Lack of power

[Mancseat]

Hi all, hoping for advice or at least a second opinion. I would have posted this in the Tdi specific forum but site will not allow me to do that.

My 110 Toledo 1.9 tdis has been suffering an imo severe lack of power in higher gears , also seems to get excessively noisy if it does accelerate past 2500 rpm going up hill/overtaking etc.

Based on what I have read on here and over at Tdiclub, common causes for low power/boost issues are, sticky actuator arm/vanes on the turbo (vnt type) blocked egr/air inlet, split/holed vacuum pipes, N75 valve, shot Maf, coolant temp sensor and bad timing.

As I got a 17958/p1550 code
I disconnected the Maf and got no appreciable difference so am waiting for delivery of a new OEM one.

In the mean time I have swapped N75 valve, no difference.
Checked vac lines, all good if frayed in the odd place.
Cleaned the EGR/Inlet manifold, disgusting, never seen an air intake so filthy/clogged, no difference.
Split turbo, cleaned/freed vanes/ actuator ring / actuator arm (the actuator ring was by far the most clogged and more by rust from the casing than carbon deposits) reassembled, refitted and able to move actuator arm full swing with just lung powered vacuum, no difference.

So I was left thinking that the timing may be out out, so did the VCDS tdi timing got dead on results 3 times. What I did notice was that the timing advance solenoid seemed to be stuck at 28% duty cycle instead of dropping to about 5/6% as specified.

Whilst this seems to be indicating an issue there was no code thrown to indicate a fault / short.

I've noticed it seems to take forever for this engine to reach normal operating temperature, is this normal?
Whilst I was sitting doing the timing check, engine temp dropped dramatically and quite quickly, indicating coolant temp sensor works. It's the first time I've noticed this happening, and running temp was hard to maintain without loading the engine.

I'm guessing the cause of this fluctuation is the thermostat is stuck open or has been removed.

Now the crunch question. If the thermostat is not doing it's job, maintaining engine temperature, could the injection advance solenoid stay at cold start position leading to a mistimed injection when under load at higher revs?

I ask because at a quoted £ 176 + vat for a new n108, plus the work to fit it, timing belt etc, I'd prefer to change the thermostat before if that may be the cause.

I'm beginning to dislike this car.

 

[WK2010]

Mine gets up to temp pretty quick and stays there.

Change the stat and see what happens

 

[Mancseat]

Cheers WK, will do, would be nice to find a quick fix.

 

[Mancseat]

After a wet and unconstructive day yesterday, fitted the new thermostat today and got a much quicker warm up time and coolant temp seemed to stay stable and much closer to specified operating temperature.

Sadly this has not cured the problem, so with the new MAF overdue I will wait until this has been fitted and tested before going any further, then report back.

 

[Mancseat]

Well the new MAF arrived so I quickly fitted it and went for a test drive.
No difference.

Now I'm a bit stumped.

I get a 17946 fault code for the fuel shutoff switch n109 but it's intermittent and I can't see this being the problem as in general the car starts and runs. My understanding is if the solenoid or power to it fails the engine should cut out completely.

I have ordered a replacement, due wednesday but has anyone got any further suggestions whilst I'm waiting.

 

[Mancseat]

Since the last post I've replaced the fuel shutoff solenoid, hasn't seemed to make any difference.

I then tried to eradicate any air from the fuel system, having read a certain amount was acceptable.
Replaced the thermo t valve in the fuel filter and routed a fuel feed directly from the tank to the fuel filter.
This did remove all traces of air from the fuel lines but does not seem to have had any positive effects on the lack of power.

I also tested the ignition advance solenoid which seems to produce results within spec (14ohm resistance according to the workshop manual).

Unless anyone has any further suggestions I'm going to have to bite the bullet and take the car to a specialist. This does go against the grain a bit as I haven't used a garage for about 25 years, so if anyone can think of anything I might be missing I would be endlessly grateful.

 

[Mancseat]

Just to clear the mystery up, I took the car to Volksmaster.

After a couple of hours of diagnostics they asked me to give them a week to do some research.
I have to admit it made me feel better about my inability to fix it myself

On my return both the vacuum system and the engine loom were checked.
An improvised power supply to the fuel shutoff was discovered but nothing else.
It was decided to send the ECU for testing.

This came back good with a suggestion that a bad power supply could cause the issues.
Armed with this information James tracked the problem to a faulty relay which the bodged wire had been masking.

I've done just short of 1k miles since picking the car up and the power delivery remains consistent.

So, a huge thanks to the Volksmaster team for their help and a recommendation of their fair and friendly service.

 

[Seatmann]

So is it going good now? All the power restored?

 

[Mancseat]

Yeah it's so much more fun to drive. I can do advanced things like overtaking now.
TBH it's a different car. The bodge was completely bypassing the ECU so the N75 valve wasn't operating properly and the monitoring sytems were not doing their job.

The guys at Volksmaster said the car had probably been bodged just to sell on as it should have arrived at theirs as a none runner, adding it would only have taken them a couple of hours to sort out had that been the case.

I'm still very happy with the outcome and I know quite a bit more about the car now, as I changed the ip, water pump, timing belt and tensioners before I gave it them.
Means I've got a good few thousand miles in her without that and other potential panics (VNT vanes jamming etc)

 

[Seatmann]

Cool, I'm up at the same sort of power with my nozzle upgrade and loving it, still got plans though but need to convince the wife it's a good idea lol

 

[Mancseat]

I read your nozzle thread and was very interested, glad to see your so happy with the mod.

If I go anywhere with this, it will be with the handling/suspension first, if a big brake kit came up at a reasonable price that would be considered too. The stopping power seems to be an often overlooked aspect of car tech.
A heavier clutch and a SMF would also be fitted in advance of power mods.

MOT's due in a couple of weeks so get through that and see where we stand.

 

[Seatmann]

Yeh I did the suspension first and just replaced the standard brakes but I also run the uniroyal rainsport 2's so the stopping power is pretty good anyway. My car has the G60 smf as standard so that's a bonus and I can get the VR6 sachs kit for about £150 and with your turbo and ecu I could get around the 150 mark, I'll await the gifts with anticipation lol. You can pick up the G60 flywheels second hand on ebay or you could go for the full kit,

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140551425977

What age is your car and what's the engine code? I'll check the part number and see what's in your car.

 

[Mancseat]

It's an AHF engine in a late 1999 shell.

I'm getting a bit of vibration through the clutch already so I'd rather do the upgrade when the time comes to replace.
Cheers in advance for the info.

 

[Seatmann]

It looks like yours is a dmf even with the same engine as mine (AGR) it still a dmf in the toledo for some reason according to etka. If you can find one though you could get the flywheel second hand because even if it was a little bit scored I don't think it costs that much to have them resurfaced/skimmed then you could get the VR6 sachs clutch kit with bearing for £150.