Thom's 4.0l thread

[gerg 5,416]

1.
Get a proper O2 sensor - EF/EL ran NTK's from factory.
The aftermarket equivalent NTK part no. is OZA729-D2
They cost around $60.
 
2. you can't see TPS dead spots properly, without an ocilloscope.
3. check the Broadband Manifold vacuum actuator functions properly.
4. A failing hall effect sensor INSIDE the dizzy, often causes oddball running at certain RPM/re-starting issues.
 
If it were my car, I would start with two things -
a. get a proper O2 sensor, and hope you haven't burnt out the driver in the ECU.
b. new hall effect sensor for the dizzy
 
Those two, should be a good start.
 
E-series wagons have a slightly lower diff ratio than the sedans (3.23 vs 3.08)
Speaking from experience -
Around town auto wagon fuel economy should be 12-15L/100km
Highway = 8-10L/100km
The sedans, are slightly more fuel efficient, but not by much.
 
edit -
the above figure are for OHC six.
My EL V8 wagon, gets 15-17L/100km city, and 10-11L/100km highway.
I think it needs O2 sensors though...
 
 
 
 
 

OK then, I did take out the old O2 and it looked fairly clean. Soaked it in petrol overnight, very little carbon came out. Car has only 195k on the clock, pretty young for a Ford.

I will order a new O2 next pay. Cheers for the part number

Gotta spare brand new MAP sensor at work to throw at it. They don't tend to fuck up generally though, I imagine.

The dizzy module definitely has something screwy about it. Wiggling it from the plug end (and scraping bits of bark off my arm) causes it to work/not work, so next chance I get, I'll try and pinch one from the wreckers, complete with sensor. Kids back to school Wednesday.

TPSs are available online for about 30 bucks. Could just order one of em too. I'm a single dad going through separation, etc blah blah so money is scarce at the moment, gotta watch every cent now (hence the XE wags still being off the road).

Broadband actuator works as required, not seized or sucking air.

Burnt out the driver, you mean for the HEGO function? Fair enough. Didn't think of that.

Hall effect sensor sounds like a shit to remove/ replace. Can it be done with dizzy installed/cap off?

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[SPArKy_Dave 4,484]

14 minutes ago, gerg said:

 I'm a single dad going through separation,

Burnt out the driver, you mean for the HEGO function? Fair enough. Didn't think of that.

Hall effect sensor sounds like a shit to remove/ replace. Can it be done with dizzy installed/cap off?

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Well that sux dude... hopefully things turn out ok.

 

I meant if you just plugged it in, with the polarity incorrect...
The HEGO circuit is pretty basic on the e-series - just a relay which gets energised by the ignition circuit from memory.

 

I definitely wouldn't go second hand for the Hall Effect sensor - that's inviting disaster.

They're a semi-conductor switch, and their ability to switch correctly, wears out over time.

https://www.electronics-tutorials.ws/electromagnetism/hall-effect.html

 

If the TFI feels loose or something, make sure it's still a factory Bosch Dizzy, and Motorcraft or Bosch TFI module.

Yeah it's a distributor out job, to replace the hall effect sensor. (Ford calls it the PIP sensor - Profile Ignition Pickup)

 

Edit -

if the car has ever done a head gasket - coolant out the exhaust, then the O2 sensor can get contaminated.

 

 

[gerg 5,416]

Thanks for the advice, didn't know that about the PIP sensor. Now for the process of elimination.

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[Thom 4,348]

Dave's suggestions are a good start, but other things to check, is the cat falling apart or one of the mufflers may have a loose baffle? When you put the new thermostat in did you test it first? I have had a few that are 10 or more degrees out of their operating range right out of the box, if it's not running warm enough it will stay in cold start mode and just dump fuel in (but they usually still perform ok)

[gerg 5,416]

No rattles out of cat, deleted rear resonator as it fell apart. Exhaust note sounds fine, doesn't hiss or whoosh or feel restricted when you plant it. It's mainly part-throttle acceleration where you feel the need to push further on the accelerator than what seems right. I will check further when I have it on ramps for an oil change. Maybe dump the exhaust at first joint and test drive.

Economy is showing correctly through the trip computer so the ECU knows how much fuel it's injecting (ie not a stuck fuel regulator or sucking through diaphragm).

Tried running with temp sender disconnected (gauge goes to max, fans come on) economy didn't change, so coolant temp sender is doing its job.

Yesterday's run was better, 13.4 with a trailer full of furniture and some stop/start driving.

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[CHESTNUTXE 2,940]

hey is my 3.9i eb 1 engine the same as ea ? just wondering if it has that bigger cam than later 4.oL 

[Thom 4,348]

If the cam has a 91da part number you should have the correct cam

[gerg 5,416]

 
Well that sux dude... hopefully things turn out ok.
 
I meant if you just plugged it in, with the polarity incorrect...
The HEGO circuit is pretty basic on the e-series - just a relay which gets energised by the ignition circuit from memory.
 
I definitely wouldn't go second hand for the Hall Effect sensor - that's inviting disaster.
They're a semi-conductor switch, and their ability to switch correctly, wears out over time.
https://www.electronics-tutorials.ws/electromagnetism/hall-effect.html
 
If the TFI feels loose or something, make sure it's still a factory Bosch Dizzy, and Motorcraft or Bosch TFI module.
Yeah it's a distributor out job, to replace the hall effect sensor. (Ford calls it the PIP sensor - Profile Ignition Pickup)
 
Edit -
if the car has ever done a head gasket - coolant out the exhaust, then the O2 sensor can get contaminated.
 
 

Dave's suggestions are a good start, but other things to check, is the cat falling apart or one of the mufflers may have a loose baffle? When you put the new thermostat in did you test it first? I have had a few that are 10 or more degrees out of their operating range right out of the box, if it's not running warm enough it will stay in cold start mode and just dump fuel in (but they usually still perform ok)

Well an update on this....

The TFI was getting worse, as you could wiggle it from the plug end and the engine would cut out. I ordered one and it couldn't have come sooner. The car cut out 3 times trying to leave for work, actually coasting down the hill and pulling into my driveway (just) on the last occasion. So I missed a day of work and ended up walking to the post office to collect the new one.

They are a pain to fit. Required removing the front 2 bolts of the AC compressor and swiveling it downwards to access the screws that hold it to the dizzy. The old one was toast, I basically pulled the backing plate off with my fingers, the sealant had perished and the heat sink compound had dried up. There's a little IC on the inside of the plate that had 2 solder joints that may have already been broken. Maybe that was the problem all along.

Anyways, the new one went back in nicely. The heat sink compound they gave me wasn't white like the others I've seen. It was clear like silicone sealer.

Set timing with the diagnostic plug grounded. Reset base idle too.

Economy still wasn't great, so it wasn't the TFI causing this.

I happened to have a MAP sensor given to me by a workmate, so I plugged that in and noticed a slight improvement (in the 17s around town) but still not where it should be.

Now, for the biggest difference... The Italian tuneup! Took it for a decent drive, got it warm, then popped it back to 2nd for some 40-100 runs at WOT. Reset the trip computer, and drove normally, instant improvement from before. I'm now in the 10s on country runs, 13s around town. Seems like the computer needed to do some learning before any real changes could happen.

I'm reasonably happy with it now, part-throttle is smooth and effortless, goes pretty well for a heavy auto wagon.

Only niggle now is an occasional stumble while idling at the lights. Feels like it's going to stall.

I wouldn't have thought the MAP would be the faulty one, but changing it made a huge difference, especially after some "tuning".

Still might do the TPS though. They're not expensive.

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