So I have a stock 96 gt 4.6 sohc. I was having fuel pressure issuses( dropping to 0 psi on full throttle) fixed that, replaced fuel pump. The return line was rusted thru. After repairs car ran great until one day I was sitting at idle at a light then the car stalls. Would not restart. Pushed it to the side of the road. Went and got a few tools came back and it fired right up. Drove it almost home and stalled again. No fuel pressure. Now it will not start back up. I checked the 20a fuse it's getting power to both side. Checked the inertia switch for power and wiring to fuel pump no power at either of them. So I went to the ccrm to check power and I'm not getting power to #5 pin. Would that mean the ccrm is bad and could it be fixed without replacing it
96 gt no power to fuel pump
- Thread starter Awebster96gt
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wmburns
SN Certified Technician
IF there is:
Note, best to do all test with a test light that will "load" the circuit. Especially the ground tests.
Note, that ALL of the above tests need to be true to call a bad CCRM fuel pump relay.
BUT it's important that there are other conditions that could also cause a no CCRM pin #5 power. So don't cut corners on any of the tests.
- power at CCRM pin #11 (LB/OG)
- key on power at CCRM pin #12 (RD)
- Confirmed good ground at CCRM pin #18 (BK), #15 (BK/WH), and #16 (BK).
- AND no power at CCRM pin #5 (DG/YE)
Note, best to do all test with a test light that will "load" the circuit. Especially the ground tests.
Note, that ALL of the above tests need to be true to call a bad CCRM fuel pump relay.
BUT it's important that there are other conditions that could also cause a no CCRM pin #5 power. So don't cut corners on any of the tests.
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Thanks for the information, I plugged in a spare ccrm from a 98 gt and still no power to #5 pin and it did not start. Just to be sure I sprayed some starting fluid in and it runs until it burns out. I'm having it towed home and tomorrow I'm going to trace the wires and check for ground to #18 and also key on power for #12 pin
wmburns
SN Certified Technician
Based upon the above test results the fuel pump relay inside the CCRM is BAD. Likely bad relay contacts creating excessive voltage drop.
It is possible to replace the relay yourself. However it's not an easy process to replace a soldered in part. Most people simply buy a re-man'ed unit.
wmburns
SN Certified Technician
Soooooooooooooooooooooooo. Either:
- The problem is actually in the CCRM connector. IE bad pin fitment.
- Your test results are not accurate.
- your donor CCRM is not compatible. Not all CCRM's are the same. There are differences in the model years and engine types.
- your "donor" CCRM is also bad.
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The donor came out of my friends running 98 mustang gt but I was getting the same results and the car started with starting fluid with the donor ccrm. I am having someone to come help me further diag the electrical tomorrow. I just don't understand why it's only pushing out 6.5-6.7 volts to the pump. Still no fuel pressure
wmburns
SN Certified Technician
Here's some information on voltage drop testing. This may help you to understand HOW it's possible for the voltage to be sooooooo low.
Howto perform charging system voltage drop test
Howto perform charging system voltage drop test
To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...
www.stangnet.com
Want more proof that you are on the right track? Back probe CCRM pin #5 (DG/YE) and then inject 12 volts using a fused jumper. Does the car start now?
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Here's some information on voltage drop testing. This may help you to understand HOW it's possible for the voltage to be sooooooo low.
Howto perform charging system voltage drop test
Howto perform charging system voltage drop test
To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...
Want more proof that you are on the right track? Back probe CCRM pin #5 (RD) and then inject 12 volts using a fused jumper. Does the car start now?
#5 pin is not red it's (circled) green with yellow tracer and it did not start applying 12v to that wire
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wmburns
SN Certified Technician
Sorry. Typo. CCRM pin #5 should be DG/YE.
Did the fuel pump RUN when power was applied to pin #5? Did the wire spark at all? Did anything change at all?
What is the condition of the CCRM connector when disconnected? Any corrosion? Any bent/pushed pins?
wmburns
SN Certified Technician
Since the voltage at the trunk mounted IFS switch goes to battery voltage when external power is applied to CCRM pin #5, this proves we have the correct pin/wire.
With the key off, measure the resistance between CCRM pin #5 and battery negative. This should give a reading of the fuel pump motor coil windings.
If applying power directly to the Trunk mounted IFS switch does not make the fuel pump run, it's also time to consider:
- The fuel pump is bad.
- there's a bad ground from the fuel pump
- There's a wiring fault to the fuel pump between the IFS switch and the fuel pump itself.
A possible "long shot" theory is a shorted pump winding took out the CCRM. Now the fuel pump winding is open. So this gives two related issues.
I'm assuming if there were any modifications to this car that they would have been mentioned.
Thanks for all the help. After further testing I dropped the tank and the pump is bad. (Just replaced a week ago). I had a friend come over to crank the engine while testing #5 pin And it Reads 12v while cranking 6 not cranking. So I was tracing a problem that wasn't there. Again thanks for the input and in going to replace the pump and I will update if she runs again
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