Detonation under load...

[MrShorty]

Actually, the computer's response to cold is to richen the mixture. If the computer's temperature sensor (which isn't the same as the one for the dash gauge) were too much hotter than actual, then it might be running too lean. It doesn't take much to test the ECT (computer's sensor), since it's a basic thermistor.

 

[TPLYNCH]

Sending unit/connetion could very well be bad. Do you still have the old thermostat? Did it appear to be in the open position when you pulled it? You can test it by putting in boiling water and seeing if it opens.

 

[ThespecialistKC]

Hmmm, so how does one test the ECT??? Seems I will have a few open hours this weekend. Might as well check for the fun of it. I also just ordered a simple scanner, so I'm gonna pull the codes myself. The old thermostat appeared fine. It was closed when I pulled it, so it wasn't stuck open. I may throw in another sending unit for fun as well... wheeeee!!!

KC

 

[MrShorty]

ECT is a thermistor, which means the resistance is a function of temperature. A table of resistances vs. temperature can be found in many repair manuals including Chiltons. It typed the table up and posted it at www.xmission.com/~vondm/fordtempsensor.txt
And be sure you're testing the correct sensor. The sender for the dash gauge (one wire) is different from the one for the computer (two wire).

 

[Rhett]

And be sure you're testing the correct sensor. The sender for the dash gauge (one wire) is different from the one for the computer (two wire).

Very useful piece of info there. Thank you. I will store it with the rest of my Ex info.

TheSpecialistKC: If you determine that the temp sender is ok then you might want to test the thermostat that you just installed. Take it out and boil it in some water; make sure it opens and closes when it's supposed to.

 

[ThespecialistKC]

Once again, Mr. Shorty comes through. I bow down. Truly a Demi-God of Ford-dom if there ever was one. I shall make the appropriate checks and report back......

KC

 

[ThespecialistKC]

And one more question... is there a way to check the sending unit for the gauge with a voltmeter. I looked around for specs but couldn't find any.... thanks again!

KC

 

[00XLS]

What exactly does aping sound like? I know that sounds stupid but I'm not sure if I've ever heard one. Does the intake gasket hold true for a '00 4.0 OHV as well? I have coolant disappearing and I have no idea to where.

 

[Mic_]

What exactly does aping sound like? QUOTE]



...P I N G ... J/K


Sounds kinnda like a dieseling effect but on a gasser.

 

[msmith65]

Sometimes an exhaust manifold leak will sound like a tick. Worth putting your broomstick (I use a length of PVC) down there to check.

 

[msmith65]

"Ping"

Ping (pre-ignition) sounds just like one of those diesel pickups at idle. I interpret it more as a clatter with a gurgling undertone. Don't know where "ping" came from.

It's bad for engines because it puts undue stress on the pistons, rings, and rod bearings. The piston is trying to compress a mixture that is already burning (expanding). On aluminum-head engines it is lethal.

History Lesson:
Back in the '70s, when the first unleaded fuels were very low octane and all the engines were made for, like, 95 octane, ping was commonplace, as was "dieseling," or the engine's running on after the key was turned off. Low-octane fuel ignites so easily that just the compression was enough to set it off without a spark. So the engine wouldn't die, or would take a few seconds to do so. People would leave the car in gear to kill it.