Technical Punto 55S Problem with ECU or could it be something else.

[beechmore]

Hello Everybody,

Firstly I'd like to say how useful I've found this forum in the past and it has helped me solve many problems I've had with my Punto. This is my first post.

My Punto 55S P reg which won't start.

It was initially misfiring so I checked the spark plugs. All seemed to be firing OK. I suspected the timing and checked this. Tensioner was worn so I replaced that and timing now fine.

Still won't start. I then noticed that the petrol pump wasn't priming when I switched it on so I suspected the relay switch on the bulk head. Replaced this but no joy.

I again checked the spark plugs but now this time there is no spark from any of them.

My reasoning is that if there is no spark and no pump priming then it has to be the relay or the ECU. Could I have blown a fuse or damaged the ECU when checking the spark plugs. Could it be anything else?

Thanks for any guidance you can offer.

beechmore

 

[varesecrazy]

Hi,

does sound a strange one,
no warning lights..??,
even when it was misifiring..??

My 1st thought was the Crank Sensor = non- firing,

BUT - Pretty sure the fuel pump should run no matter what,

have you had the battery off overnight,
may JUST reset something..??,

Charlie

 

[fingers99]

Yeah, fuel pump should run regardless. I doubt it's the ECU: Mk1 Punto ECUs are exceptionally robust.

To my mind, misfire suggests ignition system issue (plugs, leads, coil pack), while total non start suggests issues with the big fat master relay or TDC sensor.

 

[beechmore]

Thanks for the ideas.

I thought about the TDC sensor but reckoned that the crank had to be spinning before it did it's job. Would a duff sensor prevent the fuel pump from priming?

I forgot to mention that the fuse for the relay I replaced is fine.

beechmore

 

[beechmore]

There weren't any warning lights prior to the failures varesecrazy. I'll leave the battery off overnight as suggested.

Fingers x'd

beechmore

 

[dumbledore]

I would trace back the work you done recently, as you now seem to have lost sparks after doing some work. As said most likely culprit here is the crank sensor. So check the to see if you upset the wiring to it or upset the pulley when you redone the timing belt job. If the pump is not priming you need to check if it gets the voltage. If it does the pump will be knackered and you will need to remove it check it and replace it if faulty. If there is no voltage at the pump then check the relevant fuses. There should be a couple of fuses associated to the relay and fuel pump and fuel injection system according to the Haynes manual.

 

[blu73]

faulty TDC won't stop it priming no it will just stop the injectors and spark, so you should be able to hear the pump prime.

 

[beechmore]

Tried a new TDC sensor but that didn't work. It would therefore seem to be a bust ECU.

Thanks for the ideas and thoughts.

beechmore.

 

[Most Easterly Pandas]

Tried a new TDC sensor but that didn't work. It would therefore seem to be a bust ECU.

Thanks for the ideas and thoughts.

beechmore.

I take it you've checked the obvious fuses and even if there is a feed at the pump or not. I'd say the pump is more likely to fail than the ECU. As fingers has said, they're fairly bomb proof on the mk1 Punto.

 

[fingers99]

:yeahthat:

Check for 12v (+ and -) at the pump, if not, check wiring (all this after fuse). Check the pump by applying 12v direct to it (while in tank).

If all else fails, get the ECU tested.