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I have a 97 Acura RL that won’t start. Attached is a picture of the fuel pump circuit. I have two questions about this circuit.
1 What is the purpose of the Fuel pump resistor in this circuit? It seems that when the relay is activated the closed contact shorts out the resistor.
2 The Red/Wht wire goes to the under dash fuse 22 (20 amp). Where does the Yel wire designated #14 on the schematic go to?
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Replies
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1. Resistor is for arc subpression so that contacts don’t get pitted.
When contacts are closed, resistor is by-passed.2. Maybe fuel pump but you need to check a better wiring diagram
Try http://www.bbbind.comWrench Turner, thanks for your reply. In your attached schematic of the fuel pump ckt, you show a blue line showing a low voltage path. Where is the low voltage coming from? Is the fuel pump relay activated while the engine is running? If it is, the closed contacts in the fuel pump relay would short the resistor thereby nullifying the low voltage path (I think). When I put the ignition switch in the “ON” position, the fuel pump relay activates. I am trying to verify why my fuel pump does not turn on. I don’t think I am getting voltage at pin 3 of the fuel pump relay. It is hard to test because of the location of the fuel pump relay. I am in the process of trying to verify that there is no voltage at pin 3. If there is no voltage at pin 3, I am thinking about attaching direct voltage to pin 3 with some kind of cut off switch and a in line fuse to remove the direct voltage when I cut off the engine. What do you think about this idea?
There are many diagnostic tests you can perform. You should pull the relays and test for voltage at the relay sockets. You could arbitrarily replace relays with known good working relays (like the horn relay for example.) You could also jump relay terminals in the sockets using a paper clip and attempt to ‘force’ the fuel pump to run. Lastly, you could test for opens in the circuit via continuity (ohm) testing.
Many ways you can go from here. The preferred repair would be to locate the actual problem in the circuit. However, if you’ve spent a long time probing and testing, running your own lines is also a viable option.
check your fuses are good. If there is no voltage on #3
power is supplied from the main relay with key on engine
off or running.In your attached schematic of the fuel pump ckt, you show a blue line showing a low voltage path. Where is the low voltage coming from?
Not my schematic. Its not low voltage. The resistor
is in parallel with the relay and keeps contact arcing
down.see if this helps.http://www.justanswer.com/honda/1hf67-1997-acura-tl-trying-replace-fuel-pump.html
https://www.ericthecarguy.com/faq/solving-automotive-no-start-problems
In your attached schematic of the fuel pump ckt, you show a blue line showing a low voltage path. Where is the low voltage coming from?
Is this a no crank – no start or a crank – no start problem.
Do you have a volt/ohm meter and know how to use it.
Great, first I would check fuses 14 and 22.
Next check inputs/output from main relay.
With key in and in the on/run position,
check input pin 3; should be 0vdc
check input pin 5; should be 12vdc
check output pin 2A (yellow wire); should be 0vdc.If above check good, next with key in and in the start/crank position.
check input pin 3; should be 12vdc
check input pin 5; should be 12vdc
check output pin 2A (yellow wire}; should be 12vdc.If all above check are good, main relay is good.
Now need to check inputs/output from fuel pump relay.
With key in and in the start/crank position,
inputs pins 2 and 3 must have 12vdc
output pin 1 must have 12vdc
(pin 4 is coil ground control by PCM)If all above check are good, fuel pump relay is good.
Next disconnect connector at fuel pump and check black/yellow wire for 12vdc.
IF 12vdc at fuel pump connector, now need to check for good ground to fuel pump.
With ohm meter, check black wire to body ground.IF 12vdc and ground is good at pump fuel, replace fuel pump.
Before replacing fuel pump, run a 12vdc line and body ground directly to fuel pump and test fuel pump.
Thanks for your quick response. Your directions are great. Please have patience with me. The first part of your directions refer to the main relay. Here is my problem. I went to the parts store and got a main relay so I could know what I was looking for under the dash by the steering column.. I looked under the dash by the steering column and found what I thought was the main relay. However, the new main relay did not match the one I thought was the main relay in my car. The one I found in my car had two connectors. One connector had four wires going into it and the other connector had multiple wires going into it. I figure the connector with the four wire was the fuel pump relay part of the main relay. However, when I unplugged the connector it had pins while the new main relay had spade contacts. Plus the new relay was upside down and backwards to the one in the car. I searched everywhere under the dash for another black box to match the new one but I cannot find another black box that matches the new Main Relay. If I can find the main relay in my car, using your directions, I think I can fix the problem. Do you have any ideas about how to find the main relay?
This is a continuation of my previous response to you. Here is what I have done so far to find the no start problem. I checked the fuel pump relay and that works fine. I put a new fuel pump in and that works find. However, I am not getting 12 volts to the make contacts of the fuel pump relay. This is the voltage that drives the fuel pump through the fuel pump relay. This voltage comes from the make contacts in the fuel pump relay part of the main relay. I cannot find the main relay in my car.
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