Lupo 1.0 sluggish/ EPC rabbit hole.

[Shanks255]

Hey guys,

I’m hoping one of you can help me out because I’m honestly at my wits’ end here.

I successfully completed the charity car rally I was planning on doing last summer—ended up doing about 10,000 miles in a month in my 1.0 Lupo with only the fuel pump giving out. Since I’ve been back, though, the car’s had a few issues.

It all started on the journey home when the car would randomly lose all power. Restarting it would fix the issue, and it wasn’t happening often, so I just ignored it. Then more recently, the auxiliary belt snapped while I was out and about. I managed to limp the Lupo home and changed the belt. But that’s when the real issues began.

It’s been noticeably down on power ever since, and it won’t rev above 4000 rpm. It just cuts all fuel, even if I’m flooring it downhill. So far, I’ve replaced the front lambda sensor (since I’d had a lambda code for the last year anyway), the exhaust manifold, the MAP sensor, and the oil pressure sensor. After doing the exhaust and the oil pressure sensor, the car does seem to run smoother with what feels like a little more power, but I’m still having the same main issues.

The car is:

• Still down on power

• Won’t rev past 4000 rpm

• Occasionally throws an EPC light and loses all power

The problem is, I haven’t been able to pull any error codes, and now that I actually have a code reader on me, I can’t get it to throw the EPC light again.

I’m not sure what to try next. Maybe cleaning the intake manifold might help? It’s just hard to diagnose anything with no fault codes to go off of. Could it be a fueling issue? I genuinely don’t know anymore.

Any help from someone wiser than me would be massively appreciated.

Thanks a bunch,
Shanks

[ObjectiveAway]

Hi, a lot of options, you should get code reader.

Is your alternator charging? Might be diode rectifier is goner, then the more its charging the worse it gets.

Might be ground between car and engine is damaged.

[Shanks255]

12 minutes ago, ObjectiveAway said:

Hi, a lot of options, you should get code reader.

Is your alternator charging? Might be diode rectifier is goner, then the more its charging the worse it gets.

Might be ground between car and engine is damaged.

I've just checked the voltage on the battery and it's 14.37 while running so looks like the altinator is good. 

I've got a half decent obd2 scanner but no codes on the system. The epc light came on 2 times earlier today but when I went back out again this time with the reader I couldn't get it to throw a code for love nor money. 

I could check the ground between the engine and car. Do you know where I'd find that?

Thanks

[ObjectiveAway]

Could be also as simple as bad ignition coil.

I have replaced the engine, but I dont remember where exactly is the ground anymore. EPC comes on every time it misfires several times.

[Shanks255]

Just now, ObjectiveAway said:

Could be also as simple as bad ignition coil.

I have replaced the engine, but I dont remember where exactly is the ground anymore. EPC comes on every time it misfires several times.

Doesn't sound like it's misfiring to me and I forgot to say the ignition coil was the first thing I replaced.

[mk2]

Fuel? As in not enough. Can you read live data while driving? Look at the O2 numbers.

Else it also sounds like cam belt may have jumped a tooth.

Cutting out is often crank sensor.

[Shanks255]

21 hours ago, mk2 said:

Fuel? As in not enough. Can you read live data while driving? Look at the O2 numbers.

Else it also sounds like cam belt may have jumped a tooth.

Cutting out is often crank sensor.

I'll try looking at the o2 numbers if I can read them. I think I remember being able to see voltages. What should it read? And what could I do about fueling other than replacing the new fuel pump? I've already done the filter. 

 

And how would I check the cam belt is in time? Is it those dots I can see on the top cog.  It could be that as I did find a big chunk of aux belt in the timing belt enclosure. 

for £15 it might be worth changing the sensor to see if it helps. Idk how much of a bitch it is to remove tho. 

 

Thank you!

[ObjectiveAway]

On 4/13/2025 at 9:05 PM, Shanks255 said:

 It could be that as I did find a big chunk of aux belt in the timing belt enclosure. 

 

You can check timing by removing covers and cranckshaft pulley, then rotate the engine to match both marks. I don't advice to replace good parts before you do this.

 

Edited April 15 by ObjectiveAway

[Shanks255]

6 minutes ago, ObjectiveAway said:

You can check timing by removing removing covers and cranckshaft pulley, then rotate the engine to match both marks. I don't advice to replace good parts before you do this.

 

Amazing, I'll give this a go and cross all my fingers. I'm lucky to have a donor engine for parts but it's on twice the milage so I'm not sure how much I'd trust parts from it. It's gotten to the point where I've changed like 5 parts I've thought it could be to no avail . Crossing fingers for this tho. 

[mk2]

Depending on which gearbox you have, you can see the zero TDC marker on the flywheel through an access hole in the gearbox bell housing, at the top. Often it is under a plastic or rubber cover to keep dirt out.

Put the car in top gear to turn the engine (by pushing the car). 👍🏻

[Shanks255]

4 hours ago, mk2 said:

Depending on which gearbox you have, you can see the zero TDC marker on the flywheel through an access hole in the gearbox bell housing, at the top. Often it is under a plastic or rubber cover to keep dirt out.

Put the car in top gear to turn the engine (by pushing the car). 👍🏻

Yeah I've got that cover. What does seeing the engine at tdc show me?

[mk2]

So you can check the cam timing without taking everything to pieces...

 

[Shanks255]

2 hours ago, mk2 said:

So you can check the cam timing without taking everything to pieces...

 

Ah OK, so I'll line up tdc with the mark on the cam gear then. Thanks

[Shanks255]

I couldn't see any marking on the fly wheel but I could see the one on the camshaft gear. As you can see the engine is slightly out of time. What would be the easiest way to slacken the belt enough to be able to match up the top gear? Ik there's a tensioner I should slaken but I can't get the bottom cam cover off because one of the bolts is being blocked by the aux belt pulley. I could pull off the aux belt and try but I wanted to see what the consensus was on the easiest way.

Thanks. 

Edited April 14 by Shanks255

[Shanks255]

UPDATE

Its fixed! Turns out it was the timing belt that had jumped a couple of teeth. I prised it off using a pry bar and then did the same in reverse while pushing the car 😭. 

 

@mk2 thank you for suggesting it was the timing belt you've singlehandedly saved my sanity. And thanks to everyone else for your suggestions. Idk where I'd be without this forum . 

[mk2]

If you keep car, I'd change the belt and tensioner. Then it'll be good for another 6 years or 50k miles. 👍🏻

Sounds like a good little car. Any more pics- in and out?

[Shanks255]

22 minutes ago, mk2 said:

If you keep car, I'd change the belt and tensioner. Then it'll be good for another 6 years or 50k miles. 👍🏻

Sounds like a good little car. Any more pics- in and out?

It's been one hell of a work horse and I've got to be honest I've not been kind to it thrashing it around Europe fully loaded roof tent and all. I'll find some pictures from my camera roll and take a couple tomorrow when it's light and post them. 

It's definitely earnt some love so I'm goign to tart it up this summer and get it in good shape, hoping this thing lasts another 20 years. As for the timing belt it's had a new one a couple of years and about 20 odd thousand miles ago so should be good for a while. Or until I can afford the insurance on an engine swap. 

[ObjectiveAway]

Im always glad to see someone who is not only asking questions but also doing real work, nice job! 🦾

For the next time – it is very easy to replace the timing belt with a floor jack under oil pan, just remove all engine mount bolts on this side of engine and jack the engine up and down as much as you need to access everything, no need to put hands in small gaps at all.

[Shanks255]

1 hour ago, ObjectiveAway said:

Im always glad to see someone who is not only asking questions but also doing real work, nice job! 🦾

For the next time – it is very easy to replace the timing belt with a floor jack under oil pan, just remove all engine mount bolts on this side of engine and jack the engine up and down as much as you need to access everything, no need to put hands in small gaps at all.

That's a good plan. Would make it a lot easier to access. But I'm touching wood it's a while before I need to do that.

Next on the list is replacing the snapped coil spring. Then maybe upgrading the rear coils and dampers to ones from a golf as when it's loaded the cars on the bump stops, and it would be nice if it wasn't lol. 

[Shanks255]

On 4/14/2025 at 8:08 PM, mk2 said:

If you keep car, I'd change the belt and tensioner. Then it'll be good for another 6 years or 50k miles. 👍🏻

Sounds like a good little car. Any more pics- in and out?

I've attached a few photos of the car during the rally. It's been amazing, and the amount of stuff you can cram into one of these is astounding, including a 240ah leisure battery and an inverter in the spare wheel well for unlimited tea, and a fridge😂. But 23 mpg flat out at 75mph is pretty dire, though, so looking to swap the engine for a diesel.

In an ideal world, i's do a 3l swap to it as I love those engines and their fuel economy. But sadly, those engines aren't super cheap, and then manually swapping them after diesel swapping is quite a bit of work and uncertainty. So, as it stands, the plan is either the 1.4tdi or 1.7sdi. I've read that they both get similar mpg, but with the TDI being more powerful makes it the obvious one to go for. Despite this, though, I've got my eye on a crash-damaged 1.7sdi with the open-air roof that I'm hoping to convert mine to be open-air. I've also got my eye on a Lupo trailer that matches my car's colour, which I think would be pretty sick for shows and stuff.

 

So I guess my question is:

Despite being a bit gutless, is there any major reason not to go with the SDI?

Is the conversion pretty painless if I have a donor car?

And finally, has anyone got any experience with doing a Lupo pen air conversion and could give me some tips and tricks / fitting a towball to a Lupo?

 

As it stands, here's my list of jobs to do to the car:

install new coil springs in the front,

Replace the rear suspension with stiffer ones from a Golf (would help with towing)

Install a tow ball

Open-air conversion,

SDI swap it.

As promised, here are some pictures of Lance's tour of Europe:

[mk2]

Superb!

Well, I'm not really surprised at that fuel economy considering that slab on the roof and all that weight in the back... I bet you were hitting bumps stops all the time. Love the pics. More please! Why didn't I hear about this before you set off?!