Fuel pump control electronics, internal fault error at track day

[Subydude]

Lol, okay.

One LRP lap in my supra is basically this for 56 seconds, over and over and over again with no rest, in a 600whp+ Supra with ethanol:

Braking from 148 mph to mid 60 mph, WOT to mid 80 mph, braking to low 60 mph, WOT to 122 mph, braking to mid 80 mph, WOT to 115 mph, braking to approx 98mph, WOT to 148 mph.

If that isn't enough WOT for 20-30 minutes and 15+ laps per session for you then we can use Pocono which is 55mph to 130mph and 60mph to 158mph in the two biggest WOT sections, and a bunch of other WOT moments per lap.

But yea, totally different. Good luck with your arts and crafts project.

Did I hit a nerve there?

You're proving my point either way. The delta at LRP is similar to RRR in a lot of ways and that's not a track known for causing heating issues. Yes, you make 600 whp, we get that. I know the fuel requirements for that also. I have no clue what pump setup you have, but I'm guessing it's the stock FPC. I also have no idea if you run with the covers off in the back. I do know however, that you are a single data point, and a slightly pretentious one at that. Your tone continues to show that if people aren't praising you or fawning over your wisdom on this forum your default is to make fun.

It's kind of a weird insecurity/flex to feel the need to sarcastically wish someone good luck with arts and crafts while touting how much you do on your own which is basically a slightly different arts and crafts.

And now, back to actual tech discussion. I likely won't get to update this thread until after SCCA TT Nats in later Sept when I get on track again. Kind of hard to test or replicate without being on track. Pitt Race should be a different setup as well given it'll be cooler and I'll be running with all the rear trunk covers off. If it shows up again there I'll know it's either a bad fuel pump pulling too much current or a faulty sensor/chip in the FPC. In which case I'll take it to the dealer to see what they say.

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[razorlab]

Did I hit a nerve there?

You're proving my point either way. The delta at LRP is similar to RRR in a lot of ways and that's not a track known for causing heating issues. Yes, you make 600 whp, we get that. I know the fuel requirements for that also. I have no clue what pump setup you have, but I'm guessing it's the stock FPC. I also have no idea if you run with the covers off in the back. I do know however, that you are a single data point, and a slightly pretentious one at that. Your tone continues to show that if people aren't praising you or fawning over your wisdom on this forum your default is to make fun.

It's kind of a weird insecurity/flex to feel the need to sarcastically wish someone good luck with arts and crafts while touting how much you do on your own which is basically a slightly different arts and crafts.

And now, back to actual tech discussion. I likely won't get to update this thread until after SCCA TT Nats in later Sept when I get on track again. Kind of hard to test or replicate without being on track. Pitt Race should be a different setup as well given it'll be cooler and I'll be running with all the rear trunk covers off. If it shows up again there I'll know it's either a bad fuel pump pulling too much current or a faulty sensor/chip in the FPC. In which case I'll take it to the dealer to see what they say.

Guess we both hit a nerve. I also stated in my original reply that I could be wrong and my experience so no need to fawn over anything. Let's not ignore you have the typical "I used to race cars" superiority complex going on too, so this ain't one sided.

My current relevant setup since you stated you don't know:

Dorch HPFP
S58 injectors
E40 fuel
Hatch cover is in every session. I do take it off after every session with the hatch open to help cool down my lithium battery and external mic for my gopro. As you stated, it gets toasty in there because the exhaust and diff are right under it. The hatch area actually gets a ton of airflow at speed, which is why I keep the cover on so my external mic doesn't blow out.

 

[itzTang]

Tracking in the SE is not like tracking in the NE. 80F+ ambient is late October to early November here. 147 in a straight also depends on what your starting speed was, because if you're referencing LRP then isn't the starting speed around 90ish? CMS has the entry to the banking at 40ish mph to 135 down to 45ish for the bus stop back to 125, rinse and repeat. The delta is what matters for a straight speed, not the overall top speed (usually).

I don't know if I'm chasing a phantom or not, but I do know this sub $20 test will tell me if I'm on the right track. It's a pretty simple system given there's a commanded duty cycle and the power flows through the FPC to the fuel pump itself. If the fuel pump has a fault inside then it'll show up as over heating again. If not and it was just the general heat along with a track that has a lot of full throttle for a long time then this should fix the issue (for me).

A few other things I realized at the time was I hadn't removed the carpet mat in the trunk area, or the little package shelf over the battery. I left the windows down between sessions, but with the sun shining it was easily over 110-120 in the car when I'd get back in. My little bit of searching says 150 F is where the board starts giving errors (based on the older EKPM stuff, no clue if it relates to this). That's not a ton of buffer, especially in the hatch area where there's very little air flow.

i dont think ive heard of running with mat and trunk cover off on stock power for cooling. Unless you're doing it for the slight weight reduction. Your issue might just be a one off electrical gremlin

 

[Subydude]

i dont think ive heard of running with mat and trunk cover off on stock power for cooling. Unless you're doing it for the slight weight reduction. Your issue might just be a one off electrical gremlin

When I run in timed competition I would have it off for weight. Gotta offset the beer and bbq from the night before somehow.

I wouldn't think it's needed on stock power for cooling either and I'm definitely not ruling out it's something else. This little test is the first step in seeing what it is though. I won't be able to make it back to the speedway while it's hot, so unless I make it down to Daytona or similar before it cools off I might not get the same test. I'll find out either way.

 

[Subydude]

Guess we both hit a nerve. I also stated in my original reply that I could be wrong and my experience so no need to fawn over anything. Let's not ignore you have the typical "I used to race cars" superiority complex going on too, so this ain't one sided.

My current relevant setup since you stated you don't know:

Dorch HPFP
S58 injectors
E40 fuel
Hatch cover is in every session. I do take it off after every session with the hatch open to help cool down my lithium battery and external mic for my gopro. As you stated, it gets toasty in there because the exhaust and diff are right under it. The hatch area actually gets a ton of airflow at speed, which is why I keep the cover on so my external mic doesn't blow out.

Haven't hit one for me, and I'm happy to keep chatting either way. I saw the caveat line of could be wrong for sure. I'm pretty agnostic when it comes to forums and posting so almost nothing gets under my skin anymore. Don't take the "haven't hit a nerve" as posturing so much as "no biggie, it's fine". The decades of racing do bleed through sometimes since I've been there and seen a lot prior. I would say I still race cars and haven't stopped really since 2008 (2006 if you count autox/rallyx) lol. The cars have changed over the years though, and my wheel to wheel days are mostly behind me unless I rent a seat in a Lemons car (which hasn't happened since before Covid). That said I do a good bit of untimed events along with TT/TA/One Lap. I'll keep it in mind though and see if I am putting the tone out of superiority. I try to avoid that since we were all noobs once.

Assuming your HPFP has greater needs, it would stand to reason that my FPC might be weak, or the pump itself might have some sort of issue. Again, hot day, lots of laps, way to many variables so I need to start removing the low hanging fruit first.

My luggage cover/cargo carpet/cargo floor were all in and I wasn't opening the hatch between. I didn't think about opening the hatch since I didn't think it would matter. I'm surprised there's airflow on track in there since it's a dead zone, but I'll still take the "open the hatch too" approach.

 

[razorlab]

Haven't hit one for me, and I'm happy to keep chatting either way. I saw the caveat line of could be wrong for sure. I'm pretty agnostic when it comes to forums and posting so almost nothing gets under my skin anymore. Don't take the "haven't hit a nerve" as posturing so much as "no biggie, it's fine". The decades of racing do bleed through sometimes since I've been there and seen a lot prior. I would say I still race cars and haven't stopped really since 2008 (2006 if you count autox/rallyx) lol. The cars have changed over the years though, and my wheel to wheel days are mostly behind me unless I rent a seat in a Lemons car (which hasn't happened since before Covid). That said I do a good bit of untimed events along with TT/TA/One Lap. I'll keep it in mind though and see if I am putting the tone out of superiority. I try to avoid that since we were all noobs once.

Assuming your HPFP has greater needs, it would stand to reason that my FPC might be weak, or the pump itself might have some sort of issue. Again, hot day, lots of laps, way to many variables so I need to start removing the low hanging fruit first.

My luggage cover/cargo carpet/cargo floor were all in and I wasn't opening the hatch between. I didn't think about opening the hatch since I didn't think it would matter. I'm surprised there's airflow on track in there since it's a dead zone, but I'll still take the "open the hatch too" approach.

It's all good. I've been tracking cars since 1997 and been on forums since even before that so I tend to be a bit less filtered than others. As some famous person said... "I've seen some shit."

It could be your component is faulty, it could be that the code tripped was from something else in the chain too. Like I explained earlier, sometimes the code description is too focused and not exactly the center.

Was the corner that this happened in a right hander? Sweeper?

 

[Subydude]

It's all good. I've been tracking cars since 1997 and been on forums since even before that so I tend to be a bit less filtered than others. As some famous person said... "I've seen some shit."

It could be your component is faulty, it could be that the code tripped was from something else in the chain too. Like I explained earlier, sometimes the code description is too focused and not exactly the center.

Was the corner that this happened in a right hander? Sweeper?

It was in a right hand bus stop. I had to find a track map to display it, but it's the 135 to 45ish mph left turn into right bus stop turn. I wouldn't expect fuel starve there given the pump "should" have been submerged as I still have 5 bars of fuel left. It was also immediate, not like the usual fuel starve I've experienced in other cars where it takes a few seconds to show up as the air bubble makes it's way through the system. That was why I expected it was actually a FPC overheat since it was coming off a long straight and had maybe 3-4 seconds tops of partial throttle before I matted it again to exit the bus stop. That behavior would match an overheated IC.

Arrows to show counter clockwise direction. X where the fuel starve was noted. I don't disagree that it could be something else. I would also say adding this little cooler fan is a possible fix and I won't know until the car either shits itself again or I run CMS next August with all the covers in place to test.

 

[razorlab]

It was in a right hand bus stop. I had to find a track map to display it, but it's the 135 to 45ish mph left turn into right bus stop turn. I wouldn't expect fuel starve there given the pump "should" have been submerged as I still have 5 bars of fuel left. It was also immediate, not like the usual fuel starve I've experienced in other cars where it takes a few seconds to show up as the air bubble makes it's way through the system. That was why I expected it was actually a FPC overheat since it was coming off a long straight and had maybe 3-4 seconds tops of partial throttle before I matted it again to exit the bus stop. That behavior would match an overheated IC.

Arrows to show counter clockwise direction. X where the fuel starve was noted. I don't disagree that it could be something else. I would also say adding this little cooler fan is a possible fix and I won't know until the car either shits itself again or I run CMS next August with all the covers in place to test.

View attachment 146245

It could be fuel starve, that looks like a big WOT section before the bus stop as well. Plenty of stock supras have fuel starve over half tank, depending on the track. The DME has some interesting safe guards, one of which is a faux misfire it will do if it anticipates fuel starve. Designed to make it so the driver will lift when it happens. Kind of genius I think.

Example of the faux misfire on my supra from a couple years back:

 

[Subydude]

It could be fuel starve, that looks like a big WOT section before the bus stop as well. Plenty of stock supras have fuel starve over half tank, depending on the track. The DME has some interesting safe guards, one of which is a faux misfire it will do if it anticipates fuel starve. Designed to make it so the drive will lift when it happens. Kind of genius I think.

I expected it to be fuel starve or some code relating to it given I was adding around or just over 4 gallons after each session. I was surprised by the over temp code though which lead to this rabbit hole. It was others mentioning they had fuel starve but no CEL that made me dig deeper.

It is a long WOT section as you mention. On the stock PSS I was at 35-37 mph at the pin turn and the banking ends up sucking some acceleration out so it was about a 97-100 mph delta right before the bus stop, and then the following section gets you to 120 mph where you're losing speed if not WOT on the banking into the front bus stop, etc. I wouldn't expect fuel starve at CMS given the banking is all left, but the two bus stops and infield both have sweeping rights with some elevation (like maybe 20-30 feet change total).

 

[razorlab]

I expected it to be fuel starve or some code relating to it given I was adding around or just over 4 gallons after each session. I was surprised by the over temp code though which lead to this rabbit hole. It was others mentioning they had fuel starve but no CEL that made me dig deeper.

It is a long WOT section as you mention. On the stock PSS I was at 35-37 mph at the pin turn and the banking ends up sucking some acceleration out so it was about a 97-100 mph delta right before the bus stop, and then the following section gets you to 120 mph where you're losing speed if not WOT on the banking into the front bus stop, etc. I wouldn't expect fuel starve at CMS given the banking is all left, but the two bus stops and infield both have sweeping rights with some elevation (like maybe 20-30 feet change total).

Yea, but as I said before, sometimes the code isn't the origin but the outcome, or reverse. I'm not saying positively it was fuel starve, but it could have been.

At Lime Rock, the whole track is right turns except for one left hander, you would think it would be fuel starve city in the Supra, but most of them aren't very long right handers so it's more rare. I can however fuel starve in the uphill or downhill at my modification level if I don't keep the tank topped off before every session. Back when my supra was 100% stock power, I could just lap all day with no issue and not have to keep my tank topped off.

Then there is Thompson, which is the video above is from. I am pretty much guaranteed fuel starve about six laps in there, no matter what.

The code that tripped from the instance in the above video was the HPFP angle maxed out, but that is part of the faux misfire strategy the DME uses. Didn't go into limp mode that time, but the next session it realllllly fuel starved and threw me into limp.

 

[Traxion]

I get fuel starve at Road Atlanta coming out of T10B which is kind of similar to that corner. I tried a couple times doing 1 session topped up, running 3 laps and then doing the next session and it fuel starved in the two attempts I did that. I do have more elevation in my example and it's a little more sustained right hander but I can see your track having that issue with way less gas than what I run.

 

[Subydude]

I get fuel starve at Road Atlanta coming out of T10B which is kind of similar to that corner. I tried a couple times doing 1 session topped up, running 3 laps and then doing the next session and it fuel starved in the two attempts I did that. I do have more elevation in my example and it's a little more sustained right hander but I can see your track having that issue with way less gas than what I run.

Interesting to note. I've driven RA quite a bit and you're right that it's a similar setup with high speed down into a switch back. Elevation there is very different as you said though. T11/12 is my favorite section of that track too, so it'd be a bummer if 10B causes that issue.

Weird that some tracks cause it quickly while others don't. I'm used to filling up during the day, but filling each session and still having starve will be annoying.

 

[Rensuhlo]

For what it's worth. I have NEVER fuel starved at CMS, and I've run the tank low.

 

[FLtrackdays]

Weird that some tracks cause it quickly while others don't. I'm used to filling up during the day, but filling each session and still having starve will be annoying.

Try both low fuel and topped off and see if you notice a difference. I personally don’t at either Homestead or Sebring. A friend of mine swears he did (he eventually sold the car). Had aero, different setup, few tenths slower, different driving style. Many variables. Who knows why it happened to him…

 

[Subydude]

Got the box installed last night and used fuse 273 to power it. The fan stays on anytime the car is “active” but the draw is super low for current. After about 10-15 minutes (or whenever the car actually shuts off the electronics) the fan shuts off.

Total cost to print the box is $.86, the fan is $14 or so, and the fuse taps were $6 for a bundle of 20.

I didn’t add any heat sink to the board so it’s 1-2 minutes to remove if this ends up not being the issue.

I used PETG for filament since it's what I had loaded up at the time. The CF look is just the print plate I use currently so it looks more fancy

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