Where is your fuel pump mounted relative to the fuel level? Pump overheating.

[Cobra4B]

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Pump overheats after 10 minutes at idle and fuel pressure drops to zero. Called Holley and tech said the pump must be at the bottom or below the cell. It is meant to be gravity fed. They are meant to push fuel and not have to pull it up from the cell. Multiple other people verified this about these type of external electrical pumps.

So what's the deal? Every Panoz I've seen has the pump mounted up over the cell. Is there some other brand/type of pump that is meant to pull fuel up out of the cell?

The car worked "OK" before but we did have some instances of the car cutting out. We attributed that to fuel cell foam breakdown, but who really knows. The Holley tech guy said he's seen people mount them as shown above and get lucky and have them run for years, but it's 100% not meant to work that way.

Said the top cause of pump failure was mounting location. The second was incorrect wiring i.e. insufficient gauge wire. Not an issue here as the pump is on its own circuit and wired with 12 gauge wire.

Thanks,

Brian

[Cobra4B]

Well loookie here... GTS cars do have the pump at the bottom of the cell.

[NZGTRA17]

Originally Posted by Cobra4B

Well loookie here... GTS cars do have the pump at the bottom of the cell.

Brian I have used Carter electric fuel pumps now for well over 20 years. I have never had the luxury of mounting the pump below the tank due to packaging or other constraints. They have never given issues mounted this way and last forever (which cannot be said for a number of other brands).

You will see I have mounted both of my Carter pumps above the tank on the Panoz as well. Likewise no issues todate.

Interestingly even if they are mounted below the tank, given how the pickup works in our tanks the pump still has to draw the fuel up from the bottom of the tank. Yes there may be a siphon effect but its not like it is gravity feed in situation where fuel is drawn from the bottom of the tank!!

Kel.

[Cobra4B]

I moved the pump to the location of the GTS I had pictured above (guess Wirewheel changed the link as the picture isn't showing). It still got burning hot. Holley tech says the pump was most likely already shot. Got another Holley Blue and will be installing tomorrow. If it doesn't play nice I'll return it for a refund and get a Carter (others have recommended it as well).

Tech says locating the pump below the cell level creates a siphon effect once the initial bit of fuel has been pumped and greatly reduces the effort on the pump. Makes sense... but we'll see.

[NZGTRA17]

Originally Posted by Cobra4B

I moved the pump to the location of the GTS I had pictured above (guess Wirewheel changed the link as the picture isn't showing). It still got burning hot. Holley tech says the pump was most likely already shot. Got another Holley Blue and will be installing tomorrow. If it doesn't play nice I'll return it for a refund and get a Carter (others have recommended it as well).

Tech says locating the pump below the cell level creates a siphon effect once the initial bit of fuel has been pumped and greatly reduces the effort on the pump. Makes sense... but we'll see.

Brian, I'll come clean now then........I use Carters as I have seen so so many Holley pumps crap out. Wont speculate on why as I have never owned one or pulled one apart. I can also say I have never pulled a Carter pump apart as I have never needed to. My last car had a Carter in it that I purchased in 1987. Did a heap of miles on the street then race duty for a number of years and was as good as new..........

[Cobra4B]

I've heard similar... going to give it one more shot in this new position and see if creating the siphon helps it. The Carter requires the pump body to be mounted downward which would interfere with part of the chassis in the new location.

[Panoz60]

Brian, try temporarily bypassing the fuel filter and test it again.
Those Fram style filters can be very restrictive because they filter a bit too well. That could be the cause of your overheating.
Personally, all I run are 40 micron screens on racecars like pictured below. No filters. FYI-


The only other thing I can think of is testing the ohm resistance of the pump (it may be bad) and/or there is insufficient/faulty ground.

[panozracing]

The GTS comes with just a screen style filter as well like what Mark pictured above.

[Cobra4B]

Thanks guys. I installed the new pump in the GTS location and have the filter after it. It reads 12.9X volts when on and I think my ground is fine. It runs back to my fuse panel to the main ground; all 12 guage wire.

The new pump does get hot after about 15-20 minutes idling, but fuel pressure remains constant.

I think it's the nature of the beast with the dead-headed pump. Once the car is running/moving it should be fine.

Interesting point about running the screen only. Do you have to change them out periodically? How often?

[Panoz60]

Brian, I was more concerned with the ohms (not voltage) resistance of the pump. It may be trying to draw too much current.

I check my screens before each race weekend. They can be cleaned with air pressure and carb cleaner. Takes about five minutes total. I also use a fuel funnel with a built in screen.

Aside from that, I still believe your problem lies with the fuel filter. I think the pump is struggling to push the fuel past the elements in that style of filter. What cools the pump is fuel passing through it. The optimum set-up is a return style regulator, that allows the fuel to pass free through the pump and returns the unneeded fuel back to the tank/cell. That's what I run, and my pump runs at ambient temperature all day long. While fuel demand will go up when the engine is loaded (car moving), it may not flow free enough to solve your problem without a return style regulator. Full demand (non-bypass) regulators are really meant for drag racing.
Here's a picture of a bypass regulator and a link. Fuel comes in the bottom, exits to the carb out of both sides, and residual pressure is returned to the fuel cell from the front port (as pictured) they also cure the problem of "pressure creep" and IMO helps the car return to idle more consistently, especially after the throttle slams shut from wide-open during a braking event.

http://www.summitracing.com/search/d...age/carburetor

[panozracing]

I almost never check my filter. I should probably start :-)

[Cobra4B]

1. How exactly do you clean the screen type filter? Do you just uninstall it and spray carb cleaner in it and blow air through it the reverse direction of the normal fuel flow?

2. My VP racing fuel jug nozzle has a screen on it FWIW (Instead of having it in the funnel)

3. We put a carb on the 302 and ran it for a season (before it snapped the crank) and then the 347 SBF for most of a year with the holley blue up over the tank and the fram filter before it as pictured in the "before" picture in the original post. Never had issues with the fuel system, but may have just been getting lucky.

4. Tonight I ran the car for 10-15 minutes with the filter element removed from the canister. Toward the end of the run the pump got good and hot again. The pump housing at the base gets hot but not burning. The top of the electric motor cylinder (I guess that's the capacitor) gets burning hot. When you hold the car at 3000 rpms for a bit it all cools down somewhat.

I checked my ground for continuity and it's perfect with 0 ohms. Voltage at the pump read 12.8. Fuse is fine, not blowing any fuses. Voltage drop causing a current spike should be blowing fuses. Car runs off the battery when stationary due to the pinion driven alternator. Using a deep cell Optima yellow-top now.

The folks from Holley called back and this particular tech guy said it was the Fram filter. He said they recommend a 100 micron filter before the pump and 40 micron after it. This Fram filter is 5 micron! That's what prompted me to test it w/o the filter element, but it still heated up over time.

That said, the fuel pressure was fine. Got some false pressure drop from the fluid filled gauge getting hot, but a bag of ice on it and it went right back and held steady betweeen 6.5 and 7 psi where I had set it.

5. To recap the issues/trouble shooting with the pump:

1. Last week car got rained on when I was trying to load it for a dyno appt (didn't have dad's enclosed trailer). Got it back inside the garage and ran the car to help dry things. While running the fuel pump got so hot the car lost fuel pressure and shut down and the pump stopped too; not just vapor-lock. This was with the pump in the original spot over the cell.

2. I call Holley and they tell me the pump needs to be moved below or near bottom of the cell. I make this thread. Next day I move the pump down to the GTS spot. Pump still gets hot at idle and fuel pressure drops.

3. Call Holley again and they tell me about false pressure drop with liquid gauge. Tech thinks the pump is already shot and states it should never get burning hot.

4. Get a brand new pump and install it. Run the car. Car runs fine but pump gets hot over time. Use the ice bag trick to verify false pressure drop. Pump is getting hot put pressure staying at 6.5-7 and car isn't dying. Running fine. Call Holley and leave message... surprised brand new pump in proper location is still getting hot.

5. Holley calls back tonght (as mentioned above) and says filter is the issue. Run the car w/o filter element tonight and it still gets hot over time.

End of the day I think the issue is inadequate fuel flow to cool the pump. I'll bet it'll be fine on track. If it's not, and it acts up again, I'll swap to a carter pump and consider a return style regulator.

~Brian

[NZGTRA17]

Originally Posted by Cobra4B

1. How exactly do you clean the screen type filter? Do you just uninstall it and spray carb cleaner in it and blow air through it the reverse direction of the normal fuel flow?

2. My VP racing fuel jug nozzle has a screen on it FWIW (Instead of having it in the funnel)

3. We put a carb on the 302 and ran it for a season (before it snapped the crank) and then the 347 SBF for most of a year with the holley blue up over the tank and the fram filter before it as pictured in the "before" picture in the original post. Never had issues with the fuel system, but may have just been getting lucky.

4. Tonight I ran the car for 10-15 minutes with the filter element removed from the canister. Toward the end of the run the pump got good and hot again. The pump housing at the base gets hot but not burning. The top of the electric motor cylinder (I guess that's the capacitor) gets burning hot. When you hold the car at 3000 rpms for a bit it all cools down somewhat.

I checked my ground for continuity and it's perfect with 0 ohms. Voltage at the pump read 12.8. Fuse is fine, not blowing any fuses. Voltage drop causing a current spike should be blowing fuses. Car runs off the battery when stationary due to the pinion driven alternator. Using a deep cell Optima yellow-top now.

The folks from Holley called back and this particular tech guy said it was the Fram filter. He said they recommend a 100 micron filter before the pump and 40 micron after it. This Fram filter is 5 micron! That's what prompted me to test it w/o the filter element, but it still heated up over time.

That said, the fuel pressure was fine. Got some false pressure drop from the fluid filled gauge getting hot, but a bag of ice on it and it went right back and held steady betweeen 6.5 and 7 psi where I had set it.

5. To recap the issues/trouble shooting with the pump:

1. Last week car got rained on when I was trying to load it for a dyno appt (didn't have dad's enclosed trailer). Got it back inside the garage and ran the car to help dry things. While running the fuel pump got so hot the car lost fuel pressure and shut down and the pump stopped too; not just vapor-lock. This was with the pump in the original spot over the cell.

2. I call Holley and they tell me the pump needs to be moved below or near bottom of the cell. I make this thread. Next day I move the pump down to the GTS spot. Pump still gets hot at idle and fuel pressure drops.

3. Call Holley again and they tell me about false pressure drop with liquid gauge. Tech thinks the pump is already shot and states it should never get burning hot.

4. Get a brand new pump and install it. Run the car. Car runs fine but pump gets hot over time. Use the ice bag trick to verify false pressure drop. Pump is getting hot put pressure staying at 6.5-7 and car isn't dying. Running fine. Call Holley and leave message... surprised brand new pump in proper location is still getting hot.

5. Holley calls back tonght (as mentioned above) and says filter is the issue. Run the car w/o filter element tonight and it still gets hot over time.

End of the day I think the issue is inadequate fuel flow to cool the pump. I'll bet it'll be fine on track. If it's not, and it acts up again, I'll swap to a carter pump and consider a return style regulator.

~Brian

Brian it is a combination of pump design and lack of flow too cool the pump as you have deduced.

I am pretty sure that the Carter pumps I use do not have the same issue due rotary vane design (suspect they have a recirc circuit for cooling).

I use an EFI style cartridge filter and replace every 2 years or so. Cant see that this is your issue more the pump working hard against the back pressure with no flow to cool it.

Kel.

[Cobra4B]

FWIW the Holley blue is rotary vane and has a recirc circuit as well. But I think that's part of the problem with it when dead-headed. You've got a pump that makes 14 psi regulated to 6-7 so at least half of the pressure it makes is "wasted". At idle I'll bet the pump is in bypass a bunch so the same fuel gets pumped around and around getting hotter and hotter.

http://www.stevesnovasite.com/forums...d.php?t=163951

[Panoz60]

Here's what I know.
1) I bet cash that the Holley techies think you have a drag style fuel cell with bottom fed pick-ups. That's why they're telling you to mount it low, so gravity can assist. Holley pumps designs do not pull nearly as well as they push. (however they self-prime better than other designs) With your cell, moving the pump down will not fix anything.
2) If you call dedicated fuel system manufacturers, like Aeromotive, QuikFuel, etc, they will tell you that you'd be best off with a return style fuel system. Why a return system? because the pump will pull north of 75gph just sitting there at idle, thereby pulling mass amounts of fuel through the pump and cooling it off. A general rule is you want to keep the pump close to the tank, and the regulator close to the carb. Its really easy to plumb. The return can go in the port on top of your fuel cell that (according to your picture) is currently not used.

Return styles are all I use now for the last 15+ years. Before that I had all kinds of problems with idle and "pressure creep" I always carried a spare pump because I was planning on it's failure. Now I can get several season out of a pump.

AND- The filter is a canister. The ends are sealed with o-rings and unscrew and expose the micron filter. I just took this pic of my spare.


Trying to help, hope this didn't sound argumentative.