VAPOR LOCK???

[-=DaemoN=-]

I have this problem, my friend told me it might be a vapor lock. When I drive my car during the day for over 20 minutes I get this banging(like backfiring) noise on the engine. Sometimes I have to leave the gear on drive and turn the car off so it won't do it(the banging). This never happened during the winter season, I live in Arizona. Any suggestions would be helpful.

Thanks in advance!

 

[Ray Hutchinson]

DaemoN,
Since you have fuel injection with a high pressure pump, vapor lock is quite unlikely. My '93 does fine on long hauls at 100+ degrees in the S .CA and NV deserts. Vapor lock is almost unheard of in newer F.I. vehicles.

I don't know what mileage you have on your vehicle, but if it is relatively high (70K+). you could have some carbon deposits in the cylinders, esp. on the piston tops. This carbon heats up and glows red hot, igniting the air/fuel charge before the spark plugs do (too early) causing severe pre-ignition and run-on after the ignition is switched off. The result is a fair ly loud banging/ knocking sound when running. I had this problem with a Mazda pick up I had, and the Ford mechanic put very SMALL amounts of water with a squirt bottle into the air intake. This creates steam and blasts the carbon off then pistons. Use CAUTION though, it takes very LITTLE water. Too much and you could crack something.

If investigating further (like pulling the EEC codes) doesn't find another problem, you might consider trying this, but If you lunch your engine, remember I told you not to use too much water

 

[-=DaemoN=-]

Thanks for the reply RAY. I have 90+K on it now.
Does going to a higher octane gas reduce carbon deposits?
Because when I did go higher the banging/knocking(whatever the right word for it) did not occur as often as when I switched back to 89.

 

[GJarrett]

I can't directly help with your problem except to say that your symptoms are NOT indicative of vapor lock. Vapor lock will stall out your vehicle, effectively starving it of fuel, and keep your vehicle killed for several minutes to a half hour or so until the fuel lines cool down enough to let fuel back through again.

 

[91Explorer]

Sounds like denation to me... Is your engine running hot? If so, that could cause it. Also if your RPMs are too high, it will diesel a little before turning off. I suggest using high octance gas and some kind of cleaner you add to the fuel for carbon deposits, try it for 2 to 3 tanks of gas and take it on the freeway and slam on the gas hard for about 1-2 seconds then let go and do it again to try and clean out the combustion chambers.

I would also check the fan clutch and coolant level.

As for injecting water, I don't recommend it... if you inject to much water, the rods might bend due to the fact that water doesn't compress.

 

[AgExplorer]

You may want to try a product from AMSOIL called Power Foam. It is used to clean the upper air intake system by spraying it into the throttle body. All of the carbon deposits in the system will be dissolved and blown out the exhaust system. If you go to a Ford dealer to have this done, they will charge you $120 to do the same thing. You can e-mail me if you have any detailed questions.

 

[Ray Hutchinson]

Daemon,

Agexplorer has a good suggestion: use somekind of" top -end" cleaner before you try the water trick. Much less risky! As for the water, you wouldnt want to put in any more that a sewing thimble or 1/2 teaspoon in at a time. About one good shot from a trigger type squirt bottle on straigt stream at a time, waiting 30 seconds or so between squirts, with a max of 4-5 squirts total is all the water you could use safely. Just to clarify my last post, as some were rightly concearned about too much water causing big problems.

 

[-=DaemoN=-]

Thanks for all the info guys. One more question, how can you tell if your fan clutch is bad? I might also try AgExplorer's advice too and try out the AMSOIL Power foam but if my fan clutch is bad, I might want to go ahead and change it.

Thanks Again.

 

[Ray Hutchinson]

Fan Clutch inspection/test

Daemon'

The Haynes Ford Explorer repair manual says:

1.Rock the fan back and forth to check for excessive bearing play.
2.With the engine COLD, turn thre fan blades by hand. They should turn freely.
3.Visually inspect for substantial fluid leakage from the clutch assy. If found,
repalce the fan clutch
4. With the Engine completely warmed up, and off (DUH!) turn the fan again by hand.
Some drag should be evident. If the fan turns freely, replace the fan clutch.

For all the above operations the book reccomends you disconnect the neg. batt terminal before handling the fan, for safety ( I assume that this is so the engine can't possibly start).

I can't find any reference to the fan clutch in my Chilton's manual.

Hope this helps.

 

[-=DaemoN=-]

My friend told me about #4, if the fan turns freely I might need to change it and it sure did. I should get me a manual . Thanks for your help again RAY.