1995 Ford Windstar Old/New Injectors held wide open

SEARCHERRR

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1995 FORD WINDSTAR
6 CYL
FWD
AUTOMATIC
158,000 MILES

Ford 3.8L FWD Engine

I have been chasing a fuel economy problem for quite some time and now it has finally given a bad symptom and turned into the engine running as if it is misfiring. Fuel economy was at 8mpg in town and 14mpg hwy before it got worse (see below).

The engine is being flooded with an unusually high amount of LIQUID FUEL (not VAPOR). It is enough to leak out onto the pavement (See below).

However, the PCM wiring harness was melted/damaged and several of the wires had to be pulled apart and repaired individually. This was due to a tech routing the harness over the EGR pipe, which in turn constantly kept re-melting it every time it was driven. This has since been rectified.

Gas was/is leaking out of the front bank exhaust manifold & down-ypipe junction and can be seen on the pavement in a 3 - 5 inch puddle. I do not run the vehicle on the road. This was discovered in the driveway one day on startup and I immediately shut it off.

After intense analysis I have discovered with a Fuel Pressure Gauge that the system is not holding Fuel Pressure AT ALL even with KOEO (Key On Engine Off) and I witness it fall extremely fast to ZERO in this state.

I recently installed new spark plugs to see if this would help and ALL OF THE PLUGS were JET SMOOTH BLACK and were only 10k miles old.

The injector wiring harness has been continuity and resistance tested to be OK too.

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QUESTION IS: Is it likely the PCM is fried since we know the wiring has been repaired, regrounded everywhere, etc. Under hood and in cabin and all fuses are good?
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Please keep in mind the following NEW PARTS that have very recently (days/months) been installed before answering:

NEW PCM (though may be blown due to previous wiring damage unknown during its replacement)
NEW INJECTORS
NEW FUEL PUMP
NEW FUEL PRESSURE REGULATOR
NEW FUEL FILTER
NEW MAF
NEW IAC
NEW IGNITION COILS
NEW ALTERNATOR
NEW BATTERY
NEW COOLING FAN DROPPING RESISTOR
NEW SPARK PLUGS
NEW PLUG WIRES (10k miles ago)
NEW DPFE Sensor (EGR)
NEW ENGINE
NEW TRANNY
GOOD ECT (tested)
GOOD IAT
Original TPS - not tested
Original ICM - not tested

6 Replies

JIS001

MECHANIC
3,411 POSTS

Have you checked for a possble external fuel leak? Also have you tried installing the fuel injector noide light to see if it flashes or if the pcm is keeping the injectors on all the time? You could have a shorted ground wire frm the melted harness?

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Monday, June 1st, 2009 AT 2:30 AM

SEARCHERRR

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Fuel is only leaking from the injectors at too high a rate, from there it leaks out of the ypipe/exhaust manifold junction where I know the two are not as flush as they should be.

I am thinking it is a short in the PCM now. I think a short in the wiring is unlikely at this point, but I'm going to resistance check some pertinent wires tomorrow/today.

Can't find my noid light. Only thing I seem to have is a 900v - 1200v light which I suppose is for checking spark. I'll have to find the light or get a new one. Where should I place the test light when I get one?

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Monday, June 1st, 2009 AT 5:02 AM

JIS001

MECHANIC
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Your parts truck usually has a set on there. Disconnect the fuel injector connector and the light takes the injectors place. When the vehicle is running the noide light should pulse the light. Do that with all the injectors one by one. If the light stays on all the time then that means the injector is on the al the time as well. Due not use a test light for this. The noide light is what you should be using since you will be checking power and ground. If light isalways on then check for the ground to be shorted or maybe the pcm itself being shorted internally?

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Monday, June 1st, 2009 AT 9:54 AM

SEARCHERRR

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Thanks for explaining the difference in a noid light and test light. I don't have one, but check out these results and tell me what you think. Thanks a lot for your help.

Resistance Tests to known good Chassis Ground C128 (main parent fuel injector harness to all injectors) Female & Male ends:

NEGATIVE BATTERY CABLE REMOVED.

Injector's harness (female end of C128) to ground:
Result: Zilch. No meter reaction. 0.0L (was checking failure in the injectors insulation here)

PCM Side (male end of C128) to Ground:
Results:
VPWR: 0.055 ohm (Confirmed link from VPWR to Ground with no Power on)
Inj 6: 0.9 to 1.5 ohm
Inj 5: 0.0L
Inj 4: 0.0L
Inj 3: 0.0L
Inj 2: 0.0L
Inj 1: 0.0L

New Test using PCM side male end of C128 only (no chassis ground): C128 Inj 6 lead pin to C128 VPWR pin
Result: 0.055 ohm

I'm still at a loss here as to whether this is the PCM itself (now since I've confirmed it to just 1 injector #6 crossing the VPWR lead) or just the wiring. It is a light green/orange striped wire. I'd really be surprised if it was grounded together where the harness melted, because that day the shop owner came over and repaired things I sat and picked through every single wire that was stuck to anything and we focused on repairing all those. He inspected it and so did I afterwards and we were satisfied.

I've only had 4 hours sleep so forgive this question for my clarity:
VPWR wire should always be grounded right? Even when there is no power via battery? Always hot when battery is connected right? - If so, then I am correct to observe an Ohm value from VPWR to Ground or not?

Helping me lean towards the PCM I have the OBD scan software not able to show me the OBD compliance information on the computer (which is available on all other car's I tested using EasyOBDII program from the web), and a fault was said to be present when I looked at fuel trims, and the TPS is not showing up in any % at all and does on other vehicles using the same software.

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Monday, June 1st, 2009 AT 12:07 PM

JIS001

MECHANIC
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I am not for certain but I think the pcm supplies the ground for every injector pulse. Disconnect the pcm connector and recheck injector #6 ground again. If you still have the same reading then you will need to find where that wire is shorted too. Also the noide light would be a good way to see the injector pulse while the car is running.