Veg oil Xantia power loss on Motorway

jgra1 · Post by **jgra1** » 14 Jan 2008, 09:57

hi all, well finally I picked up my green S2 bonnet/bumper from Leeds on Sat, some journey from Kent and back again!

Car now looks exactly as it's supposed to, at last...

Also picked up Exclusive alloys and Black Leather (estate) interior. Rear seat backs bolt down differently to the hatch models, but I am going to remove my rear carpet and see if it's possible...

Anyway, I thought as I am doing 500 miles in one hit, with ambient temp around 10C, I would run more SVO than the usual 50/50.. I put in 36L oil and about 10L Diesel..

Car was perfect for 400 motorway miles, but approaching Newport Pagnell services it suddenly started to loose power. A combination of what felt like misfiring, and general powerloss, on full throttle and car still slowing....

anyway, managed to keep it running at 50 Mph for a few mins, then it felt better again.. and so it went on, slowing, then speeding up.. All the world like fuel starvation... Fuel warning light wasn't on so had over 10L in tank..

Stopped at services and out of desperation put straight diesel in, and after lots of turning over, it chugged back into life, never to go wrong again..!

been fine ever since.

Only thing I can think of is, that many motorway miles without corners, means SVO and deisel could seperate? Maybe I was low enough on Fuel to be pulling only SVO in? Tank contents should have been well warmed by fuel returns for 3 hours... not really convinced by this theory..

Any thoughts?
John

Xaccers · Post by **Xaccers** » 14 Jan 2008, 12:48

I've run 100% svo in less than 10C conditions without problems (other than the hunting when it first starts so I don't hang around with it idling.
Could be fuel filter blockage, or fuel sender filter blockage, or even a block on the return pipe (TehAgent had one of those until CitroJim blasted it clear with some compressed air).
Diesel being less viscous is more likely to be able to get past any partial blockages.

Pop the fuel return pipe off the pump and see if you can blow down it, once the blockage was clear in TehAgents, it was possible.
Check your fuel filters.

Post by **CitroJim** » 14 Jan 2008, 12:57

You know the story of the Bermuda Triangle John. Well, we have our very own Newport Pagnell Triangle hereabouts.

It's all a cunning plan to bring custom to the Newport Pagnell Services...

You should have given me a call...

It was, I recall, pretty chilly on Saturday around these parts. It was beautifully sunny but savagely cold. My thought is that yes, there is a good possibility the veg and diesel settled out and that it was cold enough, given wind-chill as you're motoring along, to bring the veg down to it's cloud point and not far off its Cold Filter Plug Point (CFPP). This is where wax crystals of sufficient size form in the veg to plug the fuel filter.

All your symptoms point to classic fuel starvation. You'd have thought the fuel heater below the fuel filter would have warmed it sufficiently but I guess it was overwhelmed.

It took a bit of starting after filling with diesel as it was necessary to drag up enough diesel to melt the veg in the filter and unplug it.

I'd swap your fuel filter soonest John, all that sucking by the pump against a plugged filter may well have damaged it, apart from that, no harm done.

Post by **CitroJim** » 14 Jan 2008, 13:03

Sorry, it took sooooooo loooooong to submit my post that it crossed with yours Xac and repeats roughly what you said. Sorry

But yes, what Xac says is most valid. A blocked return will eventually cause the pump and filter housing to leak, especially down by the white bit (the filter thermostat).

Xaccers · Post by **Xaccers** » 14 Jan 2008, 13:03

Ah didn't spot the Newport Pagnell part!
Obviously your car sensed the presence of the mighty Jim and tried to force you into visiting.

KP · Post by KP » 14 Jan 2008, 14:37

As mentioned above it seems more like a fuel filter/ fuel pipe issue as ive run near 100% SVO on my 1.9td without any issues, just stick to at the most 5k miles before swapping the fuel, oil and air filters as well as the engine oil and you should be fine.

Also what was your engine temp? does it warm up enough as it could be not enough heat is being dumped to the filter housing if the stat is stuck open it could be loosing all its heat to the rad and not the veg first off? Just a thought mind you

jgra1 · Post by **jgra1** » 14 Jan 2008, 14:56

thanks all, yep pretty certain Jim was up to something, think he wanted the leather seats!

Jim haven't your number, but the way I felt after all those hours on the road, a wait for (another) breakdown truck would have killed me! Hadn't even had breakfast by this point , 7pm!...

Um, tried to add to my initial post to say that oil fuel and air changed 2 weeks ago, or now about 1000 miles.. but gave up after 20 mins attempting to post..

Engine temp varies quite a lot with speed, up to 90C at indicated 85, and down to 70 at 60ish..

But it was 200 miles into a journey, or thereabouts..

Will investigate the pipework and have a look in filter soon..

John

KP · Post by KP » 14 Jan 2008, 16:08

Also check the filter type as i saw a post about some generic ones from GSF coming apart from the metal top

The only other thing i can think of is water in the fuel maybe? try draining some off and seeing what amount of water there is in the filter housing?

Post by **CitroJim** » 15 Jan 2008, 08:09

jgra1 wrote:thanks all, yep pretty certain Jim was up to something, think he wanted the leather seats!

Your seats were quite safe John, I'm not into leather

To be honest, I don't much like the swede ones in my 2.1 either. Now If I heard about a nice set of early MK1 velour seats or a set of velour Activa seats, you'd not see me for dust...

KP wrote:Also check the filter type as i saw a post about some generic ones from GSF coming apart from the metal top

Good point KP

There was a batch of counterfiet green plastic Hengst filters in circulation a while back that used to break up. They also used to swell and lift the filter housing lid and admit air

I was unfortunate to have had two of them...

On a general note, anyone passing Newport Pagnell on a long journey are always welcome to pop in and have a cuppa. Just PM me before you leave.

jgra1 · Post by **jgra1** » 15 Jan 2008, 10:18

thanks all

well..
I never made it home last night... this time the fuel was getting low, the light had been on a while, and the car stopped shortly after going uphill..

same symptoms...

Friend brought a gallon of deisel (nexxus on FCF) over for me kindly..

Tried to start it and at best (after 50 turns) it would idle roughly at 800rpm.. any throttle would use up whatever little fuel was about and stall it...

I did take the fuel filter housing cover off, the filter was there looking as good as new.. primed the bulb and out came clean diesel, with fine air bubbles in...!?

anyway, got it to idle, and left it for 6 minutes until we were sure it wouldn't stall.. rope towed it 5 miles home.. a few hills .. back on level ground, revs went back to 1000 and car has been perfect ever since.. drove it 10 miles today no probs

Am starting to think the fuel gauge and light are both erratic (more than usual

) will run car now and never let it get below a 1/4 tank and see if it's all ok again..

John

Xaccers · Post by **Xaccers** » 15 Jan 2008, 11:31

It's never a good idea to let veg or even diesel get to low.
Large volumes of liquid retain their heat better.

I had a genuine Hengst fuel filter fail on me before, so I'll never use them again.
It was an open bottom one, and the filter paper was held in with silicon glue.
This came away and started breaking up.
Thankfully the filter paper stopped it getting to my pump, but I'm stucking with metal bottom ones.

steelcityuk · Post by **steelcityuk** » 15 Jan 2008, 13:35

Hi,

Is the tank pick up clean, I had problems with my XM and when I checked the tank filter was half blocked with something brown and slimey.

Steve.

jgra1 · Post by **jgra1** » 15 Jan 2008, 14:38

thanks Steve, will check..

J

XantiaMan · Post by **XantiaMan** » 15 Jan 2008, 16:15

steelcityuk wrote:Hi,

Is the tank pick up clean, I had problems with my XM and when I checked the tank filter was half blocked with something brown and slimey.

Steve.

Echo... mine was like this and caused the engine management light to come on intermittantly because there was air locks in the fuel pipes.

mrbump · Post by **mrbump** » 17 Jan 2008, 22:35

Could be the old case of the veg 'cleaning' out the tank. you get lots of crap coming up the lines and basically giving the pump a much harder time to draw the fuel through. Then it manages to find any little air leaks in the fuel lines that you wouldnt normally. Try running a transparent hose (carb hose) from the filter to the pump to see if you are getting air bubbles next time it happens. Other than changing the lines, a gallon of unleaded(!) in the next full tank of diesel/oil may help to blow it all through. Then change the filter again!

I hope you dont have a lucas pump....

I dont think a whole tank of veg would get cold enough to cause problems as there is always a good supply of 80 deg c return, enough to keep the tank at a good temp.