How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask A. Penland Your Own Question
A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6215
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
14865528
Type Your Ford Question Here...
A. Penland is online now
A new question is answered every 9 seconds

Ford thunderbird: I have a 1996 Thunderbird and getting 6 volts

Customer Question

I have a 1996 Thunderbird and getting 6 volts to the fuel pump. I believe the pcm to be at fault. Your opion?
Submitted: 1 year ago.
Category: Ford
Expert:  A. Penland replied 1 year ago.
Hello and thanks for using JustAnswer.I will try my best to help you with your question.
What is the voltage with the fuel pump unplugged?
Customer: replied 1 year ago.
Voltage was 6.9. Pink wire with black stripe, I've chased it from the trunk, up the drivers side of car. The car wouldn't start, I went over most grounds I could find. It started and ran. Drove it the next day and it broke down. The check engine light comes on, tach movement, will start with starting fluid. Just not enough voltage to fuel pump. I've checked fuses, changed the ccrm (junkyard items). With key on, radiator fans come on.
Expert:  A. Penland replied 1 year ago.
You get 6.9 volts even with the pump unplugged?
By the way, what engine does this TBird have?
V6 or V8?
Customer: replied 1 year ago.
Yes
Expert:  A. Penland replied 1 year ago.
By the way, what engine does this TBird have?
V6 or V8?
Customer: replied 1 year ago.
4.6. Been in my family since new. No modifications.
Expert:  A. Penland replied 1 year ago.
Check the battery cables, especially the grounds. Also check fuse ## ***** #15 in the engine bay fuse box.
Customer: replied 1 year ago.
I will do that all tomorrow. 15 only?
Expert:  A. Penland replied 1 year ago.
Sorry, meant #3 and #15
Customer: replied 1 year ago.
Those fuses are good.
Customer: replied 1 year ago.
I did find a wire in the back of the motor. Looks like it comes from the O2 sensor, but it's yellow with a white stripe. It's not plug into anything but it has a plug on it. It has bare wire showing. Does it go anywhere or is it for an option I don't have.
Expert:  A. Penland replied 1 year ago.
Can you post a picture of this wire and connector on this page? I can go look at my wife's 1995 and 1997 TBirds.
Customer: replied 1 year ago.
I'll try..I have an innova code reader and it won't connect to the car anymore.
Expert:  A. Penland replied 1 year ago.
We are getting pouded by rain right now down here in Tampa, Florida. Give me some time to get out to my TBirds and check the wiring. I could not find it in the wiring diagrams.
Customer: replied 1 year ago.
No problem... I appreciate your time.
Expert:  A. Penland replied 1 year ago.
It will not be till tomorrow. We have an 80% chance of rain and it is pouring the 80% now. My back yard is a swamp where the TBirds are.
Customer: replied 1 year ago.
When I turn the the on the radiator fan turns on. Is that normal?
Customer: replied 1 year ago.
Key on....thus car is killing me...
Expert:  A. Penland replied 1 year ago.
When you turn the key to on, is the AC on when the fans come on?
Customer: replied 1 year ago.
All accessories are off. I first thought was the ccrm. I got two from the junkyard. I've wriggled wires, check voltage. Don't think it's getting spark now. Is there a way to check the pcm or am I thinking to far ahead.
Expert:  A. Penland replied 1 year ago.
Did you have the fan problem with the original CCRM?
Customer: replied 1 year ago.
Yes.
Expert:  A. Penland replied 1 year ago.
Ok. I do not think the problem is the CCRM. It is more like a wiring issue.
As for that wire on the back of the passenger side cylinder head, I have not had a chance to look at my two TBirds. We also got pummeled with rain this morning. 7" this morning from 4 AM till about 1 PM. Major flooding here in Tampa, Florida.
Customer: replied 1 year ago.
I have an innova 3100 code reader and it won't connect to the car any more.
Expert:  A. Penland replied 1 year ago.
Do you have power on pin #16 of the DLC where the code reader connects.
Pin #16 in the last pin to the right on the bottom row of pins.
Customer: replied 1 year ago.
I'll have to check tomorrow. Hope you get better weather soon, and again I appreciate your time.
Expert:  A. Penland replied 1 year ago.
I hope so too. 31 days of rain, it is just too much. Been in Florida for 35 years, this one is the worse.
Customer: replied 1 year ago.
Pin 16 ha 12 volts
Customer: replied 1 year ago.
If I unhook this, I get voltage to the fuel pump. And pressure to the fuel rail. Cranks but no start.
Expert:  A. Penland replied 1 year ago.
What are the wire colors on the harness side of that connector? Not the side connected to the negative battery clamp, the other side.
Because the diagram is showing 4 wires in that connector on both sides, not three.
Customer: replied 1 year ago.
The center is black/yellow stripe, the others are black/white stripe. Flipped it over and it's solid. Has never had a fourth on they side.
Expert:  A. Penland replied 1 year ago.
Those are the grounds for the PCM (Engine Computer). Which is odd, because the PCM sends a ground to the CCRM to energize the fuel pump relay inside the CCRM to turn the fuel pump on.
Customer: replied 1 year ago.
Can you tell me which pin number they are on the pcm? I could check continuity at the pcm just to make sure they aren't broken somewhere. Or do you have a better idea?
Expert:  A. Penland replied 1 year ago.
Better than that, below is the wiring diagram of the connector and the circuits.
Customer: replied 1 year ago.
I'll have to check it out tomorrow. Storms moving in, dodging yard furniture from a couple streets over.
Expert:  A. Penland replied 1 year ago.
No problem.
Sounds like your getting the type of weather we had yesterday and this past weekend.
Stay safe.
Customer: replied 1 year ago.
We had the NSRA in town this weekend.. But I've chased all the grounds down and they're good. I did find one in the passenger door that was loose. Check for spark today, and it's getting spark to the plug. Is there a way of testing the pcm?
Expert:  A. Penland replied 1 year ago.
Only power and grounds to the PCM unless you have a scan tool that can do a KOEO (Key On Engine Off) self test or KOER (Key On Engine Running) self test.
Customer: replied 1 year ago.
Scan tool won't link to the car anymore. That's why I thought the PCM was bad.
Expert:  A. Penland replied 1 year ago.
Do you have power on pin #16 of the DLC (Data Link Connector) that the scan tool connects to?
Customer: replied 1 year ago.
Yes
Expert:  A. Penland replied 1 year ago.
Then use a meter and set it to OHMS and check the resistance or continuity between the PCM and the DLC on these three wires. with the PCM and the battery disconnected. If the wires are good, then the problem is the PCM.
Customer: replied 1 year ago.
Ok, I'll check it tomorrow.
Expert:  A. Penland replied 1 year ago.
Ok.
Customer: replied 1 year ago.
All three have continuity.
Expert:  A. Penland replied 1 year ago.
Since all powers and ground to the PCM are good.
The wiring from the DLC to the PCM is good.
You have power on pin #16 at the DLC.
The scan tool does not communicate with the PCM.
The check engine light does not come on.
That points to a bad PCM.
Customer: replied 1 year ago.
Is this a junkyard part? Are they interchangeable? Or am I buying a new one?
Expert:  A. Penland replied 1 year ago.
Ford no longer sells them. But there are many aftermarket manufacturers that do. Call any auto parts store to check and see if they can get one. I do not recommend a used junkyard one. You do not know if it is correct and you could also be buying someone else's problem