Runs very bad in hot weather

[Idris]

'96 Diesel

I thought I'd had problems with runnimng a bad batch of veg oil - now 90% diesel - all filters are fine - I can instantly get a mouthful of nasty diesel when I disconect the fuel line and suck on it - the banjo filter (yes the one on the return line as well) are both clean.

Not fuel tank vapour lock as I've tried driving without the cap

Does not do this in cold weather

Today ran like fuel starvation or a petrol with vapour lock and bad plugs - would crank and crank then fire and run but after a short while would misfire and no power, but fulctuate badly, as soon as you back off all the way or idle it would die - got worse and worse and would die if revs not over 2500 - sometimes would hunt badly at idle, but with accelerator flat to the floor.

But after waiting a bit would always crank, crank then 30 sec, 2 min and restart and rev as high as I dare

Any ideas?

It has a cold start pack, which is the open position on the flap thingy, energysied (with vacuum) or without? I want to try and isolate stuff - in the next day or 2 I'll rip that contraption of the exhaust so it can't be blamed.

I'm guessing not turbo, because it ran bad in the last hot spell and then fine in the cold and now it's hot again it won't run?? The only reason I was thinking turbo is there is oil in the pipe air pipe going into the turbo (the ubend) but all my previous (Turbo deisels) vehicles dropped some oil from their turbos - any easy way to check?

Sorry if I'm rambling I'm just stuck for ideas

[BongoBongo123]

Pure guesswork.. severely blocked fuel filter ? Tut, sorry I see you mentioned that.
Cylinder head crack/ head gasket ? See any creamy stuff in your oil filler pipe or dip stick?

I think you should not 2,500 rev it anymore could be causing further damage.

[Simon Jones]

Only time I ever experienced any problems running at high revs was just prior to bango filter being cleaned. It didn't look especially clogged but afterwards it ran perfectly. Have you checked air filter and all the intake pipework especially around the turbo? It's pretty much only going to be a fuel or air problem.

[Idris]

Pure guesswork.. severely blocked fuel filter ? Tut, sorry I see you mentioned that.
Cylinder head crack/ head gasket ? See any creamy stuff in your oil filler pipe or dip stick?

I think you should not 2,500 rev it anymore could be causing further damage.

No water in the oil or vice versa - and no that its' in the cool of the evening, she starts and runs fine - there is the noise of the fuel pump cavitating some of the time.

Jobs for sunday (don't have any time tomorrow) check the banjo filter again - can you leave these out?

Open all the lines to the fuel tank and make sure they are clear, fit a booster fuel pump with a bypass valve

Remove the cold start/warmup actuater thingy and jam the flap in the open position.

Open up the intercooler plumbing and make sure there is no blocages there.

Spin the turbo by hand and make sure its free.

Anything else I shlod check? I've replaced the front and back seal on the pump (the rear one was leaking a bit).

Simon, the Air filter has 4000 miles on it and looks fine

Oh I need to check the EGR valve end of the egr is blanked, I found (after buying some plates) the small end is platedn shut.

[Northern Bongolow]

it sounds like fuel, so try taking the fuel supply pipe off the filter housing and blow back to the tank, the tank filter is known to block or restrict flow.

is the fuel pump free from leaks?? stalling on low revs sounds like air entering the pump when on low revs.

there are 2 lecky solenoids above the glow plug rail, the thin pipework on these from the vac pump can harden and break, then peeps replace the original with the wrong grade pipe, this gets soft when hot and the vac closes the pipes flat, this can put the cold start solenoids into (choke ) mode so the engine can stall/falter, check these pipes carefully.

maybe replace/check the fuel shut off solenoid switch on the pump top, maybe it sticks when hot in the shut position, check the voltage to it. they are cheap to replace.

[hijimhere]

EGR Valve? Looks like the the valve may be sticking? Same circumstances as a dump valve issue!

[Idris]

Thought I'd fixed it

EGR Valve? Looks like the the valve may be sticking?

- Blanked the EGR (thought it was already)

and

it sounds like fuel, so try taking the fuel supply pipe off the filter housing and blow back to the tank, the tank filter is known to block or restrict flow.

is the fuel pump free from leaks?? stalling on low revs sounds like air entering the pump when on low revs.

there are 2 lecky solenoids above the glow plug rail, the thin pipework on these from the vac pump can harden and break, then peeps replace the original with the wrong grade pipe, this gets soft when hot and the vac closes the pipes flat, this can put the cold start solenoids into (choke ) mode so the engine can stall/falter, check these pipes carefully.

maybe replace/check the fuel shut off solenoid switch on the pump top, maybe it sticks when hot in the shut position, check the voltage to it. they are cheap to replace.

bypassed the fuel system and pluming, tank straight to IP, disconected the winter pack/exhaust flap thingy (the only remaining solenoid is for the high speed idle/cold start), drilled holes through the fuel cap - even made sure the origional spring operated breather system works.

Ran fine for a week - today very hot and sticky (30C+) back to rough running again - but not stalling + starts on the button, before bypass she always had to crank to start??
Any ideas?

[psquiddy]

I can instantly get a mouthful of nasty diesel when I disconect the fuel line and suck on it

Is that the best way to do whatever you are trying to do?

[Northern Bongolow]

look on here, as the pipes come forward you will see part number 42-590a, this is a vent, in the pipe near it is a tiny one way valve, it clips end on to the inside of the chassis rail
it just pulls off, strip out the one way valve and clean /blow through, there is also the filling vent at the bottom of the filler hole at the 6 oclock position, blow clear with a foot pump.
the fault maybe tank pressure rather than a red herring temp issue.
i came across this one recently when the owner had been given 2 separate bills for several hundred pounds from 2 different garages for work done that had not fixed the problem.

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

[Idris]

look on here, as the pipes come forward you will see part number 42-590a, this is a vent, in the pipe near it is a tiny one way valve, it clips end on to the inside of the chassis rail
it just pulls off, strip out the one way valve and clean /blow through, there is also the filling vent at the bottom of the filler hole at the 6 oclock position, blow clear with a foot pump.
the fault maybe tank pressure rather than a red herring temp issue.
i came across this one recently when the owner had been given 2 separate bills for several hundred pounds from 2 different garages for work done that had not fixed the problem.

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

Shouldn't be possible for this to be causing an issue, have cleand and checked it - fuel filler cap has 6mm hole drilled through it.

Only does it on very hot days after running for a bit - never (even before I bypassed the fuel line and filters) did it on a cold day - drove over a 6000ft pass on 70% veg oil 4 weeks go, but was 5 to 15C, never missed a beat, fuel pump never cavatated either??

Will take the tank end one apart (there are two) and just fit a pipe to vent to atmoshphere