1.4 16v AFH Kangarooing and Stalling at idle

[jackanyon]

I’m after some advice.

I recently AFH swapped my mk2f polo. I got it from a donor mk2 which had already been AFH swapped, so the loom etc was already done.


Immediately after fitting the engine, it developed this strange thing where between about 2000rpm and 3500rpm the car... kangaroos (best way I can describe it). If flooring it from a standstill, this doesn’t happen - its only on partial throttle. However, in the donor car, this symptom wasn’t present. Recently as the colder weather sets in, the idle has begun to fluctuate. Occasionally it stalls at traffic lights, and when putting the clutch in as I come to a stop.


I’ve gone to extreme lengths to try and sort it before resorting to help, but being a Honda guy, I’m worried I might be missing something obvious to someone who knows VW’s. Steps taken so far:

• Used ‘premium’ fuel
• Adjusted throttle cable
• Checked for vacuum leaks (none found)
• Partially cleaned the throttle body
• Replaced coil with known good OEM one
• Replaced main chassis ground
• Replaced HT leads
• Replaced spark plugs
• Replaced dizzy cap
• Replaced dizzy rotor
• Replaced entire dizzy after the above
• Replaced in tank + exterior pump with walbro 255
• Replaced the entire fuel feed, and return lines and filter
• Fitted new coolant sensor (non OEM, Hella made)
• Italian tuneup

A scan with VCDS initially revealed a code for the O2 sensor, EGR and coolant sensor. After replacing the coolant sensor and clearing the codes, only the EGR code has returned after a 200 mile run. The symptom is still present.


When the engine was removed from the donor car, the only thing I removed from the engine was the engine loom itself. So any gaskets, or seals should hopefully remain undisturbed.

I've read about issue regarding the ECU being defective, it has the part number 030 906 030 D. I've also seen many similar forum posts describing my issue, but nobody has ever given a fully comprehensive explanation of how they resolved it. I have VCDS so if anyone can suggest something I can check, please share.

I really like the power delivery of the AFH, and its really grown on me so if anyone can shed some light I’d be so grateful. Please bare in mind that in the donor car, none of these issues existed and it behaved and drove exactly as one would expect.

Jack


polo.jpg

[Crasher]

Mrs Crasher had a 6N1 16v from new and this had the same ECU and all sorts of running problems which were rectified by fitting the E revision ECU which is now obsolete maninstream but can be bought from Suchergebnisse für: '030 906 030 E' for daft money. If the EGR code is excessive flow then the valve may be stuck open and this will cause terrible running problems. Have you calibrated the TB in Basic Settings 098 then set the ignition timing at 6 degrees with the ECU in Basic Settings 001 where the idle should automatically lift to approx 1300rpm?

[jackanyon]

Thank you for the quick response.

I was concerned you’d confirm that it could be the ECU at fault. I may shop around for a used working one, if I can find one for a reasonable cost.

I’ll rescan it tomorrow and just confirm what codes its throwing. I haven’t tried either of those options yet. Mind giving me a quick run down of the procedure?

Thank you

[Crasher]

Do you have a timing light? It is not the ideal way as viewing the timing mark is extremely difficult but an inductive timing meter is a rare thing to own, mine went **** up years ago.

[jackanyon]

I do yeah, conveniently needed it for my other more Japanese project. Who would’ve thought I’d need it for the daily!

[jackanyon]

I’ve limped the car down to my unit today. After rescanning these are the codes I get. All symptoms were present during the 14 mile drive.

4 Faults Found:

00525 - Oxygen (Lambda) Sensor (G39)
06-10 - Signal too High - Intermittent

00609 - Ignition Output 1
31-10 - Open or Short to Ground - Intermittent

01247 - Activated Charcoal Filter (EVAP) System Solenoid Valve 1 (N80)
31-10 - Open or Short to Ground - Intermittent

01265 - Exhaust Gas Recirculation Valve (N18)
31-10 - Open or Short to Ground - Intermittent


Do we think any of these could be the culprit? Or is this a red herring.

Jack

[Crasher]

Prod me Monday, I need to check the wiring diagram.

[jackanyon]

Prod me Monday, I need to check the wiring diagram.

Consider this as me prodding!

A little research is pointing towards the ecu being at fault. I found the attached little table somewhere on the depths of the internet which looks to be confirming the worst case.

IMG_4866.jpg

Jack

[Crasher]

Possibly but the code definition is short to earth which means there is more likely a problem with the green/red from pin 24 of the ECU to pion 2 of the coil OR if the coil is a cheap and nasty, the coil itself as they were bad enough genuine but white box specials... I have known them fail straight out of the box so make sure it is OE quality such as Bosch. For the EVAP valve, check the continuity of the green/yellow from pin 3. On the wiring diagram it says the EGR valve solenoid is N121 and this shares a power feed wit the N80, the coil, lambda sensor and ECU from the fuel pump relay.

[jackanyon]

Thanks for this Crasher, its probably the best help I’ve had yet.

I’ll get on testing the wiring at the weekend. I dont suppose you’ve got a numbered pinout of the ECU connector do you?

Okay thats interesting, so this really could come down to part of the loom being damaged then...