Fuel temperature sensor.
#1
Fuel temperature sensor.
i just noticed that a lot of Jags dont have the fuel temperature sensor, but mine does. and it looks as if the plastic sending unit has been broken off.
can anyone tell me what color the wires are that go to it, because during the rebuild i noticed a rogue wire was spliced into the IAT that wasnt on the schematic. Then i got to thinking that if i was as cheap as the previous owner, i would probably just splice it into the IAT instead of buying a new one.
The car had no top end when i bought it. i found a bad TPS and a bad vacuum advance to be the issue. However, once i did the TPS, and patched some of the junk wiring around it, i disconnected the wire that had been spliced into the IAT, and the car has never been right since.
i thought i remember reading on here that if the FTS gets a certain reading or goes bad, then the ECU will max out the fuel pressure to clear the line.
i still havent gotten all the new wiring spliced in yet, so i was just looking for some input since i wont be able to test it for a few days.
can anyone tell me what color the wires are that go to it, because during the rebuild i noticed a rogue wire was spliced into the IAT that wasnt on the schematic. Then i got to thinking that if i was as cheap as the previous owner, i would probably just splice it into the IAT instead of buying a new one.
The car had no top end when i bought it. i found a bad TPS and a bad vacuum advance to be the issue. However, once i did the TPS, and patched some of the junk wiring around it, i disconnected the wire that had been spliced into the IAT, and the car has never been right since.
i thought i remember reading on here that if the FTS gets a certain reading or goes bad, then the ECU will max out the fuel pressure to clear the line.
i still havent gotten all the new wiring spliced in yet, so i was just looking for some input since i wont be able to test it for a few days.
Last edited by M90power; 05-13-2012 at 09:57 PM.
#3
@M90
(I'm assuming your fuel temp sensor is on the underside of your fuel rail ?)
I don't have a good picture handy but I can take one tonight if you need one
From memory, on my facelift car, the fuel temp sensor looks like the water temp sensor, although it doesn't have the fancy connector, it only has 2 male spades.
On my car the fuel temp sensor activates when the fuel temp goes over 175deg (I think). Once it activates a vacuum solenoid closes so that when the fuel pump runs for the 2 seconds at ignition on, the fuel pressure regulator allows more pressure at the rail, in theory to combat vapor locking. My system "works" but it's never been able to fix my hot starting problem...... (I have now fixed my hot starting problem by installing a remote control system where I can run the fuel pump constantly before I get into the car and try and start it. This has been working like a charm since I installed it)
While troubleshooting the hot start issue I disconnected the fuel temp sensor, and while the car started ok, it ran badly. Main issue was when you revved it, the RPMs would go up then come down all the way and the car would just stall.
So, it sounds like you could be getting max pressure at the rail which is not allowing the car to run properly.....?
(I'm assuming your fuel temp sensor is on the underside of your fuel rail ?)
I don't have a good picture handy but I can take one tonight if you need one
From memory, on my facelift car, the fuel temp sensor looks like the water temp sensor, although it doesn't have the fancy connector, it only has 2 male spades.
On my car the fuel temp sensor activates when the fuel temp goes over 175deg (I think). Once it activates a vacuum solenoid closes so that when the fuel pump runs for the 2 seconds at ignition on, the fuel pressure regulator allows more pressure at the rail, in theory to combat vapor locking. My system "works" but it's never been able to fix my hot starting problem...... (I have now fixed my hot starting problem by installing a remote control system where I can run the fuel pump constantly before I get into the car and try and start it. This has been working like a charm since I installed it)
While troubleshooting the hot start issue I disconnected the fuel temp sensor, and while the car started ok, it ran badly. Main issue was when you revved it, the RPMs would go up then come down all the way and the car would just stall.
So, it sounds like you could be getting max pressure at the rail which is not allowing the car to run properly.....?
#4
well im pretty sure its multiple issues, but the car hasnt been right since i tried to tackle the TPS replacement and goofed around with that wire. its certainly indicative of high fuel pressure, although i havent tested it. its running crazt CRAZY rich. mine is a white and pink wire IIRC, and the sensor is definitely electric.
and my FTS isnt under the rail, it sticks bolt outright of the side of the rail between 2b and 3b IIRC.
and my FTS isnt under the rail, it sticks bolt outright of the side of the rail between 2b and 3b IIRC.
Last edited by M90power; 05-14-2012 at 03:15 PM.
#5
You fuel temp switch wire colors are both Y/K (yellow/pink). The switch when open creates an open circuit for the intake air temp sensor. This increases the pulse width of the injector creating a rich running condition until the temp drops and the switch closes. If your switch is broken you should jump them together so the ECU gets the correct intake air temp reading. The later cars had a vacuum fuel temp switch which would prevent vacuum from going to the fuel pressure regulator which increases the rail fuel pressure. If you have a vapor lock issue just cycle the key several times to clear the rail of vapor and bring cooler fuel from the tank.
Is your fuel rail bent? Or is it camera distortion? You need to replace the injector hoses and ditch those clamps.
Is your fuel rail bent? Or is it camera distortion? You need to replace the injector hoses and ditch those clamps.
Last edited by Greg Edge; 05-14-2012 at 08:20 PM.
#6
yes, its bent. not sure why. certainly made cutting the fuel hose interesting.
and as of ten minutes ago, ive got all new hoses and got rid of the clamps. i bought some EFI type clamps just incase the barbs leak.
anyone know what pins the fuel temp sensor is on the ECU, so i can locate it on my schematic. i only managed to find one of the temp switch wires.
and as of ten minutes ago, ive got all new hoses and got rid of the clamps. i bought some EFI type clamps just incase the barbs leak.
anyone know what pins the fuel temp sensor is on the ECU, so i can locate it on my schematic. i only managed to find one of the temp switch wires.
Last edited by M90power; 05-14-2012 at 08:21 PM.
#7
yes, its bent. not sure why. certainly made cutting the fuel hose interesting.
and as of ten minutes ago, ive got all new hoses and no clamps. i bought some EFI type clamps just incase the barbs leak.
anyone know what pins the fuel temp sensor is on the ECU, so i can locate it on my schematic.
and as of ten minutes ago, ive got all new hoses and no clamps. i bought some EFI type clamps just incase the barbs leak.
anyone know what pins the fuel temp sensor is on the ECU, so i can locate it on my schematic.
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#8
should be interesting trying to wire it back up.
#9
#10
#11
why not just cut out the circuit altogether?
#12
The sensor is in series with the intake air temp sensor. If you jump the IAT wires then yes you bypass it. I meant jump the fuel temp switch wires together. This way you don't have an open circuit to the ECU for IAT. Take a look at the wiring diagram. If you need a wiring diagram the JDHT DVDs are the best bargain.
#13
The sensor is in series with the intake air temp sensor. If you jump the IAT wires then yes you bypass it. I meant jump the fuel temp switch wires together. This way you don't have an open circuit to the ECU for IAT. Take a look at the wiring diagram. If you need a wiring diagram the JDHT DVDs are the best bargain.
#14
#15
#16
Aussie term? Australian Outback Upgrade? Another term for pitched?
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