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Discussion Starter · #1 ·
Several months before my fuel pump developed a crack, my gas gauge light began the 8 flash blink code once the the gauge hit about 1/2 tank - which is the point it switches from the main tank sending unit and begins estimating remaining fuel based on mileage. I lived with it that way and was looking forward to having normal gauge/light operation restored once I replaced the fuel pump. Unfortunately, replacing the fuel pump has not cleared the 8 flash blink code at 1/2 a tank. So I thought it must be a wiring issue - probably a lose connector. So when I replaced my air filter and added the intake shim and needed to disconnect and reconnect all wiring near the the tank/console/filter - I thought surely my gas gauge/light will work once again. Not so either!!! So now I am even more puzzled as to what the issue could be. I don't think I have disconnected the battery since the problem showed up (although I have never had that actually fix anything for me on any vehicle in my life). Actually, if I remember correctly, the gas light issue started several weeks or maybe a month or so after replacing the battery. But I will try disconnecting it tonight just in case. Has anyone actually had the light problem disappear after disconnecting the battery? By the way, I did have the console gauges disconnected while I installed the air kit/filter. While the ECU didn't have power removed, from what I can read from the schematic in the manual, the fuel sending unit goes directly to the gauge console and not to the ECU at all. Not sure if the console does the interpretation of fuel level and the calculations, or it if works with the ECU to do so (in which case, possibly an ECU reset could help).
 

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Several months before my fuel pump developed a crack, my gas gauge light began the 8 flash blink code once the the gauge hit about 1/2 tank - which is the point it switches from the main tank sending unit and begins estimating remaining fuel based on mileage. I lived with it that way and was looking forward to having normal gauge/light operation restored once I replaced the fuel pump. Unfortunately, replacing the fuel pump has not cleared the 8 flash blink code at 1/2 a tank. So I thought it must be a wiring issue - probably a lose connector. So when I replaced my air filter and added the intake shim and needed to disconnect and reconnect all wiring near the the tank/console/filter - I thought surely my gas gauge/light will work once again. Not so either!!! So now I am even more puzzled as to what the issue could be. I don't think I have disconnected the battery since the problem showed up (although I have never had that actually fix anything for me on any vehicle in my life). Actually, if I remember correctly, the gas light issue started several weeks or maybe a month or so after replacing the battery. But I will try disconnecting it tonight just in case. Has anyone actually had the light problem disappear after disconnecting the battery? By the way, I did have the console gauges disconnected while I installed the air kit/filter. While the ECU didn't have power removed, from what I can read from the schematic in the manual, the fuel sending unit goes directly to the gauge console and not to the ECU at all. Not sure if the console does the interpretation of fuel level and the calculations, or it if works with the ECU to do so (in which case, possibly an ECU reset could help).

I had something similar and replaced the float assembly in the tank. That took care of it.
 

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I'm a little confused. The fuel pump and sending unit are two separate parts. Was the sending unit replaced? That 's the problem.
 

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Discussion Starter · #4 ·
The sending unit is part of the pump assembly - they are bought and installed together as one unit. So yea the sending unit is new. As for the tank float... I'm puzzled how that could cause my symptom since the gauge works normally from full to half empty, which when the float is used. After that the float is not used and gas level is a calculation based on mileage. Eventually the sub tank sending unit should trigger the low fuel light. I guess I'm not sure which sensors are checked at what point to cause the 8 blink error code
 

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You better check because I doubt it.

SENDER UNIT ASSY, FU 5C7-85752-10-00 (replaces 5C7-85752-00-00)


FUEL PUMP COMP. 1D7-13907-00-00
 

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I had the same problem and it was the float in theupper tank

i replaced my float sending unit in upper tank, It is held in by 4 screws. and works fine now. It is like $70.00
 

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The float works from full to empty, the calculations start when the upper tank is empty and the reserve tank (where the pump is located), is what is calculated on the gauge .
 

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Discussion Starter · #8 ·
You better check because I doubt it.

SENDER UNIT ASSY, FU 5C7-85752-10-00 (replaces 5C7-85752-00-00)


FUEL PUMP COMP. 1D7-13907-00-00
That is the float/sending unit in the tank.... Totally different part. The sub tank sending unit is part of the pump assembly... Thought that was clear from the first post
 

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Discussion Starter · #9 ·
Think this thread got derailed somehow... The issue is the 8 blink error code and which sensor can cause it, and when is that sensor checked? At the risk of beating a dead horse, my situation is the blink code starts at half a tank - from full to half there is no blink code and the gauge reads normally. Therefore, it seems obvious the tank sending unit/float is fine! Unless something bizarre happens with that sensors when it hits empty in the main tank. The sub tank thermistor/sending unit seems more likely since the main float at empty is when the sub tank thermistor is likely monitored for the first time. I'm really asking for someone who knows for sure how the circuit works (beyond the obvious part about float from full to half, calculation from half to empty, light on solid at thermistor dry)
 

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We just went thru this on other Raider board He got new pump and sensor , Still blinking 8 times, Its the tank float like another member said around 70 bucks.
 

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Discussion Starter · #11 ·
We just went thru this on other Raider board He got new pump and sensor , Still blinking 8 times, Its the tank float like another member said around 70 bucks.
Do you have a link to that thread? And do you know if the gauge read fine from full until half full?
 
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