Okay I'll try to be short. Last winter went thru some deep snow with my '91 shorty E4WD. Had a couple of instances of it doing a WHAM-Klunk in OD and D. Then it was fine. Did it once or twice up till last week. Checked fluid which was fine. Last week it did it a couple of more times(scares'ell out of me) checked fluid, brown. Changed fluid and filter, NO particles or metal just the thin layer of aluminum and black sludge same as I would find in my '86 AOD. Drove it to work yesterday and had four episodes of WHAM Klunk, with a bit of power loss and CEL popped on for a couple seconds, not like if it changed gears because no rpm increase. Drove home in D and it did it once but not again. (45 miles one way).
Pulled codes and got a 14, ECA has detected an intermittent loss of Profile Ignition Pick-up signal PIP during recent operation.

Question will the PIP loss cause the WHAM-Klunk or do I have two problems? This only has happen when running long distance(45+ miles) has happened on the straights and during a couple of turns(pre-new fluid). From my searches it does not sound like the vac modulator, although I have seen a couple of live with it posts. Ain't anything else got me to 150% attention like this did.
So any help in where to look would be appreciated. Won't be driving it this week till I can get underneath.

Sorry about the length

Duane
'91 Aerostar
4.0L A4LD
E4WD

 

Duane,

Is the PIP sensor the same thing as a crankshaft position sensor? If so, it generates the timing signals that tell the EEC when to fire each spark plug. If it's cutting out, I can imagine you having theproblems that you're experiencing. You can try to simulate it by cruising at some constant speed in OD, and very quickly let off and back on the gas pedal. The reaction is usually pretty abrupt due to the way the clutch in the torque converter locks up. If the reation is similar, you can try to replace the PIP sensor and see if your symptoms clear up.

 

Thanks, what I plan on doing is get underneath and do a very good visual inspection for bad wires, hoses. Something may be related to the deep snow as that was when it first manifested itself.

 

Okay a bit of an update with fingers crossed.
First I flushed the trans and put in a new filter. This did not cure it.
Second pulled the VSR (Variable Reluctance Sensor) crank sensor, tested the signal and got the 5v needed. Then I tested the sensor with a mutitester on ohm setting, by passing it past the prop rod as this sensor is magnetic. This showed a change in the meter reading so figured it was okay.
The only thing I found is about an 1/8" of oil and debris build up on the sensor end and corrosion on the terminals. Which I cleaned.
Test drove it for 100 miles and so far so good.
The crud on the tip makes some sense to me as last winter while going thru some deep snow it quit the motor just long enough to make the trans drop out of OD and go back in. Which is the wham-klunk.
So we will see guys.

 

Weeeellll nope. Drove it to work last Tues. almost had two wham-klunks. Wed. had a couple wham-klunks but only on sharp bumps?? Thurs. had about ten with CEL coming on for a second a couple of times. Drove home Thurs nite and absolutely not one glitch. What was different? Thurs. it was bucking a cross\headwind. Nite no wind.
Yesterday started it up and wiggled every connector I could reach and whapped a couple with a screwdriver nothing happened. Need to get a new code reader. Put my somewhere and blast if I can find it.
So if you have any thoughts would appreciate it.