Board logo

Pump Noise and no return pressure.
ken555 - 1/5/17 at 03:15 PM

Been having all sorts of problems over the last week or so.

The car will idle fine for 45 minutes, but once on the road, it runs for about 5 mile then starts to stutter/stop.
Dip the clutch and the revs pick back up.

I suspect the pump has had it, removed the pre-filter to check it was getting enough and still the problem is there.
How noisy are peoples external pumps ?





not the lack of return flow/pressure on the 2nd video.

theconrodkid - 1/5/17 at 04:50 PM

sounds like it,s sucking air

ken555 - 1/5/17 at 05:31 PM

But where from ?

Takeoff at bottom of tank, pump level with it.
A small pre-filter, which I've removed and same effect.

About 3" of fuel pipe, which I've replaced, each side of filter before pump.

I would expect there to be a leak of fuel, if it was sucking air in a hole.

britishtrident - 1/5/17 at 09:31 PM

Check the tank air vent is clear , symptoms fit the pump trying to pull against partial vacuum in the tank.

ken555 - 1/5/17 at 10:26 PM

Tried running with the filler cap off, no difference.

I have ordered a new pump to be safe.

But stripped the system down tonight, tried the pump in a bowl of petrol, powered by a PC power supply.
All appeared fine, connected it all back up, but with the pump hanging under the tank, and again powered by PSU.
Plenty of pressure and flow.

Now waiting for the residual pressure to disperse so I can disconnect the feed to the fuel rail to mount the pump back where it was.

So either its a power problem (Its fed via a switched relay, so I don't think so) or something was causing an air lock.

The pump is just mounted with a couple of large "jubilee" clips, just tight enough to compress the foam sleeve, level with the bottom of the tank. Can't see that being a problem, but going to leave them loose until I test it.

We'll wait and see tomorrow night.

[Edited on 1-5-17 by ken555]

theconrodkid - 2/5/17 at 07:31 AM

is this the Bosch type pump with the large inlet ?,i made the mistake of using a too small tank outlet (converting from carb to injection using same tank) causing the pump to struggle,remember these pumps suck at sucking,other than that still sounds like it,s sucking air,got any clear fuel pipe so you can see if there are bubbles coming through ?

Schrodinger - 2/5/17 at 08:08 AM

You have checked that there is actually plenty of fuel in the tank?

ken555 - 2/5/17 at 03:09 PM

Plenty of fuel, had added another 25 l to be on the safe side.

The pump has 10mmx1, in/outlet I have them fitted with M8 hose tails.

jeffw - 2/5/17 at 04:27 PM

Do you have a fuel pressure gauge? If not, you should as it will save you hours of fault finding.

So, to be clear, you have it connect as

Tank
filter
HP pump
fuel rail
FPR
return to tank?

with the fuel pump controlled by the ECU?

jeffw - 2/5/17 at 05:34 PM

I reckon it is a fault regulator which is not opening and causing the pump to run at max pressure all the time.

ken555 - 2/5/17 at 07:50 PM

quote:
Originally posted by jeffw
Do you have a fuel pressure gauge? If not, you should as it will save you hours of fault finding.

So, to be clear, you have it connect as

Tank
filter
HP pump
fuel rail
FPR
return to tank?

with the fuel pump controlled by the ECU?


Yes

Tank
40 micron filter
HP pump WALBRO GSL393
Pipe to engine,
10-20 micron filer
Fuel Rail with FPR on end
Return pipe to tank. feeds in about 5" from the outlet.

Pump fed from a relay, controlled by switch on dash, with inertia switch for safety

ken555 - 2/5/17 at 07:52 PM

quote:
Originally posted by jeffw
I reckon it is a fault regulator which is not opening and causing the pump to run at max pressure all the time.


Was another idea, last night when it did work, I sucked on the vacuum line to the regulator, and you could hear the pump working harder.
But I do wonder if it was sticking once warm.


Don't have a pressure gauge, but will try borrowing one.

jeffw - 2/5/17 at 09:21 PM

Is the FPR adjustable? It would explain some of the symptoms if it was set wrong. I've found it best to use a specific pressure FPR.

jeffw - 2/5/17 at 09:40 PM

quote:
Originally posted by ken555

Yes

Tank
40 micron filter
HP pump WALBRO GSL393
Pipe to engine,
10-20 micron filer
Fuel Rail with FPR on end
Return pipe to tank. feeds in about 5" from the outlet.

Pump fed from a relay, controlled by switch on dash, with inertia switch for safety


The relay should be controlled by the ECU as it will only run it when the crank signal is seen....stop the engine and the fuel pump stops.

ken555 - 2/5/17 at 09:59 PM

quote:
Originally posted by jeffw
I reckon it is a fault regulator which is not opening and causing the pump to run at max pressure all the time.


We may have a semi-winner.

Connected the compressor to the fuel feed line (Pressure is pressure, no matter if liquid or air) , and the FPR opens at around 36psi, according to the Honda manual the allowable range is 33 - 39 psi.

Connected everything up and no noise from the pump and a good flow from the return.



I now also have noise from the FPR that I didn't have before, a sort of gurgle/hiss/flow sound.



Everything is back together the way it was, nothing has changed.

So I wonder is with sitting the FPR had gummed up and somehow has cleaned it's self out with the little flow that there was.
Car has been sitting, with only the odd start/idle.

[Edited on 2-5-17 by ken555]

mark chandler - 2/5/17 at 10:41 PM

Bit of rubbish floating around in the tank blocking the inlet would also explain it, power down the pump and it drops away.

If you have a bare tube in the tank it needs a fish mouth end so something flat cannot block it, better still a corse filter over the end as well.

jeffw - 3/5/17 at 05:20 AM

Great, pleased it is working again.

ken555 - 26/6/17 at 09:22 PM

It worked for a while, and on the way to my MOT gave a few splutters, then had a nightmare on the way home.

Decided to swap the pump, and on removing the hose tails to fit to the new pump, found this inside the pump inlet.



Swapped the pump to be sure and will wait and see.

ken555 - 27/6/17 at 01:10 PM

So not pump related

Run fine last night, then happened again on the way this morning.

Wonder if it's a vapour lock, due to design, the feed/return runs down the same tunnel as the cooling pipes.

jeffw - 27/6/17 at 01:28 PM

Check your fuel filters, if that is what is in the pump inlet what is in the filters?

ken555 - 27/6/17 at 08:36 PM

Filter are clear, pre-pump.

Happened on the way home tonight again, even with a full tank.

Tank was cool to touch. after about 2 miles of jerking it cleared and run the 10 more miles home ok.

Going to fit a clear fuel filter pre-pump to see whats happening on the intake and going to remove the fuel regulator for a look at it.
Also planning to run some air backwards down the fuel pipes to check for blockages.