Grande Punto 1.3 multijet

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landroverman1958
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Re: Grande Punto 1.3 multijet

Post by landroverman1958 »

Hiya looks like an amplitude problem to me,either the air gap is incorrect or the sensor is cracked or damaged causing the air gap to increase lowering the signal amplitude,you can get similar fault on ac wheel speed sensors,it does nt have to be much,it could even be a dual mass fault with a partially siezed flywheel,

Dejan
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Re: Grande Punto 1.3 multijet

Post by Dejan »

landroverman1958 wrote:Hiya looks like an amplitude problem to me,either the air gap is incorrect or the sensor is cracked or damaged causing the air gap to increase lowering the signal amplitude,you can get similar fault on ac wheel speed sensors,it does nt have to be much,it could even be a dual mass fault with a partially siezed flywheel,
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RYM6746
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Re: Grande Punto 1.3 multijet

Post by RYM6746 »

Are you measuring the signal at the ECU? If so have you tried the pin fitment test between ECU and wiring harness multiplug. I find a screen wash jet unblocking tool works well. Just gently drag it in and out of the female terminal and compare the slight resistance felt to the other terminals (Definitely don't go stuffing anything in there thats going to bend/damage the terminal). Its the only part of the circuit you can't actually test with the scope easily. If you think about it, that is the tiny part between your ECU processer/scan tool data and your scope leads that is very difficult to test. Give it the good old-fashioned wiggle test to see if it misbehaves but in my experience you normally inadvertently fix it temporarily.

kona
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Re: Grande Punto 1.3 multijet

Post by kona »

How do I see your problem:

Your sensors totally OK!

Here's a look:
Event 1 - no injection.
Event 2 - no working stroke and slowing down of rotation speed.
The speed decreased - the amplitude (voltage) decreased.

Your problem is skipping the injection.
Record the "+" from the injectors on one channel
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Dejan
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Re: Grande Punto 1.3 multijet

Post by Dejan »

RYM6746 wrote:Are you measuring the signal at the ECU? If so have you tried the pin fitment test between ECU and wiring harness multiplug. I find a screen wash jet unblocking tool works well. Just gently drag it in and out of the female terminal and compare the slight resistance felt to the other terminals (Definitely don't go stuffing anything in there thats going to bend/damage the terminal). Its the only part of the circuit you can't actually test with the scope easily. If you think about it, that is the tiny part between your ECU processer/scan tool data and your scope leads that is very difficult to test. Give it the good old-fashioned wiggle test to see if it misbehaves but in my experience you normally inadvertently fix it temporarily.
Yes I measured the signal at ECU (ECM) and tried the wiggle test at the beginning because I had same thoughts like you...

But we done another test.
Dejan wrote:Because we were desperate,we try one more thing.We put another same car,side by side with faulty one.Then,we connect wiring from CKP sensor in faulty car to the ECM in reference car with unplugged CMP sensors on both cars.While we cranked faulty car we monitored RPM "pid" with scanner on reference car and it has same problem (rpm "pid" rapidly goes from 0 to 190-280 and vice verse).When we reconnect back reference CKP sensor to reference ECM on reference car (factory condition) with disconnected CMP sensor,there is no fault (rpm "pid" is constant at around 250 rpm).

Obviously there is a problem with CKP signal on faulty car with no regard to CMP signal or CKP vs CMP synchronicity but I can't see it with scope!!! WTF???

Dejan
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Re: Grande Punto 1.3 multijet

Post by Dejan »

kona wrote:How do I see your problem:

Your sensors totally OK!

Here's a look:
Event 1 - no injection.
Event 2 - no working stroke and slowing down of rotation speed.
The speed decreased - the amplitude (voltage) decreased.

Your problem is skipping the injection.
Record the "+" from the injectors on one channel
Hi Kona,
I totally agree with you but we done this...
Dejan wrote:Because we were desperate,we try one more thing.We put another same car,side by side with faulty one.Then,we connect wiring from CKP sensor in faulty car to the ECM in reference car with unplugged CMP sensors on both cars.While we cranked faulty car we monitored RPM "pid" with scanner on reference car and it has same problem (rpm "pid" rapidly goes from 0 to 190-280 and vice verse).When we reconnect back reference CKP sensor to reference ECM on reference car (factory condition) with disconnected CMP sensor,there is no fault (rpm "pid" is constant at around 250 rpm).

Obviously there is a problem with CKP signal on faulty car with no regard to CMP signal or CKP vs CMP synchronicity but I can't see it with scope!!! WTF???

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RYM6746
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Re: Grande Punto 1.3 multijet

Post by RYM6746 »

Dejan wrote:
Because we were desperate,we try one more thing.We put another same car,side by side with faulty one.Then,we connect wiring from CKP sensor in faulty car to the ECM in reference car with unplugged CMP sensors on both cars.While we cranked faulty car we monitored RPM "pid" with scanner on reference car and it has same problem (rpm "pid" rapidly goes from 0 to 190-280 and vice verse).When we reconnect back reference CKP sensor to reference ECM on reference car (factory condition) with disconnected CMP sensor,there is no fault (rpm "pid" is constant at around 250 rpm).

Obviously there is a problem with CKP signal on faulty car with no regard to CMP signal or CKP vs CMP synchronicity but I can't see it with scope!!! WTF???
That is all very well seeing a drop out of crank signal whilst cranking and not seeing it on the other car but this doesn't explain why the car cuts out when running
(You might be concentrating all your effort on this event unnecessarily)

I would focus more on that injector issue that kona pointed out.

That Will explain why it runs like poo and cuts out
If I was you I would just unplug the crank signal whilst running and see if ECU logs a fault code. If it does move away from that area.
Try to catch what is actually physically missing WHEN THE FAULT OCCURS with the scope alone. Injection voltage, current and rail pressure maybe a good place to start

Your CKP signal dropping out may well be a symptom and not a cause

Dejan
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Re: Grande Punto 1.3 multijet

Post by Dejan »

RYM6746 wrote:That is all very well seeing a drop out of crank signal whilst cranking and not seeing it on the other car but this doesn't explain why the car cuts out when running
(You might be concentrating all your effort on this event unnecessarily)

I would focus more on that injector issue that kona pointed out.

That Will explain why it runs like poo and cuts out
If I was you I would just unplug the crank signal whilst running and see if ECU logs a fault code. If it does move away from that area.
Try to catch what is actually physically missing WHEN THE FAULT OCCURS with the scope alone. Injection voltage, current and rail pressure maybe a good place to start

Your CKP signal dropping out may well be a symptom and not a cause
I agree with you that I might doing something wrong (focused on wrong direction),that possibility is always open,but I still think that cause of injector cuts out is problem with CKP signal because injectors are feeding directly from capacitors in ECM and wiring is checked twice and we tried with another ECM.Same thing is happening at cranking and idling,injectors cuts out occasionally and rpm "pid" goes to zero "0" but at idling that is happening rarely so I'm still all over CKP signal.

Of course,maybe I'm wrong...

I will scope voltage and current with rail pressure if I get chance.Car is gone,but maybe I can call him to get back if I came up with some ideas...



P.S. I'm sorry for late response...

speck
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Re: Grande Punto 1.3 multijet

Post by speck »

Hi, don't really know the set up of this engine. I am guessing right now, maybe you got an harmonic balancer which
is seperating ? Just an idea

Dejan
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Re: Grande Punto 1.3 multijet

Post by Dejan »

Please tell me,what you think about these waveforms...
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