Fuel pump relay resistor
#1
Driver School Candidate
Thread Starter
Join Date: Sep 2015
Location: Co Cork
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Fuel pump relay resistor
Hi all,
I have a 1990 LS400 and have temporarily worked around a surging/bad idling problem by bypassing the fuel pump relay resistor. I have been looking for a replacement resistor on the usual websites and can't seem to find a replacement. The part number is 23080-50010. These are available (with slightly different part numbers) for other Lexus models. I don't know if the newer resistors are compatible and after trying a newer one the problem persisted.
Does anyone know where I could source a working replacement please?
I have a 1990 LS400 and have temporarily worked around a surging/bad idling problem by bypassing the fuel pump relay resistor. I have been looking for a replacement resistor on the usual websites and can't seem to find a replacement. The part number is 23080-50010. These are available (with slightly different part numbers) for other Lexus models. I don't know if the newer resistors are compatible and after trying a newer one the problem persisted.
Does anyone know where I could source a working replacement please?
#2
Moderator
Try using 2 head light bulbs instead of the resistor in case you can't obtain it. 2 bulbs have to be connected parallel. Some heat comes out from bulbs and you have to be careful for that. The temperature reaches higher than 100 degrees C.
#3
Driver School Candidate
Thread Starter
Join Date: Sep 2015
Location: Co Cork
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Hi Yamae,
Maybe I could connect daytime running lights permanently
So if I connect headlights does this mean the pump is always running at lower voltage? I thought the resistor was there to vary the resistance based on load and not just to keep it low.
Thanks
Maybe I could connect daytime running lights permanently
So if I connect headlights does this mean the pump is always running at lower voltage? I thought the resistor was there to vary the resistance based on load and not just to keep it low.
Thanks
#4
That is how it works lower voltage means lower speed. A resistor creates a voltage drop across it and the same across the fuel pump. In essence it becomes a voltage divider.
#5
Moderator
2 head light bulbs organise the resistance about 0.75ohm. You may think it's strange and the value should be more than that because a bulb has a resistance about 3ohm when it is applied 12.6V. It s true that it shows that much when working at 12.6V. But the resistance of a bulb is not constant. It varies a lot depending on the temperature. For an example, at 25 degrees C, it shows only about 0.3ohm which is roughly 1/10th.
When it is used in series with the fuel pump, it shows about a half of the resistance compared with the operation at 12.6V. In that case the current is limited and the heat is also limited. Thus the resistance of a bulb shows around 1.5ohm each when used instead of a fuel pump resistor. There are 2 bulbs and the total resistance is a half of it which is 0.75ohm. It is quite close to 0.73 ohm. Now you see why 2 head light bulbs can be used instead of the resistor. But be sure to prepare for the heat coming out from bulbs.
Thread
Thread Starter
Forum
Replies
Last Post