Engine Management Warning Systems

Lazarus

Lazarus

Retired Moderator
My Satellite Setup
80cm Motorised.
Several small Dishes.
Much else.
My Location
North York Moors
Some months ago I reported issues with SWMBOs Car http://www.satellites.co.uk/forums/meeting-place/195224-warning-auxiliary-drive-belts.html

.............. The Alternator/~Aux.Belt turns out to have been only one factor, so SWMBOs Car is now my Car (and mine hers):

But the Check Engine light has continued to appear from time to time and I have now conclusively traced it to an Oil Contaminated MAP Sensor >> This sits at the end of the Inlet Manifold and measure both Air Flow and Intake Temperature.

Oil vapour from the crankcase and rocker box breathers has collected in the manifold and coated this sensor.

I bought a replacement for £18 (not a £70 + Bosch one) and the symptom disappeared.

Well, being a cheapskate and also not having yet proved why there is so much contamination, I cleaned the old sensor carefully by suspending it over a warm radiator to allow any oil to disperse onto some kitchen paper.

Put it back and it works fine!

Now got a spare - luckily both our cars are Grande Punto 1.2 8v, so future maintenance by substitution is easy.

Anyway, what I'm working up to is that MoT is imminent and from 1 Jan 12 any Dashboard Warning Lights including "Check Engine" that don't self-test properly or remain on while the engine is running is now a reason for MoT failure !! (Oh, yes it is)

And even though my sensor fault was (temporarily) fixed, the Check Engine light remained on (ECU is programmed not to clear it automatically until it's satisfied that a number of normal driving cycles have taken place.

So, how to turn the light off manually? Some say disconnecting the battery for a few hours works. It doesn't - although it does reset the "Learn" functions.

Good old Google came up with an ELM 327 Interface Lead (approx £14) that you can plug into the ECU diagnostic port and some free Diagnostic software especially for Fiat ECUs (The Interface comes with Drivers and also with generic Application Software - but the latter doesn't necessarily provide the correct decodes per make/model).

Tried it all this morning and it's brilliant ................. you can examine all sorts of parameters of the car, and most importantly you can read AND RESET any stored faults >>> ergo no warning lights!!

Not gone further than the basics yet as the aim is to ensure an MoT pass before I get time o remove and clean all the breathers and hopefully eliminate the oil contamination at source.
 
You can get bluetooth types too. Install the software Torque on your smartphone. While the wife is driving you can look at all sorts of interesting parameters of the engine.
 
LOL. The ultimate in back seat driving!
 
Tivù said:
................. you can examine all sorts of parameters of the car......
Click to expand...

Good Lord.....you'll be remapping the engine next....BTW, my engine warning system is an attuned ear and a refined sense of ignoring noises that don't sound expensive.
 
If it rattles or bangs then at least you know it's still attached to the car in some way
 
Just a small point the MAP sensor measures the manifold pressure whilst the MAF measures the air flow. As you say there's also a temperature sensor in the same place as air density is affected by both speed of flow and temperature.

You were very lucky that you could remove the oil contamination as the metal strip is very thin. The MAF works by heating the strip up with an electrical current and then work out the airflow by measuring the resistance. This heating up also tends to bake any oil on as a hard varnish. Thin metal plus hard varnish usually equals breakage when you touch it!

I have an interface called an Actia for my Citroens which uses a clone of the manufacturer's program (Lexia 3) to read and alter just about anything you care to mention!
 
I confess I did a little drive down the lane with my Netbook on my lap ............... fascinating stuff!

Despite my actual problem, the engine otherwise seems to be in tip-top condition.


How different it is from the days when one had to guesstimate from the banging noises how long it would be before the big-end bearings went an one spun a rod or three.
 
Tivù said:
Despite my actual problem, the engine otherwise seems to be in tip-top condition.

How different it is from the days when one had to guesstimate from the banging noises how long it would be before the big-end bearings went an one spun a rod or three.
Click to expand...

Never having owned a Fiat, but lots of school friends had 'experience' of a terminal breakdown of their 126/127/131s and have never gone back to the marque.
 
The big-ends in question weren't Fiat specific ...........

Nevertheless, we've had his n' hers Punti for twelve or thirteen years and they have generally been brilliant.

Can't afford to replace every five years or so now, hence the new found interest in getting to grips with things that don't have points and distributors in the way I understood so well as a yoof.
 
Well I confess I was also a very happy Fiat driver having having bought our first in 1988 a 127 (rustbox), in 90 got a Fiat Uno FIRE engine built by robots (white) replaced in 93 with an Uno FIRE engine with sunroof what luxury (metallic brown) replaced with a Punto Mk1 in 1995 which we had until 2008. I always found them to be good cars apart from the 127 rustbox, reliable engines, however servicing was expensive at a main dealers which put me off them in the end
 
That is why I have never, ever had a car of any sort serviced for money.

Do it all myself. Very rarely are third party repairs required - although the dreaded winter potholes broke a coil spring a couple of years ago, so that was the exception that proved the rule!
 
Tivù said:
How different it is from the days when one had to guesstimate from the banging noises how long it would be before the big-end bearings went an one spun a rod or three.
Click to expand...

Perhaps my ear isn't as attuned as I think....when I was in the third year of my apprenticeship as a TV engineer (would have been 1969 'ish) I was 'allowed out' in a three speed diesel Bedford van that the mechanic thought was on it's last legs. I seem to recall it was only twenty minutes before I ran the big ends and put a rod through the block.
 
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