K-jet

[speedyG50]

Recently had some fuel pump issues on my 240 with K-jet.

Is it possible to install a "high flow" pump in the tank (with sender) .... and then feed direct to the filter, bypassing the current main pump and accumulator.

This mod was suggested elsewhere, but I suspect the accumulator is a very necessary part of the K-jet system and is only relevant for LH systems

[Clan]

Originally Posted by speedyG50

Recently had some fuel pump issues on my 240 with K-jet.

Is it possible to install a "high flow" pump in the tank (with sender) .... and then feed direct to the filter, bypassing the current main pump and accumulator.

This mod was suggested elsewhere, but I suspect the accumulator is a very necessary part of the K-jet system and is only relevant for LH systems

well they did it with the later 940 but that runs at a fairly low 35 psi pressure . K Jetronic is a much higher pressure of about 75 psi so you might be hard pressed to find one as a main in-tank pump..
The accumulator has 2 functions , It compensates for any slight loss of fuel pressure when turned off , it keeps the full pressure up for at least 20 minutes afterwards , this prevents vapour locks and long cranking to start in hot weather .
The Accumulator also holds a small reserve of fuel to compensate for cornering with a near empty tank , it will keep the engine going if small amounts of air are picked up by the tank pump and circulated around the system .

Best keep it standard I think !

[Stephen Edwin]

Originally Posted by Clan

well they did it with the later 940 but that runs at a fairly low 35 psi pressure . K Jetronic is a much higher pressure of about 75 psi so you might be hard pressed to find one as a main in-tank pump..
The accumulator has 2 functions , It compensates for any slight loss of fuel pressure when turned off , it keeps the full pressure up for at least 20 minutes afterwards , this prevents vapour locks and long cranking to start in hot weather .
The Accumulator also holds a small reserve of fuel to compensate for cornering with a near empty tank , it will keep the engine going if small amounts of air are picked up by the tank pump and circulated around the system .

Best keep it standard I think !

How about the proposal that has been reputably made in the forum to replace both pumps with one in tank pump.

Would that be something one could connect to the accumulator so as to retain the benefits of the accumulator?

Does the answer vary between K jet and LH?

[Clan]

Originally Posted by Stephen Edwin

How about the proposal that has been reputably made in the forum to replace both pumps with one in tank pump.

Would that be something one could connect to the accumulator so as to retain the benefits of the accumulator?

Does the answer vary between K jet and LH?

K Jetronic is completely different in all ways to the electronic LH …

Yes you could use a HP pump in the tank as long as you get one which can deliver over 100 psi at full load , not that common I would think , then the line from the pump in the tank to the accumulator needs to cope with 100 + psi rather than the 25 psi of the low pressure feed pump for LH
A new LP pump in the tank would be more simple and probably more reliable than a modification .

[Stephen Edwin]

Originally Posted by Clan

K Jetronic is completely different in all ways to the electronic LH …

Yes you could use a HP pump in the tank as long as you get one which can deliver over 100 psi at full load , not that common I would think , then the line from the pump in the tank to the accumulator needs to cope with 100 + psi rather than the 25 psi of the low pressure feed pump for LH
A new LP pump in the tank would be more simple and probably more reliable than a modification .

Thanks Clan.

My 240 doesn't have a fuel pump issue so far. I do think it important to keep the remnants of my mind (NOT a joke) prepared.

Thanks again.

[speedyG50]

Clan...
thank you for taking the time to give a comprehensive and understandable answer to my query. I knew it was to maintain pressure, but had no idea about it's other functions.... so appreciate the education and I hope others benefit from it too.
You're right of course, best not to meddle at all.... standard it is
Thanks ... and all the best

[Clan]

Originally Posted by speedyG50

Clan...
thank you for taking the time to give a comprehensive and understandable answer to my query. I knew it was to maintain pressure, but had no idea about it's other functions.... so appreciate the education and I hope others benefit from it too.
You're right of course, best not to meddle at all.... standard it is
Thanks ... and all the best

you are welcome its a very reliable and simple system self calibrating , I used it on a 1 litre turbo engine in the 1980s and it ran well . They used it on ford escorts and VW Golfs , and the german cars in the 80's , I think volvo developed it for the 1974 140 ! I cant think of anything else that used it back then .