Help !!! Knocking sound 1993 3Ltr

[johnsiddle]

Hi Guy's


Just went shopping with wiffy and ran out of fuel in my tank2 (veggie) the engine stopped at a roundabout.
No problem I thought I will switch to tank1 (mixture veggie/diesel) sure enough the engine started OK.
As I pulled away I could hear a loud metalic knocking sound not unlike a big end.
Tickover sounds OK but rev the engine and there it is very loud, but it sounds too high up in the engine to be bigends. I think.

Before it ran out of veggie it was running OK with normal oil pressure (about middle when motoring). Temperature is normal.:

I called the AA who didnt think it is bigends but could not offer any other ideas other than to airlift me home.

Thanks to breakdowntruck for pointing me to where the new thread link is.

Anyone have any ideas before I strip it down.
I thought I would start with the rocker cover.

[johnsiddle]

Sorry wrong year

Sorry the car is 1995 3LTR the 93 was my old 2.4.

[charvell]

sticky injector, you may be using too much veg, try just derv on a quater tank with a full bottle of redex

[biosurf]

Just as an aside, if you are twin tanking isn't the point to have pure diesel in the first (smaller) tank to use in the system until uo to temo and to flush the system at the end of the journey to ensure there isnt any veg to gel in the fuel lines?
Just seems if you have a mixture in this tank it defeats the object of twin tanking?

If you are not twin tanking and just have a full size auxillery fuel tank then I'll get me coat

[johnsiddle]

Re

I like the injector angle.

Its been running Ok most of this winter on 95% veggie ( high quality RAPE) and was running perfectly on 100% veggie just before it ran out. It always starts in seconds no matter how cold it is, just a bit lumpy for about a min.

I have three heaters fitted, a tank heater (A 15mm water heated copper ladder inside the Landy tank2) a fuel filter coil wrapped round the veggie filter and a coaxial type heater a foot long just before the injector pump. The veggie is pumped up from tank2 via the filter into a swirl tank and mixed with the hot return veggie from the injector pump.
The wvo really runs like diesel.
john

[johnsiddle]

twin tanks

You are right but I have only just finished plumbing the second tank in and still have a mostly full tank of mixture in the original tank.

The most diesel I could fit earlier in the week was 10ltrs so I have been running both tanks down, I need to sort out the tank sender in the landy tank cuz when I connected it to the surf guage it always reads empty.
So I thought I will wait until the tank2 runs out then I can take the sender out and check it.
Well it ran out today, it obviously was telling the truth cuz it ran out today.

Hence the mixture in tank1.
John

[POPEYE]

Sorry to hear this mate, only just caught up with the thread in mods, as Charvel said, run on derv with redex and perhaps a lt or two of auto trans fluid, should free/clean things through quite well, when i overdid the mix my pump started leaking but no knocking but i did'nt run out of fuel, maybe thats the prob, expect your engine was hot at the time?

[johnsiddle]

Yippee !!!

Thanks guy's really good advice.

I got a 250ml bottle of diesel redex today, drained my swirl tank and put the whole bottle in and topped up with about a pint of diesel. I disconnected the feed to the tank2 pump.

Set it running on tickover with the occasional blip of the throttle.. KNOCK KNOCK!!!
It ran like this for about 30mins, before the swirl tank ran out I gave it a really long and high revs blip of the throttle and as if by magic the knocking faded away.

the tickover is much more smooth now, before it would jump all over the place even before it failed.
Not a sign of a knock anywhere.

I have to tell you I was worried I have heard bigends knocking and this really sounded like they had gone. I would never have thought that an injector could make that sort of loud metalic hammer sound.

I am thinking that my tank2 fuel pump is not much good cuz I am still getting veggie from that tank just not at a high rate. So I am going to search around for a high power fuel pump.

Thanks again
John

[darkdezigns]

glad yr sorted and yes they can be very loud

[POPEYE]

Glad you got it sorted, mines knocked slightly at times and you always think the worst,
as for the fuel pump i remember bj went through a couple of regular fuel pumps and both were incapable of handleing cold/cool veggie, i think he settled on a 12v caravan water pump in the end and that did the trick, i did have the link to a seller (nafin expensive tho) post it if i can find it, they were cheaper from the US but if you get collared for import tax they aint cheaper! rock and a hard place