Hunting/Poor idle

[Baller]

1.9IZ TDI When I'm driving along the car is jurkey but ok when cruzing,when you put your foot down it to excelerate it seems ok but it is hunting at idle.starts ok and always runs on all four cylinders.
Any thoughts /help much appereciated

[jtanguay]

hmmm  m-TDI pump or electronic? you might need something like an air filter, or maybe a new sensor somewhere.

[Baller]

I have got the electronic/fly by wire setup.You have just got to rest your foot on the throttle pedal and it seems ok.It starts fairly well and is allways running on all four cylinders.
Any thoughts from anybody would be a great help.
                                   Baller

[Tintin]

It's the adjustment of I.Q. which does that.

When I install a head 11mm on a TDI pump, sometimes that made the same thing, is necessary to readjust the I.Q. and/or to make Hammermod.

[Baller]

Thanks for replying to my post,I am new to the diesel engines but am trying to learn as I go along.Sorry to sound so dumb but what is the I.Q adjustment and what is the best way to do it?Sounds like you no your stuff with these engines,I have changed the stop solenoid and also the air flow thing between the airbox and intake neither made any difference.
Drove it up the road today for the first time and pleased with it.
I took the TDI out of a 94 passat and put it in my MK1 Golf.The engine was running exactly the same when it was in the passat so I know it wasn't we missing something out durring the swap.
                         Thanks again Baller

[aidan]

Is it the maf you replaced? Shame, as they very rarely fail on the earlier tdi's.
Mine is doing something similar though, caused by a slight leak at the injector. The ecu will compensate it seems to keep the idle at around 950, but I don't think it can do that with individual injectors.

IQ is injection quantity and you need vagcom (www.ross-tech.com) to see and adjust it, really the first thing you should buy if you hit a problem, check if there is a fault code before you do anything else.

[Baller]

Thanks for the info Aidan,I did change the air flow thing,I got afew things from the scrap yard which I took off myself it all added up to around a fiver so no big deel realy.I will take your advice and see how I get on from there.
               Thanks Baller

[aidan]

Just re-read your first post, when is it jerky when driving, i.e what rpm and speed?
In my experience there is a very slight jerkiness at exactly 1500rpm at part throttle, and there is a very rough 'changeover' at around 1000rpm where the car slows from coasting to having to add fuel to prevent stalling and maintain idle.
These are just characteristics of the early tdi unfortunately

[Baller]

When you are driving along with very light throttle i.e. behind other vehicles in traffic.You all but need to dip the clutch just to smooth out the ride.It is to bad to be fault from new case.
If it was a petrol car you would look at the idle jet,because it seems ok when under load.
Baller

[jtanguay]

heck my car does that too...  :lol:  (bucks a bit if i let off the throttle abruptly)

but it's a 1.6...

i've never had my audi 5k do it, but then again... it's a 5 cylinder engine with some crazy torque that is comparable to a diesel engine.

i think it might be your motor mounts, or you might need a lift pump if your pump is starving for fuel?

[uss sterett cg31]

mine is driving me crazy it surges badly at "no load" anound 1200 to 1900 rpm also at idle it get rough then smooth over and over
it is hard to drive 2o to 30 mph due to the fluctuations it seems worse when it is cold.
my mileage is horrible @ 30mpg
I have a p1562 code
just did filters, cleaned intake ( extremely bad) timing is low but within range, iq is ok, checked all wiring back to ecu all good
I even went as far as puttins an oscope on my mudulating piston displacement sensor pin 1 and pin 3. pin 3 showed modulating response
pin 1 showed a constant high amplitude equivilant of pin 3 at its max
I think my pump is scrap
any ideas?