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Technical 1.6 with poor idle [ECU?]

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Technical 1.6 with poor idle [ECU?]

Cheers deckchair.. Thats my thoughts exactly. I will check pinout to pinout on the loom and see what comes up. Will probably be later on this week as it's late now and snowing out side. will post again when i know more.
Cheers again.
 
You're welcome:)
Have a look here as this is much more the way the Stilo TB motor and position sensor works. You can see why an Oscilloscope is handy for checking TB motor signal inputs

http://www.picoauto.com/applications/electronic-throttle-control.html

Don't worry if you scratch your head a bit with some of the "explanations" as I don't agree with some of them either. Read the comments at the base too before you go nuts
 
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Hi again.
Ok. I have checked the cables from the ecu M10B connector to the TB connector, all metered out as should be, so looks like the cabling is not at fault here.
Next I re checked the TB potentiometers again these are thr true readings..
TB connector Pins 1-5 4.2kohms pins 5-2 (idle)3.6kohms to (full open)1.8kohms pins 5-6 (idle)2.0kohms to (fullopen)3.6kohms. The sweep from idle position to full open was linear in each case. I then cleared any previous errors from the ecu and performed the throttle re learn proceedure and after that got the following errors again..It seems to point to the ecu with an outside chance of the throttle body being the fault. I didn't want to back probe the TB whilst running as the idle is very rough and i was using exposed copper wires for the measuring. Did not want to short anything out!!
Don't have access to an occilascope to check correct operation of the TB motor.

Errors recorded P1687, P0638, P1686. warning light on and very rough idle
Hope this is of some help any ideas as to what to do about having ecu repaired or exchanged?
Thanks flyright.
 
Ok those are some better resistance figures being 3.6 kohms rather than the 3ohms you were listing before. Ha!

Not sure about the pin numbers you say you tested, maybe a typo but measuring between pins 1 and 5 won't tell you a lot, you want one connector on the sweep and the other at either end of the pot. But the figures sound about right

Ok now have you checked the 5v supply as in post 31

5v on the sensor pot supply pin 5?
reference earth at pin 1?
var voltage 0-5v proportional to throttle movement at sensor bet pins 1 and 2 and then 1 and 6?
==========================================
If you are getting 5v at pin 5 then you know the ecu is putting out and supply wiring is good from ECU to TB sensors

You can do those with engine off and ign on

Thinking about problems on your 5v supply rail, do you have air con fitted? The MAP sensor and the air con linear pressure switch all share the same 5v supply so see if you can test for 5v supply at the TB connector pin 5

If your 5v supply rail is being dragged down with a low resistance or short circuit elsewhere then it may well cause the fault codes

If you have to go down the ECU repair route then maybe send an email to
http://www.the-ecu-doctor.co.uk/
 
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Cheers deckchair. yes it was a typo it should have pins 2 and 5 on the TB connector.
I will check for 5v on pin 5 tommorrowand yes the car does have air con. is the 5v supply direct from circuitry within the ecu or a separate regulator with fuse?
I will look up the air con linear pressure switch on elearn.
Any other nuggets that i can check tommorrow?

Thanks again, Flyright
 
Try for a good steady 5v at TB pin 5 first, then I would just pull the plug on the aircon lnear pressure switch

linear press sw.JPG
( i think you could get to that one from above but it's easy from below) and leave it off
Try for 5v and maybe start it up to see if that's affecting things. Linear pressure switch should make no difference, if it does then you have a fault there.



map.JPG
Then disconnect the MAP sensor. It will warn you something is up but then just start the engine and see if there's any difference. Disconnecting the MAP sensor will take out the MAP but also the combined inlet air temp sensor and it willl go to assumed settings, most of all it eliminates it from the 5v supply rail.

You'll need to clear fault code P0105 before the ECU will accept the MAP again when you reconnect it

Bear in mind that for all connections, seeing a voltage by backprobing doesn't necessary mean the voltage is actually getting to the pin in the connector or that voltage is getting into the component. That seems to be quite a common problem at the ECU, supply is there but the pin isn't making contact through a slack connection
 
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Cheers will check the above.
Is the 5v rail supplied from the ecu or a separte regulator fed into the ecu?

the diagram for the linear pressure switch is that looking from below or above?
 
I believe the 5v is created within the ECU

the diagram for the linear pressure switch is that looking from below or above?
That'll be at the front, just behind the bumper, from underneath, driver's side

CIMG1022a.JPG
Here's the little devil (covered in aircon fluid after my pipe fractured but that was a long time ago). Just pull up the securing clip and pull off
 
Right measured pin 1 to pin 5 on the TB connector.
4.18v. Removed the AC pressure switch conn still the same (found it, thanks)removed the MAP sensor conn still the same..
So 4.19v at the TB .
Any other ideas? or does this mean we are looking at the ecu?
Tried to run the engine with the pressure sw disconn and the MAP disconnected and it will run for about 4-5 seconds before going very rough and dying.
Update
Reset the ecu codes and checked the 5v supply with the engine running still 4.18v steady.
If you can think of anything else this would be much apprieciated.
 
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Well that's a good test because your car should run absolutely fine without a MAP sensor connected (but not very economically) and you know you have a steady voltage supply at the TB sensors

I think you'll have to make your call as to which end you think the problem lies TB or ECU. You say BBA REMAN have already checked out the TB?
 
yes they tested over a 24 h period and returned the unit as not faulty.
I could probably send both off again and see what happens? do you think that 4.18v is ok?
 
Is it normal for the idling to drop a bit when you turn on the AC to the max? its an abarth

The butterfly is clean and lubed.
thanks
 
Deckchair5 said:
Yes I would think that voltage would be ok as that's what the throttle relearn is for, to find out the actual voltages are at the extremes
Click to expand...
Cheers again deckchair.
I am thinking of sending both the ecu and TB off to BBA REMAN for them to look at.
will probably send monday so probably looking at another week before they return.
I will keep you posted on what they find.
Thanks. Flyright.
 
Cheers deckchair.
The trace looks something like the the result that the resistance readings I took would give.
Ringing BBA REMAN tommorrow to sort out getting them both sent off to be tested and hopefully repaired....
Do you know anyone who has used their repair service before? are they reputable?
I know I sent the TB off to them but anyone could say they have tested and charge you for the privilage.
Thanks, will post again with news. Flyright.
 
Arrrghhhh. What a nightmare.....
Ok spoke to bba reman today and was told that the ecu was not repairable. But they could sell me a new one for £300, so rang ecu doctor and got the same reply but they gave me a couple of numbers to try.
They all said that the ecu was not a repairable item... but one of the companies have new ecu's for £245 on an exchange basis. but no one could sell me one supply or return to prove the fault.
So bit the bullet and ordered one (will be delivered tommorrow)
Just one more question deckchair.. are there any proceedures to follow when i fit the new ecu? I've heard of the phonic wheel learn proceedure. But don't know how to do this... Help please..
Thanks. Flyright
 
No phonic wheel on a 1.6 so you'll have no problem there, it's a straight forward rpm sensor and pick up ring, purely plug and play

But your ECU? It'll need to be a virgin ECU as a different ECU for another car won't accept your key immobiliser. If it is a wiped memory or new ECU then it'll read off your key immobiliser chip in the key fob when you first turn on to MAR

You'd need to do a throttle relearn (but you're getting used to those:))

I haven't changed an ECU on a Stilo but I would hope yours would come with full instructions or if anyone here has done one then maybe they can supply their experiences if I've omitted something

If you have a second key then you'd need to go to a Fiat garage or specialist to get its immobiliser accepted
 
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Cheers deckchair.
I was told that the ecu was brand new so you would think that it will self learn. Hopefully....
I will have to see what documentation arrives with the ecu. I ordered it from atp electronics (recommended by ecu doctor) so if necessary I can call them for advice.
We wait to see if it fixes the faults.. fingers crossed.
Will post when its been tried.
Cheers again, Flyright.
 
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