Technical Fuct FIAT '93 1.0 i.e. FAILED MOT on emissions

[jo0lz]

Well its a 1993 Uno 1.0 i.e. with an '89 block+head+dizzy with '93 SPI+CAT+Exhaust and a K&N filter fitted
Just failed its MOT on emissions results as follows
[oh and a front flexi brake hose, but that's easy to fix]

FAST IDLE TEST
Description . . Min . . .Max . . . Actual
CO . . . . . . ----- . . 0.300 . . 0.519 FAILED
HC . . . . . . ----- . . 200 . . . 100 PASS
Lambda . . . 0.970 . . 1.030 . . 1.011 PASS

SECOND FAST IDLE TEST
Description . . Min . . .Max . . . Actual
CO . . . . . . ----- . . 0.300 . . 0.600 FAILED
HC . . . . . . ----- . . 200 . . . 98 PASS
Lambda . . . 0.970 . . 1.030 . . 1.006 PASS

NATURAL IDLE TEST
Description . . Min . . .Max . . . Actual
CO . . . . . . ----- . . 0.350 . . 0.464 FAILED

So the CO is beyond the limit on every test
The MOT Tester suggests it needs a new CAT
Found one on line for £75
BUT want to be sure this is going to fix the problem before I spend any money
What do you all think?

 

[alexGS]

Yes, I think it will. Even though I've never replaced a cat before, my reasoning is that your HC emissions are plenty low enough to discount a rich mixture or misfire problem. The lambda (air-fuel ratio) is spot-on.

One thing - check the exhaust system for leaks - a hole may distort the measurements and also the lambda.

The purpose of the cat is to oxidize CO into CO2, so if that's not happening, you get the symptom you have. I guess that result is 0.6%? For a non-cat car, that would be a good result (1% would be acceptable and I think the UK limit for non-cat cars is 3.5%?). Add a cat to the system and CO should drop to 0.2% if I remember rightly. This is where environmentalists get those ridiculous claims "modern cars emit 40 times less pollutants", etc. totally ignoring the fact that CO is only a tiny part of the exhaust gases! I think we should be concerned about HC, particulates, and Benzene (air quality - respiratory problems, black soot from diesels, carcinogens etc.) but instead, CO2 is the hot topic these days...

My guess is that the cat may have been contaminated by dodgy petrol or additives during your rally?

-Alex

 

[Louie Bee]

Buy my spare exhaust that I took off my Uno 1.0ie

Clean the breather pipe, throttle body and change the air filter and the oil

 

[jo0lz]

Ta for that advice guys
I think the exhaust is leaking a bit . . . so I'll check that tomorrow
I did supect it could be the CAT as the HCs and Lambda readings were spot on
Also the car was running rough on 3 cylinders [with head gasket gone] for a while before I bought it so perhaps that helped knacker the CAT


So Louie how much do want for that spare exhaust?

 

[jo0lz]

Hhhhmmmmm

Found this
http://www.motuk.co.uk/manual_730.htm

Vehicles Fitted with a different engine

Test according to which is older, engine or vehicle.
e.g. A 1995 car fitted with a 1991 engine (of whatever make), test to 1991 standards for emission purposes.

Note: The onus is on the vehicle presenter
to prove engine age.

So got me thinking 1993 Uno with 1989 engine I could argue that it has to meet 1989 emissions
BUT
Then saw

pre cat limits of CO 3.5%, HC )200ppm.

So it would still fail as one of the CO readings was 6%!

 

[rawill]

This is where environmentalists get those ridiculous claims "modern cars emit 40 times less pollutants", etc. totally ignoring the fact that CO is only a tiny part of the exhaust gases! I think we should be concerned about HC, particulates, and Benzene (air quality - respiratory problems, black soot from diesels, carcinogens etc.) but instead, CO2 is the hot topic these days...
-Alex

Don't get me started on 'environmentalists' and 'global warming' etc etc!

 

[Louie Bee]

PM sent

 

[jo0lz]

PM sent

PM rec'd
and a CoNFuSeD response sent back....
Why oh why OH WHY did the Italians have to build the Uno 45 with THREE types of CAT+exhaust in the matter of a few years :bang:

 

[alexGS]

So got me thinking 1993 Uno with 1989 engine I could argue that it has to meet 1989 emissions
BUT
Then saw
So it would still fail as one of the CO readings was 6%!

I think your reading is 0.6%.
An Uno without a catalytic converter should have no problem at all meeting the 3.5% standard. Actually I think it should be under 1%.

-Alex

 

[the mk1 kid]

Yeah, 1% is norm - my uno t does not have a cat and that can be reduced to run 1%, although i prefer it a little richer, and nearer 1.5/1.75CO

Tom

 

[Louie Bee]

Why oh why OH WHY did the Italians have to build the Uno 45 with THREE types of CAT+exhaust in the matter of a few years :bang:

To share jo0lz's findings.. with the rest of you Unoers, the early tyoe which has the cat on the down pipe and the lamba sensor on the exhaust manifold has a bottom shift (older type) gearbox.

The later types ( with Lamba sensor on the down pipe and cat on the centre pipe or integrated down pipe and center pipe) is fitted with the top shift (punto) box.

As jo0lz found out today, if you try to try and fit the later type exhaust (including manifold, down pipe, cat centre pipe and back box) to an Uno that has the bottom shift gearbox, the gear linkage fouls the exhaust :bang::bang::bang::bang::bang::bang::bang::bang::bang:


I never knew so thought I'd share that with tou all... a New Uno fact for you all there :yuck:

 

[jo0lz]

As Louie has pointed out I found out today that my Uno has the close coupled CAT for a reason :bang:
Its the only CAT that will fit with the earlier under floor gearchange
The twin downpipes of the later underfloor CAT exhaust run straight into the earlier gearchange linkages

Taking it back to the MOT Station today having cleaned up the SPI , put in new plugs, checked the idle switch and step motor plunger as well as the temp sensor on the intake mainfold were working,
[as described here]Uno Guide for SPI checks
chucked some CatACLean in the tank and ran it for 40 miles on the motorway to get it nice and hot it was still reading about twice what it should be on the CO, pretty much all the way through the rev range
Lambda was still A-OK
HC was still A-OK
Idle sounded slightly fast to me, but the Mech's Sun Machine showed it was idling between 850-870 which seems about right
Mechanic reckoned it might pass with a new CAT but couldn't be sure
So its looking like the Fuct FIAT is a gonna!
Shame as the shell is solid
Unless I just bite the bullet and spend £80 on a new CAT and pray it passes another emissions test!!
Already changed the flexi brake pipes now as well so emissions is the only item for that MOT failure now :bang:

Then again . . .
I could butcher the existing close coupled cat and replace it with one of the under floor ones I got from Louie
But getting things to line up might be a bit of a challenge!
Then again it would only cost me my time
Rather than that £80 for a new CAT
Might as well try it eh??????
So tomorrow morning I'll get the grinder and welder out . . .
Wish me LuCK ..!

 

[alexGS]

I wonder if the exhaust system off a Punto 60 could be useful - I haven't seen the Mk1 Punto systems but I definitely know the Mk2 has a manifold-mounted catalytic converter.

-Alex

 

[jo0lz]

Well had planned to dive right in there first thing this morning and butcher a spare exhaust and known working CAT to create a working system for NO MONEY to try for another emissions test

Things conspired against me, small bit of freelance work and also the possibility of work as well as a viewing and test drive of a local S Reg silver volvo [interim motor] seen on FleaBay yesterday evening. . .
[the swede was nice, BUT not italian and too much money]

In between all this in the morning I managed to find my timing light and checked the FIATs ignition timing, as the Mech had suggested, twas about 15 BDC, so obviously NOT helping much
NOW corrected

Anyway this afternoon I undertook my own version of ScrapHeap Challenge

Checked the existing close coupled CAT
A poke down the inspection hole on its top with a bit of welding wire revealed that as the Mech suspected the honeycomb had disintergrated
There simply seems to be nowt left inside in that there existing close coupled CAT

So next was sussing out if I could cut it out of the exhaust system and substitute one of the under floor CATs I got from Louie
NO GO
Too long
Measuring things up
Even if I welded the underfloor CAT [mounted vertically] direct to the exhaust manifold matting flange that CAT would be another 100mm below the exhaust going back under the sump

SO
Leave the existing duffed close coupled CAT in place
Then looked to mount a salvaged working [second] CAT under the floor
Took a while to work out where and how it would fit
Without fouling the gear linkage
Without hitting the floor
Then took quite a while cutting[grinding] and shutting[MIG welding] various bits of scrap exhaust and the 2nd CAT
Ran out of light [so no pix]
It started to rain [got damp and COLD]
BUT by the time I came in to cook tea I had it all in place, loose fitted, with all rubbers in place, and the welding done, just need to finish off with some exhaust paste and U clamps on two sleeved connections [one original and another newly bodged one] in the Jo0Lz ScrapHeap ZorsT System

 

[alexGS]

Sounds good
Nice problem-solving skills!

Pics please!

I think you should fit standard downpipes, though - don't leave the original cat in the system - at the very least, 'gut' it by removing it and knocking all the bits out. Otherwise the bits may float around and block the flow - you may as well stick a potato in the tailpipe

It's preferable not to have the big diameter change that the empty cat housing would give - would be more efficient with the twin downpipes. With the 1L engine, I think it needs all the help it can get

Is the original lambda sensor after the cat or before? I know newer cars have them both before and after. Obviously you'd have to move it if it was 'after'.

-Alex

 

[jo0lz]

This is just a temp solution to see if a new CAT will cure the CO problem
If it works I may then blow £80 on new close coupled CAT and go back to a standard/original exhaust system

[though i might just build yet another exhaust system with no CAT and side exit under the sill once I had an MOT cert . . :devil:]

Is the original lambda sensor after the cat or before? I know newer cars have them both before and after. Obviously you'd have to move it if it was 'after'.

-Alex

Original Lambda is screwed into the original close coupled CAT just after the manifold matting flange

 

[jo0lz]

Sounds good
Nice problem-solving skills!

Pics please!

OK
Here is standard exhaust system with close coupled CAT

Top of FIRE 999 engine looking down on close coupled CAT

Exhaust manifold of FIRE 999 engine looking down on close coupled CAT; lambda sensor into manifold

close coupled CAT from below

View of standard middle section of exhaust in-situ

View of standard middle section of exhaust showing close proximity of gear change rods

Standard sleeve joint at back of mid section of exhaust

 

[jo0lz]

Pics please!

Well you asked for it
So here are a load more pix of my bodge-it under floor 2nd CAT

Standard middle section at bottom of photo
Jo0lz' bodge-it under floor second CAT at top of photo

Jo0lz' bodge-it under floor second CAT in place

Jo0lz' bodge-it under floor second CAT viewed from the side

Jo0lz' bodge-it under floor second CAT viewed from the front

Used the existing sprung connection and cut and shut bits of scrap exhaust to create a very shallow 'S' in the pipe to drop the 2nd CAT lower to miss the floor and away from the gear change

So done all this
The sleeved connection behind the 2nd CAT is a bit too bodged at the moment as I was in a rush to get back to the garage for another emissions check this afternoon
So rather than weld that connection it was sleeved, exhaust gummed and u clamped
By the time I got to the garage that dodgy joint was already blowing

Anyway ran another test
HC OK
CO now OK :slayer:
FAILED on lambda; but we know this was becasue of the leak as the previous tests showed the lambda to be A-OK

SO tomorrow I can weld up that dogdy sleeved joint properly so we have no leaks and go for an MOT retest and hopefully a PASS

 

[alexGS]

That is a TOP effort! :slayer:

I'm really impressed with the quality of your welding ESPECIALLY if that was done with a MIG welder! And also the care taken to align the catalytic converter (your 'S' bend section). This is nowhere near as much of a bodge as you imply, and I think it speaks volumes that the leak was at the horrible split-pipe-pushed-together join that comes from the factory (if anything's a bodge, it's that). I've had problems with that join as well. And the last time I tried to weld an exhaust, it was a huge cobbled mess that leaked...

You probably know this but the only slight snag is with the converter being that far from the engine, it will take a while longer to warm up to operating temperature and start working (which is why the original is 'close coupled'). However, the small size of the converter probably reduces that problem. And you proved it works, so who cares?

I just thought of one more thing - I wonder if it melts your underseal - there's usually an aluminium heat shield mounted over the catalytic converter where it's under the floor of a car, few millimetres air gap between heat shield and floor. I guess just go to a wreckers and find something? (if you change your mind and decide to make this a permanent fixture).

It's great you have shown what others can expect to find, as I imagine there will be a few other Unos with catalytic converters nearing the end of their lives.

Cheers!
-Alex

 

[jo0lz]

Ta for the comments on my MIG welding
Though the camera does LIE
It looks OK-ish BuT not great in real life
BUT to make the best of it I turned the gas flow up, especially as I was outside.
That's the joy of having a big CO2/Argon bottle
Though each time each year the £60 pa bottle rent has to be paid I question my reasons for keeping it
But I guess its paid for itself with this years use and its nice to not have to worry about running out of gas half way through a job with those tiddly little bottles you get from the MotorFacters

The trick is to do it bit by bit allowing the welds to cool as you go and so not blow holes in the thin tubing

I just thought of one more thing - I wonder if it melts your underseal

it will not be on long enough to do that
As soon as I have the the MOT Cert that 2nd CAT will come off and I'll refit the salvaged standard mid section
Especially as I've lowered the car 30mm and that 2nd CAT would scrape on so much as a piece of gravel on the tarmac . . .

MOT booked for 1pm Friday . . .