Would like some opinions. 86 240 dl wagon b230 engine: Cylinder #1 has stopped firing. Mechanic changed spark plugs, distributor / cap and wires. Did not change coil. No improvement. Engine does need new wiring harness. Engine does not smoke (nor has it ever) or seems to have any anti freeze in the oil (vice versa). Going to be getting compression test very soon. Other threads seem to point to valves, rings or entire head needing to be replaced. Does anyone think that it may be electrical, especially if it fails compression test?

Thanks in Advance
Gary

 

the only thing that distinguishes #1 from any other spark plug is the spark plug wire, and terminal in the rotor.

if it fails a compression test, thats purely mechanical. piston rings, valve, head, gasket, pick one.

 

"Stopped firing"? Firing is a misnomer, and only related to ignition, which you addressed, so if you still have a miss, compression or leakdown test is called for. Compression test is not Pass/Fail. Its results have to be evaluated. Based on the readings of the test, you can see your options, if it's done correctly. With bad wiring though, all bets are off... It may affect one or more injectors... How bad is the wiring?
Post the comp. test readings, go from there.

 

all 4 injectors are wired together, so if you suspect the wiring to one injector, you can swap it with an adjacent one.

 

I'm just curious - how have you determined that cylinder 1 is not firing (as opposed to one of the other cylinders)?

 

If you hook up an inductive pick up timing light to Cyl #1 spark plug wire does it flash? Simple test also if you pull the plug is it fuel fouled. Once again it's either a fuel or spark issue unless you have 0 compression.

 

A lot of people pull spark plug wires off of the plugs one at a time until the idle changes. If you pull a wire and have NO change, you found your dead cylinder.

What I don't understand is why a mechanic would NOT immediately check compression when diagnosing a miss? It only takes a minute, pull the plug, stick the gauge in, pull the ignition & fuel and crank.

 

no feedback from the original poster?

sigh.