|
850 / S70 & V70 '96-'99 / C70 '97-'05 General Forum for the 850 and P80-platform 70-series models |
Information |
|
850 T5R momentary cut out under hard accelerationViews : 2862 Replies : 39Users Viewing This Thread : |
|
Thread Tools | Display Modes |
Apr 16th, 2024, 16:39 | #1 |
VOC Member
Last Online: Jun 12th, 2024 16:26
Join Date: Dec 2002
Location: Tiverton
|
850 T5R momentary cut out under hard acceleration
Any help will be greatly appreciated!
Much already done recently when she wouldn't start at all or ran very badly including: - New MAF sensor - All new vacuum hoses - New distributor cap and rotor arm - New plugs and leads - New O2 sensor (Bosch) theres only one pre-cat - New fuel pump - Checked fuel pressure now and c. 40 psi ok - Cleaned and serviced injectors (new seals and filters) - Changed oil, filter and air filter - new crankshaft position sensor - new camshaft position sensor - new radiator She runs really well now and the problem manifests only under hard acceleration in sport mode when I kick down, revs are above, say 3500 to 4000. It's like I have hit the brakes - it does it 2 or 3 times, the gearbox then shifts up and revs drop and all is good again with strong turbo boost. Checked the codes and I have got: A3 (ABS) 142 Faulty brake pedal switch, open or short 424 Pressure switch for TRACS, faulty or short circuit A7 (Combined Instrument (Trip Computer)) 122 Temp. sensor interval too long The A3 codes may be historic from when I took off and cleaned the brake pedal switch during re-commissioning as it was faulty. Could there be a link or are these faults probable 'red herrings'? As I said, any help will be greatly appreciated (and apologies for the long post! Pete |
Apr 16th, 2024, 21:31 | #2 |
Premier Member
Last Online: Yesterday 22:57
Join Date: Mar 2017
Location: Manchester
|
try a new fuel filter.
|
The Following User Says Thank You to Simmy For This Useful Post: |
Apr 16th, 2024, 22:18 | #3 |
VOC Member
Last Online: Jun 12th, 2024 16:26
Join Date: Dec 2002
Location: Tiverton
|
Thanks Simmy, already done - I should have mentioned that!
|
Apr 17th, 2024, 14:08 | #4 |
Premier Member
Last Online: Jun 14th, 2024 20:20
Join Date: Dec 2002
Location: Co. Limerick, Ireland
|
Are you seeing a warning lamp flash up in the instrument panel when it happens? Could a dodgy pressure switch be triggering the TRACS and cutting fuel supply?
__________________
Liam... '96 854 TDI SE, '99 V70 2.5D S, '05 C70 2.0T Collection, '05 S80 2.0T SE, '15 V70 D4 SE Lux Nav. |
The Following User Says Thank You to Baffler For This Useful Post: |
Apr 17th, 2024, 14:34 | #5 |
Premier Member
Last Online: Today 12:59
Join Date: Apr 2011
Location: Belfast
|
Had this with my 850 and it was the turbo control valve. The car was cutting the fuel to prevent overboost due to the faulty valve. Fitted a new one and all was well again.
__________________
1996 850 T5 - Sold 2003 S40 1.9d - Sold 2004 S60 D5 |
The Following 2 Users Say Thank You to Dancake For This Useful Post: |
Apr 17th, 2024, 15:19 | #6 |
Premier Member
Last Online: Jun 14th, 2024 20:20
Join Date: Dec 2002
Location: Co. Limerick, Ireland
|
Good call, Dancake, was going to suggest the TCV once the TRACS issue is eliminated.
__________________
Liam... '96 854 TDI SE, '99 V70 2.5D S, '05 C70 2.0T Collection, '05 S80 2.0T SE, '15 V70 D4 SE Lux Nav. |
The Following User Says Thank You to Baffler For This Useful Post: |
Apr 17th, 2024, 18:00 | #7 |
VOC Member
Last Online: Jun 12th, 2024 16:26
Join Date: Dec 2002
Location: Tiverton
|
Thanks Baffler.
No, I don't see any warning light. I must admit I didn't know that the TRACS system cuts the fuel but if the brake light switch was playing up originally then maybe it's still flaky and worth pursuing. |
Apr 17th, 2024, 18:15 | #8 |
VOC Member
Last Online: Jun 12th, 2024 16:26
Join Date: Dec 2002
Location: Tiverton
|
Thanks Dancake. I had hoped it wasn't going to be the TCV! I considered replacing it when I was trying to diagnose the starting, rough running issues but it was going to be one of the last things I changed due to price - £152 from PFS https://www.partsforvolvosonline.com...b7f3c152f76652.
|
Apr 18th, 2024, 00:51 | #9 |
Premier Member
Last Online: Today 12:59
Join Date: Apr 2011
Location: Belfast
|
I'm nearly sure I've got an original one sitting about somewhere that you could try. I never tested it so can't comment on whether or not it works properly, but it could be worth a shot. Let me know if you're interested and I'll try to find it if so.
__________________
1996 850 T5 - Sold 2003 S40 1.9d - Sold 2004 S60 D5 |
The Following User Says Thank You to Dancake For This Useful Post: |
Apr 18th, 2024, 10:09 | #10 |
VOC Member
Last Online: Jun 12th, 2024 16:26
Join Date: Dec 2002
Location: Tiverton
|
Dancake, you're a star for that thought. Thanks. now that I have cleared the fault codes I am going to give it another test run also then with the TRACS turned off. If there is no improvement I may well come back and take you up on your kind offer.
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|