Stumped!

96 Ford Taurus 3.0L plain jane...

It has been acting up during the warm season. My mom has had this problem where the car will start to cut out and not want to run. With the gas peddle mashed to the floor it will die out. It seems as if it is getting hot only during the warmer times and will act up by dyeing out and acting as if it were losing power. Any hill or incline is out. She had to pull over and wait then it would go again for a little and the same happened repeatedly.

I tried a few things and noticed this. I have already replaced the coil, plugs, wires, EGR valve and solenoid, and just now the Trans relay solenoid and I did notice this. In nuetral, I revved up the engine. It cut out at 4000 rpms. Is there a rev limiter for this? I drove it around the block and mashed the gas, and at about 3000 or so rpms it was cutting out and dieing. Once I let up, it was better, but pushing the gas resulted in the same. It has only done it now that there is warm weather. Never did it all winter. I have racked my brain with this thing and can't figure it out. Any ideas are so much welcomed.

It runs ok under no load, which I would think is a coil, but already replaced that. The rev limit thing has me interested. Never had a car do that before at 4k. What am I missing here?

From what I understand, there is an electronic no load rpm limiter to prevent damage to the engine. Have you changed the fuel filter recently? Sounds fuel related. Measure the fuel pressure at the fuel rail pressure valve before and after the filter change to see if it meets spec. Does the pump sound any louder than before? It may be failing.

You talked about it getting hot having something to do with your problem. What makes you think it's hot and being hot has to do with the problem? Or as you said, this seems to be outdoor temperature related or at least wasn't a problem until the warmer weather came. This would be somewhat consistent with a failing fuel pump as it will be operating at a higher temp and that tends to accelerate its failure, and on its way to failure, the heat will slowly bind up the pump so that it no longer delivers the needed pressure.

From what I understand, there is an electronic no load rpm limiter to prevent damage to the engine. Have you changed the fuel filter recently? Sounds fuel related. Measure the fuel pressure at the fuel rail pressure valve before and after the filter change to see if it meets spec. Does the pump sound any louder than before? It may be failing.

You talked about it getting hot having something to do with your problem. What makes you think it's hot and being hot has to do with the problem? Or as you said, this seems to be outdoor temperature related or at least wasn't a problem until the warmer weather came. This would be somewhat consistent with a failing fuel pump as it will be operating at a higher temp and that tends to accelerate its failure, and on its way to failure, the heat will slowly bind up the pump so that it no longer delivers the needed pressure.

Thanks, I'll check the rail pressure.

Yep, you do have an electronic limiter on the engine speed when in park or neutral. I also agree with tripledaddy that the symptoms do sound consistent with a failing fuel pump.

Which 3.0L engine does the Taurus have, Vulcan (12V) or Duratech (24V)? The Duratech has secondary butterflies that should open somewhere in the 3-4k rpm range. If stuck, they may cause driveability issues similar to what you describe. However, if they were stuck open, it would more likely exhibit issues at cold temps.

When it gets warm and feels sluggish, does the exhaust smell rich? I suppose if the mixture was going way rich, it could bog the engine, but after sitting (hot) most of the excess fuel would evaporate and/or leak past the rings and then it would run fine again. You mention that the car is dying, but the rest of the text makes it sound like it's just sputtering. When she pulls off to the side of the road, is that because the engine stalled, or just because it is bogging? Does she shut off the engine and let the car sit, then start back up and the engine will seem fine a that point for a short time?

-Rod

Yep, you do have an electronic limiter on the engine speed when in park or neutral. I also agree with tripledaddy that the symptoms do sound consistent with a failing fuel pump.

Which 3.0L engine does the Taurus have, Vulcan (12V) or Duratech (24V)? The Duratech has secondary butterflies that should open somewhere in the 3-4k rpm range. If stuck, they may cause driveability issues similar to what you describe. However, if they were stuck open, it would more likely exhibit issues at cold temps.

When it gets warm and feels sluggish, does the exhaust smell rich? I suppose if the mixture was going way rich, it could bog the engine, but after sitting (hot) most of the excess fuel would evaporate and/or leak past the rings and then it would run fine again. You mention that the car is dying, but the rest of the text makes it sound like it's just sputtering. When she pulls off to the side of the road, is that because the engine stalled, or just because it is bogging? Does she shut off the engine and let the car sit, then start back up and the engine will seem fine a that point for a short time?

-Rod

Hello, I must correct that. It was bogging down severely, not stalling. Any incline, you could have the pedal to the floor and it just wouldn't increase in speed. Funny thing, my Dad mentioned it sounded like it was revving high, just not going anywhere. I haven't experienced that. When I test drove it, it was sounding to me like it was breaking up/sputtering/bogging badly and not gaining rpms.

The previous responses about the fuel pump have me very curious about that, but I don't have a fuel pressure guage and I'm sure if I press the schrader valve gas will come. Just no way of knowing what pressure at the moment. I either have to buy or borrow one.

All the diagnostics haven't given me too much yet. After replacing the egr valve & solenoid, o2 sensors, plugs, wires, coil pack, map, maf, fuel filter(last summer), it's getting pricey and just plain dumb of me to throw parts at something w/o a good idea. I usually have a good idea. My Dad thought for sure it was trans related, I didn't. But it did give the 1742 codes for the tranny. The only part I could find at local parts store that was a sensor type and changeable, was the Trans range sensor. And got one from boneyard, but no luck with that. Other codes were for random misfires and o2 sensors, but figured they were a product of the real problem. I know those parts were changed.

Do you have any ideas on checking fuel pressure w/o a guage, maybe some old tricks just to get an idea?

Thanks again.

Get a fuel pressure gauge from the loan a tool program at your local auto parts store.

Mike
:smokin:

Any body out there think the Cat could be plugged???

A crude, rudimentary measure would be using a tire gauge, posssibly the dial gauge being the best. I've tried using the stick gauge and eventually the gas seems to bypass the pressure piston/plunger inside no longer giving you any meaningful measurements. You are at this point mostly looking for trends as this isn't an accurate means of measurement. At key on engine off, you should get at least 10psi, and maybe at least 15 psi at idle, and at least 20 psi at high rpm. If you have an actual fuel pressure gauge then the measurements should be in psi:

koeo 35 - 45
idle 28- 45 vacuum hose on fuel pressure regulator
38 - 50 vac hose off
max fuel pump pressure
65
Pressure after engine off for 5 minutes
30 - 40

Injector Resistance 1.3 to 19 ohms
in case you want to check them

With the description provided in post #5, I don't think you should rule out a misfire. Closely inspect the plug wires. If it does this regularly enough, park in a dark area with the hood open, then look for blue arcing. If you don't see any arcing, and you have a Harbor Frieght Tools store nearby, pick up an inline spark tester for about $3. Install this in series with one plug wire at a time and check for an intermittant flash.

You could also pull one wire at a time and check for one that doesn't seem to make the engine run any worse, but they don't recommend unloading the coil packs that way in modern cars.

-Rod

That's real nice of you, Rod, to share with him how to have a shocking good time!:grinyes: But, even though I know you like to work with those little e- things, I bet after a few jolts of your own, you have a method that I hope you can share with us on how to avoid such a wonderful, I'M ALIVE!:yikes:, experience. :lol: Thanks :)

The inline spark testers reduce the liklihood of a shock significantly. I never used to use them, but appreciate them much more now. They do a nice job of indicating a bad plug wire, even if it is relatively random. The last car I used it on had a random misfire under load. With the inline tester, we could see that about every 5th pulse was missing. Swapped the suspect wire with a similar length wire that had a good pulse and the missing pulse followed the wire, so we were able to determine the coils were fine and the wires were the problem.

-Rod

The inline spark testers reduce the liklihood of a shock significantly. I never used to use them, but appreciate them much more now. They do a nice job of indicating a bad plug wire, even if it is relatively random. The last car I used it on had a random misfire under load. With the inline tester, we could see that about every 5th pulse was missing. Swapped the suspect wire with a similar length wire that had a good pulse and the missing pulse followed the wire, so we were able to determine the coils were fine and the wires were the problem.

-Rod

That is interesting also. Might have to get one of those too.

I should add that when we switched wires, the wire of similar length was fortunately on another coil so it was conclusive that the coil was not the problem.

-Rod

OKAY....

Finally got around to getting a fuel pressure guage and here are the findings.

KOEO - 0 psi
KOER - 32 psi

So, I take it that the fuel pump is bad. But one thing. I am pretty sure I changed the fuel filter a year or two ago. I may change it once more before getting into the fuel pump, just for good measure. And check the fuel pressure once more.

One question though, is how can it run fine usually and when I check the fuel pressure with KOEO, it is absolutely 0 psi? I hear the fuel pump for a second or two. Granted when the KOER is checked it is 32 psi and way low, but how can this thing still run normally most of the time, except hot weather? That just boggles me?

Guess I just don't know enough about fuel injection and I am like a sponge. I want to know why!

My blonde moment elapsed....

Guess I had the guage not on good enough.

I got

KOEO - 38 psi
KOER - 30 psi

It seems that it drops pressure when it is running. I unhooked the pressure regualtor also and got the necessary spike in pressure to 40 psi. When reapplied, it dropped again to 30 psi.

Why would the pressure drop when it is running and would this account for the shitt performance during hot weather we have experienced?

Thanks so much.

Fuel molecules becomes denser in cool weather and not only pumps better that way but performs better in the engine. That is why racers use fuel cooler cans, that the fuel line runs through ice in coils, to keep the fuel in optimum temperature range.

Hot fuel is less dense and even vaporizes in hot fuel lines sometimes resulting in vapor lock at the engine. The pump cannot pump vapor as it compresses too easily. Kind of like having enough air in a tire to mke it round and then putting the car on the ground and the air gets pushed to the other side leaving one side flat.

If the pump is weak, the fuel pressure is less when the engine is running because you have open the other end of the system by the injectors squirting fuel and the pump may not be able to keepup/maintain the same pressures.

Additionally, electric motors tend to have more issues when they are warm, either from connections or windings expanding and going open circuit, or from the short brushes making intermittant contact. Starter motors failing when hot may be a more familiar example....

-Rod

So do you think changing the fuel filter will affect anything or is it pointless since the fuel pressure is what it is?

Don't want to keep throwing money at it if I don't have to. I'd rather concentrate on getting a fuel pump.

Thanks for the responses!

Always good to change the fuel filter when changing the pump anyway. Distrubing the lines and tank ifyou drop it can compromise a questionable filter. Start with a clean slate!!!

Any body out there think the Cat could be plugged???

Check back pressure on Catalytic coverter,by taking the pre oxygen sensor
out of CAT and checking back pressure.

There should only be a few lbs. of back pressure.

If it's plugged ,it's like trying to drive a car with a potato in the exhaust pipe. ''No Power''

Will Help - knows what were talking about!

BAD CATALYTIC CONVERTERS:

If its plugged - it will not throw any codes.
Converter gets very hot,loss off Pwr,and stalling.

If it's Blown - Catalyst effeiciency error P0420/P0430
Poor EPA Emissions + fuel economy.

MCGIVER

You can also listen at the tail pipe. A plugged cat/muffler gives a sound like trying to force air through a bent straw. Kind of like pressing your lips together and blowing hard. Doesn't have that nice hollow, clean flowing sound.

Sorry that this process is taking so long to fix your problem. It isn't as easy to trouble shoot when all we can touch are computer keys. I'm a kinda hands on mechanic myself. All we can do is work with your information and we all know that heresay information won't stand up in court!!!!

You can also listen at the tail pipe. A plugged cat/muffler gives a sound like trying to force air through a bent straw. Kind of like pressing your lips together and blowing hard. Doesn't have that nice hollow, clean flowing sound.

Sorry that this process is taking so long to fix your problem. It isn't as easy to trouble shoot when all we can touch are computer keys. I'm a kinda hands on mechanic myself. All we can do is work with your information and we all know that heresay information won't stand up in court!!!!

Well thanks for those suggestions. I am a hands on mechanic myself, but been struggling with this intermittent problem for some time. Plus, I just got the right tool, that helps. I'll check the exhaust out anyway, sure it's fine though. But how can I be sure it is one and not the other(i.e.fuel pump or cat)?

Some fo these discount AutoParts will rent tools cheap!

Focus on Cat 1st.
1) Need a compreshion Tester guage. (Rent)
2) Jack-up/Rampup frnt of car.
3) Remove oxygen sensor on pre Cat side (the one closer to Eng.)
4) Screw the compreshion Tester guage in the oxygen sensor hole.
5) Start car Engine,and than turn it off.
6) What does the guage read?
7) How many lbs. ?

Note: My hearing isn't as good as will help too!

I guess it's like your car trying to Fart.

CAUTION - If your stuck in traffic behind one of those cars,turn
your Air-Cond to recycle cabin Air or you will die.

Hey!
After so much gas,you might want to change your shorts too!


MCGIVER

Ok, got a used fuel pump/sending unit assy from the boneyard. Had to go with the $20 version vs the 200+ for new. But being smart about it before I do install it. How do I test this fuel pump out of tank to make sure it is good before going through the whole process of putting it in and hoping it works? Can I put power to it to make sure it works?

Knew the pump was low so started with that because I can check the exhaust later. I didn't experience any problem over the Winter months at all, that's why I'm thinking it is fuel related when the weather turned warmer.

Thanks

If the car you got it from was there as a result of an accident, you can be 90% sure it is OK because the car was running at the time of the accident. If there was no damage to the car, then the mechanics of it become questionable. Why is it junked???

You can test it by temporarily jumping it just long enough to see if the pump runs. Make sure there is no gas in it that could be ignited by a spark.DO NOT LET IT RUN DRY FOR LONGER THAN A SECOND OR TWO!!!Running a car out of gas is a major cause of fuel pump failure.

Even though the pump may run dry is still not an indicator that the impellor assembly is working properly. Wet test would be best. DON'T STICK IT IN A BUCKET OF GAS!!! They will pump water though. You can temporarily stick it in a bucket of water for a short ( couple of seconds again ) test and drain it as best as possible before installation.

Hey!
Don't forget what elements you need for a Fire!

If that CAT is plugged,you won't get oxygen for FIRE.

Try to run up a hill with your mouth close (Exhaust) and fingers up your nose (MAF),and see how far you get.!

Keep it Real on AF!

If you need a pix,see DEI system :Automotive Forums > Mercury > Grand Marquis -
New gas saving devise.

Lets get to root cause,so we can close thread.

MCGIVER

If we are going to get to root cause and find a catalytic converter is the problem causing the poor running now, there will be something that caused the converter to fail. They shouldn't fail on their own, but rather due to an improper air/fuel ratio.

-Rod

Shorod, think back to the beginning of this. It is a 96. A cat is typically suppose to last 100,000. This one is at least 12 years old. I have a 2000 with 165,000 and a 2002 with 181,000. Could just be old age.

Kinda like at home...only so much gas can pass before the trouble starts!!!

Well, after I get the pump in and road test, I'll post back with the results!

Didn't you say it's your Mom's car?
What kind of driving Highway/City?
How many miles are on the car?

We put EGR,and PCV Gase's back in the Intake,and the catalyst is the CAT.
This is a simple Test, and it costs around $20 @ a muffler shop.
I would do it yourself just for the experience.

If this isn't,the problem than we can focus on possible fuel related problem.

The car is getting older & Ain't ''AS GOOD AS ONCE WAS'' - Toby Keith

MCGIVER

Hey!
Will Help
I wounder how may gallons a used fuel pump has it?
100k (car)/25mpg = 4000 GAL
What's the life expectancy?
This is a 1996 with how many miles?
I'am searching GOGGLE for a new cheap fuel pump.
''1996 TAURUS FUEL PUMP''

You can get a new BOSCH electric fuel pump for $119.79 @ RockAuto.com
* Don't forget to clean or put a new strainer in tank.

Note: I did have a problem with fuel pressure one time and ,it ended up being the
primary fuel filter in tank (strainer).

MCGIVER

Didn't you say it's your Mom's car?
What kind of driving Highway/City?
How many miles are on the car?

We put EGR,and PCV Gase's back in the Intake,and the catalyst is the CAT.
This is a simple Test, and it costs around $20 @ a muffler shop.
I would do it yourself just for the experience.

If this isn't,the problem than we can focus on possible fuel related problem.

The car is getting older & Ain't ''AS GOOD AS ONCE WAS'' - Toby Keith

MCGIVER

1) yes. I drive it sometimes to work on it.
2) any during hot weather, no symptoms all Winter, only when it got hot again.
3) alot. maybe 180K.

EGR PCV Gase? I take it you mean gaskets. Been done.

Catalyst = CAT > If I didn't know this, then should I be trying to fix a car?

Seriously, the EGR and PCV are newer parts I installed in the last year or two trying to slowly figure this problem out. The cat hasn't been an issue to me because the car runs fine in the Winter. If the cat was plugged, it shouldn't matter what season of the year it is.

Having said that, as said before, I believe it to be a fuel related issue as said by some else before too. It coincides nicely with the cold weather better running than warm weather. After pressure testing the system at the rail, I got 38 psi KOEO and 20 psi KOER this last time. So, I got a used pump from a boneyard for $20. It wasn't hard to do so I am trying this, but reasonably confident it will cure it. The car is now mine, as my Parent has gotten another and unloaded this to me. I am currently going through it to get all the kinks fixed. Easy peezie...

Taking me time to do this with other responsibilities (kids, wife, home duties etc) but may tinker tonight. As soon as I get that "AHA" moment, I'll post back.

Like Toby!

Thanks.

I'am like a tic on a dog,when it comes to analyzing + Toubleshooting
''Its my nature''.

When the problem is resolved,its a lesson learned + a hell of a education.

I had a CAT 95% blocked with No chk eng light,I had to drop the header
pipe just to drive it to a muffler shop.

Please Read thread ''97 Taurus car dies while driving and not batt or alternator''
'' '' '' Honda > delsol > Free Delso

MCGIVER

Fuel pressure for this car should be 39 psi. Should never drop to 20. Should only drop a couple of pounds.

I think some of these new Diesel trucks fuel pressure is 20k-30k psi and
are very dangerous.

MCGIVER

Fuel pressure for this car should be 39 psi. Should never drop to 20. Should only drop a couple of pounds.

Exactly why I am gonna do the fuel pump first.

Hell, I got so much extra parts right now i.e. Cam sensor and shaft(yep, saw in boneyard one where it was chewed up under the sensor, took whole shaft assy from one good one just in case), sending unit/fuel pump, CCRM(thought it was this too) and some misc sensors and fuel filter new. Been busy fixing family stuff(darn neighbors lol) that I haven't been able to get my own done.

But all said, I thought if the pressure was reading that low, I have to try that first. Just been getting to the "time" part to do it.

Ford Powerstroke exceeds 30,000 psi in a common rail system.

I spent 37+ years in tooling engineering in the plant that builds these.

Got to take care of family, friends and neighbors. Never know when you may have to rely on them for help!!!

Hey!
Take your time,you do have a bunch of good Technicans,that want to help you on this car.

While your in the bone yard,get a bunch of nuts,bolts,and screws for your
car.

I paid $15 for a new window regulator off of EBAY,and spent $10 on bolts + nuts.

There was a young man who grab rotors + pads off a car.

Alot of these new parts were needed,because of routine maintenance.

Once you isolated the problem,you will be good for another 100K miles.

Hey!

How much Hotter does a Engine get during summer with Air cond on?

Whats Normal Engine Temp = ? 165-180

Anti-freeze + pressure system increases boiling point.

Water = 212F / Antifreeze protection = 370F

What Temp does the cooling fan kick on?

MCGIVER

Yep, we have a u-pull-it yard not too far from here and I have been visiting regularly.

In an effort to make it easy on myself, I decided to just change the fuel filter first, just in case. It'd be a tough lesson if I changed the fuel pump and it turned out to be something much less. So, I'm trying everything easy first.

It looked as if the filter might be original. Original??? Maybe because it was Ford motorcraft unless someone had the dealer do it pre my Mom owning it. That's done and was going to check the pressure again, but I needed o-rings for the adaptor on my guage. They disintegrated the other night. Now I got some larger than needed ones, but will try to make them work later tonight.

I swear everytime I checked the fuel pressure, it was different. I checked it just before I did the fuel filter and it was 37psi KOEO and 30psi KOER. When I revved it up, it rose a few psi.

Interesting, but we'll try some more things before the inevitable(pump).

Oh, is there a rock bottom psi that you know for sure it is a bad fuel pump?

Yep, be careful not to overtighten the Ford fuel rail adapter, or the o-ring will do exactly what you found. I did the same thing, then I read the instructions. I wasn't able to find a new o-ring either, so I bought a new gauge and just snugging it worked great, no leaks, and no damage to the seal.

-Rod

Hey!
That's one way you can pump gas out of a car,threw the fuel rail valve!

MCGIVER

Best to stay away from possibly spilling gas all over the engine compartment and away from any electrical sources because of fire hazards. Every time you turn on the key, solenoids and relays activate which could ignite even light vapors.

Yep, be careful not to overtighten the Ford fuel rail adapter, or the o-ring will do exactly what you found. I did the same thing, then I read the instructions. I wasn't able to find a new o-ring either, so I bought a new gauge and just snugging it worked great, no leaks, and no damage to the seal.

-Rod

Rod,

I did the exact same thing when I got the new guage last week and yep, noone has any new gaskets. But there was a larger one that one parts store had and it just barely fit so I am using that.

Pumps out and replaced along with send unit. Just gotta get it back in now...

Hey! 82Stang
You have over 500 Views on this project,wouldn't it be cool to Grab
some views and put it onto YouTube.
When people do a Reply on AF will put it on video and show the world.

Picture the BoneYard scene!

$2 Cover charge!
GREEN - Recycled used car parts
TACO stand - Lunch
Who burnt the Crazy Horse next door?
We could hire X-girls to pull parts!
How much did we save with used parts?

MCGIVER

Hey! 82Stang
You have over 500 Views on this project,wouldn't it be cool to Grab
some views and put it onto YouTube.
When people do a Reply on AF will put it on video and show the world.

Picture the BoneYard scene!

$2 Cover charge!
GREEN - Recycled used car parts
TACO stand - Lunch
Who burnt the Crazy Horse next door?
We could hire X-girls to pull parts!
How much did we save with used parts?

MCGIVER

LOL
Imagine that!


Tank's back in. Showing 32 psi KOER. KOEO didn't look so good. It was down to 10 psi and the guage slowly moving down to 5 or 3 or something like that. One thing's for sure. I'm not dropping the tank again. Too much rust and dust in my eye's. Yes I wore goggles, but still got some. Haven't driven it yet, wish me luck!

:-)

That's what the Badger was talking about ''Rust + dust fee''
Wasn't there an access hole in the trunk of this car to get to the fuel pump?

That's what the Badger was talking about ''Rust + dust fee''
Wasn't there an access hole in the trunk of this car to get to the fuel pump?

No access on this car. It's nice when they think ahead like that though.

Got the new "used" pump in and running. I didn't hear the old pump, but hear this one. Got it warmed up the other night and drove it about 5 miles getting on it and flooring it and playing around to work it a little. It ran like a top. So, I can only assume it is fixed. Car is mine now, but will be moved. Just wanted to ge that driveability problem done and out of the way.

I appreciate all the responses.
Been a pleasure chatting with other knowledgable gear heads.