Fuel getting hot causing fuel pump noise

[daveParticipant daveVK, L98, tremec tko600 View build HERE Member since: March 6, 2015 Posts: 46]

Hi. Wondering if anyone else had this issue or got any opinions on it. I have a VK running an L98 LS  engine. Am having problems with the fuel pump getting noisy after driving for longer than 40 minutes as the fuel is getting hot. The tank is warm to touch. Am using a bosch 044 external pump. 5/8 suction pipe and 3/8 pressure line. The pump is mounted level with the bottom of the tank. Have regulator on the fuel rail and return back to tank. Pump is quiet as long as the fuel is not hot then gets real noisy as the fuel heats up. Appreciate any ideas or comments.

Dave

 

[ImmortalityParticipant 97 HSV Senator 185i 02 VX L67 Calais View build HERE Member since: August 31, 2015 Posts: 535]

What size is the return line?

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

In road cars with big fuel systems I run a pwm pump driver, it’s rpm based so under idle or cruise conditions it drops the pump speed to prevent the issue you describe.

My old Supra just bout boiled the fuel after an hour drive throwing the tune out noticeably..

[Heron SSVParticipant Central Coast NSW2009 Pajero Exceed 84 VK SL LS3 View build HERE Member since: May 5, 2015 Posts: 585]

How close are the lines to the exhaust? Can you move the fuel reg away from the bay? The return line might be too close to something hot and is heating the fuel as it goes back to the tank. I’ve got an LS3 in a VK, I run a VN tank with Walbro 460 in the standard hanger, then into a filter/reg mounted behind the diff, then dead head 3/8 to the rail.

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

Anonymous wrote:

In road cars with big fuel systems I run a pwm pump driver, it’s rpm based so under idle or cruise conditions it drops the pump speed to prevent the issue you describe.

I have one of these just another small thing I haven’t gotten around to hooking up electrically yet…

As IJ says an issue is with the system without one its flowing enough fuel constantly that it would need at WOT, so at cruising most of it is being bypassed through the regulator and back to the tank. That’s a lot of flow.  But also means the pumps working flat out (of course) so it’s getting hot and heating up the fuel as it flows through too.  Might be worth running a full tank of fuel and see if it’s better, but as others have said make sure the lines aren’t near the exhaust anywhere too.

[firebugParticipant Newcastle NSWL67 Gemini & Pathfinder Ti 550 View build HERE Member since: May 7, 2015 Posts: 89]

My Gemini does this also. It runs 2  044s and idles for about 15-20mins in the staging lane prior to the run. When I  get back to the pits you can’t touch the surge tank as the fuel is almost boiling. Usually have about 40l in the tank to try and help compensate with volume.

I’m  considering a fan fed oil cooler to see if it makes a difference?

Nothing ruins your Friday more than realising it's only Tuesday...

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

I reckon the PWM controller is the way to go. This is what I have but I am sure there lots of other brands etc.  https://www.weldonracing.com/store/14000-Pump-Controller-p56212294

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

I’ve been using AEM controllers, I think I might have one here somewhere I’m not using..

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

IJ how hard are they to wire up, is it something any competent auto electrician could do, or is it more of a tuner kind of deal?

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

Really really simple Gary!

[cava454Moderator 93 VR BT1 View build HERE Member since: February 20, 2015 Posts: 2 390]

I’m surprised a single 044 is causing this. The return line must be restrictive.

[ImmortalityParticipant 97 HSV Senator 185i 02 VX L67 Calais View build HERE Member since: August 31, 2015 Posts: 535]

Yes I agree that a PWM controller is a good idea but a single 044 should not cause these issues.  The 044 and Walbro equivalent are in thousands of cars getting around daily.

 

The missus daily comes factory fitted with a fuel pump pwm controller

• This reply was modified 5 years, 3 months ago by  Immortality.

[daveParticipant daveVK, L98, tremec tko600 View build HERE Member since: March 6, 2015 Posts: 46]

Hi, Thanks for feedback. The return pipe is also 3/8. Have considered exhaust heat but lines are not near exhaust, have run them up the top of the gearbox tunnel to rear of engine. Did consider maybe the muffler at rear next to the tank was causing the heat transfer. As cava said would not have thought it would be excessive flow with one 044 pump, but maybe it is. I might try decreasing the flow to test if that is the issue. Have considered fitting a VN tank and running in tank pump. Anyway thanks again.

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

I had the issue with a single coffee grinder (044) it’s more when idling or cruising there’s bugger all fuel being used by the engine so you’re constantly circulating the fuel through the fuel rail in the hot engine bay back to the tank, this is why it takes awhile to heatsoak all the fuel…

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

firebug wrote:

My Gemini does this also. It runs 2 044s and idles for about 15-20mins in the staging lane prior to the run. When I get back to the pits you can’t touch the surge tank as the fuel is almost boiling. Usually have about 40l in the tank to try and help compensate with volume. I’m considering a fan fed oil cooler to see if it makes a difference?

Have thought about that in the past, my “concern” is it needs to be in some cool airflow to be effective then you run the risk of a minor off escalating into a major firey death of the car..

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

Anonymous wrote:

Really really simple Gary!

  Might have to look into this cheers.  Mine is pretty noisy at idle, and the units there, I just haven’t hooked it up.  Cheers.

Don’t know if this helps, but when I did my Varex set up I bought some of that stick on heat shielding and did the side of the fuel tank.  Not easy to see on this pick but maybe it would help?

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

In the Supra I made some guards from the ACL heatshield material, didn’t make much difference, wasn’t till I installed the pump controller that it settled down and the tune remained constant, before that it would change a lot dependent on temperature, guessing it was a pressure issue in the tank.

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

Be interesting if anyone makes a simple little 12V flow through cooler, must be a reasonably common problem, especially in hot climates?  I know the drag boys do the esky kind of deal don’t they?

[Judge1 FrazerParticipant new zealand1983 VB LSA MG9 6060 6 speed View build HERE Member since: February 5, 2016 Posts: 775]

is this a internal pump thing or external or it doesn’t matter

[Anonymous View build HERE Member since: January 1, 1970 Posts: 0]

It’s a return fuel system thing Frazer..

It’s not really the pump heating the fuel it’s the volume flowed by the big pumps and circulating it through the engine bay heat.

[Author]

Posts