Technical Fuel consumption, black exhaust bottom + unburnt fuel smell

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Technical Fuel consumption, black exhaust bottom + unburnt fuel smell

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Hello once again,

I almost feel bad having posted a few threads about my car with different questions but I feel like there are quite a few things wrong with it (not wrong enough for a non-suspecting person to raise an eyebrow, as the car is perfectly usable, but enough for me to be alarmed). So far I’ve posted about the starter issue and have briefly touched on the poor fuel consumption (way before reading more into it) and haven’t talked about the front suspension issues as the solution is relatively straightforward there, I just need to set the money aside which I don’t feel like doing because the car isn’t worth reselling at this point and I’m only driving it for the next few months before I move out and it gets to sit in a garage for another eternity. (Yes, it’s only been driven 8000 KM in the period of 2013-2022)

Now when I started driving this car 5 months ago, I did notice that the fuel consumption figures I’m getting are nothing spectacular. It averaged around 7.5 L/100 KM which is not horrible (especially since I mostly drive in the city) but it’s not amazing either. But now during winter my consumption has jumped in the ballpark of 10 L/100 KM. Yes, it’s cold outside (not colder than -5°C), yes, I drive short distances (~4-6 KM per trip usually). But even at that, a little over or a little under 10 L/100 KM seems too much for a 1.1 liter Panda.

Other related things I’ve noticed:
- sometimes a little after I start the car and have to rev it a bit (at an uphill start for example), I can smell petrol for a few seconds; it’s a relatively rare occurrence but it’s something like every 10th start
- the bottom of my exhaust pipe is black; there is never any black smoke coming out of it, it seems to function normally but it’s something i’ve noticed; it’s also a bit rusty, i’ve attached photos of it.

So are these issues all related and what could be causing them? Are they even issues or is that completely normal behavior? I’ve read conflicting info on MAP sensors, some saying that it’s a common issue and others saying it’s not an issue at all with petrol Pandas. Where should I start?

Thank you once again in advance!


Edit: Forgot to mention there is a little bit of vibration when idling, every few seconds. Sounds like a spark plug thing, they’ve been last changed like 11000 KM ago.
 

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Smell of petrol isn’t normal except if you start the car and let it idle

Black soot in the exhaust is normal

MAP sensors rarely fail

MAP sensor giving the wrong signal due to a drop of oil on it is very common

Idle should be smooth and consistent

Take the airbox off and post a photo looking down the throttle body. Is it black, is it damp, is it oily

Might give us a clue where to start
 
To test, fill it with fuel do a long run and measure again accurately, we had a customer years ago whose fuel economy tripled on a decent run. His work drive was about 1 mile on choke, home for lunch on choke , back to work for the afternoon, then home in evening on choke! This was on a brand new Mazda.
I have a Skoda 4x4 that indicates around 10 MPG from cold, but as soon as warmed up on the dual carriageway same car shows around 38 MPG and averages in the mid 30s when checked tank for tank accurately. Most use is in a 15 mile radias.
 
I should add. The car isn’t running correctly

We need to fix these faults that we can see or smell

Smell of petrol
Lumpy idle

When the car running correctly the fuel consumption is what it is

There just too many variables to compare one set of figures against another

Do you have a scan tool
 
I should add. The car isn’t running correctly

We need to fix these faults that we can see or smell

Smell of petrol
Lumpy idle

When the car running correctly the fuel consumption is what it is

There just too many variables to compare one set of figures against another

Do you have a scan tool
I have no scan tool, neither do I have proper instruments (or skill) for disassembling a car. My hardware experience has been with electronics like PCs and smartphones, where things are on a much smaller scale and there are barely any moving parts.

I would most likely be trusting a service center to do these repairs for me, I just asked here in case to get an overall idea of what’s going on and prevent getting scammed.

Although if those OBD II scanners that are easy to find cheap online are to be trusted, I would get one and try that as a first step.
 
Sorry missed this one

Some suggestions here


You can go cheaper for a stand alone than the C reader 30001 if you want to just read and clear the codes. But it’s about as cheap as you can go with live data.

There’s usually some eBay sellers with a best offer. Chuck them a cheeky offer of £12.

If you have a android phone with Bluetooth there’s plenty of £5 options
 
Sorry missed this one

Some suggestions here


You can go cheaper for a stand alone than the C reader 30001 if you want to just read and clear the codes. But it’s about as cheap as you can go with live data.

There’s usually some eBay sellers with a best offer. Chuck them a cheeky offer of £12.

If you have a android phone with Bluetooth there’s plenty of £5 options
of course, I have all sorts of phones laying around, even with root permissions, so I’ll figure it out, I’ve seen those scanners, just wanted a confirmation from you guys to know they’re not complete trash and would actually detect whatever the car is saying

might just order one and test my luck
 
Okay, another unexpected update. I think I’m going insane, I find all sorts of things technically wrong with this car yet it runs gracefully.

There’s some coolant loss higher than normal to me. Exactly one month ago I saw that the coolant was quite below the MIN mark, so I topped it up to a bit after MIN (not quite MAX to leave it space to expand). I now decided to check it again and… it’s below MIN. again. Not quite down, it’s about on the seam between the bottom and the top part of the plastic container but it’s still below MIN.

Could it be air in the system or is yet another thing wrong with this otherwise lovely car? I notice no leaks on the ground (apart from AC condensation whenever I use that), the oil looks perfect (perfect color and viscosity, no mayo). Under the hood it looks fine, I don’t notice any pipe visibly torn (but then again, I’m no expert).

For now I’ll top it up again and watch it carefully for the next few weeks. Within the next few days my OBD2 adapter should arrive and I can see if that reports anything as well.

Cheers!
 

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On another note, I drove 24 KM inside town, then 55 KM outside town, then a few kilometers inside another town and fuel consumption seems to be excellent. I work this out to be about 5.2 L/100 KM. Even with margin of error this is no more than 6 L/100 KM which is pretty good for a Panda. So I guess it’s just my city driving that kills fuel consumption.
 

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NEED to figure out that coolant though.. :)

What colour is the coolant?
it‘s red for whatever reason (i’ve heard that they come with a blue one out of the factory, you can see the color on the picture i provided). I did a lot of research on coolants when I was buying the one to top-up, my conclusion was that color doesn’t really matter, it’s the class specification that does but most of the time blue is G11 and red is G12 or newer (with OAT). The one I got was G12+.
 
Fiat factory fill has been a pink/red OAT coolant since at least 2010.
yeah but this one was manufactured in 2006, so i’m sure it has been drained at some point.

OAT.. is better (Organic?)
yes, “Organic Acid Technology”.

from the heater ?
the heater doesn’t fluctuate, it blows steady warm air. of course it’s cold initially until the car warms up (it’s winter, after all) but after a few minutes (around 5, maybe less) the air is warm and temperature is stable. dashboard’s coolant temperature gauge is pointing exactly in the middle between H and C.

i’ll try topping it up later today and i’ll see how it goes through the weeks.
 
OAT.. is better (Organic?)
On modern cars with Aluminium cored radiators, definitely yes. The corrosion inhibitors in OAT antifreeze last at least twice as long as those in the blue stuff.

For older cars, things aren't that simple. Crucially, OAT corrosion inhibitors won't protect copper & brass, so pink coolant shouldn't be used on cars with these metals in the cooling system.

There are also more sophisticated combination products (some of which are green) which provide greater levels of corrosion protection in mixed metal systems.
 
Alright, so… we have a potential culprit for the coolant drain here, near the bottom of the radiator you can see a bit of rust (marked yellow on the second pic). It seems to be like a 100-200 mL loss for exactly 28 days. Anyone knows how much these repairs go for? Is this yet another case of “it’s cheaper to just keep pouring in a bit of coolant every now and then than to actually deal with all of the technical issues since they’re beyond economical repair”?

Important thing I should mention is probably that for the previous 9 years the car had been sitting in a… definitely non-dry garage. The air is quite wet and maybe that’s what caused the rust theres and on the muffler.
 

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Get underneath and see if the underside of these two hoses is dry:
Thermostat 08.jpg
Make sure the two tabs I've circled in red are fully up - they are pushed in to release the bottom hose connector.

I had coolant loss from this quick release connector after replacing my coolant.

I certainly wouldn't want to drive a car that was losing coolant, it can blow the head gasket if coolant drops too low.

Another common source of leaks is the coolant return pipe across the front of the engine.
 
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