arghhhhh! I can't figure it out!

[vampiro03]

I have a 96 taurus with a 3.0 over 100k
im usually good figuring out whats wrong with my car but, this one's got me stumped. first off, the code p0430 the catyletic system below threashold bank 2 bla bla bla, theres a million different things that trip that sensor. heres how the car acts: long start maybe 15-20 turns, fires up faster with a full tank of gas, the cat is overheating(I can smell it). the temp guage fluctuates a LOT. mostly when I have my foot off the gas and comming to a stop from highway speeds the temp guage starts filling up. after I turn the car off, if I start it up like 3 mins later the temp will show like 85% hot after being off. it always circulates back down though. new water pump(it was squealing), egr valve, pcv valve, plugs wires and coil pack. could the cat be plugged? I was thinking about replacing the coolant temp sensor but I think the cat is the heating problem, maybe a fuel pressure regulator? man! I don't know!

[GPFred]

I would take it to an exhaust shop about the cat. They would be able to tell you if its blocked up. As for the temp, I would look at replacing the thermostat and maybe the temp sensor. Is it throwing any codes?

[shawnwilliams]

Yea i would also get the cat fixed, if could be throwing off your entire system, if might also be your radiator, they begin to go around that time.

[bdog_840]

Its gotta be an exhaust restriction.

[shorod]

Originally Posted by bdog_840

Its gotta be an exhaust restriction.

But what's causing the exhaust restriction? Too rich an air/fuel mixture? Could be caused by bad plugs/wires, bad oxygen sensor(s), bad coolant temp sensor, sludged MAF sensor elements, etc. Just replacing the converter may not fix the problem, something likely caused the converter to go bad (if that's the problem) in the first place.

If you find restricted exhaust, verify all other systems are working properly.

-Rod

[Psychopete]

Originally Posted by shorod

But what's causing the exhaust restriction? Too rich an air/fuel mixture?
-Rod

I agree. Hot cat = running too rich. Check a spark plug or 2 to verify that it's running rich. Have you noticed a decrease in MPG?

When your car is off, it can't cool anymore. All of that heat under your hood stays there and increases the temperature of your coolant. This is why it went up to 85%, but that seems high. Perhaps the exhaust manifolds are getting hotter than hell? I would crack the hood after coming home from work or what not and let all of that heat out before something gets warped. A machined lower intake manifold runs about $120. But in my case I got it for $85 since the buttheads told me I wouldn't have to get it milled when I milled my heads .030" on a 60 degree Ford.. I was pretty upset when I found water in my oil.

Pete

[vampiro03]

well, I finally figured it out. I had a bad plug/wire. that was tripping the sensor. the starting thing is definately a lack of pressure in one of my cylinders. the first one I checked with the pressure guage read about 90!! and missed jumps! all the other cylinders were at LEAST 160! so, one bad cylinder = not head gasket, but it could be a cracked block or piston ring. how do you diagnose a pressure leak?

[drdisque]

best way to do it without tearing the engine completely down is a leakdown test

[vampiro03]

what do I need to do a leakdown test?

[vampiro03]

now, I found a leakdown tester online. I have two really crazy questions. 1.can you change piston rings without removing the engine?
2. how can I tell the difference between a bad piston ring or a cracked block without ripping it appart, is the tester THAT percise?

[drdisque]

with a bad piston ring the leakdown should be pretty solid whether you move the crank or not, but with a crack in the block, the leakdown should change as you move the crank.