Lpg backfire

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Tom troon

New Member
Joined
Apr 21, 2012
Messages
7
Location
South ayrshire
Car
1989 300ce
Hi folks got a 300ce with single point LPG fitted. Seems to be running lean and backfires on low revs. Popping out the idle valve rubber pipe or rubber seal on the injection system. Anybody has similar issues and have a better understanding of the root cause of my troubles. I'm in south ayrshire Scotland and not sure of the best place to take the old girl for a lpg service. Anybody know of a good specialist in these matters.
 
Hi, it maybe a mixture issue, but it's deffo something for a specialist/LPG registered technician, due to the explosive nature of LPG.
 
Single point LPG systems are notorious for the backfire issue. I had one in my last Merc and it blew the engine.

Did you have it fitted or was it on the car when you bought it? I ask because you HAVE to have it calibrated once a year or it does go out of sync and you will definitely get the backfire issue.

If it hasn't been done then go get it calibrated. Usual cost around £50.00

If you can afford it then have a Romano Multi-point system fitted.....far far better.

Just had mine done at £1350.00 and worth every penny.

Keith
 
Used to have one fitted to a 124 230te and closed the plug gap up by a couple of thou which helped the spark jump the correct gap rather than straying to the inlet manifold which causes the backfires. Helps if the cap and rotor and leads are as new and clean as possible. You can get a one-way backfire valve which is fitted into the inlet manifold which saves the rubbers from popping off. It is important not to secure the rubbers too much cos otherwise the backfire bends the fuel metering flap and that is the end of that if it happens.
 
Thanks gents. Yes it has blown the large rubber seal at the bottom of the injection system. I've had it all off twice and the rubber is now slightly fused/melted. Will need a new one. (anybody know what its called part no. Etc) Have got hold of a lpg specialist in Glasgow and will take it there to have a look at the lpg system. I bought the car with lpg fitted. Went to London to get her. Where the single point system meets the air filter there was look of black gunk around it to seal it. I had to take this all off to access the injection system. Bit of a home made job to be honest gents.*
Drum ? How do you close the plug gap. Rotor and cap were replaced after I got it. Also can you give me more details on the oneway backfire valve Druk. Thanks guys for your*
posts. Sold my 230te for the 300ce and want to stick with it including the lpg system. Any more info on my wows would be great. Any thanks
 
Thanks gents. Yes it has blown the large rubber seal at the bottom of the injection system. I've had it all off twice and the rubber is now slightly fused/melted. Will need a new one. (anybody know what its called part no. Etc) Have got hold of a lpg specialist in Glasgow and will take it there to have a look at the lpg system. I bought the car with lpg fitted. Went to London to get her. Where the single point system meets the air filter there was look of black gunk around it to seal it. I had to take this all off to access the injection system. Bit of a home made job to be honest gents.*
Drum ? How do you close the plug gap. Rotor and cap were replaced after I got it. Also can you give me more details on the oneway backfire valve Druk. Thanks guys for your*
posts. Sold my 230te for the 300ce and want to stick with it including the lpg system. Any more info on my wows would be great. Any thanks
 
The rubber seal underneath the injection system is the air flow meter diaphragm. To close the spark plug gap, remove the spark plugs one by one. Use a feeler gauge to measure the gap between the centre electrode and the top of plug, then reduce the gap by a couple of thou by gently tapping the top against a hard surface.
 
Had the same on a 500sec, had flames coming out the top of the metering head!
 
Thanks for that ss201. Do you know where I can purchase the air flow meter? I'm finding it hard to find it online. Cheers
 
Start with a replacement air flow meter rubber diaphragm. I got mine from the M-B main dealer. part number A103 141 00 90 Cost in Jan 2011 was £18.30 + VAT. The old one had split.
 
Hi ss201. Im finding it difficult to find this part buddy. I need to pin this down to get my old dear back on the road at least consuming petrol in order for me to drive her to lpg guy. Please help.
Thanks gents
 

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