Fuel Pump - No power?

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mrgrim333

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So I dropped the tank right?
And I pulled a reading from the power connector for the pump... and it's only reading 5v?
In the trunk (the inertia switch), it's reading 12v.

Bad wire between the two?!
 

mrgrim333

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Damn it.. Now they both are pulling 5v. So now it's not between the two, it's somewhere else not giving it enough juice. *rolls eyes*
 

Vnuk1

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Well I think your back to checking the stuff in the front end. Here this is a post from projectSHO89 try this out, if it works thank him!

First, you should be making ALL measurements with the key turned to RUN, the jumper installed EXACTLY as in step 1, and NOT unplgging anything unless the instructions tell you to. Again, see my last post for specific instructions on HOW to measure voltages and, please, quit ddodling around.

Fuel Pump Troubleshooting for the 91

1. Ground the FP test point on the EEC-IV connector. See the EEC self-test section of the FAQs at http://www.shotimes.com/SHO3eeccodes.html All voltage readings are referenced to a good chassis ground, unless otherwise specified. This activates the FP Relay.

2. Fuel pump SHOULD be running. If not, go to Step 3.

3. Measure at pin 5 of the ICM (PK/BK)to ground. You should measure battery voltage. If so, go to step 4. Otherwise, if reading is 0 volts, GO TO STEP 5.

4. Check inertia switch, reset as needed. Measure voltage on both leads. A good switch will have the same voltage on both leads as measured in step 3 above. If not, jumper across the switch and see if the FP runs. If so, replace the switch. Measure the voltage at the FP terminals. If you measure the same voltage at the input and the ground is good (verify it), replace the FP. If the voltage is lost at some point, you have an open circuit between that point and the previous point that did have voltage.

5. Measure IRCM pins 10 & 12. If reading is full battery voltage, the FP relay(s) in the IRCM is (are) bad. Replace or repair IRCM. If the readings are both 0 volts, there is an open circuit between the IRCM and the battery. Install a fused (10A) jumper to see if the FP kicks in. If so, sheck for an open GREEN Fuse Link H.

Some of this is supposition as I am relying on a combination of the Mitchell's and the 92 circuit. I do not have a 91 EVTM.

Follow the steps in order, exactly as given. If you don't understand something, ask. Don't putz around.
 
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mrgrim333

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lol that ought to set my in the right direction. Only thing is I can't find the icm. And the tutorial talks about the IRCM... Location on that?


EDIT: Typo. Should have read IRCM instead of ICM....

There's a sticky in the Electronics section with all this and more, including schematics and pin-outs.

Hit wrong button and ended up editing your post instead of replying.....

Steve
 
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Vnuk1

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Same thing as CCRM. I think. Try this link it might help.
http://members.bellatlantic.net/~rbruce/ccrm.htm

Also provided thanks to projectSHO89
IRCM/CCRM Functions/Pin-outs

The IRCM/CCRM performs four functions on the SHO:

1) EEC Power Switching

2) Fuel Pump Relay Switching

3) Cooling Fan Power Control

4) A/C Clutch Control


All years, all versions:

Pin 15 is ground.
Pin 16 (A/C Coil low side) is connected to pin 15 internally.
Pin 8 is ALWAYS HOT.
Pin 13 is HOT in RUN/START.

1. EEC Power Switching: When the ignition switch is turned to START/RUN, switched power is applied to the high side of the EEC POWER RELAY coil (low side is grounded). The COMMON terminal of the AC POWER RELAY is connected to pin 8. The output of the EEC POWER RELAY is supplied to the high side of the fuel pump, fan, and AC clutch coils and is distributed out pin 24 as SWITCHED B+ to the PCM and to various sensors and actuators on the engine when this relay is energized.

2. A/C Clutch Control: There are two inputs to the A/C clutch circuit and one output:

A) A/C Request signal (Pin 21). This is a switched HIGH (battery voltage) signal that is true when the EATC/HVAC control and the cycling switch have requested compressor clutch operation.

B) WAC* (WOT A/C Cutout - Pin 22). This is an active LOW (ground) signal from the PCM that is enabled when the PCM has determined that compressor operation must be disabled, i.e., under heavy acceleration.

C) A/C Clutch Coil (Pin 23). This is an active HIGH (battery voltage) signal that is true only when Pin 21 is high and pin 22 is not LOW.


Variations by Type

Fuel Pump Control

All versions provide output on Pin 5.
Type M:
(89-93 MTX) IRCM boxes contain two fuel pump relays. 89 and 90 used an external dropping resistor in the supply line for the LOW SPEED FP RELAY common (Pin 10). 91 and 92 MY vehicles have a jumper that applies full B+ to the supply of the LOW SPEED FP RELAY. All years supply B+ to the HIGH SPEED FP RELAY common via pin 12. The NO contacts of both relays are tied together internally in the box and is output on pin 5. The LOW SPEED FP RELAY is energized by the PCM by applying a ground to Pin 18 (Note: The FP TEST pin on the DLC is connected to this pin). The HIGH SPEED FP RELAY is energized by the PCM by applying a ground to pin 11.

Types D and J:
(93-95 ATX, 94-95 MTX) CCRM has a single FP RELAY. B+ power is supplied to the common terminal via pin 12. The FP RELAY is energized by the PCM (or grounding the FP TEST pin on the DLC) by grounding pin 18.


Cooling Fan

Type M:
(89-93 MTX) Single speed. Input fan power is supplied to pins 1 & 2. A single fan relay is energized by applying an active ground to pin 14. Output switched power is output on pins 3 & 4 to the electric fan.

Type D:
(94-95 MTX) Dual speed cooling fan (dual coil). Input fan power is supplied to pins 3 & 4. LOW SPEED FAN RELAY is energized by a ground on pin 14 and switches power to pins 1 & 2 which is routed to the low speed fan winding. HIGH SPEED FAN RELAY is energized by a ground on pin 17 and switches power to pins 6 & 7 which is routed to the high speed fan winding. Due to an internal switching diode, application of a low on pin 17 will result in BOTH fan relays being energized.

Type J:
(93-95 ATX) Dual fans in parallel with an external low speed dropping resistor. Input power via resistor is applied to pins 1 & 2 to the common terminal of the LOW SPEED FAN RELAY. The relay is energized by applying a ground to pin 14. Switched power is output on pins 3 & 4. Full battery power is input via pins 6 & 7 to the HIGH SPEED FAN RELAY common terminal. The relay is energized by grounding pin 17. Switched power is output on pins 3 & 4.
 
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mrgrim333

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Nevermind, I think I have a bad CCRM (IRCM). I measured the voltages on the harness and am pulling 12v.. So it's the damn relay's fault. Thanks for all the help! Time to hunt one of these pains in the ass' down.
 
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SolidState

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before you do this, remove the plastic trim at the bottom of the door opening beside the driver's seat where the trunk release is. Pull the carpet back and check the two plugs buried under there. Water and salts pool there and corrode that plug.
 

mrgrim333

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Well got my new ccrm. Still nothing. My car is still ******. No power to the fuel pump. Brand new fuel pump and a new ccrm. ARRRHHHHHH!!!!
Any ideas?

(Checked the plugs, just dusty)
 

shopartsnw

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I pulled my hair out recently on a car with an intermittant fuel pump. I tracked power all the way to the trunk just like you, but still no fuel pump (usually).

The problem was a broken clip on the electrical connection to the fuel pump on the tank. With the fuel pump circut jumpered to on, I could turn the pump on and off by just pushing on the connector on the top of the tank.

Just for curiosity, check that connector. It is very easy to break, and it does not stay plugged in if a clip is cracked or broken.

Mike
 

SHOZ123

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Well got my new ccrm. Still nothing. My car is still ******. No power to the fuel pump. Brand new fuel pump and a new ccrm. ARRRHHHHHH!!!!
Any ideas?

(Checked the plugs, just dusty)


Are you getting power out of the CCRM?
 

SHOZ123

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On the Pink/Black wire at the IRMC when the DATA link fuel pump test connector is grounded with the key in run?
 

mrgrim333

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On the Pink/Black wire at the IRMC when the DATA link fuel pump test connector is grounded with the key in run?

Like 12... 10v just because I've been trying to turn that badboy over for a while.

When we touch a battery to the pump it runs.. That mystery solved.
We cut off that stupid ******* connector that was wiggly. Contact is solid now. solved.

Now, when I try it, still no power to the pump. Even though the volt o' meter says 12v with the ground as the cable and as the frame.

:bonk:
 
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SHOZ123

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Electrical trouble shooting is strictly logical. Follow the current path from beginning to end and ensure all wires are good on both ends.
 

93rev2sev

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beside the drivers seat is a bundle of wires...two actually...each bundle has a thick pink(and black, i think) wire in it. Both bundles have large black snap together connectors to connect the front harness to the rear harness. One is the power windows/locks and one is the fuel pump hot wire. Guess what corrodes if the carpet is wet ... like in the winter...
 

Storm-Chaser

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I didn't see that anyone addressed this.

People are not being "scolded" for this. The information is often necessary in order to diagnose the problem. Without it, you'll either get no response, or possibly incorrect information.


First off, 91 mtx. (seen a bunch of people scold people for this)...


:burnout:
 

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