[SteveAZ]

Unfortunately they are still dialing in my suspension and alignment...so no car to play with today.

In the meantime I wanted to see if there were any signs of degradation in used float sensor assemblies or the female pins in the oem connector. I had 10 used passenger side float sensors on hand and tested all of them as well as a new one. These were installed in the top hat and I used a standard OEM connector on the topside of the top hat connected to my DVM. Two of the sensors were slightly damage and it's noted in the results.

I got the following results:

1. E = 51.1ohms F = 993ohms (new assembly)
2. E = 51.2ohms F = 990ohms
3. E = 51.2ohms F = 991ohms
4. E = 51.2ohms F = 994ohms
5. E = 51.4ohms F = 996ohms
6. E = 51.3ohms F = 993ohms
7. E = 51.1ohms F = 992ohms (pinched wire)
8. E = 51.0ohms F = 996ohms
9. E = 51.1ohms F = 992ohms (repaired wire)
10. E = 51.3ohms F = 994ohms
11. E = 51.1ohms F = 992ohms

As you can see, not much variance in those assemblies. In addition I hooked up a stage 2 assembly to the test bench and ran it for a while with a float sensor installed. During that time I played with the float sensor and the float sensor wires to see if I could influence them with electrical interference or anything of that sort....nothing, it was pretty stable. I also put a 255 pump under the float sensor....those readings were 150ohms with the float sitting flat on the pump and 211ohms with the float sitting vertically on the pump.

I also attempted to look the p2a22 code up in the Bentley manual and couldn't find it.

[JStang]

Thanks Steve. Do you think the pump could have gotten wedged between the bottom of the tank and the float? That's the only thing that I could think of at this point.

For those of you who have had this issue, are all of you running the inline setup?

[danniexi]

Originally Posted by JStang

For those of you who have had this issue, are all of you running the inline setup?

yup. running steve's stage one (255 + OEM). didn't happen in the beginning but suddenly the dial stopped at 3/4 when filling up. good news is that i let the car run near empty and it DID drop below the 1/4 mark. however, i attempted to fill up and it again stopped at 3/4. argh.

[JStang]

Update: 8 days later I need to fill the tank up again. I have kept an eye on the fuel gauge and the low fuel light came on this morning so it seems like I am back to normal on this tank. I hope this was just a fluke accident or maybe the inline pump just happened to get stuck under the float.

I will update this thread if it happens again.

[drfrink24]

Originally Posted by danniexi

subscribed. i have the EXACT same issue that has happened only recently. my install was perfectly fine as my gauge was working before (went to 1/1 tank to near empty), but one day after filling up, the gauge went only went up to 3/4.

this situation happened after two thousand miles or so. not sure what to do.

Same here, with the SteveAZ kit.. I measured the ohms on the new vs. old, exactly the same. I've been into the tank 2x trying to find something interfering with the float, nothing.

Interestingly enough.. it read normally for a few tanks a few months ago on a longer trip, but now its back to 3/4 full on a full tank, then reads perfectly normal after it gets to 3/4 in reality.

I don't think its something wrong with Steves kit, we're just missing something...

I mean, this isn't rocket surgery, the float is stupidly simple. If its not reading 1.00 ohms +/- 2% at full tank, then the float isn't moving to its full position. The cause of that I think would be something hitting the float, the bucket sitting up too high, or the secondary tank not being balanced correctly. If it reads 1.00 ohms at or near full, and the gauge is still showing 3/4.. then I don't know what would cause that.

[Jeef]

I recommend opening it back up and looking again, as its pretty quick and easy!

edit: For those that don't go below 1/4 tank, have you check to see if the float will sit perfectly flat/level when in the tank?

[2jzn54]

Originally Posted by JStang

Thanks Steve. Do you think the pump could have gotten wedged between the bottom of the tank and the float? That's the only thing that I could think of at this point.

For those of you who have had this issue, are all of you running the inline setup?

i could see the float getting stuck under the bucket if it wasn't secured properly when reinstalled.. but since your car was running fine before this i think its unlikely as the connections under the seat keep it pretty snug

[musc]

I am one that has had issues since I did my Stage 2 install. I had a DIY Stage 1 kit for about 8 months with no issue. When I fill my tank up it goes barely above 1/2 tank. After 100 miles it will still dinging fuel reserve then it goes to range ----. At a full tank the sensor on the drivers side is reading correct fuel level but not the one on the passenger side. I have taken numerous steps with no resolution.

1. Replaced float sensor on Stage 2 kit.
2. Replaced top hat on Stage 2 kit.
3. Had unit in/out 3 times and positive there is nothing binding up the float sensor.
4. Reset gauge cluster through JB4, hidden OBD menu and BT software.
5. Replaced car battery and reset.
6. Reflashed backend flash with full write.

I have hooked up another float sensor externally and it manually move the arm and the gauge reads correct though I am moving the arm fully max and min.

I've had it in over a month now and it doesn't seem to be improving or calibrating. I am due for some service by October 14 so I am thinking of taking it into the dealer and pointing out the gauge issue and see what they say. I will put my stock pump assembly back in the car. I am curious to see if the problem improves with the the stock pump bucket but I can't see how it would as I already have the float sensor and top hat from the stock assembly swapped in as part of my troubleshooting.

I hope someone can figure this out

[JStang]

Originally Posted by drfrink24

Same here, with the SteveAZ kit.. I measured the ohms on the new vs. old, exactly the same. I've been into the tank 2x trying to find something interfering with the float, nothing.

Interestingly enough.. it read normally for a few tanks a few months ago on a longer trip, but now its back to 3/4 full on a full tank, then reads perfectly normal after it gets to 3/4 in reality.

I don't think its something wrong with Steves kit, we're just missing something...

I mean, this isn't rocket surgery, the float is stupidly simple. If its not reading 1.00 ohms +/- 2% at full tank, then the float isn't moving to its full position. The cause of that I think would be something hitting the float, the bucket sitting up too high, or the secondary tank not being balanced correctly. If it reads 1.00 ohms at or near full, and the gauge is still showing 3/4.. then I don't know what would cause that.

I like how you mixed rocket science with brain surgery. I had a high school coach who used to see "we're not building nuclear toasters here."

[shushikiary]

I believe that I have found the source of this problem as I too have ran into it.

I pulled both floats and checked them and they were both spot on. The position they had in the tank was indeed at 3/4 tank or so when I filled it, even though it would not take any more gas. The tank would also report 1/4 gas but you would "run out" of gas.

Now this may not be what was going on for everyone here, but my tank vent system was clogged.

When you take that nasty little clip off of the vent hose inside the tank that connects to the top mount (the one that steveAZ includes a replacement for in the kit) you have to be very careful that the vent hose doesnt also start to come off the connector. Mine did, and I put it back on and I thought it was on good enough, but it wasnt and fuel leaked into the vent system for the tank.

This made it so that the fuel pump had to work much harder for fuel to get out especially if vent air couldnt get in as it would just such in more fuel, it would also prevent the tank from tanking a full amount of gas as it couldnt vent properly to let the air out as it was filling. If the clog is bad enough the tank might not be empty but you'll stall like you are empty as you just cant pull anything else out of the tank without letting air in easily. (doesnt explain people who then put 17 gallons in though).

I have sense put a hose clamp on the offending part and I think it will solve the problem.

[drfrink24]

Originally Posted by shushikiary

I believe that I have found the source of this problem as I too have ran into it.

I pulled both floats and checked them and they were both spot on. The position they had in the tank was indeed at 3/4 tank or so when I filled it, even though it would not take any more gas. The tank would also report 1/4 gas but you would "run out" of gas.

Now this may not be what was going on for everyone here, but my tank vent system was clogged.

When you take that nasty little clip off of the vent hose inside the tank that connects to the top mount (the one that steveAZ includes a replacement for in the kit) you have to be very careful that the vent hose doesnt also start to come off the connector. Mine did, and I put it back on and I thought it was on good enough, but it wasnt and fuel leaked into the vent system for the tank.

This made it so that the fuel pump had to work much harder for fuel to get out especially if vent air couldnt get in as it would just such in more fuel, it would also prevent the tank from tanking a full amount of gas as it couldnt vent properly to let the air out as it was filling. If the clog is bad enough the tank might not be empty but you'll stall like you are empty as you just cant pull anything else out of the tank without letting air in easily. (doesnt explain people who then put 17 gallons in though).

I have sense put a host clamp on the offending part and I think it will solve the problem.

Mine has always taken the correct amount of fuel at fill ups, and the connector never came loose in my case.

[SteveAZ]

Originally Posted by shushikiary

I believe that I have found the source of this problem as I too have ran into it.

I pulled both floats and checked them and they were both spot on. The position they had in the tank was indeed at 3/4 tank or so when I filled it, even though it would not take any more gas. The tank would also report 1/4 gas but you would "run out" of gas.

Now this may not be what was going on for everyone here, but my tank vent system was clogged.

When you take that nasty little clip off of the vent hose inside the tank that connects to the top mount (the one that steveAZ includes a replacement for in the kit) you have to be very careful that the vent hose doesnt also start to come off the connector. Mine did, and I put it back on and I thought it was on good enough, but it wasnt and fuel leaked into the vent system for the tank.

This made it so that the fuel pump had to work much harder for fuel to get out especially if vent air couldnt get in as it would just such in more fuel, it would also prevent the tank from tanking a full amount of gas as it couldnt vent properly to let the air out as it was filling. If the clog is bad enough the tank might not be empty but you'll stall like you are empty as you just cant pull anything else out of the tank without letting air in easily. (doesnt explain people who then put 17 gallons in though).

I have sense put a host clamp on the offending part and I think it will solve the problem.

That is an interesting theory. I haven't been able to reproduce this issue but I can comment on a couple things in relation to what you're talking about.

Recently I had somebody contact me after a shop had been in their tank but theirs was a bit more extreme. Their symptoms were...

1. Gas nozzle kept turning off when they were trying to fill the tank but the gas gauge didn't show as full.

2. Car was sputtering a bit and not running quite right.

Immediately when I spoke to them I thought it was because they had an issue with the gas gauge, they had over filled their tank, and the excess fuel made it in to the evap system. That system is comprised of a bunch of hoses, one of which goes to your throttle body. Given it's a closed system, if the pressures can't be equalized then it either continues to build or creates a vacuum.

In their case when they went back in there...their large vent tube had come off the connector inside the tank. Once it was replaced, the problem disappeared.

One other problem with fuel getting in that system is that it will eventually ruin your DTML pump.

Ultimately I guess the message there is...

1. Don't access your tank with a lot of fuel in it as this will also result in you potentially filling that vent line with fuel.
2. Don't put undue stress on the connections and verify they are seated properly when you replace them.

As for the gas gauge being 1/4 tank when they ran out of fuel. What I don't think anybody has verified is if the tank on the driver's side still has fuel in it. If it does, it may very well be at 1/4 tank but if that fuel isn't transferred to the passenger side...you'd still run out of fuel.

Also, in thinking about it that hose wouldn't have to come off that connector and there could be a couple other ways it could become defective.

1. If the connector and hose got rotated 360 degrees
2. If the line became kinked
3. If the hose got pulled off at the other end inside the tank

[streetsweepinn]

Originally Posted by JStang

On my way to work this morning, I plugged in my Cobb AP and checked for codes. Code P2A22 (reservoir fill status, correlation) was present. I looked up that code and found little to no information on it. I cleared those and it didn't come back.

On my drive home from work, the car stuttered and shut down conveniently across the street from a Shell station. I checked the code and codes P29DC (Cylinder Injection Shutdown) and P2AAF (Fuel Pump Plausibility) were present.

My first thought was an injector issue and second was fuel pump. I cleared the code hoping the car would restart and no dice. I had run out of fuel once before after installing my Walbro inline pump so I remembered it acting the exact same way when I would try to start the car. I looked at the fuel gauge and it was just below 1/4 tank.

I had the AAA card out and decided that I should buy a gas can and put a gallon and a half in the car to see if it would fire up and it did immediately. I drove across the street and put another 15.5 gallons in so I now realize that the tank had to have been bone dry.

For those who are wondering, the tank will hold 17 gallons when bone dry. My question is, what could have caused the gauge to read 1/4 tank when in reality I was out of gas? I look forward to hearing your thoughts.

hey I installed my walbro also, I found out that I have the same problem as you months ago, what I found out is going on is you probably used hoses for fuel lines right now aluminum bent lines, if you did the hoses hit the float inside the tank, and causes it to misread how much gas Is inside of there. so just use your odometer as mileage. and reset it every time you fill up.

[shushikiary]

Originally Posted by SteveAZ

That is an interesting theory. I haven't been able to reproduce this issue but I can comment on a couple things in relation to what you're talking about.

Recently I had somebody contact me after a shop had been in their tank but theirs was a bit more extreme. Their symptoms were...

1. Gas nozzle kept turning off when they were trying to fill the tank but the gas gauge didn't show as full.

2. Car was sputtering a bit and not running quite right.

Immediately when I spoke to them I thought it was because they had an issue with the gas gauge, they had over filled their tank, and the excess fuel made it in to the evap system. That system is comprised of a bunch of hoses, one of which goes to your throttle body. Given it's a closed system, if the pressures can't be equalized then it either continues to build or creates a vacuum.

In their case when they went back in there...their large vent tube had come off the connector inside the tank. Once it was replaced, the problem disappeared.

One other problem with fuel getting in that system is that it will eventually ruin your DTML pump.

Ultimately I guess the message there is...

1. Don't access your tank with a lot of fuel in it as this will also result in you potentially filling that vent line with fuel.
2. Don't put undue stress on the connections and verify they are seated properly when you replace them.

As for the gas gauge being 1/4 tank when they ran out of fuel. What I don't think anybody has verified is if the tank on the driver's side still has fuel in it. If it does, it may very well be at 1/4 tank but if that fuel isn't transferred to the passenger side...you'd still run out of fuel.

Also, in thinking about it that hose wouldn't have to come off that connector and there could be a couple other ways it could become defective.

1. If the connector and hose got rotated 360 degrees
2. If the line became kinked
3. If the hose got pulled off at the other end inside the tank

I have also been having the "sputtering" or "stumbling" as I called it in another thread if you remember responding to it. I've noticed that the stumbling occurs mostly when I'm at full tank or near to it.

What I found on mine is that when I was trying to take the clip off that large vent tube I pulled hard enough to get my hands in there that I pulled the hose off the hat side connector. When I put it back on it didnt seat as well as it was before, but I figured it would be ok.... turned out it wasnt.

I stuck my hand down into the tank and fallowed the tube to the "breather vent" and it seemed to still be connected to that guy just fine, but just to be sure I put a hose clamp on the hat connector to make sure it wouldnt leak anymore. I had to be careful about how I put it on too. The hat connector has 2 stages of "barbs", one big barb, then 2 smaller sets of barbs. I had to make sure I put the hose clamp closer to the connector elbow so the clamp didnt go on top of the large barbs but only the small barbs which then forces the hose to seal by pressure against the large barbs.

Sadly in the process of this I busted the nipple on the fuel feed line and am having to replace the fuel feed line and passenger side hat/filter, so I cant test to see if me blowing the lines out and putting the hose clamp on fixed the issue until parts come in on tuesday.

When I pulled the fuel feed line I saw the white tube you're talking about that goes to the throttle body. I bet under partial throttle when you're at vacuum if your vent lines are filled with some gas that the gas will get sucked into the throttle body through that tube and cause the "stumbling" due to being rich like I am having.... guess it helps clean my valves? lol. But under boost you will never get the problem... explains why no issues at higher throttle %.

[shushikiary]

Parts came in, tested it. This fixed my problems. The stumbling is now gone once I got all the fuel out of the vent system, it took a full tank of gas without turning the gas pump off early, and I had been having some issues where my LPFP was always at 80-83 PSI, now it sits back at normal around 70-72 PSI at idle and still stays around 60 or so at WOT high RPM 3rd and 4th gear.

[NihonX]

This has happened to me in my 1M AND I was 100% stock at the time. I believe I was still under 10,000 miles as well. I had 330 miles on the TRIP readout and the 1M only has a 14 gallon tank.

I always reset after I refuel in order to get a good idea how much mpg I am getting.
I knew something was up when I look at the miles ran and how much fuel the needles said I had left - 1/4...I ran out of fuel on the interstate somewhere in Central California.

I've not had this happen ever again.

[danniexi]

Originally Posted by JStang

Just thinking out loud, does anyone think that the Walbro pump floating in the tank could be blocking the float?

Originally Posted by danniexi

doubt it. i have the fuel pump retention fitting (pump zip tied to the side of the oem lpfp) and it's definitely not moving around anywhere.

Originally Posted by JStang

Mine isn't attached so I thought maybe that could have been the case with my issue.

Originally Posted by danniexi

subscribed. i have the EXACT same issue that has happened only recently. my install was perfectly fine as my gauge was working before (went to 1/1 tank to near empty), but one day after filling up, the gauge went only went up to 3/4.

this situation happened after two thousand miles or so. not sure what to do.

Originally Posted by JStang

Update: 8 days later I need to fill the tank up again. I have kept an eye on the fuel gauge and the low fuel light came on this morning so it seems like I am back to normal on this tank. I hope this was just a fluke accident or maybe the inline pump just happened to get stuck under the float.

I will update this thread if it happens again.

UPDATE: Yeah it was the inline that was blocking the float. Stupid mistake.

I went to the shop and wanted to finally tackle this issue. As we were uninstalling we discovered that the fuel line (from Walbro inline to the OEM) was sitting on top of the float sensor. My inline was attached to the retention fitting (not floating around), however was located far too left where the fuel level somehow got snagged by one of the rides of the fuel line. Solution: zip tied the inline closer towards the passenger side (fitting is closer to the fuel line that connects to the oem pump). The fuel line is out of the way and the float sensor is able to freely move about with absolutely no obstructions whatsoever.

Special thanks to Alex at TNT Racewerks for helping out.

Picture that shows off the issue.

BMW OEM LPFP with Walbro 255 inline. by danniexi, on Flickr

[Blaster400]

Originally Posted by danniexi

UPDATE: Yeah it was the inline that was blocking the float. Stupid mistake.

I went to the shop and wanted to finally tackle this issue. As we were uninstalling we discovered that the fuel line (from Walbro inline to the OEM) was sitting on top of the float sensor. My inline was attached to the retention fitting (not floating around), however was located far too left where the fuel level somehow got snagged by one of the rides of the fuel line. Solution: zip tied the inline closer towards the passenger side (fitting is closer to the fuel line that connects to the oem pump). The fuel line is out of the way and the float sensor is able to freely move about with absolutely no obstructions whatsoever.

Special thanks to Alex at TNT Racewerks for helping out.

Picture that shows off the issue.

Thanks for posting this fix! I have exactly the same 3/4 tank reading problem since installing the SteveAZ kit. Hopefully this is the cause of my problem too.

[JStang]

Originally Posted by danniexi

UPDATE: Yeah it was the inline that was blocking the float. Stupid mistake.

I went to the shop and wanted to finally tackle this issue. As we were uninstalling we discovered that the fuel line (from Walbro inline to the OEM) was sitting on top of the float sensor. My inline was attached to the retention fitting (not floating around), however was located far too left where the fuel level somehow got snagged by one of the rides of the fuel line. Solution: zip tied the inline closer towards the passenger side (fitting is closer to the fuel line that connects to the oem pump). The fuel line is out of the way and the float sensor is able to freely move about with absolutely no obstructions whatsoever.

Special thanks to Alex at TNT Racewerks for helping out.

Picture that shows off the issue.

BMW OEM LPFP with Walbro 255 inline. by danniexi, on Flickr

Thanks for doing the dirty work! I will take the time to look into my issue as soon as I feel motivated to do so.

[SteveAZ]

Hey guys, if you're having issues with the float hitting the fuel line, as was noted you may need to secure your pump with the fuel line more taunt. Or, run the line on the other side of the top hat guide, then it won't be able to reach the float.

[danniexi]

Originally Posted by SteveAZ

Hey guys, if you're having issues with the float hitting the fuel line, as was noted you may need to secure your pump with the fuel line more taunt. Or, run the line on the other side of the top hat guide, then it won't be able to reach the float.

tried running the line on the other side but goddamn that fuel line is on there TIGHT. we couldn't take it off. at least there is the reassurance that this thing is built with quality.

so for others with stage 1, seriously, USE THE RETENTION FITTING STEVE PROVIDES. it's there for GOOD reason. dont let the walbro float around in there and get that sucker fastened TIGHTLY onto the OEM LPFP with no lines in the way of anything else.

[Blaster400]

Originally Posted by SteveAZ

Hey guys, if you're having issues with the float hitting the fuel line, as was noted you may need to secure your pump with the fuel line more taunt. Or, run the line on the other side of the top hat guide, then it won't be able to reach the float.

PROBLEM SOLVED!!! I took my car back to the shop today with a copy of this post. 10 minutes later I got my car back and filled up the tank. Full tank is now showing on fuel gauge for the first time since my LPFP upgrade. Hopefully my issue is now resolved.