W123 230E Backfire

[cdc02254]

Yesterday the only problem I had with my w123 was the fact that it was losing vacuum when parked, so after checking all the doors and reservoir I decided to check the pipe going to the manifold. I removed the complete air filter housing and then the rubber pipes underneath, cleaned them all up, check the joint and put it all back together.

Now the car is backfiring or popping. Its a strange issue as it doesn't happen until the car has been driving for a while, its not really evident when in neutral and revving the engine and it seems to come and go. Its more evident at low rpm and the oil pressure now seems to be more active then before. It is not effecting the performance.

Any ideas what I have done or what it could be?

 

[RBYCC]

Is the "backfire" coming from the exhaust or the intake ?

Ed A.

 

[cdc02254]

Its coming from the back of the exhaust.

 

[cdc02254]

Im am going to give this a bump as I need help.

 

[grober]

There is a good explanation for "BACKFIRING" here. Back-fire - Wikipedia, the free encyclopedia

Since this has occurred after you removed some of the inlet manifold pipework this would indicate you have an inlet air leak somewhere causing a lean mixture. Old brittle pipes can split when disturbed/bent and this can be difficult to pick up sometimes. You might get an indication from an examination of the spark plugs as to whether the engine is running weak or rich or get a garage to stick it on their exhaust gas analyser?