93 Sable won't start - PLZ help!

[jmoritz]

My sable station wagon will crank but not start. Thought it was the fuel pump and replaced it. Turns out it wasn't getting power. Runs fine when wired to the battery. The Integrated Control Unit over the radiator is getting 12 volts but not sending any power to the fuel pump. I replaced the integrated control unit with a new one from the dealer. Still no power to the fuel pump. We also hard-wired the fuel pump and tried to start the car with no luck. Is there another component that can cause the control unit to NOT send power to the fuel pump? Is it possible that the same problem isn't allowing the car to start even when the fuel pump is running? This has me stumped. I hope there is an expert out there that can help. Thanks.

John

[shorod]

Originally Posted by jmoritz

My sable station wagon will crank but not start. Thought it was the fuel pump and replaced it. Turns out it wasn't getting power. Runs fine when wired to the battery. The Integrated Control Unit over the radiator is getting 12 volts but not sending any power to the fuel pump. I replaced the integrated control unit with a new one from the dealer. Still no power to the fuel pump. We also hard-wired the fuel pump and tried to start the car with no luck. Is there another component that can cause the control unit to NOT send power to the fuel pump? Is it possible that the same problem isn't allowing the car to start even when the fuel pump is running? This has me stumped. I hope there is an expert out there that can help. Thanks.

John

Did you measure voltage to the fuel pump at the Constant Control Relay Module ("Integrated Control Unit over the radiator") or at the pump? There is a fuel pump shut off safety switch between the CCRM and the fuel pump that opens the positive voltage supply to the fuel pump. Access to the switch should be through a hole in the trunk trim panel. I believe the access hole is on the left rear trim panel (as looking from the back of the car.

Do you have a DMM and something to backprobe the Constant Control Relay Module (CCRM)? If not, find one. Probe pin 24 with the red DMM lead and ground the black DMM lead. I would suggest using pin 15 of the CCRM as the ground. Pin 15 is THE ground for the CCRM and therefore, if that ground is not good, the CCRM will not function properly. Verify that with the key in the run and start positions there is battery voltage present on pin 24. If so, next probe pin 12 with the red lead and verify that battery voltage is present (should be battery voltage at all times, regardless of key position). Assuming those are both fine, next probe pin 18 with the black DMM lead and connect the red DMM lead to battery positive. Pin 18 should be at ground potential with the key in the "run" and "Start" positions. This lead controls the fuel pump relay in the CCRM. If you have ground on pin 18, the ground the black lead again and connect the red lead to pin 5 of the CCRM. Pin 5 should have battery voltage with the key in the run and start positions. If so, this is the feed through the fuel pump shut off switch to the fuel pump. If you have battery voltage here, check for voltage at the shutoff switch. If you have voltage at the switch, then the switch may be bad or just tripped.

Good luck!

-Rod

[jmoritz]

Originally Posted by shorod

Did you measure voltage to the fuel pump at the Constant Control Relay Module ("Integrated Control Unit over the radiator") or at the pump?

There is a fuel pump shut off safety switch between the CCRM and the fuel pump that opens the positive voltage supply to the fuel pump. Access to the switch should be through a hole in the trunk trim panel. I believe the access hole is on the left rear trim panel (as looking from the back of the car.

Do you have a DMM and something to backprobe the Constant Control Relay Module (CCRM)? If not, find one. Probe pin 24 with the red DMM lead and ground the black DMM lead. I would suggest using pin 15 of the CCRM as the ground. Pin 15 is THE ground for the CCRM and therefore, if that ground is not good, the CCRM will not function properly. Verify that with the key in the run and start positions there is battery voltage present on pin 24. If so, next probe pin 12 with the red lead and verify that battery voltage is present (should be battery voltage at all times, regardless of key position). Assuming those are both fine, next probe pin 18 with the black DMM lead and connect the red DMM lead to battery positive. Pin 18 should be at ground potential with the key in the "run" and "Start" positions. This lead controls the fuel pump relay in the CCRM. If you have ground on pin 18, the ground the black lead again and connect the red lead to pin 5 of the CCRM. Pin 5 should have battery voltage with the key in the run and start positions. If so, this is the feed through the fuel pump shut off switch to the fuel pump. If you have battery voltage here, check for voltage at the shutoff switch. If you have voltage at the switch, then the switch may be bad or just tripped.

Good luck!

-Rod

*Checked it at the CCRM. Took the cable harness off the CCRM and checked pin 5 for voltage. Book said pin 5 goes to the fuel pump and the wire is the right color pnk/bk. From the battery, the harness is getting 12 volts. I shaved back the fuel pump wire and connected the harness. After it is connected to the CCRM, no voltage gets through.


The shut off safety switch is fine. We checked it in the open and closed position for resistence. Can't check voltage since none is getting to it from the CCRM.


I'll get a multimeter and check the things you suggested. I don't know how to use one but might be able to figure it out. Please check later as I may have questions when I check the voltages and ground. Thanks for the help.

[jmoritz]

Ok. Got the testing done on the CCR module.

tested pin 15 for ground - passed
tested pin 24 using 15 as ground - run position -7.9 volts, start position +1.7 volts
tested pin 12 - 2.5 volts
tested pin 5 using pin 18 as ground - 1.15 volts

Can you make anything of these results? Thanks.

John

[shorod]

Originally Posted by jmoritz

Ok. Got the testing done on the CCR module.

tested pin 15 for ground - passed
tested pin 24 using 15 as ground - run position -7.9 volts, start position +1.7 volts
tested pin 12 - 2.5 volts
tested pin 5 using pin 18 as ground - 1.15 volts

Can you make anything of these results? Thanks.

John

Hmmm, according to the diagram, pin 24 should be the +12V feed to the Powertrain Control Module (PCM). You did backprobe the wires, right? By backprobing, I mean you had the CCRM connected as normal and probed the wires through the back of the connector. If not, that could explain a lot of you readings. All of my suggestions yesterday and below will only be accurate if the CCRM is connected and the readings are made by backprobing the connector. You may find an unfolded paper clip works well for this, just be careful to not let the uninsulated clip touch anything else metal (other than the DMM probe).

Pin 24 feeds all of the internal relays as well as the PCM, so if it does not have power, then none of the other functions controlled by the CCRM will function either (including the fuel pump). If that really has -7.9V with the key in the run position and +1.7 V during start, the computer isn't getting voltage. Because you saw a negative voltage and so many of your readings are very low, I wonder if the ground to the CCRM is bad. You might try the same measurements but use the battery negative terminal as your ground for the DMM. If now you see +12V on pin 24 and pin 12, then measure the resistance from pin 15 to battery negative. If you have anything more than a few tenths of an ohm (taking into account the resistance of the DMM leads) then that might be your issue. Pin 12 should have essentially a direct connection to battery positive. I'm assuming here that your battery has a sufficient charge on it. That might be another good test for the DMM. Measure the voltage across the battery (DMM set to VDC and red lead to battery positive, black lead to battery negative). You should see something higher than 12 Vdc.

There was a misunderstanding on the way to measure pin 5. I wanted you to connect the red DMM lead to the positive terminal of the battery and then check for ground on pin 18 (indicated by a reading of battery voltage with the key to the run or start positions). If you see a reading of battery voltage with this configuration, then connect the black DMM lead to ground and the red DMM lead to pin 5 and again check for a reading of battery voltage. It sounds like you've already done this.

Pin 18 is the ground to the fuel pump relay coil, and the other side of the relay coil should receive battery positive by being internally connected to pin 24. So, if the PCM power relay internal to the CCRM module is working properly, a good ground on pin 18 should close the fuel pump relay allowing battery voltage to be applied to the fuel pump circuit.

If you think the block diagram to the CCRM would help you, let me know and I'll post the diagram.

-Rod

[shorod]

I went ahead and posted the diagrams on my website. The path is http://www.members.aol.com/Rod241473...uff/CCRM-1.jpg
and http://www.members.aol.com/Rod241473...uff/CCRM-2.jpg

-Rod

[elvisload]

Originally Posted by jmoritz

My sable station wagon will crank but not start. Thought it was the fuel pump and replaced it. Turns out it wasn't getting power. Runs fine when wired to the battery. The Integrated Control Unit over the radiator is getting 12 volts but not sending any power to the fuel pump. I replaced the integrated control unit with a new one from the dealer. Still no power to the fuel pump. We also hard-wired the fuel pump and tried to start the car with no luck. Is there another component that can cause the control unit to NOT send power to the fuel pump? Is it possible that the same problem isn't allowing the car to start even when the fuel pump is running? This has me stumped. I hope there is an expert out there that can help. Thanks.

John

Hi John,

Have your exact same problem with a 92 Taurus and I'm in the middle of it right now, so I'm watching this post very closely. I pulled my fuel pump and it's fine too. I was about to run down to the dealer this morning and buy a PCM until I read this. PLEASE LET ME KNOW IF YOU RESOLVE YOUR PROBLEM. It's maddening to see the problem and possible solution keep jumping back and forth from fuel side to electric side, I feel for ya.

Thanks in advance, and Rod, thanks for your valuable help too!
Russ

[jmoritz]

OK Rod, here goes.

I checked and double checked EVERY test. Meaning that I took the harness off and checked the resistence to make sure the paper clip had a good connection. A couple times I shave the wire a tiny bit and touched the wire. Either way, I think I did it right.

Pin 24 only gets 3.5 volts run, 3.25 start. ???
Pin 12 gets 12 volts run.
Pin 5 gets 2.93 volts run. Is that enough for the fuel pump to run?
Pin 18 gets 8.87 volts run.

I checked and double checked the resistence from pin 15 to battery negative and got nothing. I double checked by taking the harness off and measuring the resistence to the pin on the other side and got .6(normal)

Is this enough info to help? Could the lack of ground on 15 be causing the other readings to be off? If so, is there an easy way to fix this? Thanks so much. Your instructions have been very clear and easy to understand considering this is the first time I have used a multimeter.

[jmoritz]

Wow. I ran a wire from the paperclip on post 15 to the negative post on the battery and the car starts....Can I just cut the wire on the harness and patch in a wire to the negative terminal??? Freeking amazing Rod. Let me know what I should do.

Money spent. $155 on a new PCM. Dealer part non-refundable. $79 on a fuel filter. 15 cents on a 2 foot wire. The look on my face when it started - Priceless.

[jmoritz]

I meant $79 on a fuel PUMP. Doh.

[elvisload]

Originally Posted by jmoritz

Wow. I ran a wire from the paperclip on post 15 to the negative post on the battery and the car starts....Can I just cut the wire on the harness and patch in a wire to the negative terminal??? Freeking amazing Rod. Let me know what I should do.

Money spent. $155 on a new PCM. Dealer part non-refundable. $79 on a fuel filter. 15 cents on a 2 foot wire. The look on my face when it started - Priceless.

You are lucky John, they wanted $200 for a PCM here!

I was just looking at the connector to my PCM... The numbered connections only go up to 12. There's more than 12 wires but I'm assuming each position (number) refers to both the upper and lower wire(pair), although 7,8,9,10,11 are single wires (no pair). Are there more numbers somewhere on it or are you counting your connections differently? If not, were you able to see which is the ground by inspection?

Thanks,
Russ

[elvisload]

The above comment refers to my 92 Taurus, that may explain the different pin numbers on the PCM. Sorry for any confusion. But John, I think our problems are essentially the same.

[jmoritz]

WOW! I clipped the wire at post 15, spliced in 2 feet of wire, added a connector and bolted it with other grounds on the frame. Runs great again!

Thanks Rod. You are the man!!! Email me at [email protected].

Russ. Look at the wiring diagrams Rod posted. There are 2 rows of connectors. The ground is black/green at 15.

[jmoritz]

Out of the frying pan, into the fire. I turned on the airconditioning and the compressor started intermittently buzzing loudly and emmitting a smoke like vapor. Is the compressor going out or did I do something in the wiring that caused this?

John

[elvisload]

NOTE to Rod:

Just wanted to say thanks for posting those PCM wiring diagrams!

Russ