Fuel Pump, ECU, Relay, Fuse, or God Just Hates Me
06-04-13, 08:59 PM
#1
Pole Position
Thread Starter
Fuel Pump, ECU, Relay, Fuse, or God Just Hates Me
99 RX300, I had a CEL for the gas cap/vacuum hose that showed up after cleaning the PCV. I was waiting for it to clear itself. Last week I was running very nearly empty when I splashed a few gallons in the tank. The car started up fine, I pulled out of the station and just as I turned onto the road, the engine stopped. No warning, no flashing CEL, just stopped as if there wasn't fuel. The other dash lights came on for the standard test, but not the CEL. Weird. Because I left my OBDII reader somewhere, I purchased a new one, which couldn't connect. However, the instructions for this unit stated that the engine has to be running to get the codes. After a tow home and some discussion with a mechanically inclined neighbor, it was decided that the fuel pump had gone. I had the pump and filters replaced by a mechanic about 1.5 years ago as part of a preventative maintenance. The place is a little dicey, so I began to believe that the fuel pump wasn't actually replaced.
He's not familiar with the Lexus and I'm an idiot, but we did remove a fuel line in the engine compartment to see if the pump was working. No pressure. We (mainly he) removed the rear seats to get access to the pump. We checked there and still not working. I put a meter on the wire plug and found voltage being delivered to the pump, so I was convinced and ordered a new pump.
Today we replaced the pump. For those in the know, there are wires inside the housing that connect to the bottom of the pump to the housing wall. There are two, each one had a very small (3-5mm) crack in the insulation. It was recommended by another mechanic (airplane) neighbor to wrap the wire in the shrinkable material available since ordering the part would take days to be delivered. So we did that, everything seemed fine and liquid proof. Without fully assembling we plugged the new fuel pump in. Nothing. I tested the wires again and this time there was a jump in voltage, a drop to zero, less voltage, and drop, and then some fluttering followed by nothing.
Because my neighbor is young, he thought reassembling everything might get it to work, which is what we did. The car was already disconnected, we checked fuses and looked in vain for a relay. The pump is still not getting power.
I don't know if it isn't getting power from the car because the computer is sensing something wrong with the internal wires, or if the ECU is somehow broken, or if there is a relay or special fuse somewhere. I need a little help trouble-shooting because the nearest Toyota dealer (who is normally no help with my car) is 50 miles away, the nearest Lexus much further. The wire harness is $6, so I'll be ordering it anyway, but I don't see how it can be the problem and I would like to run some troubleshooting while I await it's arrival. I've been searching the forums to no avail.
The starter motor does work and tries to start the engine. It sounds strong and fully powered. All other electronics seem to work.
Is there a fuel relay? If so where and how do I access it?
How many ECU fuses are there? Are any hidden somewhere?
How do I check or replace the ECU? I'm sure I can find a new one, but can anyone describe how to access the old to replace it?
I'm not sure about the CEL light. The "D" has been out for some time, and I just lost the "door ajar" light a few months ago. I don't know if this was a coincidence or an indication of something more ominous.
Does God exist and if so, why is He hating on me so badly this year and why can't I get a nice e-mail or letter from the Almighty instead of me trying to interpret dreams and fluttering butterflies for messages? I'll even settle for a terrifying burning bush that talks.
Please don't give me the "take it to a dealer or mechanic" advice, it won't help. I live in a very rural area and if I were able to afford the long and arduous troubleshooting costs, it would have been towed in forthwith and I'd be sipping mint juleps on my porch enjoying the weather while some maid cleaned the house.
Thanks in advance.
He's not familiar with the Lexus and I'm an idiot, but we did remove a fuel line in the engine compartment to see if the pump was working. No pressure. We (mainly he) removed the rear seats to get access to the pump. We checked there and still not working. I put a meter on the wire plug and found voltage being delivered to the pump, so I was convinced and ordered a new pump.
Today we replaced the pump. For those in the know, there are wires inside the housing that connect to the bottom of the pump to the housing wall. There are two, each one had a very small (3-5mm) crack in the insulation. It was recommended by another mechanic (airplane) neighbor to wrap the wire in the shrinkable material available since ordering the part would take days to be delivered. So we did that, everything seemed fine and liquid proof. Without fully assembling we plugged the new fuel pump in. Nothing. I tested the wires again and this time there was a jump in voltage, a drop to zero, less voltage, and drop, and then some fluttering followed by nothing.
Because my neighbor is young, he thought reassembling everything might get it to work, which is what we did. The car was already disconnected, we checked fuses and looked in vain for a relay. The pump is still not getting power.
I don't know if it isn't getting power from the car because the computer is sensing something wrong with the internal wires, or if the ECU is somehow broken, or if there is a relay or special fuse somewhere. I need a little help trouble-shooting because the nearest Toyota dealer (who is normally no help with my car) is 50 miles away, the nearest Lexus much further. The wire harness is $6, so I'll be ordering it anyway, but I don't see how it can be the problem and I would like to run some troubleshooting while I await it's arrival. I've been searching the forums to no avail.
The starter motor does work and tries to start the engine. It sounds strong and fully powered. All other electronics seem to work.
Is there a fuel relay? If so where and how do I access it?
How many ECU fuses are there? Are any hidden somewhere?
How do I check or replace the ECU? I'm sure I can find a new one, but can anyone describe how to access the old to replace it?
I'm not sure about the CEL light. The "D" has been out for some time, and I just lost the "door ajar" light a few months ago. I don't know if this was a coincidence or an indication of something more ominous.
Does God exist and if so, why is He hating on me so badly this year and why can't I get a nice e-mail or letter from the Almighty instead of me trying to interpret dreams and fluttering butterflies for messages? I'll even settle for a terrifying burning bush that talks.
Please don't give me the "take it to a dealer or mechanic" advice, it won't help. I live in a very rural area and if I were able to afford the long and arduous troubleshooting costs, it would have been towed in forthwith and I'd be sipping mint juleps on my porch enjoying the weather while some maid cleaned the house.
Thanks in advance.
The following users liked this post:
Radahab (06-02-23)
06-02-23, 01:37 AM
#4
99 RX300, I had a CEL for the gas cap/vacuum hose that showed up after cleaning the PCV. I was waiting for it to clear itself. Last week I was running very nearly empty when I splashed a few gallons in the tank. The car started up fine, I pulled out of the station and just as I turned onto the road, the engine stopped. No warning, no flashing CEL, just stopped as if there wasn't fuel. The other dash lights came on for the standard test, but not the CEL. Weird. Because I left my OBDII reader somewhere, I purchased a new one, which couldn't connect. However, the instructions for this unit stated that the engine has to be running to get the codes. After a tow home and some discussion with a mechanically inclined neighbor, it was decided that the fuel pump had gone. I had the pump and filters replaced by a mechanic about 1.5 years ago as part of a preventative maintenance. The place is a little dicey, so I began to believe that the fuel pump wasn't actually replaced.
He's not familiar with the Lexus and I'm an idiot, but we did remove a fuel line in the engine compartment to see if the pump was working. No pressure. We (mainly he) removed the rear seats to get access to the pump. We checked there and still not working. I put a meter on the wire plug and found voltage being delivered to the pump, so I was convinced and ordered a new pump.
Today we replaced the pump. For those in the know, there are wires inside the housing that connect to the bottom of the pump to the housing wall. There are two, each one had a very small (3-5mm) crack in the insulation. It was recommended by another mechanic (airplane) neighbor to wrap the wire in the shrinkable material available since ordering the part would take days to be delivered. So we did that, everything seemed fine and liquid proof. Without fully assembling we plugged the new fuel pump in. Nothing. I tested the wires again and this time there was a jump in voltage, a drop to zero, less voltage, and drop, and then some fluttering followed by nothing.
Because my neighbor is young, he thought reassembling everything might get it to work, which is what we did. The car was already disconnected, we checked fuses and looked in vain for a relay. The pump is still not getting power.
I don't know if it isn't getting power from the car because the computer is sensing something wrong with the internal wires, or if the ECU is somehow broken, or if there is a relay or special fuse somewhere. I need a little help trouble-shooting because the nearest Toyota dealer (who is normally no help with my car) is 50 miles away, the nearest Lexus much further. The wire harness is $6, so I'll be ordering it anyway, but I don't see how it can be the problem and I would like to run some troubleshooting while I await it's arrival. I've been searching the forums to no avail.
The starter motor does work and tries to start the engine. It sounds strong and fully powered. All other electronics seem to work.
Is there a fuel relay? If so where and how do I access it?
How many ECU fuses are there? Are any hidden somewhere?
How do I check or replace the ECU? I'm sure I can find a new one, but can anyone describe how to access the old to replace it?
I'm not sure about the CEL light. The "D" has been out for some time, and I just lost the "door ajar" light a few months ago. I don't know if this was a coincidence or an indication of something more ominous.
Does God exist and if so, why is He hating on me so badly this year and why can't I get a nice e-mail or letter from the Almighty instead of me trying to interpret dreams and fluttering butterflies for messages? I'll even settle for a terrifying burning bush that talks.
Please don't give me the "take it to a dealer or mechanic" advice, it won't help. I live in a very rural area and if I were able to afford the long and arduous troubleshooting costs, it would have been towed in forthwith and I'd be sipping mint juleps on my porch enjoying the weather while some maid cleaned the house.
Thanks in advance.
He's not familiar with the Lexus and I'm an idiot, but we did remove a fuel line in the engine compartment to see if the pump was working. No pressure. We (mainly he) removed the rear seats to get access to the pump. We checked there and still not working. I put a meter on the wire plug and found voltage being delivered to the pump, so I was convinced and ordered a new pump.
Today we replaced the pump. For those in the know, there are wires inside the housing that connect to the bottom of the pump to the housing wall. There are two, each one had a very small (3-5mm) crack in the insulation. It was recommended by another mechanic (airplane) neighbor to wrap the wire in the shrinkable material available since ordering the part would take days to be delivered. So we did that, everything seemed fine and liquid proof. Without fully assembling we plugged the new fuel pump in. Nothing. I tested the wires again and this time there was a jump in voltage, a drop to zero, less voltage, and drop, and then some fluttering followed by nothing.
Because my neighbor is young, he thought reassembling everything might get it to work, which is what we did. The car was already disconnected, we checked fuses and looked in vain for a relay. The pump is still not getting power.
I don't know if it isn't getting power from the car because the computer is sensing something wrong with the internal wires, or if the ECU is somehow broken, or if there is a relay or special fuse somewhere. I need a little help trouble-shooting because the nearest Toyota dealer (who is normally no help with my car) is 50 miles away, the nearest Lexus much further. The wire harness is $6, so I'll be ordering it anyway, but I don't see how it can be the problem and I would like to run some troubleshooting while I await it's arrival. I've been searching the forums to no avail.
The starter motor does work and tries to start the engine. It sounds strong and fully powered. All other electronics seem to work.
Is there a fuel relay? If so where and how do I access it?
How many ECU fuses are there? Are any hidden somewhere?
How do I check or replace the ECU? I'm sure I can find a new one, but can anyone describe how to access the old to replace it?
I'm not sure about the CEL light. The "D" has been out for some time, and I just lost the "door ajar" light a few months ago. I don't know if this was a coincidence or an indication of something more ominous.
Does God exist and if so, why is He hating on me so badly this year and why can't I get a nice e-mail or letter from the Almighty instead of me trying to interpret dreams and fluttering butterflies for messages? I'll even settle for a terrifying burning bush that talks.
Please don't give me the "take it to a dealer or mechanic" advice, it won't help. I live in a very rural area and if I were able to afford the long and arduous troubleshooting costs, it would have been towed in forthwith and I'd be sipping mint juleps on my porch enjoying the weather while some maid cleaned the house.
Thanks in advance.
06-02-23, 05:02 AM
#6
Thread
Thread Starter
Forum
Replies
Last Post
