VW Lupo 1.7 problems

[Jlshepherd]

Hi, I have a 2002 VW Lupo 1.7 SDI.

Recently it has started blowing out black soot from the exhaust when I start it up. Also when it is idle the rev counter drops to below 1000 rpm and then back to 1000 rpm and the engine sounds as though it is about to cut out.

Also when driving in a low gear, the car will start to 'chug'.

Furthermore when driving on a dual carriageway or motorway it will struggle to get to over 60 mph.

This seems likes alot of problems, do you have any idea what they may be or maybe it just needs a service as the service notice has come on?

Thanks in advance

[Dblock]

air filter and fuel filter clean?

[Skezza]

air filter and fuel filter clean?

definitely sounds like it could be a fuel filter issue. I think you're supposed to change them every 15k miles but I know people who leave them in for 20k to 30k miles which isn't too clever.

It's easy enough to replace, look left in your engine bay, you can't miss it.

As dblock says, check your air filter while you're at it.

Edited September 12, 2013 by Skezza

[Mini_ash]

mine is the same i start it and mine stuggles at 70and will not go over 80

[James827]

check for a blocked air filter. lack of power and black smoke, blocked air intake somwhere

[Jlshepherd]

Thanks for the quick responses, so basically all that I need to do on it is replace the fuel filter? Is this a job that can be done easily or should I take it to a mechanic?

In regards to the air filter, how would I check that to see if it is blocked?

Thanks again.

Edited September 13, 2013 by Jlshepherd

[Skezza]

Thanks for the quick responses, so basically all that I need to do on it is replace the fuel filter? Is this a job that can be done easily or should I take it to a mechanic?

In regards to the air filter, how would I check that to see if it is blocked?

Thanks again.

This was the best photo I could find of a SDI engine bay (yes it's a rubbish photo)

Fuel Filter is the thing the looks a bit like a baked bean tin to the left of the induction kit.

Both reasonably easy jobs to do

[Jlshepherd]

This was the best photo I could find of a SDI engine bay (yes it's a rubbish photo)

Fuel Filter is the thing the looks a bit like a baked bean tin to the left of the induction kit.

Both reasonably easy jobs to do

Brilliant, thanks alot! Just picked up a new fuel filter, will attempt that once the engine's cooled down and will post to let you know if it was indeed the problem.

[Mini_ash]

dont forget to fill it so you dont need to get the air out of your injectors

[Jlshepherd]

Just finished taking it for a run after changing the fuel filter, I revved it up and clouds and clouds of black smoke came pouring out for about a minute or 2, then it cleared and it started running better, took it for a run around and it seemed to be performing better, was no longer chugging when in a low gear and when idle it maintained revs. So I just wanna thank you for your help, and ask is it worth changing the air filter even though the problems seem to have cleared?

Thanks

[Mini_ash]

if you dont know when it was last done might as well

[Dblock]

I would change the air filter just incase.

[lupoluke]

Do the oil and filter too while your there, routine maintenance makes all the difference and is often overlooked.

And just to add LOL at that filter.

[Foogzy]

Take the egr apart and give it a good clean aswell. I had a vauxhall tigra with a similar thing , and I took the manifold off and blasted the inside with carb cleaner , cleaned out the throttle and it made a huge difference aswell , diesels can get funky if not kept clean

[GeoffD]

yup, that's what I was about to say. be careful not to drop any shite into the intake though. if its chuggy you could also remove the black intake manifold at the back of the engine and clean it out. the four pipes going into the engine get gummed up, virtually closing the intakes. now, some people remove these and it's supposed to make the engine rev better-it's up to you, but cleaning them will definitely help BUT REMEMBER DON'T LET ANYTHING GO DOWN THE INTAKE PORTS as this may cause your engine to lock up, nasty, geoff

[Dblock]

Take the egr apart and give it a good clean aswell. I had a vauxhall tigra with a similar thing , and I took the manifold off and blasted the inside with carb cleaner , cleaned out the throttle and it made a huge difference aswell , diesels can get funky if not kept clean

Do sdi's even have a throttle body?

[James827]

ish, i think its to do with EGR, its what the filter is clipped onto on that picture. it doesn't seal well, i guess it just helps to warm up.

[Dblock]

ish, i think its to do with EGR, its what the filter is clipped onto on that picture. it doesn't seal well, i guess it just helps to warm up.

I thought that was the anti shudder and run away valve?

[Foogzy]

I'm not upto scratch on diesels .. but y would it not have a throttle body ? I know every petrol does ...

[Foogzy]

N how else is a diesel meant to get air into the engine

[Dblock]

I'm not upto scratch on diesels .. but y would it not have a throttle body ? I know every petrol does ...

I'm no expert so could be wrong. But petrols generally have an air to fuel ratio. Stoich is when there is the right amount of air to petrol. Too much air your running lean so less power and hot and too little your running rich which means wasting fuel generally but still has its uses.

With diesels it didn't have an air to fuel ratio like petrol. It works on high compression so the cylinder fills as much as possible ok the intake. Then only the amount of diesel is added changes. E.g. Full cylinder of air and a little diesel = slow acceleration maybe foot on the pedal a little. Full cylinder of air plus a lot of diesel= more power. That's different to a petrol where the throttle body governs the amount of air. Technically a diesel engine is simple since it only has 1 variable.

[Jlshepherd]

Bump.

So the problem didn't go away and in the end I had to take it in to the garage, I left it with him and he said he would take a look at it. He tried a few things but the problem persisted so he decided the best option was to replace the engine. We brought a new one (45000 miles) and he fitted it however he told me today that the problem still remains, how can that be? Is it a case of just needing a good run through or could the problem not have been directly linked with the engine?

Any help would be great as he's driving me insane!

Thanks

[Dblock]

Fuel pump?

[Bigplum]

Get a New mechanic first , run away from one you used to misdiagnose the engine ,

[GeoffD]

no fuel pump on the sdi, but the diesel lines from tank to engine can suck in air, which is a big problem. when the car is running can you see any bubbles in the clear pipe beside the engine? also check the tightness of the fuel filter connections. and what happened to your old engine? as the problem didn't seem to lie there. geoff