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" > S40 / V40 '96-'04 General

Notices

S40 / V40 '96-'04 General Forum for the Volvo S40 and V40 (Classic) Series from 1995-2004.

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

Excessive smoke

Views : 429

Replies : 2

Users Viewing This Thread :  

Reply
 
Thread Tools Display Modes
Old Jan 5th, 2019, 22:23   #1
nickar
Junior Member
 

Last Online: Nov 17th, 2019 14:43
Join Date: Nov 2018
Location: Chester
Default Excessive smoke

My V40 2.0T with aftermarket LPG conversion is putting out a significant amount of smoke at quite specific moments. I have my mechanic looking into it but thought it would be worth sticking on here in case the combination of symptoms brings up an obvious problem to someone!

If I do 70 on the motorway and slow down to around 60, a thick cloud comes out briefly and lingers slightly where it comes out as opposed to spreading with the speed of the vehicle. It also seems to do it more at lower speeds but mostly when I lift off the accelerator. It's almost like something is building up under acceleration and then burning off when I take the pressure off.

When I stop and leave the car idling, the smoke comes out consistently thick. It seems worse with petrol than LPG but I may be wrong with that. There are multiple error codes that mention lambda sensors and fuelling mainly. I reckon the smoke has a slight blue tint when I see it on the motorway but it looks more white at idle.

The LPG system is also struggling to kick in over the past week despite being full of gas. The car has always had a problem with hesitation under initial acceleration now and again but that's mainly on LPG. One more thing: the fuel pump was replaced recently.

Based on the error codes and the fact it's been running on LPG, I'm tempted to think it is over-fuelling. However, I am aware white smoke is generally water and blue is oil.

Thank you.

Last edited by nickar; Jan 5th, 2019 at 22:25.
nickar is offline   Reply With Quote
Old Jan 6th, 2019, 18:23   #2
nickar
Junior Member
 

Last Online: Nov 17th, 2019 14:43
Join Date: Nov 2018
Location: Chester
Default

Just in case anybody else is reading this with the similar symptoms, I think it is the valve stem seals based on this article at https://dannysengineportal.com/valve-stem-seal/:

Quote:
Idle and Stop and Go Driving
Bad valve stem seals will show themselves during prolonged idling at stop signs or stop lights in congested city conditions. When the vehicle sits at idle for prolonged periods, high levels of vacuum at the intake manifold result. The high vacuum attracts oil in the heads to congregate around the valve stems. Upon acceleration, the oil gets sucked past the seal and down through the valve guide. Huge clouds of blue-white smoke exit the tailpipe after each acceleration from a stop. The burning smoke will disappear during cruising or highway speed.

Off-Throttle Braking
Evidence of valve seals being compromised will also show up during off-throttle braking. More so when descending a steep downgrade where the accelerator pedal remains static. High manifold vacuum, coupled with the downward slant of the engine, oil collects toward the front of the valve cover. Upon pushing the accelerator after a long coast, burned oil will exit the tailpipe in large amounts. After that the smoke will stop again.
nickar is offline   Reply With Quote
The Following User Says Thank You to nickar For This Useful Post:
Old Jan 9th, 2019, 23:12   #3
nickar
Junior Member
 

Last Online: Nov 17th, 2019 14:43
Join Date: Nov 2018
Location: Chester
Default

Nobody else seems to have any knowledge on this one so I stopped by the garage today. My mechanic said the smoke smells like fuel so it looks like I may be wrong about the oil burning!
nickar 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 10:02.


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