Volvo Community Forum. The Forums of the Volvo Owners Club

Forum Rules Volvo Owners Club About VOC Volvo Gallery Links Volvo History Volvo Press
Go Back   Volvo Owners Club Forum > "Technical Topics" > C30 / S40 & V50 '04-'12 / C70 '06-'13 General

Notices

C30 / S40 & V50 '04-'12 / C70 '06-'13 General Forum for the P1-platform C30 / S40 / V50 / C70 models

Information
  • VOC Members: There is no login facility using your VOC membership number or the details from page 3 of the club magazine. You need to register in the normal way
  • AOL Customers: Make sure you check the 'Remember me' check box otherwise the AOL system may log you out during the session. This is a known issue with AOL.
  • AOL, Yahoo and Plus.net users. Forum owners such as us are finding that AOL, Yahoo and Plus.net are blocking a lot of email generated from forums. This may mean your registration activation and other emails will not get to you, or they may appear in your spam mailbox

Thread Informations

V50 p0172, still no fix.

Views : 1363

Replies : 10

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old Mar 6th, 2023, 16:43   #1
John Mawson
Volva
 

Last Online: Oct 24th, 2023 19:16
Join Date: Mar 2023
Location: Ismaning
Default V50 p0172, still no fix.

Hi.
V50r
2.4i
2004
214,000km
Lpg added 2016

I've had the code p0172 since I owned the car for18 months now.

other codes include P0300, multiple misfire and P0137 o2 sensor voltage low (first time I saw that one)

Parts I have replaced.

Sparkplugs with 1 electrode
Air filter
MAF sensor
Lambda,2
Throttle Body, Oem.
Battery.

At first when I got the vehicle it had a hard job driving at low revs and giving throttle, like out of a roundabout, so I would have to shift down to alleviate misfiring, after changing the spark plugs it,s 80% better. Driving on Petrol is ls ways better. There was a period for about 5 months where I only used Petrol and no engine light came on.
I think the problems are associated with the LPG side of things.
I went to an LPG mechanic and he did something ? for 200 euros so
Idling on petrol or lpg is really steady now.
The engine lamp is still on. I use the Volvo every day and it seems to drive fine but one thing I now do is to turn the Lpg off until the engine temperature shows 90 as in cold weather the Lpg switches over to early and I get a warning to switch the Lpg off, so I wait a few more km before switching over.
I don't think I have a vacuum leak, I tried an improvised Smoke test and didn't see anything obvious.
I have a screen shot of the LTFT reading -23.4, so that's quit bad from what I have been reading STFT was 10.2%
engine speed 721
MAF 4.02
Time since engine start, 26 sec, which means its on petrol.
Fuel system 1 status CL which I think means closed.

I really don't know what to do, Mechanics don't like Lpg and Lpg mechanics don't really mess with engines.
I phoned a few Mechanic´s but they don´t have Volvo software.
If I found a Volvo Mechanic they'll probably charge me 300 euros to tell me to find an Lpg mechanic, that's my fear anyway.
Anyhow I hope someone has an idea about this.

Last edited by John Mawson; Mar 6th, 2023 at 17:12.
John Mawson is offline   Reply With Quote
Old Mar 6th, 2023, 16:47   #2
Clan
Experienced Member
 
Clan's Avatar
 

Last Online: Today 01:00
Join Date: Jun 2007
Location: L/H side
Default

Quote:
Originally Posted by John Mawson View Post
Hi.
V50r
2.4i
2004
214,000km
Lpg added 2016

I've had the code p0172 since I owned the car for18 months now.

other codes include P0300, multiple misfire and P0137 o2 sensor voltage low (first time I saw that one)

Parts I have replaced.

Sparkplugs with 1 electrode
Air filter
MAF sensor
Lambda,2
Throttle Body, Oem.
Battery.

At first when I got the vehicle it had a hard job driving at low revs and giving throttle, like out of a roundabout, so I would have to shift down to alleviate misfiring, after changing the spark plugs it,s 80% better.
I think the problems are associated with the LPG side of things.
I went to an LPG mechanic and he did something ? for 200 euros so
Idling on petrol or lpg is really steady now.
The engine lamp is still on. I use the Volvo every day and it seems to drive fine but one thing I now do is to turn the Lpg off until the engine temperature shows 90 as in cold weather the Lpg switches over to early and I get a warning to switch the Lpg off, so I wait a few more km before switching over.
I don't think I have a vacuum leak, I tried an improvised Smoke test and didn't see anything obvious.
I have a screen shot of the LTFT reading -23.4, so that's quit bad from what I have been reading STFT was 10.2%
engine speed 721
MAF 4.02
Time since engine start, 26 sec, which means its on petrol.
Fuel system 1 status CL which I think means closed.

I really don't know what to do, Mechanics don't like Lpg and Lpg mechanics don't really mess with engines.
If I found a Volvo Mechanic they'll probably charge me 300 euros to tell me to find an Lpg mechanic, that's my fear anyway.
Anyhow I hope someone has an idea about this.
you will probably find the LPG exhaust gasses are very different to the petrol gasses which the lambda sensors are used to, so the reading will not be what the ECU expects. does the engine light stay off when on petrol?
__________________
My comments are only based on my opinions and vast experience .
Clan is offline   Reply With Quote
Old Mar 6th, 2023, 17:45   #3
ele288
Member
 

Last Online: Yesterday 20:21
Join Date: Jun 2019
Location: Havant
Default

On the 5 cylinder engine, weak point is the ignition coils, but you have multiple misfire so I would look for cracked coil or in the loom there is ground wire for coils, over time they are getting brittle and may cause missfire as the lpg needs strong spark its more noticeable on lpg. If I remember the engine has ecu made by denso and lambda is made by denso/ngk. They don't like bosch universal o2 sensors. What brand was the lambda?Did you replace just one or both? Lambda life span is around 150k and pi172 is indication for over fueling so it's running rich which is controlled by first lambda and map sensor and maf, before cat, the second lambda is monitoring cat efficiency.

Last edited by ele288; Mar 6th, 2023 at 17:53.
ele288 is offline   Reply With Quote
Old Mar 7th, 2023, 04:46   #4
John Mawson
Volva
 

Last Online: Oct 24th, 2023 19:16
Join Date: Mar 2023
Location: Ismaning
Default

Quote:
Originally Posted by Clan View Post
you will probably find the LPG exhaust gasses are very different to the petrol gasses which the lambda sensors are used to, so the reading will not be what the ECU expects. does the engine light stay off when on petrol?
The engine light did stay off, but I need to verify that again.
John Mawson is offline   Reply With Quote
Old Mar 7th, 2023, 05:00   #5
John Mawson
Volva
 

Last Online: Oct 24th, 2023 19:16
Join Date: Mar 2023
Location: Ismaning
Default

Quote:
Originally Posted by ele288 View Post
On the 5 cylinder engine, weak point is the ignition coils, but you have multiple misfire so I would look for cracked coil or in the loom there is ground wire for coils, over time they are getting brittle and may cause missfire as the lpg needs strong spark its more noticeable on lpg. If I remember the engine has ecu made by denso and lambda is made by denso/ngk. They don't like bosch universal o2 sensors. What brand was the lambda?Did you replace just one or both? Lambda life span is around 150k and pi172 is indication for over fueling so it's running rich which is controlled by first lambda and map sensor and maf, before cat, the second lambda is monitoring cat efficiency.
The whole point is to get rid of the p0172.
I replaced the rear 02 sensor with a Denso. the front one looked new as the cable was clean and like new.
I get misfires at low revs, anything under 1500 and accelerating which as you said it could be resistance to the spark. I think ill have to check all grounds and coils. This could help the misfire.
As for the rich condition and the "long term fuel trim" being -24. This is the proof of something odd going on.
John Mawson is offline   Reply With Quote
Old Mar 7th, 2023, 11:08   #6
ele288
Member
 

Last Online: Yesterday 20:21
Join Date: Jun 2019
Location: Havant
Default

Check if the front lambda is denso not bosch or aftermarket. There is ground wire in the loom to the coils as they age they may crack.
ele288 is offline   Reply With Quote
Old Mar 7th, 2023, 16:53   #7
John Mawson
Volva
 

Last Online: Oct 24th, 2023 19:16
Join Date: Mar 2023
Location: Ismaning
Default

Quote:
Originally Posted by ele288 View Post
Check if the front lambda is denso not bosch or aftermarket. There is ground wire in the loom to the coils as they age they may crack.
I tried a look but its the wrong way round. I cant see any righting on it.
That will be a difficult one to remove.
I read a bit today, my spark plug gaps are to wide, had a bit of spare time and adjusted them to 0.48 mm. I checked the coils and they look like new, seriously
I know when something looks old, of the, another repair I cant see in the maintenance log, they are Bosch. ground cables cleaned, doing a resistance test on them will need me to find the beginning of the cable.
deleted codes, 10 mile run and p0172 there again.
John Mawson is offline   Reply With Quote
Old Mar 8th, 2023, 00:18   #8
ele288
Member
 

Last Online: Yesterday 20:21
Join Date: Jun 2019
Location: Havant
Default

Disconnect front lambda and check if it will make the difference.
ele288 is offline   Reply With Quote
Old Mar 8th, 2023, 17:26   #9
John Mawson
Volva
 

Last Online: Oct 24th, 2023 19:16
Join Date: Mar 2023
Location: Ismaning
Default

Quote:
Originally Posted by ele288 View Post
Disconnect front lambda and check if it will make the difference.
so unplugged.
I will probably need a longer test over a few days.

On Gas 2 codes 0033, 172. it detected the missing Sensor.
codes erased.
.
Petrol only, was the same result, 2 codes, still unplugged.
codes erased.

plugged in, petrol only and same 2 codes, so I thought somehow they where still stored.
codes erased.

petrol only , a short 1 mile spin, engine still warm, no codes.

LTFT , there was no difference, I red them between each test.
idling, -24
2000 reves, -10 or lower.

I did drive for a period last year and I didn't have the engine light on, that's how I got through the mot, they switched on the gas by the emissions test
and it passed, but they didn't notice the engine light came on.
John Mawson is offline   Reply With Quote
Old Mar 19th, 2023, 09:25   #10
John Mawson
Volva
 

Last Online: Oct 24th, 2023 19:16
Join Date: Mar 2023
Location: Ismaning
Default

Driving on petrol gives no fault codes.

Using Lpg activates the fault code p0172 Ritch.
John Mawson is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 12:00.


Powered by vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.