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Location:
cambo
Registered:
May 2002
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fuel pump stops when hot (again)
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Mon, 03 October 2005 09:44
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i posted this a while ago but anyway ill repeat 
VL fuel pump in boot, fed from surge tank. on a hot day after about 15 mins of driving (more so in traffic) the pump will get real noisy then stop, not good in the middle of a busy lane. so i let it cool for a few minutes, then im off again only to stop again a few minutes later.
being a tightass, i just replaced the pump with another second hand one. so again this new one is doing the same thing. so what i did this time was get another pump, mount it next to the other one in the boot. when one gets hot, i flick a switch on the dash and the other one kicks in. this keeps me going for a bit till this other one gets hot then i have 2 hot fuel pumps that dont wanna go.
WHAT TO DO? i think there are 2 things contributing. firstly, pump is in boot getting no flow like it would under a VL. secondly, the fuel return goes to the surge tank hence running warm fuel through the pump.
im thinking of hooking a a small fan near the pumps. stupid idea?
discuss
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Location:
sydney
Registered:
March 2003
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Re: fuel pump stops when hot (again)
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Mon, 03 October 2005 10:19
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buy a new pump u tight ass
they should be able to handle some heat
after 3 or 4 2nd hand pumps u would have spent enough money to buy a new one
if u cant afford new one sell yr car and buy a pushie
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Mon, 03 October 2005 10:41
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haha yeah i know
the only thing im worried about is buying a new pump only for it to do the same thing.  just seems strange 4 pumps would do the same thing, and they are fine any other time
and yes after a 5th pump that would be the same as 1 new one. 
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Mon, 03 October 2005 10:50
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About to open a new thread, but this seems to be the same problem. I have overhauled my 1J engine and the ECU connections with a good result. But I still have the same problem as you, not after 15 mins, more like 1 hour.
I was wondering if we talk about plain dirt in the tank? That would account for the time frames. There are macro filters on the in-tank and out-tank fuel pumps, and what will happen when dirt collects? Sooner or later it will choke the pump.
The second problem is that when you start to choke the fuel pump it will start to draw more amps, thereby heating the relays. I had 1 relay (Toyota, metal housing) that in fact melted the plastic that it touched. I replaces all the relays controlled by the ECU (With Bosch and higher rating), but I still have the problem. The relays can stand the AMP drawing, but still get hot. Strange on a fuel pump relay with very tiny wires.
I think I'll have someone check the fuel tank (especially for signs of "collapses" of the pump filter. I dont believe in coincidences. When my problems start after a certain period, in town or on the freeway, then.... Filter? (The pump will move the same amount of fuel, low speed, or high speed). My main fuel filter has been replaced twice. Dirty like H..., but after only 5-10K Km.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Mon, 03 October 2005 14:08
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Something so simple...
Pumps have a limited life, so you only know what you get if you start with a new one. HOWEVER!
A new pump will leave a short and unhappy life if it gets dirt, and/or doesn't get enough fuel. Fix these problems first! i.e. no mounting a VL pump in the boot, above the level of the fuel tank, then crying every time the pump goes west... Also pumps use the fuel for cooling - and will therefore cook if the don't have enough fuel going through them. A PC fan next to the pump will do very little to help....
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: fuel pump stops when hot (again)
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Mon, 03 October 2005 14:36
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stupid question, but are you running a lift pump?
if you make your surge tank a swirl pot, you can virtually seperate hot and cold fuel.
i'm just running one unknown second hand inline fuel pump, mounted roughly level with the bottom of the fuel tank sucking on the standard fuel pickup, never had the problem you describe (surge on the other hand...)
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Tue, 04 October 2005 06:41
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yeah i got a lift pump feeding the surge tank. there is a fuel filter after the lift pump but before the surge tank which i change regularily, so im convinced its got a constant supply of clean fuel.
so that sorta rules out the pump being under any stress, i can only conclude its due to heat, especially since the two pumps are silent on a cool day but noisy on a warm day.
if i could be sure the problem is second hand pumps, i would buy a new one, even tho they are over $200 compared to $50 second hand. but the thing is the first and second pumps lasted longer, and the more recent pump lasted less time making me think there is another factor but i cant see that there is. just seems wierd that even tho they are second hand, they all have the same problem.
its gotta be heat cause it only happens when hot but others have ran pumps inside the cabin no trouble, AND with surge tanks that have the return from the rail going into them recirculating warm fuel.
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Location:
Terrigal
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Tue, 04 October 2005 23:31
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My bosch pump gets really noisy also when it gets hot. Haven't noticed it during winter but these last few 30 degree days you can easily hear it whining away over the noise of the exhaust.
Thats a new pump though, with a huge 4 ltr surge tank and prime pump.
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 06:54
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thats a bit scary to know. cause if i had to buy a new pump, a standard bosch VL pump is around $200 so i was gonna spend the extra $50 and get a bosch motorsport pump. but if yours is nearly new, AND you have a large surge tank yet your pump still gets noisy, i wonder if me getting a new bosch motorsport pump would fix it? i mean my surge tank i would estimate is less than 2 litres, prob closer to 1 or 1.5L.
also i noticed today on way home from work (10 minutes) it was noisy near home. when i got home i opened the boot, and the pump that was running was warm, the standard by pump was warm but less so, and the surge tank itself was warm aswell. so methinks the fuel running through the fuel rail and back warming it up is a part of the problem.
what to do???
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Location:
Pilbara
Registered:
November 2004
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 08:23
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Here is a little trick that might help keep your fuel cool, perhaps help with the pump problem. First, how big is your surge tank/ swirl pot? If it's a wee one then you may need to get one at least 1.5 litres in capacity.
Secondly, you can use a small oil cooler running inline to the return fuel line ( I have used a cordia one to good effect) mounted some where the air can get to it as a fuel cooler. Works fine.
A VL pump will be happier if it's running atleast on level with your tank and really happy if it's mounted underneath the car.
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 11:42
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yeah i considered some sort of cooler, might consider it some more
yeah surge tank aint huge, prob around 1.5L. pump is level with the bottom of the surge tank.
after a 1/2 hour drive to narellan which took about 1 1/2 hours due to random stopages, i managed to speak to a mechanic friend whom is into a bit of drag racing. i ran by him the idea of the fuel getting hot from circulating through the engine then surge then pumps again, and he swears this is the problem. he reckons returning the fuel to the tank again rather than surge tank will eliminate the problem as the hot fuel makes the fuel pumps too hot.
my concern then is whether or not the lift pump will flow enough fuel for the high pressure pump without the added assistance of the return line to feed the surge tank, so im thinking i should look into a higher flow low pressure lift pump.
bunky, are you running a fuel cooler with a surge tank that returns the fuel to the surge rather than main tank? and is it a relatively small surge you are using?
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Location:
Pilbara
Registered:
November 2004
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 12:25
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yeah turbo on a 4a.
each VL pump (i have 2 one as a spare in parallel as mentioned) is siwitched by its own seperate relay.
the surge tank has a 1/2in conection right at the bottom for the VL pump, about 2cm from the TOP of the tank is the feed from the lift, above that and right below the top of the surge is the overflow to tank, and the return from the rail comes into the top of the surge. hang on ill go take a pic
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 12:34
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as you can see, not a huge tank and not alot of airflow 
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Registered:
October 2004
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 13:10
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i'm running a camira fuel pump also, and mine buzze's really loud on hot days.
if there some sort of reason for this?
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 13:38
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For starters, the feed from the main tank should be at the bottom too,
how are the lines from the two pumps plumbed to the fuel rail?
nice carpet too!
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Wed, 05 October 2005 15:02
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Maybe I am just plain stupid, but here are my 2 cents.
On my 1J engine I dont have a surge tank (as far as I know). I also read that a 5 liter engine running at 4800 rpms uses about .220 Kg of fuel per min. Most pumps, including in-tank pumps, can handle that without problems. That is only about 15 l/hour.
BUT, I have seen my in-tank pump. It has a "macro"-filter to filter out large particles. What if you have dirt in your tank? The sediments, including rust, will collect in that filter, and prevent the flow of fuel. (my engine ran without problems for 2-3 years. It started after being parked for about 1 year).
In case of a surge tank. Normally the purpose is to cope with excessive use of fuel, a buffer. Under normal conditions (supply from the tank is sufficient), there will be a flow back to the tank. Then you dont get "hot" fuel, it is exchanged all the time.
If the flow from the tank is obstructed, what will happen? The fuel will circulate from the surge tank, through the rails, and back to the surge tank. No renewal of the fuel from the main tank. Then for sure you will get "hot" fuel.
My symptoms are that there is not enough fuel after about 1-1 1/2 hour of running the engine. That is on hot days, cold days, in the city, and on the highway. Knowing that a normal pump will supply the same amount of fuel all the time, it points to one problem.... Dirt in the tank!! That would account for the timeframe. The dirt will collect in the "macro" filter depending on the flow of fuel and not on weather conditions. It could be, that in hot conditions it happens quicker, but that would also heat the fuel quicker.
I dont know. Maybe I am just stupid. But for sure I'll let the local garage remove the fuel tank and clean it. Then I'll let you know if it solved my problem or not.
[Updated on: Thu, 06 October 2005 00:58]
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Location:
Pilbara
Registered:
November 2004
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Location:
Pilbara
Registered:
November 2004
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Re: fuel pump stops when hot (again)
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Thu, 06 October 2005 01:33
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Let me get this straight. Each pump is run by it's own 'relay'? But you just said before that you switched on on manually. On my 3TGTEU the circuit open relay works to power the pumps through two different inputs or triggers; first the starter motor and then the AFM. Input from the AFM varies according to how much air is flowing, metered by the how open the flap is on the AFM. Principal is the same with the Karmann Vortex (shudder) or a 'hot wire' AFM.
On most efi cars, this how it works with variants of trigger inputs.
ChrisTH It's likely that your intank fuel pump is rooted mate, and you do have a surge or swirl pot inside your fuel tank. That is where the end of your filter will sit and is usually a cup/ bucket like arrangement that will ensure fuel will be there in the event of cornering etc.
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Thu, 06 October 2005 10:56
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bunkyT18, yes there is a dash mounted switch for the fuel pumps. there is a fuel pump relay controled by the ecu, this i have controling the lift pump. i take a signal from this relay to the dash mounted switch, which then switches on one of the two main fuel pump relays.
each main pump relay has a fused power source deirectly from the battery. so when i turn the ignition on, the efi relay siwtches the lift pump on, and one of the VL pumps. there is not a metered amperage, just a constant supply from the battery to the VL pumps. i was under the impresion all electric fuel pumps just had a direct power supply and would draw whatever current necessary, maybe im wrong?
ChrisTH, in my situation its not a matter of dirt in the tank as there is a filter before the surge, its DEFINATELY temp related.
shinybluesteel, why should the tank feed be at the bottom of the surge? i cant see how it would make a difference.
over next week i will obtain a higher flowing lift pump (just for piece of mind) and run the return line to the main tank and just block off the top surge tank line. im fairly confident this should fix it, wanna get it sorted by megacruise
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: fuel pump stops when hot (again)
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Thu, 06 October 2005 13:45
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simple really, you want cold fuel to go out the bottom of the surge tank, so you want cold fuel to go in the bottom of the surge tank.
you want hot fuel to go out of the surge tank (back into the main tank) so you want hot return fuel to go in the top of the surge tank.
Nearly all fuel pumps are just fed a constant 12 volts, and they do just draw the current they need (like any electrical thing)
some cars have two pump supply voltages, but our dinosaur sprinters and the like just have one.
I think what bunky was getting at is that AFMs can have an output that will switch the pump off when no airflow is going into the engine, when starting the pump relay is powered by the start signal so it will turn on.
If your sprinter has an australian fuyel tank, then it has basically nothing in the way of cup/bucket swirl pot, just one diagonalish baffle and a little mesh filter on the end of the fuel pickup.
Lift pumps are pretty pricy, i'd get a better swirl pot made up first, but what you suggest should work fine. Just remember the lift pump will have to deliver much more fuel than the engine is using (which by the sounds of it you already know)
maybeye fit a fuel cooler between the return line and your surge tank?
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Fri, 07 October 2005 04:50
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EVOSTi
I was not hinting at the VL pumps being fed dirty fuel, more like the lift pump delivering insufficient flow of fuel due to dirt at its suction point.
A lift pump is normally a high flow/low pressure device (think about a propeller pump in a fish tank). It has a max flow rating (based on rotation speed and propeller size), but the inlet and outlet size (and piping) sets the limits of the flow rate. Any obstruction in inlet/outlet will not affect the pump very much (in worst case it will just move the same liquid around in the propeller housing) but the flow rate will be seriously affected.
A high-pressure pump will normally deliver a constant flow. That flow is independent of pressure or obstructions. Pumps like that, e.g., geartype or piston pumps, will basically run or blow up, unless there is a safety feature (internal feedback or cutout).
I do agree that you probably have a temperature problem. But that could be cause by the bad flow to the surge tank. Then the fuel being circulated there will be the fuel from the fuel rail. That could cause your pump to cut out due to overheating.
I would check the flow from the lift pump. There should be sufficient flow to flush the return fuel back into the main tank. I noticed that you were thinking about a new (and bigger) lift pump, so we think in the same way. Returning the fuel from the rail directly to the main tank might be a bad idea. It might solve the heat problem, but if the inflow to the surge tank is too low, you might end up draining the surge tank.
What you could also consider is to look at the piping from the main tank, over the lift pump, and to the surge tank. By using bigger pipes/hoses you might get sufficient flow from your existing lift pump. If you do check the fuel pipes then you should probably also take a short look at the mesh filter in your main tank:
"If your sprinter has an australian fuyel tank, then it has basically nothing in the way of cup/bucket swirl pot, just one diagonalish baffle and a little mesh filter on the end of the fuel pickup."
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Location:
Thailand
Registered:
September 2005
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Fri, 07 October 2005 08:59
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Sorry for hijacking your thread.
I have made up my mind. I'll rip out the in-tank pump, increase pipe sizes, and put a 2-hand (there are lots here) in-line pump just after the main fuel filter. That will leave me with a single-point-of-congestion, the fuel filter.
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Sat, 08 October 2005 01:31
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i was under the impression the surge tank was to prevent surge while cornering, especially when converting from carb to efi as carb tanks usually (to my understanding) have limited baffling.
if i were to run no surge tank as suggested, sure i could run a high flow lift pump to the VL pump and all would be sweet until the lift pump was momentarily starved of fuel, hence starving the VL pump.
a VL fuel fump will flow 2.3L/min at 36-40psi equating to 138L/hour. i did a bit of hunting around and a P4070 carter fuel pump will flow 272L/hour at 4-6psi and cost $117.50. so this lift pump will give me nearly twice as much fuel to the surge as what a VL pump can use. ill probably got get this pump today. but with such fuel flow i wonder if it would heat the entire contents of the main tank
and in regards to the tank, the pick up in the tank appears to have been modified (tank was already in a converted car) with a larger than standard pipe running straight to the bottom of the tank and no filter on the end. but as mentioned im running a fuel filter before the lift pump (low pressure filter not EFI filter) so its unlikely anything is getting to either of the pumps.
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Sat, 08 October 2005 10:10
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Just re-read your post, hence this edit.
From my "studies" the surge tank is there to provide a fuel buffer, especially in carb -> EFI converted vehicles. A normal carb will have a "built-in" surge tank. Most carb engines were supplied by an engine driven mechanical pump. The flow from that pump will pick up as the engine revs, hence the need for the buffer.
I dont know about the bafflers. I have one in my tank (I saw it today), but has been partly damaged during installation on the intank pump. My engine can be starved during cornering (1-2 secs), but only if I am down on 10-15% fuel in the tank (and I hardly wait that long to refill)
BTW, i had my Van at the garage today. When we removed the main fuel tank, there were about 200-300g of silicone in the tank!. Being there for some time it had turned into a couple of big jelly fish. No wonder that my engine would be starved after a time.
We removed the intank pump and installed a inline bosch pump. Before getting to that pump, there is a new mesh filter that I can check and replace when needed. What we also found was a "bend" return hose that basically prevented return flow to the main tank.!
Now everything have been replaced. Now I have: suction from the tank (no intank filter). An inline filter (a Mercedez plastic mesh filter). A Bosch inline fuel pump. An additional fuel filter (1/2l canister. I dont know if it is official Toyota). The fuel rack. The return flow.
After the first test drive all problems are gone and the engine is at full power under all conditions.
I wonder from where the silicone came. I dont think it is from the garage that did the conversion (far too much). I have a feeling that I might come from a refill at a new gas station with newly installed pipes and pumps. But anyway, I am happy that I got rid of my "jelly fish".
EDIT:
(I saw a nice mod in the garage today. A BMW 535 with a 1J Twin Turbo engine. The engine work was very nicely done. I asked for the price and got a surprise... 290K Thai Baht which equals about 8K US$. Considering....!!! (It needs painting, someone gave it a "key" work). But very cheap).
[Updated on: Sat, 08 October 2005 10:37]
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Sat, 08 October 2005 14:43
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EVOSTi
You can wellcome me in the club. LOL. I had a LONG test run, and sure, when the fuel gets hot, the inline pump starts to run into problems. My new pump does not stop, but gets VERY noisy. The moment the fuel cools down (the feed), the noise is gone. I am going to have it checked tomorrow, but they have to solve a bigger problem first. They did not seal the cap of the main fuel tank properly. I just made a full tank (to get some chilled fuel) and I got a swimming pool (of gas) under the car. T_T. Not too bad, I park on a slight slope, so it will be OK for tonight. But you are probably right, hot fuel might kill the inline pump. And in my case there are for sure no dirt left.
There must be a solution to the heat problem, but it would look stupid if you have to put a heatsink on the pump. LOL.
Get back to you tomorrow.
[Updated on: Sat, 08 October 2005 14:44]
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Sun, 09 October 2005 09:01
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i got my carter lift pump yesterday, its a big heavy bastard but flows nearly triple the amount of the VL pump. once i have that installed (next few days) ill take it for a long drive on a hot day and see how it goes.
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Location:
Thailand
Registered:
September 2005
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Mon, 10 October 2005 06:52
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i dont think that would be a good idea, i think its best to leave it be.
and my VL fuel pump is not overkill on the engine infact its running around its limits. ok sure when its idling and off boost (most of the time) it might be overkill but when on boost its only just enough.
went to enzed, they didnt have a fitting i needed so cant put pump in today, will do so tomorrow.
also, pump got a bit noisy again today on way home, felt the surge tank and it was warm but not real warm, i reckon it could get that warm on a 35 degree + day. so returning fuel to main tank from engine may not solve the problem but it definately cant help.
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Mon, 10 October 2005 08:29
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I think that you will have your problem solved. If your VL pumps are correctly dimensioned, the new lift pump will flush out the hot return fuel (from the surge tank) and then you probably get rid of your heating problem.
My post was a more general one. If you, as in my case, might have received an overdimensoned VL pump (single pump in the system), there might be a smart way of controlling the flow to prevent it from acting as an engine coolant system
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Tue, 11 October 2005 03:26
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I talked to my garage yesterday, and YES, you can modify the pump to be multi speed. (their business is only conversions).
The signal that you use depends on your ECU. In my case I have this option:
Use the ACV signal (the manifold airflow control)
That would be a simple circut with a Resistor and a bypass relay. The pump will run on low voltage until the ACV signal get high (some 4000+ rpm) and close the bypass relay. Then the pump is supplied full power. I have to do some testing to get the right Resistor value.
Another option is to use the TT signal (but I dont remember if it is on in normal ECU work mode). That will give me signals ranging from 2 to 12 volts showing the throttle position. But in that case I would need a more complicated circut to control the Pump voltage and is probably not worth the effort.
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Location:
Thailand
Registered:
September 2005
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Location:
cambo
Registered:
May 2002
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Re: fuel pump stops when hot (again)
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Sat, 15 October 2005 04:05
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thats a big change.
ive installed my new high volume low pressure lift pump, its a big bastard! but yeah there hasnt been a hot day yet, but so far the VL pump still makes some noise tho nowhere near as bad. if i feel the surge tank its a little warm but not much, and the fuel pump isnt very warm either. so i dunno if this is due to the new instalation or just lack of a hot day but so far i think its helping. i just hope for a hot day before next week for megacruise.
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Location:
Thailand
Registered:
September 2005
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Re: fuel pump stops when hot (again)
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Sat, 15 October 2005 04:20
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Glad to hear that your problem might be gone now. A bit of noise is normal, it also depends on how you have mounted the pump. If you do not have sufficient insulation (vibration), you will get some "humming" from the VL pump. But that is easily fixed. The main point is that your pumps apparently dont stop anymore.
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