1.9TDI BLS Running Issues

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Phillstine
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Engine size/power: 1.9 TDI (104bhp)

1.9TDI BLS Running Issues

Post by Phillstine » Sat Sep 12, 2020 11:44 am

Hello All,

I’ve recently taken on a project in the form of the old work van. As mentioned in my hello thread it was destined to be scraped and I couldn’t let that happen.

So the issue with the running is that it idles fine but when applying throttle it starts jumping/kangarooing/hesitating and kicking a lot of black smoke out.

I got to cleaning the EGR which didn’t help, it wasn’t that bad to be fair.

Ran diagnostics with VCDS which also shows no engine faults.

When removing the plug from the MAP sensor (boost pressure sensor) it no longer exhibits the hesitation and revs freely and no black smoke, so I bought a replacement sensor and it still has the issue with the new one.

I’m very new to diesels so as a result have little to no knowledge on them.

The engine is a 1.9tdi pd 104/5? BLS engine code.

Any assistance would be greatly appreciated, as I’m at a bit of a loss now.

Thank you
Phill
Last edited by Phillstine on Fri Sep 25, 2020 12:10 pm, edited 2 times in total.

Caddy-Dan
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Re: Running Issues

Post by Caddy-Dan » Sat Sep 12, 2020 3:12 pm

Had a very similar fault on a golf 1.9 a while ago where it wouldn’t rev up properly, I did the same with cleaning egr valve, I could get it to run fine if any sensor was unplugged but never got to the bottom of it. Tried new maf sensor, boost sensor and everything. Customer ended up taking the car away and I never found out what the cause was. I’d like to know when you fix it what the problem was.

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Phillstine
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Re: Running Issues

Post by Phillstine » Sat Sep 12, 2020 6:44 pm

Yeah it’s a real pain to track down, I’ll update on here once I get anywhere in case someone in the future is struggling.

I pulled every hose on the intake & turbo side. None of which appeared to have any splits or damage. Some play in the turbo but nothing major. There was quite a bit of oil in the Intercooler but doubt that that would cause my issue.

The tandem pump gasket looks to be leaking so I pulled all of that off and cleaned it, will order a new gasket. I understand that deals with vacuum so that could be part of the problem?! I guess I’ll retest once I have the gasket in.

The problem is clearly boost related but where! There is a little vacuum solenoid on the back of the engine that controls the wastegate amongst some other things, I’ll investigate that further too.

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Re: Running Issues

Post by Sparky01 » Sat Sep 12, 2020 11:05 pm

I had a similar problem and I was told it was a very slight problem with one of the injectors, I put some Millers injector cleaner into the fuel and that cured it.

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Phillstine
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Re: Running Issues

Post by Phillstine » Sun Sep 13, 2020 10:09 am

I’ll also give that a go. Although would unplugging the MAP make the injector run differently, as it’s not getting the expected air flow?

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Doc
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Re: Running Issues

Post by Doc » Sun Sep 13, 2020 2:01 pm

I'd do a VCDS data log on the requested Vs actual boost along with n75 duty cycle, see if it all adds up.
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I have genuine VCDS Hex V2 & VagCAN Pro for any of your programming needs.

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Phillstine
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Running Issues

Post by Phillstine » Sun Sep 13, 2020 2:19 pm

Thanks Doc, would it be beneficial to post a report here? As I’m not so sure what will be in tolerance. Will probably be at the weekend after I’ve replaced the radiator and refilled the coolant.

Thanks again everyone for your input!

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Phillstine
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Re: Running Issues

Post by Phillstine » Thu Sep 24, 2020 2:05 pm

So after a massive battle with the Radiator and being given the wrong one, don't ask!

I've finally been able to get VCDS logged in and tested.

To my untrained eye it seems there is definitely a boosting issue.

N75 Duty cycle output test yielded:
ON: 97.5% - 969 absolute Pressure
OFF: 4.8% - 969 absolute Pressure

Boost Pressure:
Idle: 969 actual 1091.40 specified
Rev: 979.20 actual 1162.80 specified
More Revs: 1040.40 actual 1183.20 specified
As above: 1030.20 actual 2070.60 specified

So the requested and actual are way off, almost like the actual isn't even changing. I have removed and cleaned all of the boost pipes, there also doesn't appear to be any hissing etc. I also pulled the vacuum hose from the actuator and it quite evidently opened.

Could the Turbo actually be the fault?

Thanks again everyone
Phill
Last edited by Phillstine on Fri Sep 25, 2020 12:38 pm, edited 1 time in total.

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Doc
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Re: Running Issues

Post by Doc » Thu Sep 24, 2020 2:34 pm

It might be the MAP sensor playing up.
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Phillstine
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Re: Running Issues

Post by Phillstine » Thu Sep 24, 2020 2:35 pm

I did replace the MAP sensor, it was the first thing I did when I noticed it was running better with it unplugged, unfortunately to no avail. I did pop that in the original post but then again it was a wall of text, sorry!

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Re: Running Issues

Post by Doc » Thu Sep 24, 2020 2:56 pm

If the VNT is moving, I'm inclined to think it's MAP sensor related. If you have access, it's be worth getting a pressure gauge in the intake and see it it moves in sync with the MAP reading.
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2013 Caddy with EA888 Gen3 2.0TSI DSG, Superplus MSP19 , Caddy4 rear lights, Polo GTI (mk7 style) steering wheel, Relentless Tuning front coilovers, Audi A6 S-Line front seats, Boxster fronts & GTI rear Brakes, 3D Colour Premium dash cluster, Caddy life arm rest, Motexion bulkhead, MIB head unit


I have genuine VCDS Hex V2 & VagCAN Pro for any of your programming needs.

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Phillstine
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Re: Running Issues

Post by Phillstine » Thu Sep 24, 2020 3:03 pm

So the VNT is controlled by the actuator (What I referred to as a wastegate actuator) when I pulled the vacuum off it clearly made a difference in tone (deeper exhaust note).

Is there anyway to actually test this I'm not sure I want to put my finger on the arm and see if it physically moves? I don't have access to a pressure gauge. Assuming the N75 is what pressurises and moves the Acutuator?

Aside from replacing the MAP sensor, the cabling looks to be okay as it exhibits different behaviour when being unplugged. What else can be check to determine a fault with the MAP?

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1.9TDI BLS Running Issues

Post by Phillstine » Fri Sep 25, 2020 12:09 pm

Okay the VNT is definitely moving I've pulled the hose off the actuator and can clearly see it moving up and down, without any resistance. So assuming the normal behaviour is to be under vacuum then that seems to be function correctly.

So as DOC mentions above I need to look into the MAP sensor, I also notice today when unplugging the MAP sensor the exhaust note changes too, there is still a little bit of blue smoke when revving but nothing close to the levels when it's plugged in and codes are cleared.

I have uploaded a video to YouTube showing the symptoms, for easier diagnosis.

https://www.youtube.com/watch?v=5r09drdul0k

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