[Prev][Next][Index][Thread]

<E36> Stumbling/Backfire Update

To: BMW List Server    <bmw-digest@domain.elided>

FROM: David Skirzenski      PHONE: 744-4872   ID: SKIRZ                        
Subject: <E36> Stumbling/Backfire Update                                       

Thanks to those who responded with tips on curing the                          
stumbling/backfiring/hesitation on my '92 325i.  Since                         
I've gone through about 8 tanks of gas, used a few bottles                     
of drygas and fuel injection cleaner, and the problem only                     
occurs below 2000 RPM, I ruled out bad gas.  Was I right                       
to do that?  Can water or something in the gas keep on                         
causing a problem like this?  The problem is intermediate                      
on some days, bad on others, non existant once and a while.                    

Backfiring was probably a bad description of what happens.                     
It actually "pops" in the engine compartment, via the airfilter.               
The explosion of the air/fuel seems to happen with one of                      
the INTAKE valves open.  The backfire is not through the                       
exhaust.  This is bumming me out!                                              

I've been trying to see if the problem occurs worse on humid                   
days, which would lead to some sort of grounding/arcing of the                 
induction/spark system.  But the car has 6 coils, one on top                   
of each spark plug.  So the high voltage is pretty isolated and                
I've replaced the plugs and cleaned all of the connectors in                   
that area.  So far no pattern I can tell.                                      

The dealer doesn't seem to have any idea of what the problem                   
is and will only replace one thing at a time to get to the                     
bottom of it.  I was just hoping someone had a similar problem                 
and it turned out to be something like a bad injector or                       
coil.  I will check out the plugs soon to see if one looks                     
worse than the others, maybe to isolate the cylinder at least.                 

Thanks in advance.  Sorry for the long note.                                   
Dave                                                                           

***************************************************************