Thread: 300 tdi problem

Originally Posted by justinc

Heres another one concerning the fuel shut off solenoid.

I hope this helps someone, because I am not likely to see anything like this again, thank goodness. It took a while to find and rectify.


The symptoms were 300Tdi manual D1, driven hard, it would jerk, like the key being quickly turned on and off. Fuel solenoid thought I. Checked it, it clicks, it shuts off and turns on, can't fault it. Engine NEVER stopped completely, just violently jerks when pushed hard, even worse when cold.
Check wiring harness for problems, IE wiggle tested every inch all the way to the ignition switch, still nothing. I even ran a straight 12 volt jumper wire from the battery and it STILL did it.
Couldn't duplicate it AT ALL unless driving.
So, I removed the fuel solenoid and inspected it. All OK, or so it seemed...
Gasses and fluids can induce a sideways pressure, called bernoullis principle, where a fast moving fluid or gas can cause a negative sideways pressure, like how a spray gun works. When demanding more fuel flow, the coil in the stop solenoid was too weak to hold the plunger against the combined spring pressure and fuel flow rate, sucking it closed and momentarily shutting off fuel flow. As soon as the flow stops, the valve pops open again and so on.
I replaced the tested 'OK' solenoid, and all is now OK.


Made the brain cells work a bit that one.

JC

The earth strap can also cause similar symptoms if it is carrying resistance in the lead or has bad corrosion.

Ive had it a couple of times on machines but never on the Landy.....yet.

As far as the manual fuel shut off, I doubt there is one available commercially but if you have an old one you could drill a hole in the back of it and connect a rod/cable and see if it would work or keep it for a spare in the kit.

Originally Posted by justinc

...The symptoms were 300Tdi manual D1, driven hard, it would jerk, like the key being quickly turned on and off...

So, I removed the fuel solenoid and inspected it. All OK, or so it seemed...
Gasses and fluids can induce a sideways pressure, called bernoullis principle, where a fast moving fluid or gas can cause a negative sideways pressure, like how a spray gun works. When demanding more fuel flow, the coil in the stop solenoid was too weak to hold the plunger against the combined spring pressure and fuel flow rate, sucking it closed and momentarily shutting off fuel flow. As soon as the flow stops, the valve pops open again and so on...

JC

On my trip to Sydney last year I had the same symptoms on the Defender, only when going up hill (long climbs) at 110kph. It happened 2-3 times, never since. I put it down to a poor connection on the cut off solenoid, but now there's something else to think about. - Thanks.

re the VE pump manual shut off, my old Fiat tractor uses either a CAV rotary pump (which is what we have) or a Bosch rotary pump with a manual rod shutoff.
The photo in the manual isn't easy to make out, and it doesn't really look like a VE pump, but not sure.

Originally Posted by rick130

re the VE pump manual shut off, my old Fiat tractor uses either a CAV rotary pump (which is what we have) or a Bosch rotary pump with a manual rod shutoff.
The photo in the manual isn't easy to make out, and it doesn't really look like a VE pump, but not sure.

I just looked at a VE manual pdf. The models equipped with manual shut offs are completely different and have two manual shut off levers mounted in another part of the pump. So unfortunately it isn't as simple as a manual shutoff screwing into the housing. Bugger.

...

Originally Posted by B92 8NW

I just looked at a VE manual pdf. The models equipped with manual shut offs are completely different and have two manual shut off levers mounted in another part of the pump. So unfortunately it isn't as simple as a manual shutoff screwing into the housing. Bugger.

The question I would ask is, why would yoou want a manual shut off?

Originally Posted by slug_burner

The question I would ask is, why would yoou want a manual shut off?

Well if it came down to it and the soloniod failed, the question is, would it not run or not shut off.

If not run, it could be a problem for if the soloniod failed, as well as you could run a Tdi minus any power from the battery all together.

I havnt looked into it that much so I havnt got any answers Im sorry.

Dave may be able to help, he's much more up to date with this stuff.

its a fiddle with the pump in situ but you can remove the stop solenoid, take out the plunger, replace the housing and voila electricless 300tdi, clutchie to go and stall to stop...

I have done it once when trying to test a similar problem to Justins... in my case it would have been a whole lot quicker to check all the fuel line connections and find the leaky one!!!

S