2005. 1.9 TDI Caddy limp mode issues

[Nuuns]

Howzit.
I know there are treads related to limp mode but mine is slightly different.
I Overhauled the injectors
Refurbished the Turbo
Replaced the injector loom.
Cleaned the intercooler and all piping.
Van ran fine for around 45kms. Stopped and on the way back it hit limp mode uphill. I assumed due to the steep hill I did not give enough gas. Recycled key and I was back to power. Further up it did the same. Stopped and checked oil , water etc and found positive terminal was a bit loose. Tightened that and she performed again. Cold weather and I cannot start it in the morning. Bought a new battery with no difference.
Taken it to a merchanic / auto electrician and he suspects a loose wire of sorts as it does not do this all the time. Sometimes I can drive for over 20kms no issues. Sometimes 2kms and limp mode. Turbo still boosts.

I am tired and frustrated now but I enjoy driving this do much when it behaves and want to keep it.

[Ashveer03]

Limp mode on these is almost always boost related. Easiest thing to DIY check is the vacuum pipes, any other diagnosis gonna be best to do with a scan tool.

Scan the car for codes and post results, with freeze frame data if any.

Regarding cold start, the timing may be slightly off or faulty glow plugs/coolant temp sensor.

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[Nuuns]

Thank you @ Ashveer
I agree timing could be off. When I replaced the injectors the timing could have been adjusted incorrectly.
This issue happens on the worst of times. Imagine driving 45 k.s with no issues and then 5 kms and its starts doing this and will keep on.

I have an Autel diagnostic machine and it shows EGR flap signal error. It also shows injectors signal low.

On 1 YouTube video with the same issues they found a wire on the loom before the radiator damaged.

I need to find someone with a VC? Machine

[Ashveer03]

The timing has nothing to do with injectors, however the injectors do have a lash adjustment which needs to be set according to the camshaft position. It must be set each time the injectors are refitted.

If Im not mistaken the caddy has separate valves for the turbo and egr, the pipes could have also been swapped around.

Egr fault code will not cause limp mode.

Seeing that u have had the turbo reconditioned, I'm quite sure it was not set correctly. Each car is different and each turbo requires different adjustments. Most turbo "rebuilders" who don't have proper equipment just adjust all the turbos the same and expect it to work.

Maybe clear the fault codes, drive the car until it goes into limp again and see what codes comes back.
I'm not sure how the autel machine reads, I'm more familiar with launch and vcds.

Check if the autel features live data then I could advise what to look for regarding timing [group 4 block 4 (torsion / synchro angle) value should be +-0.5 to 0]

and

Injectors [group 13 block 1-4(injector deviation / smooth idle control) here theres a positive+3 and negative range-3, also should be close to zero]. If the values are more than +-1 then there is an issue waiting to happen.

Depending on the injector fault code, a faulty injector harness shows itself in group 23.

Not sure if your machine reads blocks or not.
The best thing to do is to log the car using vcds so u can see actual boost Vs specified boost Vs n75 value. That way we can tell if the turbo is set correctly or not.

Who rebuilt the turbo for u? Was it flow tested / set by a machine?

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[Nuuns]

Hi.

Thanks for the informative breakdown.

Turbo was done by Fastech Turbo. Lots of the members here recommended them. They did all the tests as well as provided a list of what to clean/ replace before fitment. I did have the intercooler cleaned professionally.

Something I relalise in your answer related to the way the Turbo was set. If it is correct. Yes, it did work fine when I collected the van. Deteriorated therafter with more incidents of limp mode. This could be the reason why limp mode happens more often.

Appreciate the advice and assistance

[Ashveer03]

Hi.

Thanks for the informative breakdown.

Turbo was done by Fastech Turbo. Lots of the members here recommended them. They did all the tests as well as provided a list of what to clean/ replace before fitment. I did have the intercooler cleaned professionally.

Something I relalise in your answer related to the way the Turbo was set. If it is correct. Yes, it did work fine when I collected the van. Deteriorated therafter with more incidents of limp mode. This could be the reason why limp mode happens more often.

Appreciate the advice and assistance

Cool

I use fastec myself. They have proper equipment to set turbos.

Without actually logging the car to see what the ECU is seeing we just gonna be guessing.

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[Nuuns]

I am stumped. Merchanic decided to see to a rear main seal leak and says the Turbo is leaking oil again.

Is this possible. Fastec did a test and complete overhaul.

How is it possible

[Ashveer03]

Turbo is leaking?? From where?

From what I know, these top mounted turbos leak from either the inlet pipe (induction pipe going to the airbox) or the oil drain pipe. (If u have a bls/bjb)

1. If it's leaking oil from the inlet pipe, that's all your blowby/breather gases from the engine.
2. If it's leaking from the drain, well that's a drain problem.
3. If oil is coming out the boostpipes, check step 1 - that could be the cause.

A turbo that has recently been refreshed, especially by fastec is not likely to fail so easily.

Further more, these tappet covers are kak. I find them not doing a very good job separating oil from vapour. I changed a few of them to the asz/atd type tappet cover.

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[Nuuns]

Thank you.
I was at Fastec and they are confident it is not the turbo.

They say it has to either do with a blockage on air line or blowby.
I agree the tappet cover has been modified by myself to eliminate the spline.

I will update when merchanic refits everything

Regards

[Nuuns]

Hi
I finally have my Van back. Took it on a 100km round trip. Runs like a dream. Only now on uphill acceleration it blows thick black smoke. No limp mode. The crank pulley was worn. Holes in the pulley were "torn". First I have seen this.

I am planning on buying a VCDS tool to chexk the reason for the black smoke
Almost certain it's incorrect injector seating.

@ Ashveer03. You are honestly the most clued up person when it comes to TDI's. I could confidently tell my merchanic it's not turbo.

I almost gave up on this van. This was my last try to see a change. Feels good to overtake uphill with minimum effort even with the smoke. Power is incredible.

Thanks again Ashveer. Hope I am not counting my chicken's prematurely

[Ashveer03]

Black smoke on acceleration would be acceptable if the car has software upgrades..
Or if it has a boost leak after the map sensor towards the intake. Intake bolts are a nightmare on top mount turbos, could possibly be loose.

If these injectors are incorrectly seated I doubt the engine will even run.

Well the crank pulley is just a damper it shouldn't cause limp mode at all, u have any pics of the holes that you are talking about?

On the Mk5 gen engines, rear main seal replacements are not as simple as the previous ones. Engine has to be at tdc when replacing them, and they also use a different crank locking tool on the front crank gear compared to previous TDI engines.
If the RMS has been replaced, thats something u gonna want to confirm with the mechanic.

Glad it's working out for u. Vcds will be a good Investment if u planning to keep the car for a while.

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