Hi guys out there somewhere,

I'm struggling with an unwilling brandnew fuelpump. Just build in my new engine with bigbore and lots of new parts - among them a new Valeo fuelpump - trying the first start-up without positif result ; new engine so enough compression, sparkplugs working leaving air-fuel mixture as most likely missing item. taking off the fule-line entering the carb and starting the engine : no fuel being pumped out !?!

next test performed was with the help of some one else : blowing by mouth in the fuel filling opening resulting in squirting fuel out of the fuel-line, so no debris of obstruction in the new fuel-line or pump.

Am I missing something here ? what did I do wrong or forget ??

only thing I can think of is the lenght of the pushrod and/or thickness of the thick gasket underneath the fuelpump. Anything that can be measured of the length of this pushrod and how far it should stick out in low and high position ?

I would appreciate your collective wisdom and suggestions - thanks in advance !

Did you refit the spacer between the pump and the engine?

Hi Neil , yes - the spacer is between engine and pump.

new pumps are rubbish ive seen plenty just not able to pump.

there were 2 types of pumps available - cheap one & more expensive Valeo - because of my suspicion of cheap rubbish I bought the Valeo ...

is there any info of correct sizes of the pushrod and how far it should stick out on top of (or below) the tich spacer / gasket ?? couldn't find any info in my primitive manual.

There was a batch of pumps around in the UK a few years back which often stopped working shortly after being fitted.
When I opened one up, instead of the thin fibre diaphragm you'd usually find in the valves, they'd used hard plastic discs, which could tip and fail to seat correctly.

As regards the details of pushrod, projection above base 'gasket' at lowest point of the stroke and length of stroke...
For a late 602 engine, they're 110.6 to 110.7mm, 1.2mm & 2.6 +0/-0.16mm.

Putting a pump in a bucket of liquid (water?) with a length of pipe pointing upwards and moving the operating lever by hand is a 'quick and dirty' test, mind you.

try another pump

thanks Ken ;
I will take the pump out, do the measurements of the length pushrod . About the position of the pushrod : is this how much the pushrod sticks above the spacer / thick gasket as shown on the picture ? I'm not quite how to measure this ?? Could you perhaps explain some more detailed ?

Next I will do the test in a bucket of water to see if it does pump at all. Final option is to take the old (but definitaly working) pump off the old engine - do the same measurements.

And yes Ajay : final option is to mount this old pump, for which I'm sure it works

I'll keep you posted of my findings.

Hi Azuiper,
the picture in Citroen's manual isn't really clear enough to copy, but they'd placed a depth gauge on top of the pushrod, measuring from its highest edge to the top surface of the spacer.

Thinking about it, the only reason that measurement could change was if the length of the pushrod or the thickness of the spacer was incorrect.
I've certainly never checked either of them, but I have checked the output pressure of more than a few pumps, which should be 2.5 to 3 psi...

Update : today I removed both the old pump & the new one to do some measurements

old pump & gasket :
- length of pushrod 110.65 mm (correct)
- spacer/gasket 9.9 mm
- stroke 1.9 mm (measured 90 degrees to the mountinsurface = appr. 45 degrees angle)
- no functioning test in a water bucket (this pump was functioning fine a few days ago)

new pump & gasket :
- length of pushrod 110.70 mm (correct)
- spacer/gasket + paper gasket 10.55 mm
- stroke 1.7 mm (measured 90 degrees to the mountinsurface = appr. 45 degrees angle)
- functioning test in a water bucket oke - squirting like hell
- pushrod in lowest position = 1.5 mm above spacer/gasket (manual : should be at least 1.2 mm)

I opened both pumps to have a look at the inside, both look oke, valves mounted coorectly, old pump with white fiber ? disc - new one with black fiber? disc

conclusion so far : both pumps seem to function oke, only difference is the thickness of the package of spacer/gasket of 10.55 - 9.9 = 0.65 mm. Is this difference of 0.65 mm so critical to the functioning of the pump ??

Unlike the manual says I will put the pushrod in the highest position when mounting the old pump to the engine so I should be able to feel that the pushrod is "pushing" the lever of the pump.

to be continued ...