I wonder if you may be able to shed some light on the problems I am having with this beastie. It belongs to the son of one of my regulars and finance is an issue. Initially it had a problem with high idle speed and a stutter/lurch which he cured himself by fitting a complete throttle body from another car with a better injector and after I had cleaned up the idle motor idled well and drove nicely for a short while. Reading the codes I had 10 separate codes mainly for, I suspect, sensors etc disconnected with the ignition on. All cleared off except for one "Battery Voltage" (No codes only a narrative) Battery voltage is not bad at 14.02 but battery voltage on live data varies between 8 and 15 volts. I've not physically measured the voltage at the ecu pin yet. The multi function relay has been replaced. My gut feeling is an ECU problem but am I right in thinking the immobiliser is integral with these? Its a Weber -Marelli 16F.EB. Incidentally he purchased the car with these problems
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Andrew
Was that the white relay that you changed? Bad earth?
Edited by Screwloose on 24/11/2008 at 19:22
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Yes it was the white relay, he'd got a pocketful of them from the breakers! The voltage on the earth pins on the ECU was about .01-.02.
O2 sensor output is a little strange hangs about 0.8v but dips if you blip the throttle so I'll check fuel pressure in case its high measure the duty cycle and do a cold to hot plot on the CTS. As I say he inherited the problem and is limited on finance but I have agreed to give him a couple of hours of my time on Saturday to help the lad out.
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Andrew
AD seem to show fuse 1 [5A] in the engine box as the ECU feed - through the relay. Worth seeing if there's a corrosion issue.
The other thing that comes to mind is the lurch - could this have an engine earth cable issue? Might tie in with the O 2 sensor issue? [Not that the metering of a Marelli single-point is exactly precise... Is it the correct TB?]
What is the running fault now?
I've a feeling that new Marelli ECUs on these [£156??] are plug and play - just a phonic wheel learn to do?
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The lurch has gone with the fitting of the replacement TB /injector. It didn't like the TPS so I switched it for the original and reset the throttle base position. Runs ok for a short time then once you get it on the open road and open it up the EML comes on and we have the Battery Voltage error code.
Thanks for the suggestions, I am in awe at the depth of your knowledge. I have been in this game for twenty odd years now, originally with HomeTune then with Tune-Up but the more modern technology leaves me cold. Just keep asking myself 'Why' every time I open the bonnet. Do these cars HAVE to be so complicated?
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Andrew
Don't know about depth - not only are whole chunks of memory disappearing every day; but keeping up, even with one make, is now impossible. [Although I can still remember your articles in the WSCT.]
This one is almost as if it can't cope with high duty cycle on the injector? I'd be thinking of bridging-in a direct feed to terminal 35. Or I wonder if it's solder has cracked on the board?
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I'll take the ECU apart on Saturday to check for damage then as you suggest feed in a switched, fused supply to the ECU. While I am in there I'll hang an extra earth onto the earth pins.
Alas t'was not me writing for the WSCT but my colleague from Worthing, Adam Going, (now retired to pastures sunny), are you Sussex based?
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Andrew
Told you the memory was going; although I'm sure that I remember you from somewhere....
Yes - for now. I was going to move to the People's Republic of Scotland; but they don't want me, so now it's me too off to pastures warm. [If I've got some money left that will actually buy anything...]
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With all respect to Screwloose and Andrew.
a couple of things:
I have a feeling the immobiliser is part of the ECU on the Punto
Make sure you have a good earth to the lambda sensor, I don't know how many leads your new sensor has, but if it's relying on the manifold - it doesn't always make a good electrical connection to the head/block despite being bolted to it.
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AJH
Yes; it is - but IIRC [and there are several systems on these] they come from the dealers virginized and accept the first key-code that they see.
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Ah, I've got the wrong end of the stick, again - I thought the drift was to pop down the breakers and fit the first one that came to hand.
Looking closer, Andrew does talk about getting a new unit.
My mistake.
The comment about the earth for the lamba still stands though :o}
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