Still limping home...

allypug

Member
My TDi still goes into limp home mode, although it generally behaves itself when I have some diesel cleaner in the tank. Almost went a whole week without problems. The morning after a fill up with no cleaner additive (Sunday) It's gone into limp on each journey this week so far!

Would a blocked fuel filter cause a limp home? When my previous TDi (BHC engine) needed a filter change there was a slight hesitation or hiccup when driving at full power. Maybe my current AMF engine TDi is different and just goes into limp mode.. is this possible?

(error code is 17964)

I know there could be lots of causes, just wondering if fuel filter could be one.

Steve T
 

A2 Louis

Banned
My TDi still goes into limp home mode, although it generally behaves itself when I have some diesel cleaner in the tank. Almost went a whole week without problems. The morning after a fill up with no cleaner additive (Sunday) It's gone into limp on each journey this week so far!

Would a blocked fuel filter cause a limp home? When my previous TDi (BHC engine) needed a filter change there was a slight hesitation or hiccup when driving at full power. Maybe my current AMF engine TDi is different and just goes into limp mode.. is this possible?

(error code is 17964)

I know there could be lots of causes, just wondering if fuel filter could be one.

Steve T
Could be the fuel filter. How long has it been on the car ?

Cheers
 

allypug

Member
Could be the fuel filter. How long has it been on the car ?

Cheers
Not long, but (long story) fuel pump failed a while ago, garage changed it and cleaned out fuel system + new filter as engine oil was leaking into fuel system, headgasket then went, they changed it (twice) as new valve oil seals weren't fitted properly and leaked oil out into the turbo, since then it's been limping home quite a lot.

Hmm..
and I'm NOT taking it back to the garage before anyone asks, as it comes back with more problems!

I have a fuel filter so when I have time I'll change it just to rule it out.
 

A2 Louis

Banned
Not long, but (long story) fuel pump failed a while ago, garage changed it and cleaned out fuel system + new filter as engine oil was leaking into fuel system, headgasket then went, they changed it (twice) as new valve oil seals weren't fitted properly and leaked oil out into the turbo, since then it's been limping home quite a lot.

Hmm..
and I'm NOT taking it back to the garage before anyone asks, as it comes back with more problems!

I have a fuel filter so when I have time I'll change it just to rule it out.
I would advise going to get a new mechanic and start over again
 

AndyP

Member
That code is most likely boost pressure related, so I would say it is unlikely that a restricted fuel filter would trigger it. Think boost leaks, intercooler leaks, maybe boost pressure sensor.
 

allypug

Member
The turbo does (when behaving itself) have a good 'whine' on acceleration, although it doesn't do this all the time and is noticeably slower, a new N75 valve needed perhaps? was quoted just over £50 new from local Audi dealer
 

Colin 540

Member
Found this thread from member just just maybe helpful.

Just some info for anybody coming across this code I've been trying to diagnose limp mode for a couple of weeks now and finally sussed it today i got underneath the car and fastened a vacuum pump to the actuator on the turbo and turns out it's seized,something to look for if anybody comes across the same.
 

kp 115

Member
Found this thread from member just just maybe helpful.

Just some info for anybody coming across this code I've been trying to diagnose limp mode for a couple of weeks now and finally sussed it today i got underneath the car and fastened a vacuum pump to the actuator on the turbo and turns out it's seized,something to look for if anybody comes across the same.
This is the wastegate actuator mine was seized on the pivot point, once the clip was removed the arm would move & the wastegate could be moved by hand, it would suggest that the pivot point should be greased with high temperature grease, probably never been done in its lifetime!
I’ve just got to find the vac pump in the garage.

Keith.
 

allypug

Member
Interesting.. I was just thinking my problem was the fuel system somewhere.. unless it's just a coincidence it goes into limp mode more often when there isn't any cleaner/additive in the diesel?
 
Where did the oil get to in the turbo?

I had a problem with mine where the actuator for the variable vanes was ever so slightly sticky, and every so often, would cause limp mode because of under pressure in marginal situations, where small movements didn't happen. I got to be a dab hand at turning off and on again on the motorway.
 

kp 115

Member
Where did the oil get to in the turbo?

I had a problem with mine where the actuator for the variable vanes was ever so slightly sticky, and every so often, would cause limp mode because of under pressure in marginal situations, where small movements didn't happen. I got to be a dab hand at turning off and on again on the motorway.
I had his on the galaxy I had , I used the mister muscle trick & it cured the sticking vanes , the car had never driven like it & I’d owned it from 15000 to 214000 miles
Followed by an good spirited run .
But the AMF engine has a normal geometry turbo with a waste gate.
 

philward

Member
I'm clueless but based on the input so far I would take a good look at the waste gate. Also given there has been semi combusted engine oil blown through the turbo I would put some turbo cleaner in my fuel tank.
Yes I know AMF turbos are fixed geometry but I got improved smooth running benefits when I treated my AMF turbo.
 

allypug

Member
Where did the oil get to in the turbo?

I had a problem with mine where the actuator for the variable vanes was ever so slightly sticky, and every so often, would cause limp mode because of under pressure in marginal situations, where small movements didn't happen. I got to be a dab hand at turning off and on again on the motorway.
from badly fitted exhaust valve stem oil seals, oil then getting into the exhaust and through the turbo.
I've had turbo cleaner in the fuel, and a complete carbon clean 'Terraclean', after which it was fine for maybe a week.
 

allypug

Member
at last.. an UPDATE! well fingers crossed.. again, The limp home problem may be sorted. Certainly felt a lot more lively on the drive back from picking it up, and the turbo whine was much more than before.
Turned out to be a corroded pin on a connector causing an open circuit.
Very good friendly service from INDE-TECH in Milton Keynes.
 

audifan

A2OC Donor
That does indeed sound a likely and simple cause. I know it is more expensive than regular diesel but I would run three tanks of super diesel through the car. Has a better effect than running most of the additives you can buy and when you work out the total cost probably pretty close. Nice to know you have found a good garage that take their time to find out what is really wrong and not just swap parts needlessly.
 

Biggsy

New Member
at last.. an UPDATE! well fingers crossed.. again, The limp home problem may be sorted. Certainly felt a lot more lively on the drive back from picking it up, and the turbo whine was much more than before.
Turned out to be a corroded pin on a connector causing an open circuit.
Very good friendly service from INDE-TECH in Milton Keynes.
I'm currently trying to diagnose the very same issue. Do you happen to know which connector was at fault please?
 

mjsbrabus

A2OC Donor
Some years back I owned a TDI that had an annoying habit of repeatedly going into 'limp mode'.

Turned out to be a VERY small hole on the intercooler (where the plastic top joins the alloy).

Only a new intercooler cured it.
 

audifan

A2OC Donor
Have a VCDS scan done that will tell you if it is overboosting - unlikely or lack of boost. Lack of boost check the pipes carefully from the turbo to the intercooler to the engine. The boost sensor could be faulty more likely leak from intercooler. Check the small hoses to and from the turbo for deterioration and looseness a tiny leak will cause turbo loss of boost also check the hoses on the N75 valve on the bulkhead.
 

allypug

Member
I'm currently trying to diagnose the very same issue. Do you happen to know which connector was at fault please?
it was a while ago now.. it was one of the connectors to the little solenoid valve that controls the turbo.. the valve is near the expansion tank.. which is why the bubbling over coolant sprayed all over it and made it corrode.
 
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