Fuel Pump Problem

[William2]

Getting ever closer to starting my S4 after restoration, I put fuel in the tank. With spark plugs removed I cranked the engine over but no sign of fuel pumping through in glass bowl of pump. Removed the carbs and pipes from the fuel pump and gently sucked on inlet pipe from the tank. Good news, fuel came up the pipe ok.
Pump is obviously at fault. Rightly or wrongly, I took the decision to leave the pump bolted to the block and remove the screws that hold the glass bowel assembly to the diaphragm. The pump separated easily and then I twisted the diaphragm 90 degrees and removed it and the large spring from the pump part. Couldn't see anything obvious wrong but the pump was secondhand and the diaphragm looks a bit dodgy.
I had another pump which I have stripped down and I was intending to use the upper valve/bowl assembly and the diaphragm as it loos to be in better condition. However, I have noticed that the oil seal in the pump part (still attached to the block) looks split at the top and also when I tried inserting a screwdriver blade into the pushrod hole and crank the engine over I can't feel the pushrod lever going up and down.
My Elan doesn't have the optional rubber blanking grommet in the transmission tunnel grp opposite the pump so I assumed there may not be enough room to remove the pump from the block to strip it down if this is necessary. Am I wrong in saying this? Also, if I did try and remove the pump I gather there is a danger in replacing it with the jack shaft in the wrong position. Not sure of the best way forward. Any help greatfully received!!

[ericbushby]

Hi,
When my pump developed an intermittent fault, I fitted a new one.
I had no difficulty removing it except for the usual limited access.
It does not matter what position the shaft is in , but it does matter that the operating lever goes above the shaft.
You can tell it is above because you will have to press the pump downwards to locate the screws.
Best of luck
Eric in Burnley
1967 S3SE DHC

[nmauduit]

From a quick reading I did not follow all of it, but if the fuel pump has not been overhauled, you may check on the condition of the (essential) 2 valves by being able to blow in one direction (towards the carbs) and not the other.
I understand that the action of the pump rod is not huge, that may explain why it is not visible (to be confirmed).

Then if you are eager to get going (I know I would be) there is always the option to stick an electric pump in series somewhere along the line, to address that mundane issue of later...

good luck !

[alan.barker]

take the pump off the car and test it by hand. You can remove the pump test it and refit in an hour with a bit of swearing

[Chris]

Why not remove it permanently, and fit a Facet electric pump and regulator. After enduring problems with the mechanical pump ie. Stuck valves etc. I fitted a Facet, and it transformed the car, no more fuel vapour problems or wet plugs after standing idle for lengthy periods such as all winter, just turn on the ignition wait 10 secs until the pump stops ticking, meaning the carbs are primed pull the choke for instant starting. I should say my car has Delorto carbs.

[alan.barker]

hi Chris,
sorry but i have dellorto carbs on my elan sprint and never use choke. Two pumps like with webers and starts. Just a little reminder if you have an electric pump you should fit a solenoid valve to cut off fuel in case of accident. With the mechanical pump in an accident, engine stops, no fuel being pumped everywhere
Alan

[billwill]

I think you mean an Inertia Switch as in many cars or a VW Fuel Relay which acts as a watchdog because it requies a stream of pulses from the ignition circuit to stay closed.

You don't need a solenoid valve as such if you are able to cut the electricity to the electric fuel pump, since that will act like a solenoid valve.

[Grizzly]

If your using the Glass bowl original pump its worth taking the top off and fill up the center with fuel then try, my fuel pump wouldn't pull fuel through when it was dry.

Also worth pre filling the carb float bowls.

[jk952]

Just a couple of two cents worth, I recall when putting in a rebuild kit the diaphram is to be pressed down when tightening the body screws so it can have sufficient movement, this would be difficult if in the car. Also just a thought is the block spacer the correct thickness, as would affect stroke obviously? The valves are just held in with side peans so valve could dislodge if not secure enough.

[William2]

In the end I removed the pump from the engine block and fitted a new diaphragm kit and followed the workshop manual. I was careful to make sure the pump lever arm was seated on top of the jackshaft cam. I have read warnings saying you must make sure this is done, but it looked to me as though it would be difficult to put the pump back on the block with the arm underneath the jackshaft. Here's hoping my lever is correctly seated as I hope to try and get the pump to successfully pump fuel through tomorrow.

[alan.barker]

I think you mean an Inertia Switch as in many cars or a VW Fuel Relay which acts as a watchdog because it requies a stream of pulses from the ignition circuit to stay closed.

You don't need a solenoid valve as such if you are able to cut the electricity to the electric fuel pump, since that will act like a solenoid valve.

o.k. we can say inertia switch imho i think it is needed because in an accident you can be unconscious and petrol being pumped everywhere. But it's your choice
Alan

[billwill]

Ouch misunderstanding here. My post was ambigous.

I meant that YES you do need some means to stop the flow, but NO it does not need to be a SOLENOID VALVE. Stopping the electric fuel pump with either an Inertia Switch or a VW Fuel Relay is enough.

So I'm in agreement with you.

[rgh0]

In the plus 2 at least the higher fuel tank means that the fuel will flow though an electric pump under gravity if the fuel lines in the engine bay are damaged so you do need a cut off solenoid valve.

cheers
Rohan

[jimj]

I`m well aware that with the original mechanical pump the engines always need some cranking to pull the fuel through if the car hasn`t been used in a while. Apart from that, what`s the problem? I`ve never heard of anyone breaking down with a faulty mechanical pump and yet, personally, I can think of more than a handful of occasions when pals have had trouble with electric pumps. Many people I know carry spares and some older cars even came equipped with a spare one bolted on, ready.
Add in further issues with wiring, switches and valves and, for me at least, it`s a complication I can do without and I wouldn`t recommend that the original poster go down that route.
I`m no purist but it does seem, quite often, that original is best. So many queries on Lotuselan.net (not this one)relate to problems with so-called improvements.
Jim

[gus]

Oh let's see,

excess cranking

horrible access

troubleshooting[this thread for instance, troubleshooting over in 30 seconds]

I have lost one electric pump in 30 years, due to alternator dying, over voltage killed pump and later electronic ignition

virtually every car on the planet now has an electric fuel pump and I think the concept has proven itself to be reliable.