V40 T4 (1.9) Misfire / backfire - running rich - Page 4

T4Rick · Jul 5th, 2010, 20:38

Lol i meant the blue like blocks that plugs into the coil packs,your right about the red and green wire,(RED live and GREEN earth).Did you say you bought a maf?,to reset ecu just undo the live off the battery for about half hr and try again.Can you or have you put the throttle cable back to where it was?

Madmax43 · Jul 5th, 2010, 20:51

I have a '97 S70 T5 that has the same problem as yours... Backfiring and misfiring, but mine does it when the transmission is in S mode and I nail it with the engine speed above 3,500 rpm.

I read you got an aftermarket MAF... GSF have a genuine Bosch one for £160 + the dreaded... Everyone I have spoken to has said an aftermarket one is good for 6 months or so. As a result my new MAF will go in when I am paid next.

Also ensure the wastegate actuator on the turbo works and moves freely.

If you have a bad front lambda you might get fault code P0134. This means it is open circuit and will lead to very rich running and the exhaust will ming gloriously.

A bad MAF could lead to fault P0171 (Bank one fuel trim lean) and P0108 (Manifold Absolute Pressure sensor fault - I think) as well.

If you have independent coil packs then I doubt you have a throttle cable - I think yours might be a 'fly by wire' system.

Ebay have OBD2 scanners and fault code readers for about £80, try this link:
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=180529339047

Good luck...

Martin

gmain1967 · Jul 5th, 2010, 20:55

I wouldn't disconnect the knock sensor - especially given that the engine isn't running correctly.

If the HT leads are connected with insulating tape, bin them. What other reason would there be, other than they were shot, and someone was trying to get a little longer out of them - possibly before they sold the car? These could quite possibly work at lower rpm but when needing to work harder and draw more power at high rpm, are breaking down, hence the misfire.

As for resetting the ECU. Disconnect the battery completely and leave it overnight. Time for ECU to reset varies depending what you listen to, but a minimum of 2 hours seems to be commonly accepted.

With the issues you are having, you need to resolve the known problems first e.g. HT leads, otherwise you will end up chasing your tail for ever.

mikeyskona · Jul 5th, 2010, 20:55

Yeah rick.. the throttle is back to normal now. just a millimetre off being taught

..

I did buy a MAF... Only one of those cheap £60 ebay jobs, but i want to cure this problem. In 6 months when it dies (cause i know they're crap) i'll go off and buy another one... I just dont want to chuck endless amounts of money in to it to find it's a scrapper at the moment, if that makes sense.

I'll go take another video of the actual lump now.... before i disconnect the battery.... You never know.. Someone might see something i can't

cheers, back in 10

T4Rick · Jul 5th, 2010, 20:59

The knock sensor rather works or it doesnt there common for going,it works like a microphone and detects noises and sounds in the engine.Its a 12mm nut under the inlet but if you remove it it needs torquing back up to 20nm,the lead goes up to the bulk head under a plastic cover where the map sensor goes.Im not saying that it is the problem but worth a look.Even if it was another maf sensor (not genuine) and new it would work.
so you have replaced the following

spark plugs
fuel filter
maf
coil packs

Did you replace the ht leads?

Madmax43 · Jul 5th, 2010, 21:02

I have also been advised to check the PCV system as this can cause backfiring and misfiring. Small leaks in the system between the turbo charger and inlet manifold will result in similar issues.

Do you need Volvo FCR or is your car totally OBD2 compliant? There is a seller on eBay who flogged me a OBD2 adaptor and the Volvo FCR s/w (torrented that anyway) and it scans for faults as well as resets most DTC's on the car subsystems.

Cheers,
Martin

T4Rick · Jul 5th, 2010, 21:09

It will be some thing or nothing lol

mikeyskona · Jul 5th, 2010, 21:25

Rick:
Correct.

So far i have done the following.
New plugs (twice)
New MAF
New Coil Packs w/ HT leads (bought as a set).
New fuel filter.

I've checked as best as i can for vacuum leaks, but there's so many hoses it's hard to see what is what sometimes, lol

I have another video.. Is it me, or is it revving better when i use the throttle body rather than the pedal?
oh... and you'll notice i pulled one of the vent hoses a little bit too hard and made myself jump, LOL

vid #2:
http://www.mikeyskona.co.uk/random/standingtest2.3gp

The battery is now disconnected. I have a book, but it doesn't give me a great amount of detail on the turbo system.

Are there any diagrams about where i can get a good idea of what's supposed to go where? just incase i start pulling off hoses and forgetting where they go, lol.

Martin:
Mine requires the Volvo FCR.
Again. Any Diagrams on the PCV / Turbo system?

Thanks guys, i feel we're starting to make a little progress on this

lol

T4Rick · Jul 5th, 2010, 21:59

Lol at the vacum pipe coming off.It revs past 5k now which is a plus.You have wired the coil packs up right as well.Are the ends slack though?i crimped my ends up abit then stuck them on so there tight.

mikeyskona · Jul 5th, 2010, 22:01

just about to do that now, and also the stretching the springs trick, as these packs aren't brand new (guaranteed tested used from continental cars).

Jul 5th, 2010, 20:51	#32
Madmax43 Junior Member Last Online: Dec 31st, 2018 13:07 Join Date: Mar 2010 Location: Neyland	I have a '97 S70 T5 that has the same problem as yours... Backfiring and misfiring, but mine does it when the transmission is in S mode and I nail it with the engine speed above 3,500 rpm. I read you got an aftermarket MAF... GSF have a genuine Bosch one for £160 + the dreaded... Everyone I have spoken to has said an aftermarket one is good for 6 months or so. As a result my new MAF will go in when I am paid next. Also ensure the wastegate actuator on the turbo works and moves freely. If you have a bad front lambda you might get fault code P0134. This means it is open circuit and will lead to very rich running and the exhaust will ming gloriously. A bad MAF could lead to fault P0171 (Bank one fuel trim lean) and P0108 (Manifold Absolute Pressure sensor fault - I think) as well. If you have independent coil packs then I doubt you have a throttle cable - I think yours might be a 'fly by wire' system. Ebay have OBD2 scanners and fault code readers for about £80, try this link: http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=180529339047 Good luck... Martin __________________ '97 S70 T5 Auto - Mine '05 XC90 Auto - Mine '07 S40 2.0D - Mum's '67 P1800S Manual with o/d - MK2 son's Last edited by Madmax43; Jul 5th, 2010 at 20:53. Reason: Blatant illiteracy on my part

Jul 5th, 2010, 21:02	#36
Madmax43 Junior Member Last Online: Dec 31st, 2018 13:07 Join Date: Mar 2010 Location: Neyland	I have also been advised to check the PCV system as this can cause backfiring and misfiring. Small leaks in the system between the turbo charger and inlet manifold will result in similar issues. Do you need Volvo FCR or is your car totally OBD2 compliant? There is a seller on eBay who flogged me a OBD2 adaptor and the Volvo FCR s/w (torrented that anyway) and it scans for faults as well as resets most DTC's on the car subsystems. Cheers, Martin __________________ '97 S70 T5 Auto - Mine '05 XC90 Auto - Mine '07 S40 2.0D - Mum's '67 P1800S Manual with o/d - MK2 son's

Jul 5th, 2010, 20:38	#31
T4Rick Premier Member Last Online: Oct 11th, 2012 08:49 Join Date: Jun 2010 Location: manchester	Lol i meant the blue like blocks that plugs into the coil packs,your right about the red and green wire,(RED live and GREEN earth).Did you say you bought a maf?,to reset ecu just undo the live off the battery for about half hr and try again.Can you or have you put the throttle cable back to where it was?

Jul 5th, 2010, 20:55	#33
gmain1967 Premier Member Last Online: Mar 16th, 2021 14:49 Join Date: Oct 2009 Location: Coedpoeth	I wouldn't disconnect the knock sensor - especially given that the engine isn't running correctly. If the HT leads are connected with insulating tape, bin them. What other reason would there be, other than they were shot, and someone was trying to get a little longer out of them - possibly before they sold the car? These could quite possibly work at lower rpm but when needing to work harder and draw more power at high rpm, are breaking down, hence the misfire. As for resetting the ECU. Disconnect the battery completely and leave it overnight. Time for ECU to reset varies depending what you listen to, but a minimum of 2 hours seems to be commonly accepted. With the issues you are having, you need to resolve the known problems first e.g. HT leads, otherwise you will end up chasing your tail for ever.

Jul 5th, 2010, 20:55	#34
mikeyskona Premier Member Last Online: Aug 24th, 2012 12:10 Join Date: Jun 2010 Location: Plymouth	Yeah rick.. the throttle is back to normal now. just a millimetre off being taught .. I did buy a MAF... Only one of those cheap £60 ebay jobs, but i want to cure this problem. In 6 months when it dies (cause i know they're crap) i'll go off and buy another one... I just dont want to chuck endless amounts of money in to it to find it's a scrapper at the moment, if that makes sense. I'll go take another video of the actual lump now.... before i disconnect the battery.... You never know.. Someone might see something i can't cheers, back in 10

Jul 5th, 2010, 20:59	#35
T4Rick Premier Member Last Online: Oct 11th, 2012 08:49 Join Date: Jun 2010 Location: manchester	The knock sensor rather works or it doesnt there common for going,it works like a microphone and detects noises and sounds in the engine.Its a 12mm nut under the inlet but if you remove it it needs torquing back up to 20nm,the lead goes up to the bulk head under a plastic cover where the map sensor goes.Im not saying that it is the problem but worth a look.Even if it was another maf sensor (not genuine) and new it would work. so you have replaced the following spark plugs fuel filter maf coil packs Did you replace the ht leads?

Jul 5th, 2010, 21:09	#37
T4Rick Premier Member Last Online: Oct 11th, 2012 08:49 Join Date: Jun 2010 Location: manchester	It will be some thing or nothing lol

Jul 5th, 2010, 21:25	#38
mikeyskona Premier Member Last Online: Aug 24th, 2012 12:10 Join Date: Jun 2010 Location: Plymouth	Rick: Correct. So far i have done the following. New plugs (twice) New MAF New Coil Packs w/ HT leads (bought as a set). New fuel filter. I've checked as best as i can for vacuum leaks, but there's so many hoses it's hard to see what is what sometimes, lol I have another video.. Is it me, or is it revving better when i use the throttle body rather than the pedal? oh... and you'll notice i pulled one of the vent hoses a little bit too hard and made myself jump, LOL vid #2: http://www.mikeyskona.co.uk/random/standingtest2.3gp The battery is now disconnected. I have a book, but it doesn't give me a great amount of detail on the turbo system. Are there any diagrams about where i can get a good idea of what's supposed to go where? just incase i start pulling off hoses and forgetting where they go, lol. Martin: Mine requires the Volvo FCR. Again. Any Diagrams on the PCV / Turbo system? Thanks guys, i feel we're starting to make a little progress on this lol

Jul 5th, 2010, 21:59	#39
T4Rick Premier Member Last Online: Oct 11th, 2012 08:49 Join Date: Jun 2010 Location: manchester	Lol at the vacum pipe coming off.It revs past 5k now which is a plus.You have wired the coil packs up right as well.Are the ends slack though?i crimped my ends up abit then stuck them on so there tight.

Jul 5th, 2010, 22:01	#40
mikeyskona Premier Member Last Online: Aug 24th, 2012 12:10 Join Date: Jun 2010 Location: Plymouth	just about to do that now, and also the stretching the springs trick, as these packs aren't brand new (guaranteed tested used from continental cars).

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