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Discussion Starter · #1 ·
Alrighty, I've been lurking for a while and I figure it's time to push this out here before I take him to the shop.

98 Taurus Wagon, Vulcan (U) with about 125k on it. Really a steal, or so I hope!

When I got him, he had a horribly rough idle, but a really smooth ride at speed

I ran an OBDII Scan and came up with P0301, P0302, and er...bank 1 lean, I think it was 0174, but I may be mistaken. I cleared the codes and they came back partially. Only the P0301 came back, the 0302 and the lean bank code never came back, not ever.

I'm like "Oh, he needs a tuneup, he still has the OE plugs and wires" so I put in new plugs, new wires..still runs rough.

Okay, let's check the coil. The secondary windings on the 1/5 coil were shooting at about 7k and change, so I swap out the coil too. It improves my mileage and it runs better, but still that stutter and still that miss, but now it's only Cyl1, and only at idle, and only when warm.

Heard it could be a vacuum leak so I check all my vacuum lines with ether, nothing out of the ordinary.

I physically inspect them, nothing out of the ordinary.

The PCV is a bit gunked up, so I changed that, too..only a couple bucks so what's the harm, ne?

During this, I notice that my tensioner pulley is a bit squeaky..I plan on changing it but it's the least of my problems ATM ( And no it's not the cam synchro, I know my left from my right! )

The car essentially runs..sorta smooth at cold in p/n. Stays about 900-1k. When I put it in gear it drops to about 650-800 and I hear a very exhaust-leaky sound, but only when it's in gear. Once warm, though? Starts dipping into the 4-500's when in gear, and starts flashing the MIL, but only with P0301. It goes away if I bring it over 1800. Also flashes MIL when in p/n and it sounds all misfire-y, but it never goes below 600.

So, Deeper into the troubleshooting, we go.

I figured it could be a dirty MAF, the air filter was also disgusting. Changed that, took the MAF out and cleaned it with a whole can of MAF cleaner, letting it dry in thirds through. While I had the MAF off I cleaned the throttle body with a very soft baby bottle brush and throttle body cleaner, also disgusting ( I think I might put a catch can on my PCV line, that's where all of that oil and crap is coming from right?)

Still no change. I disconnected the IAC, and the idle didn't change @ all, so I replaced that and its gasket (the old one was disgusting inside, btw) and no change. Then I'm like D'oh, gotta reset the PCM by unhooking the battery, so he can relearn idle! So waited till the car was warm, disconnected the battery lead..powered engine off and turned it back on..

I also decided to replace the fuel filter, well, because it was a rusty piece of crap that looked OE.

And, wow, now it's really different.

Idles in p/n at 700ish, sounds like crap. When I put it in gear, though, it drops to 650 and behaves for about five seconds..then he races to 1.1 and tries to leap out from under my brake! I almost crashed into my porch! Then it stays at 1.1k for about 30 seconds, then drops back down to 650.

Rinse, and repeat.

Now, it hasn't flashed the MIL or thrown any codes yet. I think the racing is coinciding with the IAC opening, but why would it be opening the IAC that wide for that long when it's in no danger of stalling...or is it? And what happened to my misfire?!

( Through this entire process I've been running injector cleaner through the fuel. One tank of lucas in 93 octane ( garbage!!!! ) and two tanks of techron in 87 octane )

Just to sum up, the problem was originally P0301, P0302, and a bank 1 lean condition stored in the car when I bought it. The only code that comes back is P0301, and it hasn't come back since I did all of the following work.

  • REPL All Spark Plugs with Bosch Double Plats. No visible wear or fouling on old plugs, not even in CYL 1. Cyl 1's old plug looks like it's really clean.
  • REPL IAC / Gasket
  • REPL Spark Plug Wires
  • REPL Ignition Coil
  • CLEAN Mass Airflow Sensor
  • REPL Positive Crankcase Ventilation Valve
  • CLEAN Throttle Body, Intake Manifold.
  • REPL Fuel Filter
  • TREAT Fuel System /w Lucas and Techron

On an ancillary note, and this may or may not be relevant.
At the exhaust, when this issue is happening..it sounds like 'putt putt putt putt' at the speed of the idle, and sometimes there is barely visible vapor..like a breath coming out of the exhaust. I am imagining that this is from incomplete combustion in Cyl 1 when it is misfiring, and more of a symptom than a differential. The exhaust has a noticible puffing sensation when this is happening as well, like it's blowing puffs of air on my hand as opposed to coming out more steadily.

I get an audible whining/whirring that coincides with my power steering pump's activity..a bit louder than I'm used to with a ford but still not unusual, imo. The whining changes pitch, and reduces pitch when the engine is running slower, and increases pitch when the engine is running more quickly. It never goes away. I never get a voltage drop on the accessory.

AC is Ice cold and running beautifully. AC on or Off doesn't affect issue, nor does AC + Radio + Rear Defroster grid.

When I shut the engine off, it doesn't immediately die, it has about a quarter a second of life left in it before it dies..enough to make the tach not drop smoothly, but drop , stop for a bit, then finish dropping. It is not dieseling though.

My current posits are as follows
  • Something wrong with the EGR System that I do not know how to test for and that isn't throwing a code
  • A vacuum leak that does not involve any hose visible from the top of the engine compartment, nor responds to ether being sprayed on it, such as a leak in the plenum gasket or LIM gasket. or somewhere I don't even know about.
  • A faulty or clogged bank 1 catalytic converter, resonator, or muffler.
  • A fuel injector that is stuck open, flooding the engine @ idle. When I disconnected the fuel filter, I lost almost nothing from the engine side of the fuel lines. I have not checked my fuel pressure because I don't own a gauge.

Thank anybody in advance for any input on the subject. I'm not a mechanic, and I'm a bit intimidated by this stuff. I'm a technician in another field, so the same differential process applies..it's just that I don't blow up my car if I'm wrong ^.^

edit--one last thing. My speedometer reads about 2-5 MPH faster than my GPS indicates. I think this is within tolerances, but it could be a differential.
 

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QUOTE (scalyblue @ Jun 4 2010, 12:35 AM) index.php?act=findpost&pid=809172
edit--one last thing. My speedometer reads about 2-5 MPH faster than my GPS indicates. I think this is within tolerances, but it could be a differential.[/b]
You can see I did read through your post, although I don't have much to offer.

Speedo reads 2 MPH faster than GPS is normal. 5 MPH is a bit high. Worn/under-inflated tires?
 

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Discussion Starter · #3 ·
QUOTE (hhu168 @ Jun 4 2010, 02:07 AM) index.php?act=findpost&pid=809181
QUOTE (scalyblue @ Jun 4 2010, 12:35 AM) index.php?act=findpost&pid=809172
edit--one last thing. My speedometer reads about 2-5 MPH faster than my GPS indicates. I think this is within tolerances, but it could be a differential.[/b]
You can see I did read through your post, although I don't have much to offer.

Speedo reads 2 MPH faster than GPS is normal. 5 MPH is a bit high. Worn/under-inflated tires?
[/b][/quote]

Fronts are brand new, rears are bad..need to be changed, but I'm really hesitant to do that at this point, if I'm going to just drive him into the ground, he's a good bull, and he's trying so hard!

I also have a ball joint with about an eight inch of play on the pass front side, but that's not really relevant to the issue. I'm not going to bother to change a ball joint if I need to drop 3k on him to get him past a sniff test.

I really like being proactive, because driving until something fails fails is going to just be a can of worms..
 

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You are misfiring because I think you are using Bosch plugs. Bosch plugs are known not to work with our cars...or maybe Ford's in general. Change them to Motorcraft or Autolites.

And using an entire can of MAF spray is too excessive.
 

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Discussion Starter · #5 ·
QUOTE (fdogg96 @ Jun 4 2010, 02:23 AM) index.php?act=findpost&pid=809190
You are misfiring because I think you are using Bosch plugs. Bosch plugs are known not to work with our cars...or maybe Ford's in general. Change them to Motorcraft or Autolites.

And using an entire can of MAF spray is too excessive.[/b]
Citation needed.

I seriously doubt that such a widely available product would be so faulty as to cause a fundamental engine malfunction prior to being installed in my bull.

If I start having problems with ping or with bad mileage due to the spark not being TDC, I might consider changing my plugs again; until then I don't care how much you hate Bosch plugs, my brand new plugs aren't causing a misfire in only one cylinder at idle, whilst performing perfectly fine at any other condition aside from idle, as well as replicating the symptoms of the plugs that I just removed.

Now, unless you can furnish a double blind study published in a peer reviewed journal that indicates otherwise, I consider there to be no fundamental difference between the base functionality of Bosch spark plugs versus Autolite spark plugs, therefore the plugs are no longer a differential. I am eager to educate myself, and to be proven wrong, yet anecdotal evidence is not proof of anything.

Now let's say they were part of the problem, and that I did replace them.

Consider that both brands of plugs are creating a spark, as they are both designed to do.

My current plugs are clearly creating a spark, as the engine is running. Despite the characteristics of the spark, the direction, or the alignment of the spark, any adequate spark will initiate ignition and the ignition will be consistent throughout all of the cylinders.

Were my Bosch plugs causing my misfire, they should be causing a misfire in all of my cylinders, not just one. Since I was getting a misfire condition in one cylinder, there is a condition that exists for that cylinder that is aside from the plugs. Therefore, replacing my plugs a second time will either do nothing, or will act as a temporary panacea to a larger problem that still needs to be resolved. Either way, it's not a differential.

Edit--Also, I don't have too many MAF's to clean ^.^ So it was either throw it away, toss it in a garage until I need to clean another MAF, or use it all and make sure my MAF is squeeky clean.
 

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Discussion Starter · #6 ·
Hmm, it seems that we aren't very scientifically minded on this forum, now are we.

Well, I decided to waste my money and buy motorcraft platinum plugs, installed them and guess what..the exact same thing is happening! What a shocker! It's almost like I predicted that it wasn't a differential to my problem before I bought them. So, now I have the same problem I originally had with older Autolite plugs and brand new Bosch plugs with shiny new motorcraft plugs, and my wallet is sixty dollars lighter.

This community's been a great service so far, you know? Well now I don't have the evil, bad, naughty, frightening bosch plugs in my vehicle, just like before I owned it, and it still has the same problem, just like before I owned it. Now what?
 

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QUOTE (scalyblue @ Jun 4 2010, 10:58 AM) index.php?act=findpost&pid=809281
Hmm, it seems that we aren't very scientifically minded on this forum, now are we.

Well, I decided to waste my money and buy motorcraft platinum plugs, installed them and guess what..the exact same thing is happening! What a shocker! It's almost like I predicted that it wasn't a differential to my problem before I bought them. So, now I have the same problem I originally had with older Autolite plugs and brand new Bosch plugs with shiny new motorcraft plugs, and my wallet is sixty dollars lighter.

This community's been a great service so far, you know? Well now I don't have the evil, bad, naughty, frightening bosch plugs in my vehicle, just like before I owned it, and it still has the same problem, just like before I owned it. Now what?[/b]

I don't have any advice for you, but would be interested in what corrects the problem if you can find it.

I will help you rule out a clogged exhaust. You lose power and can't seem to get up to speed with clogged exhaust.
 

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Discussion Starter · #8 ·
QUOTE (kgrantkey @ Jun 4 2010, 12:22 PM) index.php?act=findpost&pid=809285
QUOTE (scalyblue @ Jun 4 2010, 10:58 AM) index.php?act=findpost&pid=809281
Hmm, it seems that we aren't very scientifically minded on this forum, now are we.

Well, I decided to waste my money and buy motorcraft platinum plugs, installed them and guess what..the exact same thing is happening! What a shocker! It's almost like I predicted that it wasn't a differential to my problem before I bought them. So, now I have the same problem I originally had with older Autolite plugs and brand new Bosch plugs with shiny new motorcraft plugs, and my wallet is sixty dollars lighter.

This community's been a great service so far, you know? Well now I don't have the evil, bad, naughty, frightening bosch plugs in my vehicle, just like before I owned it, and it still has the same problem, just like before I owned it. Now what?[/b]

I don't have any advice for you, but would be interested in what corrects the problem if you can find it.

I will help you rule out a clogged exhaust. You lose power and can't seem to get up to speed with clogged exhaust.
[/b][/quote]

Hm, interesting. It makes sense, if there was sufficient backpressure the combustion products wouldn't be able to leave the engine fast enough and acceleration would be affected. He never has difficulty getting up to speed @ all; if he never idled you'd never know there was a problem!

I'm going to attempt to replace the EGR gasket, and perhaps rent or borrow a vacuum pump to see if opening the EGR stalls the engine.

Does anybody feel that a compression test is necessary at this point?

Oh, another unusual thing. I cleaned him off today with some foamy engine brite, and the UIM gasket is blue. I've never seen a blue gasket before, is this indicative that it may not be OE? Would it damage the UIM to torque the bolts down about 5 LBS over spec?
 

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Discussion Starter · #9 ·
Update!

I replaced his EGR gasket ( His old gasket had some silver material on it, and the silver material was gone in several areas..it could very well have been a vacuum leak.

Anyway, at a cursory glance he idles a lot more steadily now..but I haven't actually driven him around, so even if it wasn't my entire problem I think some of my problem was a vacuum leak.

He stays around 650, still a rough 650..when I turn the AC on, he rises to and stays at 1k, drops to 650, then back to 1k, then down..and back..and down. I can replicate the RPM spike by turning the steering wheel back and forth until the accessory system stresses it, I suppose?

Anyway, once I ride him to work tomorrow I'll post another update.
 

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QUOTE (scalyblue @ Jun 4 2010, 07:23 PM) index.php?act=findpost&pid=809392
Update!

I replaced his EGR gasket ( His old gasket had some silver material on it, and the silver material was gone in several areas..it could very well have been a vacuum leak.

Anyway, at a cursory glance he idles a lot more steadily now..but I haven't actually driven him around, so even if it wasn't my entire problem I think some of my problem was a vacuum leak.

He stays around 650, still a rough 650..when I turn the AC on, he rises to and stays at 1k, drops to 650, then back to 1k, then down..and back..and down. I can replicate the RPM spike by turning the steering wheel back and forth until the accessory system stresses it, I suppose?

Anyway, once I ride him to work tomorrow I'll post another update.[/b]
The increase and decrease in idle speed with the A/C on is the a/c compressor kicking on and off. When you start reading the book on emission and engine controls, almost every sensor can cause a rough idle. There's even a power steering pressure sensor that sends a signal to the PCM to increase idle under load.
 

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When you changed the pcv valve, how did the hose look? Check the UIM gasket-there could be a leak near cyl 1. The blue gasket on the LIM I believe would be a Fel-Pro gasket, of which are the best-it was replaced at some point. What about the dpfe sensor?
 

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Discussion Starter · #12 ·
QUOTE (austex04 @ Jun 4 2010, 11:32 PM) index.php?act=findpost&pid=809451
When you changed the pcv valve, how did the hose look? Check the UIM gasket-there could be a leak near cyl 1. The blue gasket on the LIM I believe would be a Fel-Pro gasket, of which are the best-it was replaced at some point. What about the dpfe sensor?[/b]
The hose was wondrous. The UIM gasket is what is blue, I can't distinguish what the LIM gasket is.

Hm, some cursory research on the DPFE shows that symptoms are somewhat consistent with what's happening to me. I'll try replacing it and see what happens.
 

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QUOTE (scalyblue @ Jun 4 2010, 11:04 PM) index.php?act=findpost&pid=809460
QUOTE (austex04 @ Jun 4 2010, 11:32 PM) index.php?act=findpost&pid=809451
When you changed the pcv valve, how did the hose look? Check the UIM gasket-there could be a leak near cyl 1. The blue gasket on the LIM I believe would be a Fel-Pro gasket, of which are the best-it was replaced at some point. What about the dpfe sensor?[/b]
The hose was wondrous. The UIM gasket is what is blue, I can't distinguish what the LIM gasket is.

Hm, some cursory research on the DPFE shows that symptoms are somewhat consistent with what's happening to me. I'll try replacing it and see what happens.
[/b][/quote]
Not a cheap part, and they fail with age, only buy a Motorcraft part for this: I replaced two aftermarket ones in mom's Explorer, all failed within a few months. Now there's a Motorcraft in there, still running great!
 

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Bosch plugs do have problems with Vulcans AFAIK. I had problems with all except the ones i am using now. I am using the Bosch IR Fusion plugs but i had misfires with the Bosch Platinum, +2, and +4s i have tried.
 

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Discussion Starter · #15 ·
QUOTE (austex04 @ Jun 4 2010, 11:29 PM) index.php?act=findpost&pid=809465
QUOTE (scalyblue @ Jun 4 2010, 11:04 PM) index.php?act=findpost&pid=809460
QUOTE (austex04 @ Jun 4 2010, 11:32 PM) index.php?act=findpost&pid=809451
When you changed the pcv valve, how did the hose look? Check the UIM gasket-there could be a leak near cyl 1. The blue gasket on the LIM I believe would be a Fel-Pro gasket, of which are the best-it was replaced at some point. What about the dpfe sensor?[/b]
The hose was wondrous. The UIM gasket is what is blue, I can't distinguish what the LIM gasket is.

Hm, some cursory research on the DPFE shows that symptoms are somewhat consistent with what's happening to me. I'll try replacing it and see what happens.
[/b][/quote]
Not a cheap part, and they fail with age, only buy a Motorcraft part for this: I replaced two aftermarket ones in mom's Explorer, all failed within a few months. Now there's a Motorcraft in there, still running great!
[/b][/quote]

It's about 60 bucks aftermarket with a 2 year warranty, not really that expensive in my book. Unless we're not speaking of the same part.
http://www.autozone.com/autozone/catalog/p...95712_0_0_&
 

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Hey guys,
This is going to sound really stupid but I was wondering if someone could put the possible answers to the part about the bucking while idling in slightly "dumbed down" terms for me? Like what parts could be causing it? I read all the posts twice, but without better technical knowledge I get a little lost.

I'm curious because I think my car has a similar issue. Often when I take my foot off the break, like getting ready to go at a stoplight, or if I release the gas to coast on the road, it will rev up and start going faster for a minute, sort of a "buck" then vroom issue. It's been doing it for years, I just always say it's a sign she's ready to go, not a huge problem, but after reading this thread I want to know more so I can research what could cause it. I've never experienced it in a different car.

So far I've got fuel injector, EGR system/gasket, catalytic converter, leak in plenum/LIM/UIM gasket, and spark plugs as possible things associated with bucking that I could research. Does that sound right?

Thanks!

:wub:
 

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QUOTE (kismetmiss @ Jun 5 2010, 08:16 AM) index.php?act=findpost&pid=809511
Hey guys,
This is going to sound really stupid but I was wondering if someone could put the possible answers to the part about the bucking while idling in slightly "dumbed down" terms for me? Like what parts could be causing it? I read all the posts twice, but without better technical knowledge I get a little lost.

I'm curious because I think my car has a similar issue. Often when I take my foot off the break, like getting ready to go at a stoplight, or if I release the gas to coast on the road, it will rev up and start going faster for a minute, sort of a "buck" then vroom issue. It's been doing it for years, I just always say it's a sign she's ready to go, not a huge problem, but after reading this thread I want to know more so I can research what could cause it. I've never experienced it in a different car.

So far I've got fuel injector, EGR system/gasket, catalytic converter, leak in plenum/LIM/UIM gasket, and spark plugs as possible things associated with bucking that I could research. Does that sound right?

Thanks!

:wub:[/b]
Idle Air Control (IAC) valve. When you're stopped at a light, your throttle plate is closed, not letting a lot of air through. There's an alternate path above and over your throttle plate, where a computer-controlled valve blocks or allows air through based on engine speed. Because your throttle plate is closed, the valve opens to let enough air through to keep the idle at a desirable speed, rather than cough out and die. In a perfect world, it turns off when you press the gas pedal to open the throttle plate, returning control of engine speed to you. If the valve gets dirty and starts to stick, then it will stay open when you press the gas, letting a lot more air through than you intended; or when you let off the gas, it will stay wide open and let in enough air to rev the engine up and get you moving.
 

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Your idle speed problem sounds like it could be a sticking Idle Air Control valve. If the PCM thinks the speed is too high it will lower the signal to it. If it sticks it will lower it more until it moves. Then the speed is too low and the cycle repeats. It may leave it alone if it is 'close enough' so the reduced idle may not be corrected. The PCM may not be accurate enough to properly detect a misfire at low speed, so it throws a code but the only real issue is low idle speed. Yes, I pulled this scenario out of thin air because it's never happened to me. I have had one occasionally stick open, though. Had to turn off ignition and restart to restore it to normal. Good luck!
 

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Thanks!

I was just reading about the IAC and poking around in my engine. Looks like it could eventually lead to stalling if it's left dirty, so I guess it would behoove me to clean it at some point. And maybe check hoses and throttle body too.

I couldn't find any identical pictures or diagrams of my engine exactly, but I looked at photos online and in the forums and I think I've pinpointed it. Pardon the dusty engine, it hasn't had any cleaning since pollen season.
 

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