Re: annoying misfire

["content22207" <brobertson@xxxx>]

You didn't mention iginition timing... 

Pull at least one spark plug -- it's the only way to tell what's going
on inside your engine. Plugs could be fouled with soot -- retarded
timing (leaking vacuum advance?), too rich fuel mixture, or a weak
coil. Could be burned white -- too lean fuel. Could be fouled with oil
-- bad news (engine is sick). Could be gapped incorrectly (.026"?
Don't have factory book at hand). 

Since they're easy to get to (move your idle speed motor out of the
way for #4), why not pull all 6 to compare. While they're out of the
car, run a resistance check on each. I prefer as low as possible (6-8
ohms).

In the bad old days, 99% of a car's problems were electrical (a slight
exaggeration I know, but more common than fuel supply).

Bill Robertson
#5939

>--- In dmcnews@xxxx, "jamesrguk" <James_rg@xxxx> wrote:
> Hi all,
> 
> I am still having an annoying misfire, I am pretty sure it down to an 
> injector that is passed it's sell by date, as it is not spraying very 
> nicely. 
> 
> To my knowledge the spray pattern on a mechanical injection system is 
> more crucial than on an EFI system because the valves are not always 
> open at the point of injection.
> 
> I am fairly sure the misfire is fuel related for the following 
> reasons:
> 
> 1) My timing light suggests that all plugs are sparking
> 2) All plugs are less then 8 months old. 
> 3) 2 of the injectors are new, 4 are 2nd user but appeared to be 
> clean and ok when 1st installed approx. 10 months ago, and the engine 
> has run fine until recently.
> 4) All of my HT leads are new as well as the cap and rotor arm.
> 
> Anyway my question is really why are the injectors getting blocked?, 
> have I just been unlucky?
> I have a new fuel pump, clean tank, and a filter on the fuel pickup 
> and had the main fuel filter change about 10 months ago.
> 
> Any ideas?
> 
> 
> James RG