New coil; still missing/bucking; '99 3.8L

[danielsatur]

Originally Posted by danielsatur

Poor deliverable of a engine, can give a false symptom of a hydraulic transmission.
A bad TCC shutter is while the auto is in motion.

I heard of a good transmission, and engine being replaced at the customers expense.

The root problem was the drive-by-wire system, had a stickey throttle plate.

MAF sensors only throw codes when hard at fault, but a slow one with a dirty throttle body will not.

Try running with your fingers in your nose, and see how fast you can go without a misfire.

Isolate the EGR + PCV systems from the loop.
Focus on the Engine 1st.

[Windywoes]

Please elaborate.

[serge_saati]

I don't think that it caused my the PCV valve, althought it can be bad.
It worth to test the MAF sensor for proper operation. Use a voltmeter.

[Windywoes]

I've been giving this mess lots of thought and here is where I am:
- obviously lots of oil being drawn into intake via PCV system
- my catch can has not worked all that well; some oil has been trapped, but not much; maybe I need to mount the can lower
- I wonder if the oil vapor quantity being drawn in is enough to lower the octane rating of the fuel/air charge and this is causing the miss?
- I wonder what all this burned oil mist is doing to the rings, piston tops, valves, 02 sensors, and catalytic converter?
- what is causing this much oil to be drawn in? Bad rings? I have not checked compression, but she runs very well except for the miss problem.

Unless someone tells me to stop I am plan to run the van a while with the PCV valve breathing to atmosphere and the line going to the throttle body plugged. I want to see if the problem goes away and if the plenum cleans up.

Should I?

[serge_saati]

Originally Posted by Windywoes

- I wonder if the oil vapor quantity being drawn in is enough to lower the octane rating of the fuel/air charge and this is causing the miss?

No, the oil doesn't lower the octane rating. And octane rating have nothing to do with air mixture and miss. Your Windy doesn't ingest enough oil to miss. If it was the case, you should see blue smock at exhaust, and CEL flashing and stall at idle, which it's not your case.

Originally Posted by Windywoes

- I wonder what all this burned oil mist is doing to the rings, piston tops, valves, 02 sensors, and catalytic converter?

Oil does nothing but help rings, valves, pistons to perform better. Yes, it may clog the O2 sensor but not that much. And nothing to the catalyst.

Originally Posted by Windywoes

- what is causing this much oil to be drawn in? Bad rings? I have not checked compression, but she runs very well except for the miss problem.

Yes rings and valve guide. But when it's valve guide, you may expect more oil that that. Hom much oil do you put each 200 miles?

Originally Posted by Windywoes

Unless someone tells me to stop I am plan to run the van a while with the PCV valve breathing to atmosphere and the line going to the throttle body plugged. I want to see if the problem goes away and if the plenum cleans up.

Should I?

No, cause dirt can enter in your engine and wear it. Check the valve condition, and replace it as necessary. Once again, I doubt that it's the cause of your problem. I think the problem is the PCM or battery connection.

I remember, one time my system voltage was low (no belt installed), and when the gear changed, the engine stumbled. Cause the PCM wasn't getting enough power, so it had trouble to control the engine. When belt was back, the stumbling gone.

[Windywoes]

Messing with the PCM is beyond my ability, but I can check the battery terminals.

Serge, maybe the octane rating does not change, but I still have to think that oil vapor being ingested with the fuel/air charge would have to lower the detonation temperature, Oui?

[Windywoes]

Serge! I checked the battery voltage after the van sat all night. I was surprised to see that the resting voltage was only 11.7 volts. That is very low, n'est pas?

I cleaned the terminals (not too dirty) and checked the running voltage, which was about 14.5 volts. After 30 minutes of resting it had fallen to 11.8 volts. The battery is a 72 month guarantee battery bought in December 2005.

What do you think?

[wiswind]

You can get your battery checked out at most auto part stores.

As far as disconnecting the PCV line,,,,that is NOT a good idea.
The PCV line draws contamination out of the crankcase......which would otherwise cause the oil to break down and cause major sludge problems.
Unless you are having to add oil very often....what looks like a lot of oil really is not much at all.
Using a catch can to reduce oil in the intake is OK (I do it myself), but you do NOT want to reduce the airflow through the system from what FORD designed.
I also use ONLY Motorcraft PCV valve that is listed for the vehicle.
It is amazing the aftermarket PCV valves that I have seen listed for my windstar.
While a PCV valve is a very simple device.....the engineering involved is very precise.
A PCV valve is a metering device.....the one for the windstar (as with many other vehicles) has a spring inside.....and a tapered valve and valve seat.
It is designed to deliver a given air flow under varying vaccum conditions.
As vaccum increases....more air will pass through the same size opening, so the spring and valve combination make the opening smaller as vaccum increases.

So, the condensed version, as long as you have the correct Motorcraft PCV valve, in working order.....you are fine as far as the PCV system is concerned.

With the correct valve cover (with the baffel) excessive oil through the PCV system (as evidenced by needing to add oil frequently) would be cause by some engine problem, like valve guide seals (not common on windstar).

[12Ounce]

I can't believe that the suggestion of temporarily disconnecting the PCV has drawn such negative comments. No one has suggested eliminating the PCV! We all know the PCV to be beneficial .... Geez!

Here are my exact words .....

Originally Posted by 12Ounce

......Anyway, as a test, you can certainly plug the intake manifold at both points ... but "vent" the crankcase as best you can. Unplug the PCV valve, and supply lines, from the covers and leave the remaining holes open for free breathing ...

.... If read slowly, one realizes perhaps I'm not advocating engine destruction! The "test" should be reasonable ... a few days, a few hundred miles, at most. Oh, "BTW" ... avoid sand storms ... don't cross deep mountain streams ... and brush after every meal!

[serge_saati]

Originally Posted by Windywoes

Serge! I checked the battery voltage after the van sat all night. I was surprised to see that the resting voltage was only 11.7 volts. That is very low, n'est pas?

I cleaned the terminals (not too dirty) and checked the running voltage, which was about 14.5 volts. After 30 minutes of resting it had fallen to 11.8 volts. The battery is a 72 month guarantee battery bought in December 2005.

What do you think?

11.7V is acceptable. You should be afraid when it lowers under 11V.

[12Ounce]

I think you both are on to something with the low battery voltage. I would prefer to see 12.25volts as an "overnight" rest baseline low. I think the battery needs to be replaced.

[12Ounce]

Some good bedtime reading on PCV's:
.
http://en.wikipedia.org/wiki/Positiv...se_Ventilation

[Windywoes]

You guys sure are nice to help out. I never intended this to go out to 3 pages.

First, my intention in disconnecting the hose from the PCV valve to the throttle inlet was just temporary. Not even a hundred miles. I wanted to see if the miss would go away. Also wanted to see if the plenum would clean up.

Second, and pardon my ignorance, isn't the battery voltage the same as alternator output when the van is running? In other words, when the van is running isn't my battery output adequate to run the PCM? To me, 11.7 volts resting seems awfully low. I measured all my other cars and they ranged from 12.4 to 12.8 at rest.

Thirdly, I noticed today that the PCV valve was extremely loose in the valve cover grommet hole. Does the PCV system need a real tight seal there for proper function? I want to try a Motorcraft brand PCV valve. I currently have a Purolator 521 in it. New a few weeks ago when I installed the catch can (or should I call it a catchless can as it did not work very well they way I had it hooked up.

I wish you all a nice Thanksgiving (Serge celebrated last month).

[serge_saati]

For the PVC, it's a way to check it.
*Start engine and remove the valve. Feel pressure at the PCV valve cover (by pressing your finger in the hole)
*Then feel vacuum at the valve (your skin should be aspirated by the valve).
*If there's no vaccum/pressure, check vacuum at the PCV hose. You'll no know if it's the valve or the hose that should be replaced....or maybe cleaned.
*Check also if the rubber grommet in the cover is cracked or damaged.

[Windywoes]

Serge, the PCV valve is working. Hose is not clogged. Grommet in good condition, but note that I noticed today the valve was very loose in the grommet hole (I wrapped electrical tape around the valve body and now it is nice and tight). I will check for positive pressure at the grommet hole. Merci.

Still wondering about low battery voltage......and clutching for straws.