Engine: TDI: - help needed pls

dieselpower · May 13th, 2009, 07:30

Hello. Recently became an owner of 850 tdi, 1996. The light on the dash resembling lambda letter was on. Car was more than sluggish accelarating, turbo was non present, engine rough, smokes a bit unburned fuel,and barely reaches 70mph. After lots of silly suggestions by mechanics, decided to sort it out by the help of a friend of mine. We cleaned the intake manifolds, blanked the EGR, clened MAf, cleaned fuel pump, checked cables and sensors,and few other little things, and tested with vol-fcr. It gave only code 716 fuel quantity adjuster. Once we cleared the code, car became bullet, accelarates perfect, turbo kicks at around 2100 rpm and no smoke. When we switch the engine off and start again, ECU stores same code 716 again, and car is back to its previuos state, sadly. Only cures it reseting the code. Couldnt find anything else wrong, apart from overcharging alternator. Battery voltage reads 13,5 at switched off engine, and reaches 16 and above when alternator charges. Could this have any connection with the code 716 coming up? Could excess voltage give warning to the ECU and it just brings the car to this limp home mode?Any advice appreciated. Thank you

bigandquick · May 13th, 2009, 08:23

Can't advise on the mechanical side I'm afraid. But an alternator pumping out too high a voltage can be lethal to the engine management system. If you intend keeping the car I'd get the alternator changed quickly.

outnumbered · May 13th, 2009, 17:13

Quote:

Originally Posted by dieselpower

Hello. Recently became an owner of 850 tdi, 1996. The light on the dash resembling lambda letter was on. Car was more than sluggish accelarating, turbo was non present, engine rough, smokes a bit unburned fuel,and barely reaches 70mph. After lots of silly suggestions by mechanics, decided to sort it out by the help of a friend of mine. We cleaned the intake manifolds, blanked the EGR, clened MAf, cleaned fuel pump, checked cables and sensors,and few other little things, and tested with vol-fcr. It gave only code 716 fuel quantity adjuster. Once we cleared the code, car became bullet, accelarates perfect, turbo kicks at around 2100 rpm and no smoke. When we switch the engine off and start again, ECU stores same code 716 again, and car is back to its previuos state, sadly. Only cures it reseting the code. Couldnt find anything else wrong, apart from overcharging alternator. Battery voltage reads 13,5 at switched off engine, and reaches 16 and above when alternator charges. Could this have any connection with the code 716 coming up? Could excess voltage give warning to the ECU and it just brings the car to this limp home mode?Any advice appreciated. Thank you

hi
i would check the conections between the 8 pin plug at the pump to the ecu..if that code keeps reacuring
mike

alv70d1999 · May 13th, 2009, 20:05

battery should read 12 volts ish when the car is off and 16 volts while the car is running is very high.... 14.8 volts tops......get the alternator checked out..

alv70d1999 · May 13th, 2009, 20:07

just asked on other forums.....16 volts.....the alternators shagged !!!

dieselpower · May 14th, 2009, 07:06

J ust an update on the issue. Yesterday took the car and tested with vol-fcr. Mil light was on again. Came up same fault code 716. Cleared the code.And went on for a spin. Drove for half an hour and switched engine off. Strted it after 15 mins and was prepared to clear the code again , but no light came on! Went on to electrician to check the alternator's charge, battery was reading 14.1 with engine reving! Everything is so bizzare.Will take the car again today and see what will happen. Thank you all who offered advice.

RoscoMac · May 14th, 2009, 12:46

Dodgy MAF sensor?

dieselpower · May 14th, 2009, 13:13

Quote:

Originally Posted by RoscoMac

Dodgy MAF sensor?

It has a mechanical one, and has been cleaned and works ok

outnumbered · May 14th, 2009, 14:13

Quote:

Originally Posted by dieselpower

J ust an update on the issue. Yesterday took the car and tested with vol-fcr. Mil light was on again. Came up same fault code 716. Cleared the code.And went on for a spin. Drove for half an hour and switched engine off. Strted it after 15 mins and was prepared to clear the code again , but no light came on! Went on to electrician to check the alternator's charge, battery was reading 14.1 with engine reving! Everything is so bizzare.Will take the car again today and see what will happen. Thank you all who offered advice.

code 716 as said that there is a fault between the 8 pin plug and the ecu , have a look and clean the 8 pin plug out if it shows again.
mike

dieselpower · May 14th, 2009, 15:00

Quote:

Originally Posted by outnumbered

code 716 as said that there is a fault between the 8 pin plug and the ecu , have a look and clean the 8 pin plug out if it shows again.
mike

Thanks alot Mike.

Will have a look and clean the pin.

May 13th, 2009, 07:30	#1
dieselpower New Member Last Online: Feb 21st, 2011 14:51 Join Date: May 2009 Location: sofia	help needed pls Hello. Recently became an owner of 850 tdi, 1996. The light on the dash resembling lambda letter was on. Car was more than sluggish accelarating, turbo was non present, engine rough, smokes a bit unburned fuel,and barely reaches 70mph. After lots of silly suggestions by mechanics, decided to sort it out by the help of a friend of mine. We cleaned the intake manifolds, blanked the EGR, clened MAf, cleaned fuel pump, checked cables and sensors,and few other little things, and tested with vol-fcr. It gave only code 716 fuel quantity adjuster. Once we cleared the code, car became bullet, accelarates perfect, turbo kicks at around 2100 rpm and no smoke. When we switch the engine off and start again, ECU stores same code 716 again, and car is back to its previuos state, sadly. Only cures it reseting the code. Couldnt find anything else wrong, apart from overcharging alternator. Battery voltage reads 13,5 at switched off engine, and reaches 16 and above when alternator charges. Could this have any connection with the code 716 coming up? Could excess voltage give warning to the ECU and it just brings the car to this limp home mode?Any advice appreciated. Thank you

May 13th, 2009, 08:23	#2
bigandquick Premier Member Last Online: May 15th, 2024 14:37 Join Date: Dec 2003 Location: Cambridge	Can't advise on the mechanical side I'm afraid. But an alternator pumping out too high a voltage can be lethal to the engine management system. If you intend keeping the car I'd get the alternator changed quickly. __________________ Tim '16 XC60 SE Lux Nav

May 13th, 2009, 20:05	#4
alv70d1999 I've Been Banned Last Online: Sep 28th, 2010 12:05 Join Date: Apr 2009 Location: button moon	battery should read 12 volts ish when the car is off and 16 volts while the car is running is very high.... 14.8 volts tops......get the alternator checked out..

May 13th, 2009, 20:07	#5
alv70d1999 I've Been Banned Last Online: Sep 28th, 2010 12:05 Join Date: Apr 2009 Location: button moon	just asked on other forums.....16 volts.....the alternators shagged !!!

May 14th, 2009, 07:06	#6
dieselpower New Member Last Online: Feb 21st, 2011 14:51 Join Date: May 2009 Location: sofia	J ust an update on the issue. Yesterday took the car and tested with vol-fcr. Mil light was on again. Came up same fault code 716. Cleared the code.And went on for a spin. Drove for half an hour and switched engine off. Strted it after 15 mins and was prepared to clear the code again , but no light came on! Went on to electrician to check the alternator's charge, battery was reading 14.1 with engine reving! Everything is so bizzare.Will take the car again today and see what will happen. Thank you all who offered advice.

May 14th, 2009, 12:46	#7
RoscoMac Scottish Section Chair Last Online: Apr 28th, 2024 22:21 Join Date: Dec 2002 Location: Ayrshire View Photos By: RoscoMac	Dodgy MAF sensor?

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