - eAµ) ψ=mψ
15th May 2021 12:22 am
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
Ok. Will have to try and get organised with that. It doesn't get used everyday, so will need to remember to plug it in. Did a 50 mile round trip today and completely forgot!
What are the best 4 things to log? MAP, MAF Revs and boost pressure actuator?
17th May 2021 6:00 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
There's an extension available for the OBD port which you can route up to the dash and keep the tool in your line of sight!
I think there's even a switched one available which allows you to keep it plugged in but powered on or off as required.
Might be useful, but best not to leave it exposed to prying eyes when unattended!yµ (idµ - eAµ) ψ=mψ
17th May 2021 6:09 pm
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
I've already bought a 90 degree extension lead off Amazon, as the tool gets in the way of my size 13s when I am driving.
17th May 2021 11:41 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
tell me about it.yµ (idµ - eAµ) ψ=mψ
18th May 2021 12:07 am
GDM
Member Since: 18 Oct 2020
Location: Midhurst, West Sussex
Posts: 144
I never did get round to setting up the log but
P023D-22 (6C) Manifold absolute pressure - turbocharger/supercharger boost sensor A correlation - General signal failure - signal amplitude>maximum
returned again earlier this week.
28th May 2021 11:29 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4570
So it's the same story really, either overboost (sticky actuator) or a air /pressure leak somewhere.
Logging might be your only way since you have tried everything else. yµ (idµ - eAµ) ψ=mψ
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