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89 Topez Fuel Pump Voltage


Fishon's Avatar
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06-05-03, 09:54 PM   #1  
Fishon
89 Topez Fuel Pump Voltage

My 89 Ford Topez Fuel Pump voltage is incorrect. The Fuel Pump off the Vehical test OK. The Pnk/Blk wire at the Fuel Pump has a 6.5v signal. I installed a new Relay with no change.

The Inertia Switch White Wire has a 12v signal at the Relay with Ignition on. The Yellow Wire (EEC, Purge Canister, Passive Restraint, Power Relay ect.) at the Relay is 12v. The Org/Blu Wire (VIP test) shows .6v ..

Two Pnk/Blk Wires enter the Relay. one that provides power to the Pump and the other attached to the same Pin at the Relay originates at the EEC. It seems as if the 6.5v is from the EEC !

I get a 95 Code ( Fuel Pump Monitor Signal) on the Scanner. I believe this should be a 12v signal from the White Inertia switch Wire through the Relay, signaling the EEC that power is at the Pump. When I disconnect the Relay and turn the Ignition ON 6.5v appears at the connector. I'm not sure if this voltage from the EEC is correct or if voltage should come from the EEC.

Rich

 
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06-06-03, 05:54 AM   #2  
Joe_F
Early Ford Tempos like this had the fuel pump part # changed many, many times from the original service #. Seems Ford had some problems.

I'd suggest you change the pump ANYHOW since it seems you have it out?

 
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06-07-03, 08:50 AM   #3  
Ground the tan/lt green wire at the relay and let me know what happens.

 
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06-07-03, 11:57 AM   #4  
Fishon
Thank You for responding to my Post.

The Relay located behind the Glove Compartment has a White, Yellow, Orange/Blue and (2) Pink/Black Wires. This Relay appears on the Chiltons Schematic at D18. I could not find a Tan/Lt Green Wire on the schematic.

Thanks

Rich

 
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06-07-03, 12:45 PM   #5  
It might be easier to find this problem by moving closer to the fuel pump.. Make your reading at the electrical connector at the fuel pump/gas tank... See if you're getting a full 12 volts there,
If so, as Davo said, check the ground for the pump.. If memory serves, the inertia switch for this car is in the trunk behind the "felt" liner..Make sure you're getting a full 12 volts there too...

 
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06-08-03, 12:19 AM   #6  
Fishon
I verified voltage at the connector (Pnk/Blk Wire). The result was 6.5 volts. I also checked the Inertia Switch. It has a Red/Lt Grn Wire that had 12 volts and a White Wire that feeds the Relay was also 12 Volts.

I checked voltage at Pin 787 at the EEC. The Schematic identifies it as "Fuel Pump Safety Swith to Fuel Pump Motor". It has 6.5 Volts. This is the (Pnk/Blk) Wire that runs from the EEC, through the Relay and to the Pump.
Do you know if this should be 12 volts ? or no voltage.
Does the Pump receive it's voltage through this curcuit or through another Wire at the Relay ? If it gets voltage from the EEC , then perhaps the EEC is faulty.
I also isolated the Pnk/Blk wire between the EEC and Relay, it checked ok.

Thanks for your help !!!

Rich

 
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06-11-03, 08:05 PM   #7  
Fishon
Note to Davo,


I ground the Tan/Lt Green Wire at the Relay as you suggested in your prior reply. Although these Wire colors match my 87 ford Ranger, I beleive that the Pnk/Blk Wire on my 89 Topez is the same. There were no changes for Pump operation.

Resitance check at the Relay (same Wire key off) was 2.84K ohms Vs the 87 Ranger Tan/Lt Grn Wire was 1.46K Ohms.

Still not sure why there is 6.5 Volts.

Thanks

RICH

 
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06-11-03, 09:04 PM   #8  
Have you messured the voltage directly at the fuel pump?
Have you checked the resistance on the ground wire directly at the fuel pump?

 
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06-13-03, 03:42 PM   #9  
When you checked the voltage at the the inertia switch. You said 12 volts .Did you chech both sides? You may have your voltage drop across the inertia switch. I believe voltage is sent to the pump right after the inertia switch

 
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