trouble shooting electrical - not a tractor

[marks]

After having used my man-lift for tree trimming, I blew out the engine compartment with a blower. The four cylinder gasoline Ford, which had been running great, now fails to start. It cranks fine, and I can smell gasoline in the exhaust, yet it won't fire. All the electrical connections appear to be secure. When I attempted to pull a spark plug, I realized that during its life in the rental yard, that over-spray from a gunite or stucco type product had built up in the spark plug wells and will need to be chipped away first. However my assumption is that the plugs aren't firing.

After having had the frustrating pleasure of tracing electrical problems in the past, I'm wondering if any of you guys have some insights into this?

 

[Humbleto]

Sounds like the coil wire to the distributor is not connected properly. Maybe the blower got debris into the boot. Check both ends.

 

[6or7dazeaweek]

Try pulling the spark plug wire off the plug....insert a paper clip so that it touches the metal inside the spark plug boot.

Bring the paper clip close to the enging block or head while cranking...you should see a spark jump the gap. Sometimes the spark may be weak and hard to see in direct sunlight. As a last resort, you could hold onto the paperclip while cranking...but I don't recommend it.
/forums/images/graemlins/blush.gif

That would tell you instantly if there was spark available to the plug.

Jon

 

[slowrev]

Have your wife hold onto the paperclip instead ?

Ben
ps, be ready to run /forums/images/graemlins/smile.gif

 

[Soundguy]

Could be simple tune up issue.. does it have points? in any case.. check for voltage at the primary of the coil first..

Soundguy

 

[HammerFour]

I agree with Soundguy, check that the coil is getting voltage.

It is most likely electronic ignition, so check the wiring
harness that hooks all that up, a blower could have enough force to disconnect one of the connections that powers the ignition system. Grab a test light or volt meter and check those for power getting to the right places. Inspect ALL the connectors closely, don't assume its connected right because it looks ok. ( I have mad that mistake, I assumed a connector was good when it wasn't, spent hours troubleshooting stuff that was fine all along. ) Remember, don't assume, test. Use the resistance ( ohm ) meter in your voltmeter to check the wires out.

The blower could have blown the high voltage leads around enough that if they had almost failed that they are now bad.

Heat and high voltage will make those plug leads and the coil to distributor lead fail over time as well, check those out.

 

[Volfandt]

Sounds like the blower either blew off a wire on the ignition circuit or it blew a wire to where it's shorting out on something metal or blew some moisture where it's shorting your ignition circuit out.

The 1st electrical test is to determine if your getting spark to the plug(s). I've found the best way to test for spark at the plug is to remove the plug wire on the #1 plug, insert a phillips screwdriver into the plug wire, hold the metal part of the screwdriver very close to the plug (the proverbial hair away) and then try to start the engine. This may take aonther set of hands. If you don't get a good blue spark then hold the scredriver over a known good ground and try to start it up again.
If you get spark at the plug then it's probable that the plugs are good enough to run the engine and the problem lies elsewhere. If you only get spark when you hold the metal part of the screwdriver close to a known good ground then one or more of the plugs are bad.
If you don't get any spark in either case then the problem lies somewhere else in the ign circuit.
Pull the distrbutor cap and make sure theres no moisture in there. Look for carbon tracks on the rotor button and inside the cap. Carbon tracks will take a high voltage spark straight to ground instead of distributing it to the plugs where it's needed.
Also spin the engine over to make sure that the points are opening and closing and that theres nothing shorting out the points..
Make sure that you have 10 to 12 volts on the + terminal of the coil with the ignition switch on. Check for blown fuses.
Make sure all the wireing looks good and has a good tight connection. Since it ran good before you used the blower, I would suspect moisture or a loose connection first.

Good luck
Volfandt