Technical ECU know how..?

[lashlondon]

On a prayer we made it to Wales and back to London on a faulty (I believe) ECU unit..(no problems on motorway but cut out outside Baker St tube in London so the cops swooped on us thinking it was a car bomb in the making[:0]) ,although I should still test the ECU to be certain..

..question is, whats the best way of going about testing and replacing an ECU.. cheaper is always better..

Its a Uno 999cc FIRE engine, no injection or bells and whistles, just springs and rubber bands....except for this little bit of electronic wizardry that may be shorting when it gets hot...hence the engine cuts out...

..or could it be the distributor getting engine grime all over the points?...but surely that wouldn't cause such a dramatic failiure...from which, 10 minutes on the side of the road seems to temporarily fix...

thanks all

Dave

 

[lashlondon]

..Fiat dealer wants £300 for the ECU...

..I said that I didn't need it to be gold plated....

John....whaddya reckon...gents?

DaveB)

 

[Pete]

What number is your ECU ? I may have one on my shelf.
Rgds, Pete.

 

[John H]

The ECU is generally reliable - it will produce rubbish out with rubbish in: like any microprocessor controlled device.

If this is the cause of your problems it will be dirty connections or faulty sensors. Just removing the power for a couple of minutes (or unplugging it, cleaning its connectors and putting it back again) will reset it - assuming it's one of the Bosch family.

Why are you convinced it's the ECU? From your previous posts with this car there have been a number of ideas about what the problem is.

You really need to get back to basics with the thing:

Is there a spark when it's failed? (remember the common failure of the distributor unit, as mentioned in previous post).

<blockquote id="quote"> face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by fiatunofire
Hi m8,

I had exactly the same problem with my Fiat Uno Fire, it went on for months and months. I called out the RAC so much they stopped picking me up!!! Anyway, I replaced the metal fuel tank, the pipes, tried different carburettors, and this is why I didn't expect to get stuck so many times. However I did start to get somewhere when I replaced the 'furred up' ignition pack situated on the distributor... it controls engine speed ignition timing, the works!! Having replaced this, it didn't stop anymore... so I decide dto get the car tuned AGAIN and I noticed the vacuum was replaced on the distributor. I haven't looked back, I nearly had given up but you will get there!!! I tried everything related to fuel contamination as this is what the RAC thought was the problem, but it sounds very similar and I think try the distributor and ignition pack first, its cheaper!!

Tell me how it goes
Cheers
Nick
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">


Is the fuel really getting delivered? (if you're SPI you can see the fuel being injected if you take the air filter and cover off the throttle body).


Really though it's difficult to help beyond these guesses, as we've never really found out anything about your car: I still don't know if it's carb or injection

<blockquote id="quote"> face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by John H
Give us a clue - is it carbed or injected?

A lot of what you've said sounds like carbed - but then the RAC man says the injectors OK.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

If it is injected, and the pump has stopped, you have the possibility of a dirty relay in the supply to the pump - it's controlled by the ECU: when it's happy the power is applied.

Stopping when really hot in traffic does sound like the distributor though - take a look at this thread

https://www.fiatforum.com/forum/topic.asp?TOPIC_ID=1746


whaddya reckon...

 

[lashlondon]

John

Thanks for the infinite patience, you're quite right- I havn't gone down the distributer route- I'll have a good long look at this- have a go at cleaning it (it has been subject to a leaking rocker cover gasket), have a go at refitting it (more new tricks)...etc

It is a carb model, not bells or whistles...

You're problem does sound similar in ur thread...

The other symptoms (positive pressure in the petrol tank and constantly near empty fuel filter cannister) seem to be red herrings...

keep u posted
Dave

 

[lashlondon]

John and gents

I noticed that Haynes doesn't really recommend working on the distributer....I've been offered another distributer with sensor pack for 60 quid.

Do you think I should take a punt, fit a new distributer then roll it down to the garage for retuning?

Dave

 

[John H]

Seems a lot, unless it's new.
But it's cheaper than an ECU

My secondhand replacement cost £20, including postage..

Fitting is two 10mm nuts.
Timing is tricky if you haven't got a strobe light, but do it with the advance disconnected: reconnect afterwards.

It's worth replacing the "o" ring if you get a secondhand one... it's one of the many oil leaks

 

[lashlondon]

I don't have the strobe light and as
my title suggests <---- I'm new to this game so I'll pick up a new part (I'll lose more in Underground day tickets for myself and my wife than would gain by waiting for a part to arrive!) and then get the mechanic to fit-it (he reckons if I sort out the parts its time he wont charge for), and tune up....keep u posted B)

thanks for ur help John and Nick

Dave

 

[lashlondon]

..well it was a second hand distributer I got but strangely the points inside the distributer cap are squeekly clean as is the rotor [?]...came with a sensor pack and vacuum wotsit...60 quid

..the old bloke at the parts shop talked me into fitting it myself, which I did by marking the replacement unit in exactly the way the old unit had been fitted (u guys know all this but there's a small chance this may be useful to someone), so I didn't use a stroboscope thingy...

..havn't run it properly yet, it'll get a dose of jammed London on the way to church tomorrow so I'll let u know if its not problem solved (if I break down outside Parliament I imagine the Blue will be on me like a tonne of bricks with bomb sniffers:I)

thanks again
Dave

 

[John H]

Hope it does the trick

FWIW I think there is a misunderstanding in our terminology:
for me "points" are the contact breakers in an old style distributor - these are the bits that break the primary current to the ignition coil ( in a later one, like yours, it's an electronic module ).
I think for you "points" are the shiny bits inside the distributor cap which the HT goes to via the rotor arm.

No matter though, as long as it does the job.

Regarding timing and "a stroboscope thingy" it is critical to within a degree or two for best performance/not pinking .... so if it's a bit flat in the performance department, or sounds like a bag of spanners being shaken when you accelerate hard from a low speed in a high gear, you still need to look at the timing.


Regards


John H

 

[lashlondon]

..which was going to be my next question to you..ie how does a badly tuned car sound..[8)]

It seems fine at the moment, ran it through some typical jammed roads to get it hot (the cold weather wasn't cooperating) but all seems well.....there is a rattle in high gear going up hills at under load or attempting to accelerate but it has been suggested that this may be 'valve clearances' (?)

..oh, yep I probably have got the terms all wrong, need to watch that as it doesn't help with understanding the problem :I

cheers mate
Dave

 

[John H]

<blockquote id="quote"> face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by lashlondon
..which was going to be my next question to you..ie how does a badly tuned car sound..[8)]

there is a rattle in high gear going up hills at under load or attempting to accelerate but it has been suggested that this may be 'valve clearances' (?)

cheers mate
Dave
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

If this rattle is a new noise (since the distributor change) it's the timing a bit over advanced: the spark is lighting the mixture a bit too soon - piston is still on the way up when the "rapid burn" starts to push down on the piston.
It's not a nice thing to do to an engine, it shortens it's life expectancy somewhat[xx(]
Called "pinking" or "pinging" if you're American.

If you scribe a line across where the distributor and the cylinder head touch (in the direction which would go over each of the front wheels if you extended it), to use as your reference mark, then slacken and move the distributor body so its scribe mark is nearer the inside of the car (clockwise, viewed from the top of the distributor) so you have about a 3mm gap in between the lines. Re-tighten, and try.

Move further if needed.
If you over do it that way the performance will be a bit flat.

 

[lashlondon]

John and gents

do u think that I'll get away with tuning it this way (as mentioned above)? There's a bag of nails in the engine on accelerating in a high gear(only as bad as it was before replacing the distributer( Fire 999cc carb)) but the idling is a more rough and the performance is a more flat..as suggested.

I could pick up a strobe

http://www.halfords.com/opd_product_details.asp?id=16487&type=0&cat=67

but hey £30 is £30 more than anyone wants to spend on a one-off tool!

The gent at the garage will tune it for £25.

whaddya reckon

Dave

 

[John H]

Lots of options:
any car enthusiasts at work who might let you borrow one for a pint or two??
you could get nearer (than it is) with the DIY adjustments
the 25 UKP tune could be OK, especially as it's the carbed version they will be able to actually do something... and if they make a good job of it - when all's said and done, it's about a tank full of petrol... stop the engine knackering itself... get more MPG...

 

[lashlondon]

..couldn't get hold of a strobe from guys at work- incredibly, people don't tend to work on cars in London - they'll draw up a £50M residential appartment and retail scheme down to the nuts and bolts but wont touch anything under a car bonnet, so I might as well bite the bullet and let the garage tune it.

Cheers John

Dave

 

[OhSunnyboy]

<font face="Comic Sans MS">John H,

I was reviewing the notes on complaints of noises at speeds etc.
and I was wondering quite the opposite. I have an Uno45/1993/999.
In 1st and second gear, I get a distinct sound of 'Marbles' coming from the engine. Does this sound familiar, or should I see an ear Dr.?!

Thanks,
Bleeding Knuckles Dave </font id="Comic Sans MS">

[email protected]

 

[Steven]

Sounds like tappet noise. Perfectly normal.

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<h6>
Click here for pictures of my Uno </h6>