FPCM go bad from sitting?

[6T9_CHARGER_RT]

FPCM go bad from sitting? *UPDATE* not good

My '99 GT has been sitting since late November un started.
Put in a fresh battery and now she cranks but wont start. No fuel at shreader valve. Fuel pump doesnt cycle.

verified that the theft light completes its 3 second "prove out" as well as the CEL "prove out"

Checked FP fuse under hood...ok

Checked for 12v @ IFS switch in trunk....ok

Put 12v power to blk/red wire & ground to brn/pk wire off FPCM to make pump run manually....it does

Checked for voltage at FPCM terms with KOEO and got over 10.5v....this test confirms replacement of FPCM...

Question #1....is my diagnosis correct?

Question #2....why would this happen from the car just sitting? Could a defective battery (shorted cell) cause this failure? This was the reason for the battery replacement today to try and start it.
Thanks in advance!

 

[wmburns]

Reply to #1: very good work. I'm going to assume that +12 volts with the key on has been confirmed at FPDM pin #9 (PK/BK). You have worked through the possible causes in a logical way. I agree with your diagnosis up to a point. It is still possible this is a PCM or a wiring problem.

Reply to #2: IMO it is highly unlikely a bad battery has directly caused the Fuel Pump Driver Module (FPDM) to fail. Anytime a car has a problem after setting for an extended period of time, one possible cause on the list should be rodent activity. Followed closely by water leak.

To that point, a break in the FPDM #1 (WH/RD) and #7 (LB/OR) wires could cause the same symptom. As well as a bad FPDM ground. Rounding out that list is a bad PCM.

Before replacing the FPDM, I would confirm that the FPDM ground is good as well as the FPDM electrical connector is clean and corrosion free.

Good Luck.

 

[6T9_CHARGER_RT]

Thank you. Yes, I used a diagram I found posted here to verify the 12v at the PK/BK wire with the KOEO at the FPCM

By the FPCM ground, do you mean where it mounts itself? or the actual ground cables that are mounted next to it?
Either or, they are both sound. The connections at the FPCM are clean & corrosion free as well.

How can I check for a break in either of those wires? Go from the FPCM connector to the PCM?
If so where is the PCM located?

No water leaks thankfully (had her covered for the winter) & no signs of rodents either....thankfully!

Do they sell the FPCM aftermarket or is Ford the only way? I see a few on ebay verified used....wise to try a used one?

 

[wmburns]

For piece of mind, try spraying some starting fluid in the intake. This will confirm that the motor will run if it had fuel.

Another option is to power the fuel pump directly as you have already done and confirm the motor will start. Don't run for a long time as the fuel pressure will be too high (100% duty cycle).

There is a green grounding screw located within inches of the FPDM. If it were me, I would measure the resistance from the FPDM back to battery negative with the key off. The Ohm value should be very low. This will positively confirm the ground is good.

The PCM is located in the right hand kick panel.

As for possible sources of replacement parts, this may be available as a re-man part from your local autoparts store. Not sure. Could also try a salvage yard. Try car-part.com for a searchable list in your area. Personally, I would not buy used from ebay unless saving a ton of $$'s. I'm more inclined to go the salvage yard route as at least I could look the person in the eyes if it didn't work.

If this were my car and it started with starting fluid based upon the results of the tests run, I would replace the FPDM.

 

[007]

Dude. You rock. I love the quality of your tech advice on here.

Now I've kissed your ass, do you know if the bell housing hardware is the same for the 4r70w and t3650!?

 

[6T9_CHARGER_RT]

Yes I actually started the car when I pulsed the FP to run manually....kicked over then died out as a result of no more fuel PSI.

I checked the ground & its good. Removed the kick panel saw the PCM & poked around a bit....changed my mind about checking the wires there....too many & I got nervous!

I am going to try my luck with a used unit first....Ill post up my results.
Thanks for all the help!

 

[wmburns]

Dude. You rock. I love the quality of your tech advice on here.

Now I've kissed your ass, do you know if the bell housing hardware is the same for the 4r70w and t3650!?

Thanks for the kind words.

Not sure if I understand the question. However, the bell housing for the 4R70W is part of the casting. Therefore, it can not be removed or changed.

The T3650 bell housing can be changed.

So, if the question is if the bell housing can be swapped, the answer is NO.

If you are asking if the transmission themselves will swap, the answer is YES assuming both transmission came from a modular motor.

Note, the V6 and V8 do NOT share the same transmission bolt pattern. So a transmission from a V6 can not be bolted to a V8 modular motor.

 

[007]

Sorry I wasnt specific. I'm about to do a 4r70w to T3650 swap. I have assembled a pretty complete kit:

-FRPP Aluminum driveshaft with correct yoke
-RAM HDX clutch kit (inc. ford pilot bearing, throwout bearing etc.)
-OEM clutch fork kit
-Clutch cable, firewall adjuster, quadrant
-OEM Cobra manual pedal box
-SPEC Aluminum flywheel and hardware
-Ford factory remanufactured T3650 (all TSBs completed)
-Lower shift boot / plate
-MGW Shifter, upper shift boot and gasket (no silicone required)
-Leather shift boot
-FRPP Shift knob

My trans guy (hes really good) suggested I check into a few final things before I drop the car and the parts off at his place. He said :

"only few details (small ones) hardware for the clutch pressure plate is not usually included with clutch kits....and also the belhousing and starter hardware might not be the same as the automatic.. BUT it might be, im just not sure
thats great that the trans mount is the same, did that mean that the crossmember is also the same?"


As always, I appreciate any advice you can give! I think the ECU wiring harness is the same for both trans, but the guy at the Ford parts counter couldnt tell me for sure.

 

[6T9_CHARGER_RT]

Hijack!!

 

[007]

Hijack!!

Sorry man! Gotta grab this guys help when you can!

 

[trombonedemon]

Sorry man! Gotta grab this guys help when you can!

Agreed!!

 

[6T9_CHARGER_RT]

When doing searches for my fuel problem his detailed posts were the ones that helped me the most...thats why I PM'd him asking for him to look at my thread.
His diag threads definitely need a sticky up top

 

[trombonedemon]

When doing searches for my fuel problem his detailed posts were the ones that helped me the most...thats why I PM'd him asking for him to look at my thread.
His diag threads definitely need a sticky up top

Also, agreed.

 

[6T9_CHARGER_RT]

Well an update to my problem & its NOT good

Got home from work today & I installed a used FPDM that I got off eBay and she still wont start! Still just cranks.
Since its raining out I really didnt get much more into it....just closed the trunk in disgust.

WHAT AM I MISSING!?!?!

 

[wmburns]

Sorry to hear about that. FWIIW, your troubleshooting was more complete than the average shade tree mechanic. Based upon your posted results, I would have changed it as well.

Before going off the deep end, did you disconnect the battery during the work? If not, there are tons of "always on" circuits. Perhaps you blew a new fuse during the repair.

If all fuses are OK, go back and double check your work. This is important because from here on it will get ugly. This will surely test your electrical skills.

diagram attached.

 

[6T9_CHARGER_RT]

Thats pretty much how it all started.....had the battery out for the winter. I am however going to retrace my steps this AM....

Before I put the battery back in, I did a few things to the car.....

1---Installed Mach1 chin spoiler which involved drilling holes in front bumper...nicked a harness??

2--Installed Mach1 grill delete kit...nothing I can think of there but I will recheck the install

3---removed battery tray, cleaned it & vacuumed dirt from the area under it....did I disturb any harnesses there??

The thing that baffels me is that this car was FINE when I "put her away" for the winter (except for the dead battery which I knew about)

I am going to retrace the fuel circuit again as well making sure I didnt skip any wires starting at the fuse....

All tests are done with KOEO correct? I am assuming I will need a helper now to correctly verify that power comes out of the BN/PK wire from the FPDM to the pump when the key is turned on (only a 3 second pulse to start car) correct?
Thanks for the diag & your assistance!

 

[6T9_CHARGER_RT]

OOOKKK..... WTF?!?

Did all the diag steps again starting from the fuse...
12v to the IFS....12V out of the IFS to the FPDM....12v out of FPDM to BR/PK wire to fuel pump....12v on RD/BK wire from FP to FPDM (should this be?)
Voltage on RD/WH to PCM....pulsing voltage on LB/OR wire to PCM

Still no start......OK screw it. Put 12V battery power directly to BN/PK wire & ground to RD/BK wire.....pulsed (ran) fuel pump a few times to pressurize system manually....

Started car....and it STAYED RUNNING!!!! WTF???
OK revved car for a bit, let it run....shut it off...STARTED BACK UP like there was nothing ever wrong!!!
As I type this I am letting it sit for a while to try it again.

The only thing I can think of....maybe the system lost psi from sitting & made the system airbound shorting out the fuel pump or locking it up? Me manually putting 12v battery power to it re-pressurized the system freeing up the pump?
Is the pump going out? i am lost on this one.....

 

[trombonedemon]

I'm not the most mechanically inclined here, but the fuel pump would have been my first guess since there is no fuel pressure, but the car still turned over when starter fluid was added.
I'm just not seeing the computer going bad in these cars just from sitting, since these cars sit in parking lots for years at a time with just random starting. Could be still something else so don't get too excited. Keep you fingers crossed, that the problem is the fuel-pump.

 

[6T9_CHARGER_RT]

Thats the thing.....it also turned over when I put 12v directly to the pump.....only difference is that this time I ran it longer to fully pressurize system....in the beginning you could hear the fuel pump gurgling a bit as it picked up fuel.
At any rate..let it sit for 15 mins & started right up....gonna do the overnight test & see....

 

[wmburns]

OK, here's the deal. It's a problem if the FP does not prime with EACH key off/on cycle. The OP reported that it did not.

There should be +12 volts at the IFS switch the entire time the key is on. The OP reported this to be true. +12 volts was verifed to the FPDM as well.

The next step is to run the FP directly. The OP reported that the FP did indeed run when powered directly. And to top it off, the car stated and ran for a period of time.

One step not done was to confirm there is ZERO volts coming from the FPDM towards the FP at key on cycle. This would have positively confirmed the problem was upstream of the gas tank connector.

Based on the above sequence, the diagnosis was sound. Replacement of the FPDM is a reasonable next step unless there is evidence of wiring damage (the OP reported none).

IMO, it's likely there was a loose connection that has been restored by all of the work done.