simon64

New Member

• Mar 21, 2009

• #1

hi my 93 RRC 3.9 v8 has developed a backfire it does it on lpg or petrol but only if i go over 4000rpm any ideas regards simon

 

G-man

BBQ king

• Mar 21, 2009

• #2

i think its caused by a vacuum leak check your vac hoses! also check and clean your plugs

 

G

gavbriggs

Well-Known Member

• Mar 21, 2009

• #3

get new plugs and leads! check air intake is sealed and connected properly. is the backfire down the exhaust or up the air plenum?

 

simon64

New Member

• Mar 21, 2009

• #4

gavbriggs said:

get new plugs and leads! check air intake is sealed and connected properly. is the backfire down the exhaust or up the air plenum?

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hi i have just had new plugs and ht leads fitted the back fire seems to be mostly down exhaust but have had it go bang under bonnet too

 

G-man

BBQ king

• Mar 21, 2009

• #5

has the timing been checked? i still think you should check for vac leaks

 

simon64

New Member

• Mar 21, 2009

• #6

G-man said:

has the timing been checked? i still think you should check for vac leaks

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the guy next door a 70 yr old retired mechanic checked timing using a timing gun he said it was ok but dont no how good he is i sadly no nothing when it comes to this sort of thing please forgive my ignorance what do u mean check 4 vac leeks