Gary Lewis Posted September 2, 2020 Share Posted September 2, 2020 The hot fuel handling system has been through a few iterations, Gary. It's hard to keep track. Confusing at best, if not downright baffling to some. Yep, Jim. That's correct. It is confusing. But Christian's truck is like mine was. I guess I didn't have my head around that either. But at least I have the "the thread" so I can go back and find "it". For instance, the dipstick that was just asked about. Link to comment Share on other sites More sharing options...
Papelione Posted September 4, 2020 Author Share Posted September 4, 2020 Yep, Jim. That's correct. It is confusing. But Christian's truck is like mine was. I guess I didn't have my head around that either. But at least I have the "the thread" so I can go back and find "it". For instance, the dipstick that was just asked about. Hi guys Work has been keeping me busy the last couple of days. But I was able to get a little "Truck Time":=) Sprayed the TSV ports -engine feed- and Return With silikone spray, and measured Power to both tank plugs. Front tank: With engine running and Fuel tank selector switch (FTSS handle right side of ac panel) in front, I get bliking in one terminal( sender signal?) and permanent light in another(pump signal?) in the Third no signal( ground?). My guess: Power is good to this pump. With plug Attached and ear to pump Mount I hear an uneven hissing, splurting sound. ( Im guessing pump is not working correctly?) Gauge has signal but With full tank it shows below empty and upon using fuel it will go to half full and then back to empty, when showing empty its barely half empty when refueling. My conclusion is that the relativ New Airtex aftermarket pump does not work and that was the reason the add on pump was installed in the engine bay. Rear tank: With engine running and FTSS in rear, I get blinking in one terminal and permanent light in another in the Third no signal. My guess: Power is good to this pump. If I let it stay in rear, engine With eventually stall and go out. Gauge shifts and signals low fuel fuel, which is problably right, but other than that I dont know if sender is well calibrated. My conclusion is that the original pump does not work, sender might I dont know. Does this sounds reasonably? Best regards Christian Below is Picture of TSV and electrical pulg seen from inside. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 4, 2020 Share Posted September 4, 2020 Hi guys Work has been keeping me busy the last couple of days. But I was able to get a little "Truck Time":=) Sprayed the TSV ports -engine feed- and Return With silikone spray, and measured Power to both tank plugs. Front tank: With engine running and Fuel tank selector switch (FTSS handle right side of ac panel) in front, I get bliking in one terminal( sender signal?) and permanent light in another(pump signal?) in the Third no signal( ground?). My guess: Power is good to this pump. With plug Attached and ear to pump Mount I hear an uneven hissing, splurting sound. ( Im guessing pump is not working correctly?) Gauge has signal but With full tank it shows below empty and upon using fuel it will go to half full and then back to empty, when showing empty its barely half empty when refueling. My conclusion is that the relativ New Airtex aftermarket pump does not work and that was the reason the add on pump was installed in the engine bay. Rear tank: With engine running and FTSS in rear, I get blinking in one terminal and permanent light in another in the Third no signal. My guess: Power is good to this pump. If I let it stay in rear, engine With eventually stall and go out. Gauge shifts and signals low fuel fuel, which is problably right, but other than that I dont know if sender is well calibrated. My conclusion is that the original pump does not work, sender might I dont know. Does this sounds reasonably? Best regards Christian Below is Picture of TSV and electrical pulg seen from inside. While most of that sounds reasonable, I would guess that what you hear from the front tank is fuel returning. For the sender, it could be the resistance board has some corrosion or the contact point itself is misbehaving. Since you already have the rear module I would suggest replacing that one and giving a inspection of the tank while it is opened. Here in the U.S. the $100 cost of a new tank makes these not worth cleanup or repair. The CBA may be very different in Norway, I don't know. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 4, 2020 Share Posted September 4, 2020 Hi guys Work has been keeping me busy the last couple of days. But I was able to get a little "Truck Time":=) Sprayed the TSV ports -engine feed- and Return With silikone spray, and measured Power to both tank plugs. Front tank: With engine running and Fuel tank selector switch (FTSS handle right side of ac panel) in front, I get bliking in one terminal( sender signal?) and permanent light in another(pump signal?) in the Third no signal( ground?). My guess: Power is good to this pump. With plug Attached and ear to pump Mount I hear an uneven hissing, splurting sound. ( Im guessing pump is not working correctly?) Gauge has signal but With full tank it shows below empty and upon using fuel it will go to half full and then back to empty, when showing empty its barely half empty when refueling. My conclusion is that the relativ New Airtex aftermarket pump does not work and that was the reason the add on pump was installed in the engine bay. Rear tank: With engine running and FTSS in rear, I get blinking in one terminal and permanent light in another in the Third no signal. My guess: Power is good to this pump. If I let it stay in rear, engine With eventually stall and go out. Gauge shifts and signals low fuel fuel, which is problably right, but other than that I dont know if sender is well calibrated. My conclusion is that the original pump does not work, sender might I dont know. Does this sounds reasonably? Best regards Christian Below is Picture of TSV and electrical pulg seen from inside. Christian - I think your conclusions are reasonable. I think you said that they plumbed around the valve, right? So can you blow through the ports? In other words, does the valve seem to be working? I ask because it is a critical piece in the whole system, and if it isn't working you'll either have to replace it or do something different. As for the fuel senders, the one in the front tank is typical - it works at different points but not everywhere. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 4, 2020 Share Posted September 4, 2020 Christian - I think your conclusions are reasonable. I think you said that they plumbed around the valve, right? So can you blow through the ports? In other words, does the valve seem to be working? I ask because it is a critical piece in the whole system, and if it isn't working you'll either have to replace it or do something different. As for the fuel senders, the one in the front tank is typical - it works at different points but not everywhere. Gary, do you find these thermal gauges with the ICVR generally average out these fluctuations, or do they tend to jump around? I find it odd that these sender's use such a crude method, when a 'real' pot is so very inexpensive. My truck uses gauges that are driven by magnetic field. So while I know how the spring heats up I don't know how those instruments behave day to day. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 4, 2020 Share Posted September 4, 2020 Gary, do you find these thermal gauges with the ICVR generally average out these fluctuations, or do they tend to jump around? I find it odd that these sender's use such a crude method, when a 'real' pot is so very inexpensive. My truck uses gauges that are driven by magnetic field. So while I know how the spring heats up I don't know how those instruments behave day to day. The thermal guages only average out the fluctuations due to turning corners or starting/stopping. But when they hit a dead spot in the trace they go to Empty pretty quickly. It is a poor design, for sure. And I'm amazed that we don't blow trucks up since there's up to 1/2 amp of current flowing and it is in the tank. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 4, 2020 Share Posted September 4, 2020 The thermal guages only average out the fluctuations due to turning corners or starting/stopping. But when they hit a dead spot in the trace they go to Empty pretty quickly. It is a poor design, for sure. And I'm amazed that we don't blow trucks up since there's up to 1/2 amp of current flowing and it is in the tank. Hard for anything to combust when the tank is full of fumes. Think of the F/A ratios that are going to burn inside the engine. 10:1-20:1 at the extremes? Just like you can drown a lit match in gasoline. Too rich and it can't go off because the activation energy is too high. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 4, 2020 Share Posted September 4, 2020 Hard for anything to combust when the tank is full of fumes. Think of the F/A ratios that are going to burn inside the engine. 10:1-20:1 at the extremes? Just like you can drown a lit match in gasoline. Too rich and it can't go off because the activation energy is too high. If you've ever seen a car with it's filler on fire, the flame will just burn at the fill door until the tank itself gets hot enough for everything to go off at once. And with the cap off its much less likely to pop due to overpressure. Theatre is often overdramatic. Not that it can't happen... Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 4, 2020 Share Posted September 4, 2020 If you've ever seen a car with it's filler on fire, the flame will just burn at the fill door until the tank itself gets hot enough for everything to go off at once. And with the cap off its much less likely to pop due to overpressure. Theatre is often overdramatic. Not that it can't happen... TWA Flight 800 sure had problems, and that was just jet fuel: Problems with the aircraft's wiring were found, including evidence of arcing in the Fuel Quantity Indication System (FQIS) wiring that enters the tank. The FQIS on Flight 800 is known to have been malfunctioning; the captain remarked on what he called "crazy" readings from the system approximately two minutes and thirty seconds before the aircraft exploded. Dunno what kind of current the FQIS carried, but the Bullnose fuel level system is powered by a system capable of providing around 3 amps. So "crazy readings" on a Bullnose fuel gauge worry me. I've not heard or read of any truck catching fire from it, but it worries me. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted September 4, 2020 Share Posted September 4, 2020 TWA Flight 800 sure had problems, and that was just jet fuel: Problems with the aircraft's wiring were found, including evidence of arcing in the Fuel Quantity Indication System (FQIS) wiring that enters the tank. The FQIS on Flight 800 is known to have been malfunctioning; the captain remarked on what he called "crazy" readings from the system approximately two minutes and thirty seconds before the aircraft exploded. Dunno what kind of current the FQIS carried, but the Bullnose fuel level system is powered by a system capable of providing around 3 amps. So "crazy readings" on a Bullnose fuel gauge worry me. I've not heard or read of any truck catching fire from it, but it worries me. Believe what you choose to believe. 😒 I've heard, read about and even seen somebody get hit by a bus. I was run over by a tractor trailer myself! It doesn't keep me from crossing the street. 😆 Link to comment Share on other sites More sharing options...
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