Catnip64
A2OC Donor
Need to some help to fix our 2004 TDI 75 (AMF with 180k miles).
The car seemed to lose power and felt a little slow to respond to the accelerator, then it became very difficult to pull away and eventually started to misfire with smoke from exhaust at moderate revs (2-3k).
No EML or fault codes using full-fat VCDS.
Runs poorly and sometimes difficult to start (coughs/splutters with white/grey smoke), then idles okay, but response to accelerator is very slow, ie foot to floor and hits 3k in about 3 seconds!
Here's what I've checked so far to assist with diagnosis:
I'm leaning towards injector issues as one of the VCDS parameters for Switch Time Deviation looks different from the others (Group 23 if anyone wants to check ), cylinder 1 is consistently higher than the other two with a figure at idle of 35-38 whereas the others are 12-17 (not sure of units, guessing they are ms). Being higher this would suggest that cylinder 1 injector is slower than the others at responding meaning that cylinder is firing later and causing smoke/power loss.
However, I've not found any details of other tests that could be carried out to confirm this. I could whip them out and send off for testing/calibration, or maybe take a punt and replace all three with a second-hand set.
Has anyone has similar issues or have any ideas for further testing.
Any input would be greatly appreciated.
The car seemed to lose power and felt a little slow to respond to the accelerator, then it became very difficult to pull away and eventually started to misfire with smoke from exhaust at moderate revs (2-3k).
No EML or fault codes using full-fat VCDS.
Runs poorly and sometimes difficult to start (coughs/splutters with white/grey smoke), then idles okay, but response to accelerator is very slow, ie foot to floor and hits 3k in about 3 seconds!
Here's what I've checked so far to assist with diagnosis:
- Turbo - I was convinced that it was broken! But no, it spins okay and there is no play or contact. With the engine running at idle it spins fine. Boost is happening, but because the power is so low, it only builds a little. I also checked waste gate and it's closed, the control pipes are all connected with no leaks.
- Car has no EGR valve so this can be ruled out. The anti-shudder valve is operating correctly and open when running.
- Intercooler is fine and there's no excessive oil build-up.
- The cambelt was changed about 4 years ago, condition is fine and timing has been checked and is spot on. Torsion value fluctuates a little but is around 0.0.
- Injector impedances are all the same at
0.9 OhmsEdit: 0.4 Ohms (corrected for lead resistance), the loom was replaced a few years ago. - Injection Quantity Deviation from VCDS is within range (+/- 2.5 mg/str), the largest value being +0.71.
- Injection timing looks fine at around 5deg BTDC.
- Coolant and fuel temperature values are correct.
- MAF gives sensible values, disconnecting this does not improve running at all.
- The glow plugs are all switched off.
- Last fuel was a few weeks ago, tank is 1/3 full. Fuel filter replaced 2-3 years ago.
- No fuel/air leaks from tandem pump.
I'm leaning towards injector issues as one of the VCDS parameters for Switch Time Deviation looks different from the others (Group 23 if anyone wants to check ), cylinder 1 is consistently higher than the other two with a figure at idle of 35-38 whereas the others are 12-17 (not sure of units, guessing they are ms). Being higher this would suggest that cylinder 1 injector is slower than the others at responding meaning that cylinder is firing later and causing smoke/power loss.
However, I've not found any details of other tests that could be carried out to confirm this. I could whip them out and send off for testing/calibration, or maybe take a punt and replace all three with a second-hand set.
Has anyone has similar issues or have any ideas for further testing.
Any input would be greatly appreciated.
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