Fuel pump problems

[chrispitman]

I have a 99 chimaera its been layed up awhile when I put the charged battery on at first it wouldn't turn over not sure if the immobilizer was messing about but after a few goes it turned over but wont start. The fuel pump dosent make its normal whine its getting power 12v disconnected and drops to 9v across the pump when connected I can feel it move when power is connected/disconnected but not the normal whine its like its jammed can this happen? Is there a pre filter between pump and tank that could cause a problem. I swapped the two relays on the loose loom made no difference. Any idea which fuse is the fuel pump? And if pump was jammed why its not blowing?

Anyone know best place for replacment or the part number?

[taylormj4]

chrispitman said:

I have a 99 chimaera its been layed up awhile when I put the charged battery on at first it wouldn't turn over not sure if the immobilizer was messing about but after a few goes it turned over but wont start. The fuel pump dosent make its normal whine its getting power 12v disconnected and drops to 9v across the pump when connected I can feel it move when power is connected/disconnected but not the normal whine its like its jammed can this happen? Is there a pre filter between pump and tank that could cause a problem. I swapped the two relays on the loose loom made no difference. Any idea which fuse is the fuel pump? And if pump was jammed why its not blowing?

Anyone know best place for replacment or the part number?

Not aware of any other filter than the big one that is up in the chassis above the fuel pump. If it's drawing load (12V collapsing to (9V) and trying to move but not running, it sounds like it is jammed or failed. Not sure what goes on these, if it is windings or bearings but I reckon your diagnosis of failed pump is probably correct.

[Loubaruch]

There is a plastic filter within the fuel tank but unlikely to be your problem with modern fuels. I recently removed mine when relacing the fuel lines and after 60,000 miles there was little to no evidence of anything on the filter.

As previous post suggests, faulty pump. IMHO always worth carrying a spare as not the sort of thing your RAC/AA etc patrol man would carry in the event of an on road failure.

[Loubaruch]

Another thought.

If you have a poor connection (i.e high resistance) in the fuel pump wiring (numerous plug/sockets)that would also cause a voltage drop. To eliminate this connect 12 volts direct from your battery (long cable) to the pump.

If the pump then whines normally you know the problem lies in the loom.

This could help:

http://www.bertram-hill.com/fuel-pump-schematic.ht...

[chrispitman]

Thanks for the replies that wiring diagram is useful the cable colours change so many times!! When the battery is charged I will trya direct across pump see what happens still think it is jammed.

Anyone know the part number are they lucas or bosch not taken it off yet guess its marked under bracket.

[Belle427]

Tvr parts etc keep them, go for a Bosch unit for reliability. Copies are available for less but you take a risk with them.
http://tvr-parts.com/tvr-parts/part-details/tvr-l0...

[Aussie John]

My pump did something similar so I removed the pump and kept filling with petrol and draining it out; a very small bit of crap came out and its been going well for 2 years.

[Steve_D]

The pump is a rotary vane design like this...but with 4 vanes.
https://en.wikipedia.org/wiki/Rotary_vane_pump

During your layup it is possible one or more of the vanes are stuck in the rotor and are not flying out to touch the side of the pump housing.

Steve

[chrispitman]

Thanks for the info I will get it off and have a look.

[Oldred_V8S]

Loubaruch said:

Another thought.

If you have a poor connection (i.e high resistance) in the fuel pump wiring (numerous plug/sockets)that would also cause a voltage drop. To eliminate this connect 12 volts direct from your battery (long cable) to the pump.

If the pump then whines normally you know the problem lies in the loom.

This could help:

http://www.bertram-hill.com/fuel-pump-schematic.ht...

Definitely try this first.

In lay-mans terminology. The voltage at the pump connection (with the pump switched on) should equal, or almost equal the voltage at the battery posts (with the pump switched on). If not you have a faulty supply and/or earth. Wouldn't want you to buy a pump without checking the above.

[chrispitman]

Pulled it off this afternoon was jammed not spinning have managed to get it spinning after giving it a good bashing!! but its not pumping fuel guess the vaines are stuck inside, so looking like a new pump.

[chrispitman]

Before I order a new pump I'm guessing its just gummed up from being sat for awhile, wondered if there was an chemical cleaner I could try soaking it in to see if it frees up?

[Paulprior]

How about trying to spray carb cleaner inside, I guess that's designed to disolve the gunk coming from petrol after its stood a while

[IVANHOE]

Its not worth messing about with, you can get a new one from Euro Parts for about £30

Part numbers will be on here Chris

http://www.chimaerapages.com

[blitzracing]

You can spin the pump backwards by reversing the connections, it can be enough to kick any stuck bits out of it.

[Steve_D]

blitzracing said:

You can spin the pump backwards by reversing the connections, it can be enough to kick any stuck bits out of it.

I've done that with success.
Completely submerged it in a tray of warm water and washing up liquid.
Ran it backwards and forwards several times which produced quite an array of ste.
Drained it out and ran it again with some light oil then connected it back into the fuel system.

Steve

[chrispitman]

Ok thanks guys will give those tips a try, it was jammed have it spinning now but think the viens are gunked up maybe a soak will help.