Technical Loss of Power

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Technical Loss of Power

puntopower55

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Jul 9, 2010
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Morning All,

I'm after some advice, i currently have a Mk2 punto (X Reg). (72000 miles)
The car passed it's MOT last week fine, with a few advisorys, suspensions bushes etc will need replacing soon.
However, i was driving along the motorway yesterday & the car started to stutter & then just lost all drive & conked out.
I tried it again thinking it might of been over heating, but temp gauges, oil & fuel all fine, it then died again.
I had to call the AA to get it recovered to a local garage.
The AA man was fairly confident the cat was the problem & it was blocked, this was confirmed by the garage, they took the cat off, it ran for a few mins before dying again of the same problem (the cat had melted together apparently).
They also tried running diagnostics on the car but nothing showed & they're at a bit of a loose end as to what the problem seems to be.
Is there any suggestions on here as to what it might be?
Any help is much appreciated as i'm not carless with a little'un i can't ferry about!
 
I've also forgotten to add, that in the 20mins or so before it conked out it was only returning 25mpg doing 75 in 5th on the motorway (if that makes any difference).
There was also no warning signs or lights, or oil / fuel leaks etc.
 
Sorry i know what bit may be casuing the issue but can't remmeber what it's called gahh...

I'll check with my Uni "Master" when i find him to get the name of the part:p sry

In the meantime, i'd check the timing advance, because if the speedo is reading a lower speed, the engine may not be running on an advance spark meaning the fuel is still burning as it comes out of the exhaust - hence higher CAT temps..
 
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Another question - too all.
Does the mk2 use a fly-by system or a throttle cable? - this will help narrow down the possible causes(y)
 
Ha Ha, no probs, i only found out about this "fly-by" system yesterday:p

the sensors to check would be the speed sensor - gearbox
That sensor i cannot name, on engine near..... camshaft? the big one the pistons sit on:p
or cam postion sensor
 
Ok, so in idiot terms what should i actually say to the garage?

My technical ability goes as far as putting air in a tyre!

My car's 75 miles away as i had to get the train home so need to call them with any ideas i may get lol!
 
I'd wait for more responses from the Fourm members, 'Dave' mainly (Fourm Mod). he will know more detail(y)


but I'd tell them to run a manual diagnostics.

check the main sensors then the if nothing is found ecu. Not every fault can be read, only when you try a manual diagnostics will you find the problem, there was a case recently here at my uni where we couldn't find the fault to the car lossing all power, and then wouldn't run.

We found a sensor on the engine block would allow the engine to start only if we have the, ......meter across it. (someone please fill in the blanks:p i'm rubish as names) We found that the sensor had a build up of.... garhhh. well there was a build of of Blah on the coils in this sensor, with the Blah accross it this blah would burn off and the sensor would work for a while until blah would block it again. a sensor called Blah fixed it:D

sorry, this must be anoying for you aswell...:(
 
It is mightily frustrating not having a car, calling other forum members for your help ;)
 
If the timing belt jumped some teeth it could affect the valve opening so burning gases would have gone down the exhaust pipe. The Fiat techs will know if ECU can "see" this fault.

The Lambda O2 sensor could be sending the wrong signals so the fuel air mixture is wrong. That can cause an over-heated exhaust, but more usually its going to run rich (cooler) than weak (hotter).

Here's a theory:
With a faulty O2 sensor, the catalyst could have been coked with unburnt fuel from short journeys. Taking it for a good run down the M-way would have heated it up and the maybe the catalyst got overloaded while burning off all the built-up kak.

Get the O2/Lambda sensor checked
Get the cam timing checked.

Cats are on ebay for reasonable prices so be careful you dont get caught paying silly money.
 
I had something similar on our Punto recently and had to replace the Cat. I got the replacement from an online supplier and it came with fitting kit etc. and a good bit cheaper than Fiat Dealer.

I'm not sure but the reason I think my Cat got blocked really was down to the ECU failing. This caused progressively poorer running (misfire) which my family, who drive the car, didn't notice and over a period of time this put unburnt fuel down the exhaust and contaminated/blocked the cat. Car improved once the cat was replaced but then went onto only 2 cylinders and had to have the ECU repaired and chose to fit new coils as well. It now goes great again.

As to MPG, I've read on here that a new thermostat can improve this as if not working correctly the water temp can be too low and the ECU compensates by overfuelling as it thinks it is in cold start.

If garage has confirmed Cat is blocked you have no option but to renew but see if they will get an aftermarket one for you (still might need to be a Type approved one depending on vehicle age) and ask them to check ECU function. There is an excellent guide to this on this forum, written by T14086.

Hope this helps.
 
Viva may have it. A missfire would deffo put unburnt fuel down the exhaust and there is a well known ECU fault that causes a missfire. On short journeys the cat wont get hot enough to handle the unburnt fuel so could get overwhelmed.

If it is the ECU (and its a big IF) dont get stung for a new one. ECUs can usually be repaired for about £100.

Here is the sort of price I was on about - Punto cat
 
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Morning Chaps,

I spoke to the garage owner / mechanic a moment ago.
He said he thinks he found the problem - the timing has slipped 2 teeth.
He's going to try and repair it later on & make sure that was the only problem!
My next question is, is that an expensive job?
 
Yeah the cat is buggered, but i know that already.
I was just curious as to what he'd charge in labour to sort the timing out.
I dont want to go there & for him to say its taken 3 hours to do, the timing on it & for me to get my pants pulled down when in reality it took a 1/3 of the time!
 
There will be diagnosis time, then repair time.

If he's changing the cat then possibly a couple of hours, but as mentioned, you need to know why the belt slipped.

Do you know when it was last changed?

Was the tensioner changed at the same time?

Cheers

D
 
No i don't know, it has a FSH but all my documentation is at home.
Car's currently on 50k miles.
I'm fairly sure it HASNT been done before though!
 
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