Cold engine start - strange accelleration - low power

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steve2286w said:
ha I thought that’s where the breather would normally go, the dipstick wouldn’t bend easily to fit original place so chopped a bit old ally front floor up for the bracket, I never chuck things out, used a couple more pieces off floor to repair both rear wing bottoms.
Just starting to come round to the idea of clear outs now I’m retired and got more time :D
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Ah but hours/days or weeks after you throw it out, guaranteed you wll need it!
 
discomania said:
That doesn't sound right at all from what you have written and your video.

The 300tdi is a good engine, mine will pull 80mph up a steep motorway I sometimes drive on, it is almost an annual test to see how things are, if it romps up this hill in 5th then I know shes in good form.

There are just so many things this could be, fuel starvation is one of the simplest things I am thinking here.

If it was mine I would check fuel flow first. With the engine running I would undo the bleed nipple on the filter housing and expect a constant flow of diesel shooting a good 8-9inches across the engine bay, I would then expect the same from the bleeder on the pump. If I did not see this at either I would start looking into the fuel system probably first with a new filter just to be sure then go from there.

I have had many a fuel issues over the years of Landy ownership and my own top 3 issues with my vehicles were:

Shot lift pump.
Piece of silicone in the pickup pipe in the tank.
Massive air leak on the suction side drawing loads of air but of course not leaking diesel which made it a pest to find.

It could then become more complex, like injection pump issues etc. etc. but start simple. Prove good fuel flow.
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So, I just checked the fuel flow. When undoing the bleed screw while the engine is running, the diesel barely trickles out. There is definitely no shooting of diesel or any high pressure. Pushing the hand priming lever with the bleed screw undone seems to do absolutely nothing.

To me this sounds like the lift pump is gone, and that the injection pump is providing all the (minimal) suction. Is that correct? Is there any harm in still driving it before I can replace the lift pump?


EDIT: That doesn't make sense what I wrote. As there is fuel coming out of the bleed screw, the pump must be doing something. With only suction from the injector pump, there would be no fuel coming out. The situation still seems odd to me.
 
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ZeHerman said:
So, I just checked the fuel flow. When undoing the bleed screw while the engine is running, the diesel barely trickles out. There is definitely no shooting of diesel or any high pressure. Pushing the hand priming lever with the bleed screw undone seems to do absolutely nothing.

To me this sounds like the lift pump is gone, and that the injection pump is providing all the (minimal) suction. Is that correct? Is there any harm in still driving it before I can replace the lift pump?


EDIT: That doesn't make sense what I wrote. As there is fuel coming out of the bleed screw, the pump must be doing something. With only suction from the injector pump, there would be no fuel coming out. The situation still seems odd to me.
Click to expand...
When the lift pump went on my 200tdi, it would take about 15-20secs of cranking before it would start, it ran fine when it did start. As fine as I am aware, the engine should run fine with just the injection pump, providing it is in good nick and set up correctly.
Just to add, my duff lift pump didn’t work at all, the lever that pumps the diaphragm was no longer connected to the diaphragm and so did nothing.
 
ZeHerman said:
So, I just checked the fuel flow. When undoing the bleed screw while the engine is running, the diesel barely trickles out. There is definitely no shooting of diesel or any high pressure. Pushing the hand priming lever with the bleed screw undone seems to do absolutely nothing.

To me this sounds like the lift pump is gone, and that the injection pump is providing all the (minimal) suction. Is that correct? Is there any harm in still driving it before I can replace the lift pump?


EDIT: That doesn't make sense what I wrote. As there is fuel coming out of the bleed screw, the pump must be doing something. With only suction from the injector pump, there would be no fuel coming out. The situation still seems odd to me.
Click to expand...

As I suspected sounds like typical fuel starvation, start at the tank and prove everything now. I may also be tempted jus to stick a lift pump on for the sake for £20 but perhaps they are not as easy or cheap to get where you are.
 
Lift pumps are pants, I went through a few then gave up and fitted an electric pump, it runs pretty much the same with elec pump switched on or off, but is down on power at higher rpms with pump switched off.
I think it runs okay as the elec pump offers no resistance when switched off, but the mech lift pump has poppet valves inside which the fuel has to be sucked past by the inj pumps, so when lift pump dies it is quite noticeable as there is quite a bit of resistance for the fuel to get through, but still driveable.
Elec lift pump makes bleeding a doddle.

Copy facet pump off ebay about 12 quid.
 
lynall said:
Lift pumps are pants, I went through a few then gave up and fitted an electric pump, it runs pretty much the same with elec pump switched on or off, but is down on power at higher rpms with pump switched off.
I think it runs okay as the elec pump offers no resistance when switched off, but the mech lift pump has poppet valves inside which the fuel has to be sucked past by the inj pumps, so when lift pump dies it is quite noticeable as there is quite a bit of resistance for the fuel to get through, but still driveable.
Elec lift pump makes bleeding a doddle.

Copy facet pump off ebay about 12 quid.
Click to expand...
What pump did you fit? What are they key parameters to look out for (pressure, mass flow, etc.?) Might consider fitting an electric one for now. And what's the most convenient place to take the 12V line from? Diesel selenoid?

A new delphi pump will set me back around 45 pounds here.

What's the best way to find other tiny leakages along the fuel line, should this not solve the problem? I already have some clear pipe to test this out, but will need to wait a little longer before I have the time to install it.
 
The pump was a cheap ebay Facet copy and was approx 12 gbp/euros delivered.
It has not missed a beat in 6 years.
I think I just wired it to an ign live via a switch on the dashboard.
Also made an alloy blanking plate for the engine block from scrap 6mm alloy sheet.

Screen Shot 2021-11-10 at 19.55.46.png


Screen Shot 2021-11-10 at 19.58.07.png
 
The cheap ones dissolved on my bio, fine on pump diesel. Facet fine on bio.
Supposed to mount them near the tank but I fitted mine under the driver's(rhd) tool box of my 110.
The threads on the facet are 1/8" BSP so I fitted two 1/8" bsp-10mm brass compression fittings, cut the flow line and bobs yer uncle.
 
Would it be a wild idea to install an electric lift pump in series after the mechanical one? As long as the mechanical one doesn't leak, it seems like a reasonable idea to me. That way failure is less significant. Or does an electric pump typically seize up when it fails, blocking the flow?

Also, is there any maximum pressure/flow rate that should be observed with an electric pump to not overload the injection pump?
 
They fail open flow so no restrictions, 4psi is fine.
The manual pump would have one way valves in I would guess, you'd have to get them out maybe?.
The flow fuel lines are 10mm OD so with some 10mm nylon tube, available everywhere, and some 10mm compression fittings you could bypass the manual pump and connect a facet but return it to original later if you wanted.
 
I would say the idle sounds very low,

How much slack do you have on the throttle cable at the fuel injection pump?

Have you tried adjusting the throttle idle position?

Cheers
 
Flossie said:
They fail open flow so no restrictions, 4psi is fine.
The manual pump would have one way valves in I would guess, you'd have to get them out maybe?.
The flow fuel lines are 10mm OD so with some 10mm nylon tube, available everywhere, and some 10mm compression fittings you could bypass the manual pump and connect a facet but return it to original later if you wanted.
Click to expand...

Not sure I understand your one way valve comment. The way I figured the lift pump works is it sucks fuel into a chamber with each stroke, and then pushes it through a one way valve towards the filter. But because the one-way valve is in the flow direction, adding an additional fuel pump before/after should still work, no?

Regarding idle speed: I haven't checked it. What effects would a low idle speed have though? I have a cheap Chinese laser rev counter somewhere, so might check with that on the weekend.
 
Valves- yes, probably correct.
I just don't know how a facet will 'cope' with the extra effort of holding the valves constantly open against their spring returns.
I dispensed with the manual pump completely, facet straight to the filter in clear nylon, same with the return line but 8mm OD for that. Clear is useful for checking for air etc.
 
Flossie said:
Valves- yes, probably correct.
I just don't know how a facet will 'cope' with the extra effort of holding the valves constantly open against their spring returns.
I dispensed with the manual pump completely, facet straight to the filter in clear nylon, same with the return line but 8mm OD for that. Clear is useful for checking for air etc.
Click to expand...
Excellent. I'll decide how to do it over the coming days so. Why did you replace the return line btw? Also to check for air?
Got myself some clear 8/10 mm pipe, so will be using that when fitting the electrical pump. Ended up going for a slighly different design to the facet pump, as it was more easily available here.
 
Clear return helped me diagnose a problem of my own making once.
Mines a disco 200tdi conversation and the old pipes needed extending and I had plenty of the clear pipe left.
 
Finally found some time to fit the new fuel pump this weekend. Just started preparing everything, and was wondering how to best reach the old fuel pump to remove it? It seems to be in a pretty tight spot. Any advice on how to get better access?

Also, how critical is it to blank off the hole it leaves on the engine block? Would a temporary solution out of tape work fine, or is it too hot down there for tape? I don't have any tools right now to cut a nice metal cover.
 
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