Intermittent diesel engine slow start issues?

ecurb

Member
I have been having on an off intermittent engine start issues with my A2 2001 Diesel

The Problem:

The engine will not fire up immediately, it can take anywhere between 2-10 seconds of cranking the engine before it will fire up.

It seems to be random at times, sometimes the engine will start normally, other times it won't

I have collected together some symptoms, after having this issue for over 3 months:
  1. The issue can happen if the car engine is cold, or warm e.g.. (going to the shops and back, or a drive on motorway)
  2. Ambient temperature doesn't seem to affect it, it can start ok first time in cold winter or summer, other times it doesn't start immediately.
  3. It sounds like an old airplane once it fires up (like a spitfire when they start it) for a few seconds
  4. If you start driving, sometimes you can hear these high pitched sounds almost like a cat is "meowing" underneath the car
  5. Once you are driving on a road or motorway its fine, it accelerates fine
  6. If the fuel tank is below 1/2 (half) the engine will struggle to start, but if it keep it full, I am less likely to have a slow start issue
  7. There is no diesel leaks where I parked the car
  8. If you park the car facing up-hill (on a moderately steep incline) it REALLY struggles to start, however if you face it downhill, it is less likely to have an issue

Things we have tried:

  1. Got new glow plugs fitted
  2. New fuel temp sensor
  3. New fuel filter
  4. Checked the tandem pump and its seal
  5. RedX Diesel cleaner
  6. Checked the Crankshaft position sensor (its fine, with a good signal)

Any ideas?
 

dj_efk

A2OC Donor
The earth point behind the passenger headlamp, disassemble it (even if it looks fine), replace it and it’s bolt, clean up and smear with copper grease or Vaseline. Job done.
 

Rusty911

A2OC Donor
The op says slow start rather than slow crank, plus continued rough running for a while is unlikely to be earth to that extent: e.g. a brisk crank is going to test the earth to a greater degree than simply running.

Any fault codes? Do you have access to VCDS?

Regardless I'm sure there was a thread recently mentioning air getting into the fuel supply somewhere, requiring long crank and initial rough running. One way or another it sounds as though fuels running back. I'm sure someone better qualified will be along shortly.

If you hadn't said about fuel level / hills, I'd have pondered injector loom which occasionally crops up on here.

No 4 is odd: have you looked under the car whilst someone brings the revs up, ideally with all electrics and AC on to give a bit of load?
 

audifan

A2OC Donor
Profile states 2001 tdi 90......
Replace the tandem pump assuming there are no perished hoses and all connections on the fuel filter are air tight. Being a 2001 very small chance there is a lift pump in the fuel tank and that could also be the problem.

Please correct your profile. This is how people narrow down fault diagnosis to the engine type.
 

ecurb

Member
Profile states 2001 tdi 90......
Replace the tandem pump assuming there are no perished hoses and all connections on the fuel filter are air tight. Being a 2001 very small chance there is a lift pump in the fuel tank and that could also be the problem.

Please correct your profile. This is how people narrow down fault diagnosis to the engine type.
Updated my profile (that was my old A2)

Thanks
 

depronman

Member
The clue is in the tank being half full and the incline on parking
This will be a fuel starvation issue cause by the fuel running back from the tandem pump to the tank
Car then starts on one then two then three cylinders hence the strange noise when it does start up
Temporary fit a clear pipe in the fuel supply line then look for fuel after the engine as not been running for several hours


Sent from my iPhone using Tapatalk
 

ecurb

Member
Any ideas what size of transparent pipe to get, and where I can get it easily online / north west England?
 
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