98 Windstar Loss of Power / Hesitation

[Ulsterman]

Well today I invested in a new battery on the way home from work. The existing Walmart model was in service six years and I thought it due for a change as recommended by Wiswind and Tartersauce..
I installed the new one and well a faster cranking speed but no change to starting or running; still the choking and backfiring which reduces on reaching operating temp. I decided to check that the codes were clear and then to take it for a short drive and see what codes came back and go from there.
It was of course way low on power and struggled once engaging drive but I coaxed it out for a few miles taking it up to 60 at one point.
On the laneway back into my house it stalled on a short hill. I started it again and waited until it was revving freely but got an almighty boom and rock from the transmission when I selected D. Into R and the same boom so I shut it down, walked up to my house and got the truck, and my wife, and towed the van the 300 yds up into our yard so not to block the right of way.
It was dark by this time so investigation recommences in the am. I did start the van again just to check there weren't any sparks jumping around under the hood but no everything looked ok.
Any thoughts anyone - it's the first automatic I've ever owned?

[tartersauce]

wow.. Your not having any luck at all.. Stalling or Banging Torque Converter staying locked up? It will make the van jump forward and bang once stalled but this is rolling.. You were not moving? Low fluid?

[tripletdaddy]

I seem to recall reading from one of three forums I visit that there is an engine temperature sensor seperate from the temp gauge the PCM uses for fuel trim but is also used by the transmission, causing them all sorts of weird problems. I can't recall if it is separate from the ECT or is the ECT, so I'm hoping that someone here can confirm or correct this.

Additional thinking makes me think they were talking about the TFT or trans fluid temp sensor. Somehow, the trans temp influences the desired engine output, so the PCM uses that info accordingly.

[tartersauce]

Originally Posted by tripletdaddy

I seem to recall reading from one of three forums I visit that there is an engine temperature sensor seperate from the temp gauge the PCM uses for fuel trim but is also used by the transmission, causing them all sorts of weird problems. I can't recall if it is separate from the ECT or is the ECT, so I'm hoping that someone here can confirm or correct this.

Additional thinking makes me think they were talking about the TFT or trans fluid temp sensor. Somehow, the trans temp influences the desired engine output, so the PCM uses that info accordingly.

True, but giving him shifting problem should of set a Trans Light.. That would mean, Two sensors failing, one in the trans and the coolant temp. Both should set a light.

Also, remember that, when you pull your battery, The computer will have to relearn SHIFTing all over again. If your engine runs crappy, I think your trans will just be confused.. Get the engine running up to par, And I think your trans will be fine. If you must run the van, Start it then remove the TRS sensor on top of the trans. Trans Range sensor, or net saftey. You need it plugged in tho to start, but it will force the van to use a set parameter to cal shifting patterns. You wont have o/d tho, or 4th etc..

[Ulsterman]

This evening the van started with a little effort and chugged a bit until it warmed up. I was nervous engaging the transmission but it was ok (spot on again Tartersauce) and I drove it slowly uphill the 100yds or so to the side of my house. By then the engine was revving like nothing was wrong and I let it sit and idle for maybe 10 mins or more. There was no CEL at this time so I was thinking about another test drive when it conked out as I was revving it from under the hood. It was extremely hard to start now so I gave up after a few tries.
The CEL was now on with the four original lean codes, P0304 and one I hadn't seen before P0156 - downstream O2 sensor bank 2.
I checked the fuse voltages as 12Ounce suggested in the box beside the battery. Battery voltage was 12.7v and I got 12.7v on both sides of each fuse, the big ones and the little ones. I removed the relays one by one, checked that the terminal connectors were tight and sprayed the spade contacts with electrical parts cleaner before replacing. I did the same with the two little diodes?
The engine still refused to start so I called it a night.
So I'm wondering ,as it really was revving normally earlier, does this rule out the MAF being faulty or are they known for intermittent faults? Perhaps it lends credibility to the temp sensor comments raised in the most recent posts?
Anyway tomorrow I'll have time if the recommendations are to change out a sensor or two so any thoughts please.
Maurice

[tartersauce]

NIce a code that fits!! If you have a scanner that can monitor the sensor, or a Volt Ohm meter digital you can hook up to the signal wires with it plugged into connectors and exhaust to see the voltages..

A bad O2 will give you stalling, ruff running, loss of power etc. but not hard start cold or hot. Hot start, it would startup then you would get your ruff idle within 20seconds of running once it sees the coolant temps.

O2 Only works HOT.. 2 to 3 mins of running to get to Oper temps. Outside temp plays a role in the temp rise of the sensor.

o2s work better HOT and you will see that on the meter. As it will rise and fall very quick. .10 volts to 1 volt If its stuck on low voltage you will see that, but the engine will riching up the injectors until it faults Engine light etc. Then it will ignore that o2 sensor.

Low voltage Lean Sends to pcm to richen the injectors
Higher voltage rich Sends to pcm to lean the injectors

Heated O2s will work faster but not much faster. If the heater fails, It wont get hot enough to even make a true voltage reading when cold.

Most dont need the heater to still work, just makes the sensor slower getting up to temp.

ALL fail with low voltage.. And the first thing that is noticed is MPG!! Just keep that in mind. They get tired and cant make it above .3 volts etc.

[tartersauce]

who remembers the IAC setup? Were you unplug the sensor until the engine turns off. Then plug back in and restart? Sets the Idle control up..

Have you tried unpluggin your IAC and see if it does stall.. Your hard starting is something that has alot of control of the engine. IAC, MAF or MAP.. fuel pump, filter etc..

[wiswind]

A foot on the gas pedal (just a little....not way down) will overcome the IAC.

The DOWNSTREAM oxygen sensor will have nothing to do with fuel trim.
Hopefully we are not dealing with a clogged catalytic converter.
Also.....have the oxygen sensors been disconnected at any point in this process?....
It is real easy to cross those wires.....and connect the wrong sensor to the wrong wire.

With the rough running.....I was begining to wonder if a couple of spark plug wires were crossed......we had a poster with a rough running problem a while back....and he found that he had crossed a couple of spark plug wires......but I don't think that you would get a smooth idle at any time with that.

If you have a misfire condition.....it is not unusual to get lean code(s) as the PCM is going crazy trying to deal with the misfire.

I am wondering if you are getting spark to each cylinder.....consistantly.
A old fashion timing light clamped onto Cylinder #4 spark plug wire might be a good move.....for the P0304 misfire on cylinder #4.

Fuel pressure? is that staying high enough?

Less common is the electrical circuits for the fuel injectors......the have 1 side hot with the key on.....and the PCM provides a momentary ground to energize the injector.

[tartersauce]

Originally Posted by wiswind

A foot on the gas pedal (just a little....not way down) will overcome the IAC.

The DOWNSTREAM oxygen sensor will have nothing to do with fuel trim.
Hopefully we are not dealing with a clogged catalytic converter.
Also.....have the oxygen sensors been disconnected at any point in this process?....
It is real easy to cross those wires.....and connect the wrong sensor to the wrong wire.

With the rough running.....I was begining to wonder if a couple of spark plug wires were crossed......we had a poster with a rough running problem a while back....and he found that he had crossed a couple of spark plug wires......but I don't think that you would get a smooth idle at any time with that.

If you have a misfire condition.....it is not unusual to get lean code(s) as the PCM is going crazy trying to deal with the misfire.

I am wondering if you are getting spark to each cylinder.....consistantly.
A old fashion timing light clamped onto Cylinder #4 spark plug wire might be a good move.....for the P0304 misfire on cylinder #4.

Fuel pressure? is that staying high enough?

Less common is the electrical circuits for the fuel injectors......the have 1 side hot with the key on.....and the PCM provides a momentary ground to energize the injector.

Yea, If all the simple stuff passes, then you should be looking deeper.

Plugs, wires, fuel pressure

If you have a cheap tire gauge with a pointer and a dial you can get a close pressure reading on your Fuel rail. Cold engine and Unplug Coil packs!! It wont be a perfect reading, but it will give you an idea. If its way low etc.. The stick tire gauge wont work.. You should have at least 40psi I can look that up if you get a tester. It maybe much higher then that tho. in the 50s or even 60s.. Wiswind might know it off the top of his head.. hehe..

[Ulsterman]

Today I replaced both downstream O2 sensors. I'd replaced the upstream ones when I did the lower manifold gaskets (to clear a code) 15k miles ago and at 100k now they were due. When I had the vehicle raised I also replaced the fuel filter.
It fired right up and revved great for maybe 10 mins and I was clearing the tools away and planning a test drive when it conked out and wouldn't start easily again. I'd previously cleared the codes and when I checked P0171/4 and P0304, nothing else.
Wiswind there aren't any plug leads crossed as I was extremely careful and took them off one at a time and replaced before moving on when I first checked and later replaced the plugs in the course of this thread. Proof of this is that for short periods the engine does run very well, like there is nothing at all wrong and surely this couldn't happen if a plug wire was crossed. Likewise with the O2 sensors both today with the downstream pair and I have no doubt previously with the upstream.
Tartersauce I do have a fuel pressure gauge, bought it the other day but haven't connected it yet. It'll be my first task tomorrow evening. I'll follow whatever test procedure is in the Haynes manual for fuel pressure.
We're ruling things out one by one and as such making progress.
I greatly appreciate all of the help and consideration. Thank you Guys!

[12Ounce]

Good that you are now getting CEL's. I wonder if low system voltage was keeping them from being sent by the PCM earlier???

12.7v is ample for a battery "at rest". But what is the battery voltage when the engine is idling? Should be 14v or better.

Also, while the engine is idling, check the voltage from engine block to ground terminal on battery. ??? Should never be higher than .1 volt. Less would be better.

[Ulsterman]

12Ounce Battery voltage at idle 13.89v but I may have had the lights on. I tried to repeat without but the van wouldn't start again.
Negative terminal to engine block 0.1v, 2nd try 0v.

This evening I also replaced the vacuum pipe from the PCV valve back to the top of the plenum with a dealer part. The only part of the vacuum lines that I'd deemed iffy was the little rubber elbow but of course Ford didn't just sell that item it came with several pieces of pipe and a motorcraft PCV valve attached. I took the opportunity to quiz the parts guys, one mechanic and one I took to be the parts manager but didn't get anything that I didn't know already.
At least it's one more thing ruled out.

The van was difficult to start but once fired up ran and idled well. As it has done recently after warming up a little it drove very well around the yard. The engine really revs like a racecar for 10 minutes or so at this stage.
I was late home from work and it was starting to get dark and raining so I didn't have time to mess with the fuel pressure gauge as intended. Then it choked and conked out and wouldn't start again. Makes me wonder whether the coolant and transmission temperature sensors are worth some investigation.

I read the codes - P0171/4 and no misfire code.

Ideas anyone?

[tartersauce]

Originally Posted by Ulsterman

12Ounce Battery voltage at idle 13.89v but I may have had the lights on. I tried to repeat without but the van wouldn't start again.
Negative terminal to engine block 0.1v, 2nd try 0v.

This evening I also replaced the vacuum pipe from the PCV valve back to the top of the plenum with a dealer part. The only part of the vacuum lines that I'd deemed iffy was the little rubber elbow but of course Ford didn't just sell that item it came with several pieces of pipe and a motorcraft PCV valve attached. I took the opportunity to quiz the parts guys, one mechanic and one I took to be the parts manager but didn't get anything that I didn't know already.
At least it's one more thing ruled out.

The van was difficult to start but once fired up ran and idled well. As it has done recently after warming up a little it drove very well around the yard. The engine really revs like a racecar for 10 minutes or so at this stage.
I was late home from work and it was starting to get dark and raining so I didn't have time to mess with the fuel pressure gauge as intended. Then it choked and conked out and wouldn't start again. Makes me wonder whether the coolant and transmission temperature sensors are worth some investigation.

I read the codes - P0171/4 and no misfire code.

Ideas anyone?

Running for 10mins, theres no way a coolant temp will do that.. The trans temp wont do anything to engine controls. If trans temp fail it will use coolant temp but set the O/D light flashing. If coolant fails it will not use trans temp as a backup. Fuel pressure you must check it, and check it after it has stalled with the hard start as it may be failing after 10mins.. I think I have Said that in this post already.. they will run and die, then come back to life..
The only others that fail after so much time or Heat, 10mins or so ive had in the past are, Crank sensor, Coil pack and PCM Engine Control BOX.. Ouch Even the MAF wont just fail after 10mins.. NOT common, they work or dont.. Not crazy 10mins or so. At least Ive never seen one in over 15years.

[Ulsterman]

This evening I tested the fuel pressure using my new fuel tester and following the instructions in my Haynes manual.
Fuel Pressure at idle: 10psi, normal 28-45,
with vacuum hose removed from fuel pressure regulator: 10psi, normal 38-50,
Pinch fuel return line: no change, (I tried pinching the flexible section of both lines with a pair of channel locks to make sure I got the return)
Ignition off and wait 5 mins: 10psi,
Diagnosis according to Haynes is a bad fuel pump requiring dropping the tank etc - not looking forward to that one.

Overall the van was hard to start but once running revved very nicely. Once I'd finished I read the codes and once again P0171/4 nothing else. I also screwed the pressure tester onto a tire valve to confirm it's calibration and it passed.

Thoughts anyone? Is it simply buy and fit a replacement pump and I should be good to go?

[tartersauce]

Originally Posted by Ulsterman

This evening I tested the fuel pressure using my new fuel tester and following the instructions in my Haynes manual.
Fuel Pressure at idle: 10psi, normal 28-45,
with vacuum hose removed from fuel pressure regulator: 10psi, normal 38-50,
Pinch fuel return line: no change, (I tried pinching the flexible section of both lines with a pair of channel locks to make sure I got the return)
Ignition off and wait 5 mins: 10psi,
Diagnosis according to Haynes is a bad fuel pump requiring dropping the tank etc - not looking forward to that one.

Overall the van was hard to start but once running revved very nicely. Once I'd finished I read the codes and once again P0171/4 nothing else. I also screwed the pressure tester onto a tire valve to confirm it's calibration and it passed.

Thoughts anyone? Is it simply buy and fit a replacement pump and I should be good to go?

Yes one thought. Go get a fuel filter first.. If its still low and dont get up to Spec, then go get your fuel pump..

OH, If it does need a Fuel pumper, Yes, it will fit right in the tank. Some are just the pump and a sock, and some are the pump, sock and sending unit for your fuel gauge. If they offer both, I would do both at one shot since your gonna have to take down the fuel tank. You need to get the fuel outta it too.. Its a huge tank! Get a little cheap manual hand pump, remove your filler hose at the tank, and put in your Hose. 1/4 tank is 5 to 6 gallons of fuel. They have the low fuel light, so when that light it on, its about 2 gallons left or 40miles if your Lucky HEHE..

One gallon of fuel is 8LBS
10 gallons is 80lbs
full tank around 200 lbs!!

Be smart!