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Sable had a problem of not starting periodically over a period of six months. When it failed to start, the fuel pump was not priming when the key was turned initially. If you repeatedly switched the key frem off to the run position perhaps five times, it woud start. This situation would not occur for weeks or months on end. It finally got to the point it would not start and it would not prime. Went to a local Mercury dealer and the parts guy located and loaned me the factory wiring diagrams etc. for the engine controls. This is a nice manual, has location points and other data for the control systems. They also have an electrical powertrain control/emissions diagnostic manual for the sable, but I didn't want to push it to far! I first checked the 30amp fuse in the fuse box under the hood, near the firewall on the drivers side, feeds the EEC, it was OK. NOTE: the PCM is the c"computer, used be called the EEC or similar, also you could not read any codes, which may be the fault of a bad CCRM
I suspected the CCRM and a possible ground problem developing due to the prolonged period of the no start history and the required restart key manuvering. Swapped out the CCRM with no pump priming noticed or starting. Checked the inertia switch with a meter, functioning OK. With the key on, checked the CCRM wiring through the insulation while it was plugged in, power was feeding the fuel pump and the PCM power relay. Pulled the CCRM plug out and checked for power on pins 5 Fuel pump power, 12 Fuel pump relay power and 13 PCM power relay enable. All had juice 11.89 volts. There was a ground path at pin 15, but none at pin 18 the fuel pump ground. I grounded the lower right connection on the data plug, but the pump didn't run. Checked the initia swich and it was closed and working properly. Tried powering past the same swich, but pump wouldn't run. Pump is a new one. or recent.
Problem appears to be the pump ground on pin 18. The wiring diagram indicates a cross connection of the pump ground and the PCM pin# 22 (fuel pump data link connector) at the data plug, circuit C 198.
Question: is there a related problem here? The PCU apparently is working, how does one trouble shoot it? How is the pump ground restored in this situation? So where do we go from here?

Swap out the PCU or try anothr CCRM??? I will check out the power to and from the PCU,
but I think it will be OK. I may also check for codes with the different CCRM.
****





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Addentum :
Rechecked theCCRM pins for voltage and the grounds again. The problem apparently lies in the PCU, as pin 22 of the PCU is interconnected to pin 18 of the CCRM. Pin 18 of the CCRM is the fuel pump ground. The key when in the start and run position closes this ground connection and allows the current to flow via pin 8(FPM) of the CPU to the fuel pump module of the CCRM via pin 5(Fuel pump power). Shutting the key off disconnects this ground circuit and shuts the pump off. The circuit from pins 22 and 18 also serves the data link plug. That is why grounding out the lower left connection(LB/O) will turn the pump on, with the key in the run position in a normal situation. This wire is color coded light blue with a orange tracer (LB/O) and this is circuit 926. The other grounds come under circuit 60 and include the CCRM pin #15(BK/LG) and the PCU grounds pin #s 60 and 40 . Circuit 60 grounds are in the gray dual prong socket that lies close to the CCRM. The ground point is the second one over to the right by the battery. This plug is fed by a single Bk/LG wire from the grounding point S114, which serves the PCU and 6 other circuits. and a 2 wire combo of CCRM (BK/LG) and a single black wire from ground point S115. In my situation apparently, I could not get a ground connection on the single wire Bk/LG (with the key on) because of the CPU pin 22 was not "activated" allowing a circuit to pin 18 of the CCRM,( fuel pump ground). I cleaned all the plug connections throughly prior to testing. I will swap out the CPU and it should run!!
****
FYI CCRM Pin 5(PK/BK) is Fuel Pump Power
" 12(Y) is Fuel Pump (FP) Relay Power
13 (R/LG) is PCM Power Relay Enable
15 (BK/LG) Ground
18(LB/O) Fuel Pump Grond
Remember these are interrelated to the CPU!

What has been your experiece?
 

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Discussion Starter #3
:salute: QUOTE (**** @ Mar 6 2009, 04:31 PM) index.php?act=findpost&pid=706172
Sable had a problem of not starting periodically over a period of six months. When it failed to start, the fuel pump was not priming when the key was turned initially. If you repeatedly switched the key frem off to the run position perhaps five times, it woud start. This situation would not occur for weeks or months on end. It finally got to the point it would not start and it would not prime. Went to a local Mercury dealer and the parts guy located and loaned me the factory wiring diagrams etc. for the engine controls. This is a nice manual, has location points and other data for the control systems. They also have an electrical powertrain control/emissions diagnostic manual for the sable, but I didn't want to push it to far! I first checked the 30amp fuse in the fuse box under the hood, near the firewall on the drivers side, feeds the EEC, it was OK. NOTE: the PCM is the c"computer, used be called the EEC or similar, also you could not read any codes, which may be the fault of a bad CCRM
I suspected the CCRM and a possible ground problem developing due to the prolonged period of the no start history and the required restart key manuvering. Swapped out the CCRM with no pump priming noticed or starting. Checked the inertia switch with a meter, functioning OK. With the key on, checked the CCRM wiring through the insulation while it was plugged in, power was feeding the fuel pump and the PCM power relay. Pulled the CCRM plug out and checked for power on pins 5 Fuel pump power, 12 Fuel pump relay power and 13 PCM power relay enable. All had juice 11.89 volts. There was a ground path at pin 15, but none at pin 18 the fuel pump ground. I grounded the lower right connection on the data plug, but the pump didn't run. Checked the initia swich and it was closed and working properly. Tried powering past the same swich, but pump wouldn't run. Pump is a new one. or recent.
Problem appears to be the pump ground on pin 18. The wiring diagram indicates a cross connection of the pump ground and the PCM pin# 22 (fuel pump data link connector) at the data plug, circuit C 198.
Question: is there a related problem here? The PCU apparently is working, how does one trouble shoot it? How is the pump ground restored in this situation? So where do we go from here?

Swap out the PCU or try anothr CCRM??? I will check out the power to and from the PCU,
but I think it will be OK. I may also check for codes with the different CCRM.
****

This is a problem of fuel pump grounding. Pump will run with when data plug connection is grounded out and the key is on. This is the BL/O dual wires on the Rt. corner of the plug. Cut one of the wires and found the section between the plug and the CCRM is good, it has a ground and you can actuate the pump with this ground. The remaining uncut wire feeds from pin 18 of the PCU and it will not show a ground when the key is on and during the start cyle. Question is how to get this ground from the PCU completed, if a jumper can't be rigged, it may require a replacement PCU to repair this situation. This PCU wouldn't hold codes, so it has a problem. Will check further, but a new PCU may be required.
****





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