Solving a Misfire in a Sable/Taurus...

[MotoCam]

i would:

check batt voltage while engine is running. If it is less than 13.5 i would check the charging system

Using mechanics stethescope, check and compare all 6 injector sounds (clicking). If any injector is not clicking test the circuit with a NOID light. If cyl 6 sounds different, perform injector leak test with fuel pressure gauge installed onto fuel rail and car off.

if injectors are ok I would disable the fuel pump and check strength of spark @ cyl 6. you can do this by pulling fuel pump relay/fuse, removing cyl 6 wire from engine, installing properly gapped spark plug into coil, and using a thick wire with aligator clips on either end, connect threads of plug to good engine ground. have amigo crank engine while inspecting quality of spark. blue is good, orange/red is weak. If spark is weak check coil circuit.

check spark plug for proper gap/part number. inspect plug for indicators of running rich or lean burning oil etc

perform compression test

using scan tool check for proper fuel trims and coolant temp readings.

check egr function

remove valve cover to check for broken valve springs

if all else fails try new ECM

good luck

 

[Poppy]

4) When I am again driving the car I will try the SeaFoam trick in the gas tank.

6) The last thing AutoZone said was, "We put in that fuel line cleaner. Now, drive your car normally until your next oil change,
and then we'll take another look at it, for free. It is possible the problem will go away by then."

This is not awe inspiring.


8) The last time I was there, the mechanic said that while it was still misfiring, the "misfire count" was much less, indicating that
the problem was ebbing away. I do not know whether, or even if, this is possible.
.

Autozone may already have put in Seafoam. If you have a partially clogged fuel injector in cyl 6, they're right, it MIGHT clean it and your missfire MAY go away. With a quality scanner one can determine the frequency of missfire, it is possible that the fuel treatment is working.

5) Most of the tests members have suggested are beyond, if not my ability, my comfort level.

I understand, pulling the intake plenum to change gaskets, or to check EGR ports, and pulling valve covers to check valve spring tensions may be beyond your comfort zone.
Doing a compression test on cyls 5 and 6 is as easy as pulling a spark plug, and screwing in a gauge. Autozone has a tool loaner program, and they'll lend you the tools to do it. Also a vacuum gauge will allow you to test the valve train by connecting it and comparing how the engine runs to the gauges on this page.

HowTO use and interpret a vacuum guage
http://www.secondchancegarage.com/public/186.cfm

I'll post back here when I am driving the car again regularly

When do you think you will be back with the car? I don't check this section of the forums and therefore this thread too often.

 

[bshanahan14rulz]

Any recommendations for freeware compatible with a USB to OBDII, elm327-based cable? I don't trust the little panda bear CD that it came with...

 

[jrmcferren]

Any recommendations for freeware compatible with a USB to OBDII, elm327-based cable? I don't trust the little panda bear CD that it came with...

It may actually be freeware on the panda bear CD. Run a virus scan on the CD before executing any software on it and then use it, I wouldn't be to afraid of it.

Misfires can be tricky, in one YouTube video I watched they had to put a scope on the ECU to trace the problem to the injector.

 

[LEDAdd1ct]

Hi, guys. Fell and sprained my wrist and then fell and caused further damage. Didn't take a light on a dusk hike and that's the price. Reunited with the car, but haven't been able to post; typing with one hand and focusing on my job which requires constant typing.

Put about 160 to 200 miles on it since returning to work. The CEL was still on when I arrived, but turned off three or four days ago. Have been up to 70 MPH+ since being back. Not enough to activate the flux capacitor, but hopefully enough to help clean gunk out.

I am going to leave things as they are for now.

If/when it returns, I'll post.

 

[bshanahan14rulz]

never tried the CD, ended up using scantool.net v1.13 (I think that's the right version). The clones all ship with that particular version because after that version, the scantool.net program checks to make sure you have a legit tool. Dunno if it means scans to make sure you have a real elm chip, or if it means that it only works with the scanners they sell.

The error on mine looks like it's pointing to a bad O2 sensor, so I may be lucking out. Unfortunately, the clone isn't the most stable device. But, it's done more than I could have done without it! worth the $5. DIdn't see anything glaringly bad about the soldering, so I don't know where the instability is coming from. Don't care that much, was $5.

 

[LEDAdd1ct]

Last day of February 2014.

When I last checked in, they had swapped the coil pack, but the problem did not go away.

Brought it in this morning, and they ran a compression test.

Cylinder six was averaging only 55 pounds, while the neighboring cylinders were
averaging 160.

He said when the coil pack went and the gas wasn't being burned, that probably caused additional damage.

He said it is likely either a bad ring or a bad valve, and the head would have to be pulled
and replaned.

He said this is a $1,200 to $1,500 job.

He also said continuing to drive it "as is" will not cause further damage,
I just won't get the best fuel economy.

1) Does this sound like a reasonable diagnosis?

2) Does the price for this sound about right?

Thank you!

 

[orbital]

^

You probably have carbon & other junk around your valves, thus bad compression.

Do yourself this simple favor..
invest in a gallon of Seafoam & put a good quart or so in a half a tank gas,, drive that gas through~
I'll be kicking yourself for not doing it sooner.

Wait on the head work..

 

[FlashKat]

If you have a bad ring will involve much more than just pulling your head. Someone should have done a compression check a long time ago.
I was taught the 3 basics for an engine to run correctly.
1- Compression
2- Spark
3- Fuel

There are many other things that can go wrong, but those 3 things are the first to check.
Have someone do a double check on the compression test.
Check to make sure your valves are adjust correctly.
There are many mechanics out to make money.
I had a friend who owned a Hyundai which ran rough, and made a knocking noise. 3 different mechanics told her it was a cracked head, or a rod knock. I checked it, and the valve train came loose at the main bolts. I tightened the bolts down, and the car ran like new.

Last day of February 2014.

When I last checked in, they had swapped the coil pack, but the problem did not go away.

Brought it in this morning, and they ran a compression test.

Cylinder six was averaging only 55 pounds, while the neighboring cylinders were
averaging 160.

He said when the coil pack went and the gas wasn't being burned, that probably caused additional damage.

He said it is likely either a bad ring or a bad valve, and the head would have to be pulled
and replaned.

He said this is a $1,200 to $1,500 job.

He also said continuing to drive it "as is" will not cause further damage,
I just won't get the best fuel economy.

1) Does this sound like a reasonable diagnosis?

2) Does the price for this sound about right?

Thank you!

 

[StarHalo]

He said this is a $1,200 to $1,500 job.

This had better be a very important Sable; half that amount with a trade-in could get you something more reliable, a 90's-era Honda, Toyota..

 

[LEDAdd1ct]

^

You probably have carbon & other junk around your valves, thus bad compression.

Do yourself this simple favor..
invest in a gallon of Seafoam & put a good quart or so in a half a tank gas,, drive that gas through~
I'll be kicking yourself for not doing it sooner.

Wait on the head work..

I think when I brought it in last year, they put some chemical in there to try and clean out carbon deposits.

I suppose it wouldn't hurt to try again, but I just want to verify that if there is a lot of gunk in there:

1) Putting a solvent of some sort in the gas tank won't harm other parts

2) Any gunk that is broken apart and released has somewhere to go

Someone should have done a compression check a long time ago...

There are many mechanics out to make money....

Agreed on both counts.

When this problem first surfaced I should have had it thoroughly checked out,
but I didn't hear any strange noises and the car appeared to drive okay.

This had better be a very important Sable; half that amount with a trade-in could get you something more reliable, a 90's-era Honda, Toyota..

Agreed!

I spoke with someone at the shop yesterday afternoon and he:

1) Said that it would not cause further harm to drive it as is

2) Recommended against getting the work done because:

a) That amount could be put towards a newer vehicle or tradein

b) That amount would be a significant amount of the worth of the car

c) In a car of that age, something else could go wrong immediately after getting
the current problem fixed

The car gets me to work and back (I average 9.3 miles a day to work and home again),
so I will probably leave things "as is" for now.

 

[orbital]

I think when I brought it in last year, they put some chemical in there to try and clean out carbon deposits.

I suppose it wouldn't hurt to try again, but I just want to verify that if there is a lot of gunk in there:

1) Putting a solvent of some sort in the gas tank won't harm other parts

2) Any gunk that is broken apart and released has somewhere to go

^

Carbon & other junk will just be burned off in combustion. That's it.

You have to be aggressive on the amount using to get any results.
.. be serious on using 40+ oz. on a half tank (using a little bit will be completely useless)

I have no affiliation w/ Seafoam,, it simply works wonders on older stuff & preventative maintenance on newer.
If it didn't work remarkably, I would recommend it.

 

[LEDAdd1ct]

Thank you again for the help.

My bike was at work so I brought in my presta pump and when I was finally ready to bike home, the valve stem snapped off my inner tube as I was removing the chuck.

So I took the long way home, 5.1 mile walk (pleasant, easy walking), but didn't pick the
car up because the shop was closed. I am going to get it now.

I am assuming e-Bay will be the cheapest place to get this stuff.

Once I put it in, should I just commit myself to going for a scenic drive and burn
through a whole tank of gas to let it "do its stuff"?

There is a lot of exploring I would like to do, and if the car really needs
to get warmed up, I wouldn't mind driving down to a half tank at highway speeds
and then adding the Seafoam. I might even pay a premium to buy it locally
so I could do it today or tomorrow and not wait for a shipment to arrive via
mail.

 

[orbital]

^

If you can't find a gallon locally, just buy 3 of the bottles.
Buying a gallon over internet will be very costly.

Not sure how much you drive, but give it some time to do its thing, don't hurry it.

 

[LEDAdd1ct]

What I mean is, given that it is a weekend,
I could do a 150 mile drive today or tomorrow.

If I did it gradually, I would add the stuff but the car would be on (drive to work, 4.6 miles),
and then sit the whole day, and then have the car on and running (drive home from work, same),
in two chunks separated by a large passage of time.

Which is going to be the better way to go, one or two long drives, or many discrete
drives?

 

[orbital]

^

Shorter trips allowing the engine to get to full temperature.

also;; if you can get a gallon, get the white plastic jug that's sealed up.
Only purchase containers that are sealed.

 

[LEDAdd1ct]

Okay, thank you.

And to verify, "SF-16" is the proper product, correct?

 

[orbital]

+

That's it

Make sure you have a funnel handy for adding to gas tank

 

[LEDAdd1ct]

Okay, will do.

I just filled up a day ago, so, if I am not going to deliberately go for a long drive for the sole purpose
of running the tank down, I may buy the stuff today and wait until the tank gets lower to add it.

 

[orbital]

Okay, will do.

I just filled up a day ago, so, if I am not going to deliberately go for a long drive for the sole purpose
of running the tank down, I may buy the stuff today and wait until the tank gets lower to add it.

+

Remember to bring your engine RPMs' up.
(under revving a motor is terrible for it)