Hello guys, after the pump has been checked be THE reputable shop and the injectors replaced with new ones we still ended up with 3 holes in different pistons and 3 seized pistons. Then we discovered that the return valve on the diesel pump was seized up. At the rear on top of the diesel pump there is a banjo bolt that tightens the return pipe banjo. There is two pipes coming out of the banjo. That banjo bolt has got a metal ball and spring that acts as a valve. As soon as you switch of the engine the pressure in the pump pushes the diesel back to the fuel tank. If the valve is seized it goes through the injectors filling the sump causing piston seizures and holes in the pistons. Mine got stuck and caused a lot of trouble and cost a lot of money! I'll post a pic tomorrow. I really hope this post saves somebody a lot of time and money.
Interesting! Never heard of this before but definately sound like it might be the answer to some strange reported hole in pistons on some engines and others going on to run super mileages without any similar issue.
Probably not too costly to replace I suppose?
CATS
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Probably not too costly to replace I suppose?
CATS
Sent from my LG-H815 using Tapatalk
CasperA / Cats,
........ or to service/check it once in a while.
Cloyd
........ or to service/check it once in a while.
Cloyd
I have just phoned Google. The Gen4 has one on the pump and one on the rail. The rail pressure limiter opens at 2,210 bar - 1000 times your tyre pressure. My mind is boggled. The 221 MPa didn't scare me, but converting it to bar and realising it is 10 times the pressure of my dive tank sure gets my attention.
Then I realised this pressure is held back by a tiny little valve in the injector. That valve opens and shuts 5 times for every ignition - inside an exploding cylinder.
I'm going to push my diesel bakkie home and never start it up again.
I'm going to push my diesel bakkie home and never start it up again.
I did replace it with a banjo bolt with a small orifice hole. I got it from our diesel-electric shop for free. Apparently it is fool proof. Pressure is released through the little hole. When we checked the original valve 7 bar could not move the ball valve. We managed to get it moving with a screwdriver and a hammer.CATS wrote:Interesting! Never heard of this before but definately sound like it might be the answer to some strange reported hole in pistons on some engines and others going on to run super mileages without any similar issue.
Probably not too costly to replace I suppose?
CATS
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Roelf_le_Roux wrote:Then I realised this pressure is held back by a tiny little valve in the injector. That valve opens and shuts 5 times for every ignition - inside an exploding cylinder.
I'm going to push my diesel bakkie home and never start it up again.
