Help - I have a troubled ford!

About a month ago I purchased a 1999 Ford Ranger 3.0L 4x4 - 85000 miles. Since then I have had many problems - I have had the auto hubs not disengage - I have had the transfer motor fail in 4 low. I fixed both of those problems - then my belt tensioner decided to fail. It made a curious chirping noise that would wake the dead and was cyclic with engine speed.
- Even though those problems have been troublesome - the one that has given the most grief has been a lean fuel mixture problem. She runs really rough after the battery has been disconected and the PCM is trying to relearn. It takes a long time for this to get better. Eventually it will get better, but not great. It will always through a lean mixture code p0171 and p0174. I also hear a lot of pinging.
- This is what I have tried so far.
- New 02,s - made it a little better but not great.
- New MAF - no difference
- THe IAC looks new and when unplugged drops engine RPM as it should
- Coolant temp sensor -reads 40k with a cool engine and appears to be ok
- PCV seems ok
- EGR when disconnected helps with the ping - but is probably not the problem. I took the valve off and it operates freely. When closed there is a little leak by the seat. The diaphram that operates the valve is OK.
- I was unable to get the screws out of the TPS- but resistance does change linearly with throttle position. ( ON a side note - MY AC is not working either- The clutch wont engage. Could this have any connection with the WOT relay? I switched the wot relay with the fuel pump relay - no difference. The AC fuse is also ok)
- The Ford dealer said my fuel pressure was ok to the rail - though I dont know how long he watched it for.
- I have not checked crankcase or camshaft sensors.
- The Air manifold temp sensor seemed ok - it had the right resistance for the temp at hand.
- I probably will have the fuel injection cleaned next.
- I will also redouble my efforts to find a vacuum leak. Should this ford have a vacumm of around 16" at idle?
- What kind of fuel pressure should I see at the Shrader valve?
- Does anyone see any way other than the WOT that the AC could tie into this problem?

Anyone out there have any other ideas????? ANy help would be greatly apreciated.

cscottyr

 

Welcome to FTE!

Sounds like a hard problem to diagnose. You've already done a lot.

Other ideas might include checking the gasket and re-torquing the upper intake manifold. Also, don't rule out exhaust leaks before the 02 sensors, which would show up as a lean condition.

And the PCV system is very important on the 3.0L vulcan engine, any air leaks at all here will cause problems. Use a Motorcraft brand PCV valve (they fit best).

The vacuum number of 16" you got looks pretty good, according to my Ford Manual:

You can find specs and other info on fuel pressure testing here:

http://fords.kilonet.org/ken00/FuelPressureTesting.doc

HTH

 

My you've been busy with this puppy.

On the pinging, makes me wonder about a few more things.

1) EGR valve deposits, I read you checked it's operation, but how did it look & did you clean it????

2) Intake side & combustion chamber deposits can cause lean mixtures.

A can of SeaFoam http://www.seafoamsales.com/motorTuneUp.htm, slowly fed through a intake side vacuum line, or in the gas, will do wonders for this, if you suspect this may be part of it's problems.

Ford also makes a cleaner MP-3 that has lots of water in it, that's fed through a vacuum line, like the seafoam, to remove carbon.
The MP-3 fix that the dealer ran through my 99 4.0L didn't last very long though.

If you use either of these products through vacuum lines, you'll want to do it slowly so as not to hydrolock the engine, then change the oil & filter afterwards.
Oh yah, the SeaFoam will smoke up the whole neighborhood, but it's supposed to. Won't do it if you add it to the tank, just removes the deposits more slowly.

3) Faulty knock sensor.

4) Faulty or dirty MAP sensor.

5) Inlet air bypass door stuck open or partially so, such that heated air is always pesent.

6) Does it have the specified spark plugs for the engine & are they gapped & torqued properly????

7) Poor quality gas.

Why not run this puppy by the likes of AdvanceAuto or AutoZone for a no cost computer scan & see if it will pinpoint something, or at least a system problem, that may help with diagnostics, rather than just throwing parts at it & hoping for results.

Could save a lot of time & money.
May also point to just what to suspect on the AC question to

 

PawPaw,

A few corrections to your post:

2) Intake side & combustion chamber deposits can cause lean mixtures.

Combustion chamber deposits raises compression ratio, they don't lean the mixture.

3) Faulty knock sensor.

Doesn't have a knock sensor

4) Faulty or dirty MAP sensor.

Doesn't have a MAP sensor

 

Hey Thanks for the reply’s,

Didn't have time to do anything new on the truck last night - The car rudely stepped into the repair queue. Will work on it some tonight and post my findings. Thanks again -
cscottyr

 

Hey Bob, thanks for the corrections.
I should have proof read my post more carefully.

Dang, no wonder it's misbehaving. it's missing half what it needs, to know what it's doing wrong.

So the EEC-5 system doesn't use a MAP or Knock sensor. What if anything takes their place???

Yes your correct about combustion chamber deposits raising the compression ratio.

That along with intake deposits, or un-metered air leaks as Rockldge pointed out, can lean out the A/F ratio & really set things off, on the ping scale.

 

Pawpaw, the MAF sensor replaced the MAP sensor....

Intake deposits shouldn't cause a lean condition, since it isn't direct injection.

Take care!!!!!

 

Well - I've been rained out tonight - I did have a couple of questions though if anyone wants to take a shot.
- Where is the best place to take a vacuum reading on a 3.0l Ranger?
- How tight should an EGR valve be - I am sure the diaphram is ok and the valve is moving freely and is clean - however I am able to blow some small amount of air through it with it closed. (no vacuum)
- Besides the obvious fuse and wot relay in the ford AC system - is there any other interlock that might keep the ac comp clutch from getting power.

Thanks - in advance!

cscottyr

 

Well on the AC clutch question, there are two other switches in series with the AC compressor clutch.

The AC pressure cutoff switch, which is normaly closed at 230-290 psi & open at 460-490 psi.

The AC clutch cycling pressure switch which is normaly closed at or above 43.5 psi & open at or below 24.5 psi.

So if your AC charge is low (below 24.5 psi) the switch will remain open & the AC compressor clutch will not operate.

So, sounds like you need someone to hook up a manafold gauge set & check things out.

And or have the computer scanned for codes.

 

Thanks pawpaw

 

Well - I put a vacuum gauge on the engine tonight - when it was warming up it was around 17". As the engine warmed it dropped to around 16". At this point in time the truck seemed to be running pretty well. Well I took it around the block and really warmed her up and she became much worse. By the time I arrived back at the house the truck was spitting and sputtering and the vacuum was down around 8". If I continue to run this truck for 15 minute cycles at a time it will eventually run fairly well as described in my first post - (with lots of pinging and lean error codes - but not nearly as bad as it is right now). What do you think - Air manifold leak????

Cscottyr

 

After several 15 minute cycles the truck is starting to behave a litlle better. Occasionally it is still missing badly but 80% of the time it seems to be running ok (still pinging - not quite enough power) Threw several codes - 0171,0174, 0136, 1504-new one. Vacuum was sitting at 18" when I parked it in the driveway this last time. It is likely that in a couple more cycles the truck will be back to running like it was before I disconnected the battery while replacing the alternator. Every time that I have disconnected the battery the computer has been very slow to get everything in sync. It will probably start to run ok again except pinging - low power and the lean engine codes.

Any Ideas???

cscottyr

 

try spraying carb cleaner or a related solvent on the suspected area of the vac leak and if the engine shutters and then steadies out, you found your vacuum leak.

 

Let's look at it from another angle. Have you changed the fuel filter?

 

Hey Guys,

No I haven't changed out the fuel filter. When this first happened I took it to the dealer - who by the way was unable to figure it out - He said that the fuel pressure was ok. However I don't know how long he watched it. I do intend on get a fuel pressure gauge and test it at the first possible time. This morning I drove the truck to work - about 40 miles. It ran ok for the first 25 then terribly for the last 15. Somewhere around the 5 minute mark of runnning I fealt a shutter from the vehicle which I believe was the o2 sensor going into closed loop. It then ran a little poorer for the next 20 miles - and finally after about 25 miles - ran awful. I expect that it will run better on the way home after the computer adjusts things a little more. Hopefully - or I may be walking! Any Ideas?

Cscottyr