quadancer

2000 Taurus 3.0, went through heater core flush nightmare 2x and assuming the vice grips weren't allowing bypass, got my heat up to moderate from very low - it's still not going to handle the winter coming. I notice that the AC is on with the heat, and the coolant lines to the ac compressor are cold and the compressor is running. ??? Should I just pull the AC fuse for the winter?

Trying to get the mileage up since I bought it two weeks back, I've replaced the air filter, plugs, checked wires for sparks, checked the coil resistances against a new one (same), cleaned the MAF, shot the throttle plate and plenum, cleaned the oil system and changed to Mobil1 synthetic, put seafoam in the tank...and although it's gone up to 22mpg, there is still a vibration mostly under accelleration like a cylinder misfiring slightly from 45mph and up, worse the faster I'm going. Could it still be the coil, even though it checks out electrically? It was worse before the repairs, so it's definitely engine related.

I'm afraid I'm facing a leakdown test if I don't figure this one out.
It's turning into a money pit even with ME doing the work!

Bert

Have you checked for codes? Autozone will do it for free. The coil could possibly be bad even with the readings showing okay.

__________________
Bert

quadancer

I did, and the codes are clear. I'm actually hoping it's the coil because it's $65 compared to a head job and leakdown test. I'll try to see if our ottoparts dealer will "loan" me a new one for a test. (just occurred to me)

Bert

If you have a cylinder with low compression, it would be most noticable at idle. It would idle rough. I think it has to be a spark leak somewhere. Possible plug wire. The ohm reading on plug wires is aout 5k per ft. if you want to check that.

__________________
Bert

quadancer

OMG! All my years of working on my vehicles and I'd never heard of that one. Thanx Bert, I'll give that a shot -it has OEM on it; dealer lied and said they'd replaced plugs and wires. They'd replaced the front EASY plugs only. 2 in back were rusted, one didn't even go to that car. (insert duncecap smiley here!)
I looked at night for the Chinese Circus and didn't see even one spark anywhere, but that woulnd't mean they're not breaking down internally, right?
________________
Gary

Bert

They can get too much resistance and not fire properly. You don't see it then. I've done a simple compression check by disabling fuel and ignition and cranking it over. The cranking will spped up when it gets the cylinder that's low on compression. You can hear the cranking speed. That's actually how the new PCM can tell a missfire. This doesn't work for very low compression leak.

__________________
Bert

quadancer

I checked the wires, got anywhere from 7.5K to 10,000 except for one that was open, no resistance. Put a new set on this evening. My mechanic thinks that the shaking is a torn motor mount or CV joint. The mystery of the AC running with the heat is still at large and the heat isn't great.

jwko

The AC compressor will run in all modes except vent. My 01 did the same thing. It's a stupid design but that's how they made it.

quadancer

Now that kinda gets me. We're supposed to be saving gas and the powers that be leave us with a totally unecessary engine brake running. All I can say is that when I turned on the heat and fan in my '60 Chevy pickup, I was never cold and the FE didn't go down.
Progress. Hmpfh!

jwko

I guess a person could always put a simple on/off switch in the power line running to the compressor.