LPG Forum


All times are UTC



Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Thu Mar 30, 2017 2:03 pm 
New member

Joined: Fri Nov 15, 2013 4:09 pm
Posts: 23
I recently purchased a obd dongle in order to read the CVT fluid temperature on my 2011 Subaru Outback. This dongle has also allowed me to look observe other things like timing, knock correction etc. I run on lpg most of the time, but recently ran out of it and ran on petrol for a while. I noticed the engine was " pinging" slightly at about 1200rpm, especially at low speed on an incline. It does not do this on lpg. Is this caused by the petrol ecu adapting to the higher octane lpg, then struggling with 95 octane petrol.? I have observed the ECU trying and failing to advance the ignition advance multiplier ( i think its called) while on petrol to 1.0 and it didn't do it in a couple of days and about 100 miles of driving. When i switched to lpg, it got to 1.0 ( where it apparently should be?) within 10 minutes! Any input appreciated!


Top
 Profile  
Reply with quote  
PostPosted: Wed Jun 28, 2017 3:42 pm 
New member

Joined: Fri Nov 15, 2013 4:09 pm
Posts: 23
Any thoughts on this? Had to run on petrol again today for a while, and car runs a little bit @!## while on petrol, slight hesitation while accelerating, but idles spot on. Runs perfectly on lpg, smooth and quiet. Seemed to improve a little the more miles I did on petrol. Trying to convince myself that it's the ECU adapting to lower octane petrol. Would really appreciate comments to hopefully put my mind to rest...


Top
 Profile  
Reply with quote  
PostPosted: Wed Jun 28, 2017 6:06 pm 
Advanced Member

Joined: Wed Apr 09, 2008 9:00 am
Posts: 7858
Images: 0
Location: Peterborough
Some will but it depends on what Octane fuel the car was originally designed to run on. I've got a 1990 Maserati Biturbo Spyder which is intended to run on 98 Octane. If I have had to put 95 Octane in it at any time, it runs badly and is noticeably down on power. I assume this is because the timing is being backed off as a result of the output from the knock sensors. It's doubtful that an ECU would be designed to give more advance if the fuel has a higher Octane, they will just run at whatever was programmed as the optimum for the fuel they recommend, but many will retard the timing if given something inferior. Might be worth sticking some 98 or 99 Octane in it and seeing what the ignition advance multiplier does then.

_________________
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group