Fuel tank pressure and level sensors
09-19-2012, 08:09 AM
#1
Fuel tank pressure and level sensors I am working on my wiring for a 4.8 into a 98 s10. Thread is Here. The question I have has to do with the fuel level sensor and fuel tank pressure input into the computer. Do I need to try to retain these for my fuel guage to work? I have already had the evap disabled and don't intend to use it.
Also, will I have to run 2 coolant temperature sensors? One for the PCM and one for the guage?
Thanks for any help.
Also, will I have to run 2 coolant temperature sensors? One for the PCM and one for the guage?
Thanks for any help.
09-19-2012, 08:40 AM
#2
you wont need the pressure sensor for the gauge to work.
Yes, two coolant sensors. Or I know there are some engines that have a single three wire sensor to feed both the computer and gauge, if you don't have that already, that would be a good way to forgo having an extra sensor.
Yes, two coolant sensors. Or I know there are some engines that have a single three wire sensor to feed both the computer and gauge, if you don't have that already, that would be a good way to forgo having an extra sensor.
09-19-2012, 09:21 AM
#3
Thanks, that is what I was thinking.
There is also a level sensor wire that goes to the PCM, I assume it splits at the sender and one wire goes to the pcm and one to the instrument cluster. I assume this because I don't see any fuel level output from the pcm to the cluster.
Also, I looked into the 3 wire temp sensor, looks like I found one that might work, will have to dig into that a bit more. Advance auto parts # is WT5121. Connector is PT-217.
There is also a level sensor wire that goes to the PCM, I assume it splits at the sender and one wire goes to the pcm and one to the instrument cluster. I assume this because I don't see any fuel level output from the pcm to the cluster.
Also, I looked into the 3 wire temp sensor, looks like I found one that might work, will have to dig into that a bit more. Advance auto parts # is WT5121. Connector is PT-217.
Last edited by Bowtie316; 09-19-2012 at 11:01 AM.
09-19-2012, 11:00 AM
#5
Well I guess that is my question. I haven't gone into the trucks wiring harness enough to know if there is another wire from the level sender to the cluster or not. I'll just clip leave it unhooked for now, if my fuel guage works, I'll be done with it.
09-19-2012, 11:31 AM
#6
The level sender goes into the PCM. The PCM then pumps out the fuel level via serial data to the gauges. I BELIEVE it goes through the BCM, but it might just go straight to the cluster.
Nothing can split off of that purple sender wire for fuel level. If the gauge was sending voltage to ground through it and the PCM was doing the same, it would just peg the guage.
When you install an aftermarket guage, like an Autometer, the first thing you have to do is cut that purple wire from the pcm so the guage can use it. Cant have it both ways... Which is also the reason why EVAP wont work unless you use the full cluster, bcm and wiring from the donor vehicle. It all works together.
The pressure portion of it is only used for EVAP. Im pretty sure the PCM uses the fuel level and pressure to determine if it has to vent or not. If you arent using EVAP you wont need any of that. Tune on the DTCs and its like it never existed.
J.
P.S...this is going off of memory from 6 or so years ago haha... So it might not be 100% accurate, but its mostly close.
Nothing can split off of that purple sender wire for fuel level. If the gauge was sending voltage to ground through it and the PCM was doing the same, it would just peg the guage.
When you install an aftermarket guage, like an Autometer, the first thing you have to do is cut that purple wire from the pcm so the guage can use it. Cant have it both ways... Which is also the reason why EVAP wont work unless you use the full cluster, bcm and wiring from the donor vehicle. It all works together.
The pressure portion of it is only used for EVAP. Im pretty sure the PCM uses the fuel level and pressure to determine if it has to vent or not. If you arent using EVAP you wont need any of that. Tune on the DTCs and its like it never existed.
J.
P.S...this is going off of memory from 6 or so years ago haha... So it might not be 100% accurate, but its mostly close.
09-19-2012, 11:35 AM
#7
TECH Enthusiast
The cars used the serial info to the dash unless it is a 98 for the fuel gauge. If you are running a 02 411 PCM you can do the fuel segment swap and use the output from the PCM to the gauge. You should also be able to do this up through the 07 truck pcms. I'm not sure if HP Tuners or EFI can do it on the newer PCM's but Tunercat can.
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09-19-2012, 11:54 AM
#8
The level sender goes into the PCM. The PCM then pumps out the fuel level via serial data to the gauges. I BELIEVE it goes through the BCM, but it might just go straight to the cluster.
Nothing can split off of that purple sender wire for fuel level. If the gauge was sending voltage to ground through it and the PCM was doing the same, it would just peg the guage.
When you install an aftermarket guage, like an Autometer, the first thing you have to do is cut that purple wire from the pcm so the guage can use it. Cant have it both ways... Which is also the reason why EVAP wont work unless you use the full cluster, bcm and wiring from the donor vehicle. It all works together.
The pressure portion of it is only used for EVAP. Im pretty sure the PCM uses the fuel level and pressure to determine if it has to vent or not. If you arent using EVAP you wont need any of that. Tune on the DTCs and its like it never existed.
J.
P.S...this is going off of memory from 6 or so years ago haha... So it might not be 100% accurate, but its mostly close.
Nothing can split off of that purple sender wire for fuel level. If the gauge was sending voltage to ground through it and the PCM was doing the same, it would just peg the guage.
When you install an aftermarket guage, like an Autometer, the first thing you have to do is cut that purple wire from the pcm so the guage can use it. Cant have it both ways... Which is also the reason why EVAP wont work unless you use the full cluster, bcm and wiring from the donor vehicle. It all works together.
The pressure portion of it is only used for EVAP. Im pretty sure the PCM uses the fuel level and pressure to determine if it has to vent or not. If you arent using EVAP you wont need any of that. Tune on the DTCs and its like it never existed.
J.
P.S...this is going off of memory from 6 or so years ago haha... So it might not be 100% accurate, but its mostly close.
Both (2000 Sierra and 98 s10) PCMs have 2 serial data outputs, 1 yellow and 1 dk/green so it must be using one of these wires. I saved both of them too so should not be an issue.
09-19-2012, 12:02 PM
#9
The cars used the serial info to the dash unless it is a 98 for the fuel gauge. If you are running a 02 411 PCM you can do the fuel segment swap and use the output from the PCM to the gauge. You should also be able to do this up through the 07 truck pcms. I'm not sure if HP Tuners or EFI can do it on the newer PCM's but Tunercat can.
I'm not sure what PCM I have, it is from the 2000 silverado and has blue and red connectors.
09-20-2012, 07:36 AM
#11
Yes 98 s10 tank and cluster.
It should work one way or another, I have already kept the level sensor and ground wires to the pcm. If that doesn't make it work, the other wires to the tank have been left alone.
On another note, it appears that the PCM will control the temperature guage as well. The 98 s10 2.2 only has one 2-wire sensor and both leads from that go to the PCM, same as the 2000 sierra. I guess I'll try it like that and see if it works.
It should work one way or another, I have already kept the level sensor and ground wires to the pcm. If that doesn't make it work, the other wires to the tank have been left alone.
On another note, it appears that the PCM will control the temperature guage as well. The 98 s10 2.2 only has one 2-wire sensor and both leads from that go to the PCM, same as the 2000 sierra. I guess I'll try it like that and see if it works.
