General Non start

[curly43]

Hi all i have a mk 2 punto 1.2 8 v turns over but won’t start but will run on easy start, so dumped all the fuel and refilled started up after petrol got up ran for about 3 miles then the same , error code from Rac and my Scan tool was p0303 so changed coil the did 3&2 front one number 3 lead and plug still no good erased codes did not come back and still runs on easy start HELP PLEASE4.

 

[PuntoHowTo]

Hi all i have a mk 2 punto 1.2 8 v turns over but won’t start but will run on easy start, so dumped all the fuel and refilled started up after petrol got up ran for about 3 miles then the same , error code from Rac and my Shane tool was p0303 so changed coil the did 3&2 front one number 3 lead and plug still no good erased codes did not come back and still runs on easy start HELP PLEASE4.

Any signal from the crank sensor.

Used to be a very common problem on these

 

[curly43]

Any signal from the crank sensor.

Used to be a very common problem on these

No codes on me scanner

 

[PuntoHowTo]

No codes on me scanner

I’m guessing you are not using a scanner that can read live data.

if the engine doesn’t think it is turning then it doesn’t register a fault. It just doesn’t add fuel or spark because as far as the ECU is concerned the engine isn’t operating

 

[curly43]

I’m guessing you are not using a scanner that can read live data.

if the engine doesn’t think it is turning then it doesn’t register a fault. It just doesn’t add fuel or spark because as far as the ECU is concerned the engine isn’t operating

Correct just a simple code scan reader NO LIVE DATA

 

[curly43]

Ok today. 1. Connected scanner no codes present.
2. Removed number 4 injector plug tried testing with a bulb but did not light up then circuit tester on battery earth and probed both terminals one bright and one dim like me lol, then got some one to turn it over and spray easy start as it try to get the test lead to pulse , could hardly see anything, so test very inconclusive reconnected injector wire plug.
3. Did the same on number 1 injector, pretty much the same inconclusive results
4.connected scan code reader and p0301 & p0204 both these i think were to do with me disconnecting 1&4 injector leads.

5. Then thought fu_ _ it let’s see if it fires up and would you believe it she runs have no idea what I’ve done or what the issue is , so haven’t took it for a drive yet , but kept it running for 15 minutes the run it again 4 hours later for 30 minutes with no issues.

HOPING SOMEONE CAN SPREAD SOME LIGHT SO I CAN HAVE SOME TRUST IN IT NOT BREAKING DOWN AGAIN.

 

[curly43]

Any signal from the crank sensor.

Used to be a very common problem on these

No codes have appeared for crank sensor

 

[curly43]

UPDATE: warmed up engine for 20 minutes,connected topdon and code u1601 was present + coil reading were different pic to follow, low figures were the new coil so put old coil back on and had the same. Cleared code u1601 never came back engine runs well with very very slight misfire but that’s been like that for years and only on idle once revs up it clears . THEN went for spin round block and she was running rough to the point it nearly cut out and when I got back it was misfiring badly, reconnected topdon reader and U1601 came back . ANYONE SHED ANY LIGHT
ME thinking it’s possible it could be fuel related but did drain tank and refill with new. HELP PLEASE
Will ask in technical about code u1601 as well.

 

[curly43]

Any one help , how dose one chase/find can bus problems.?

 

[judderbar]

I suspect the can bus error is not important. I get a U code on my scanner but the car always runs ok

Puntohowto said it could be the Crank sensor is faulty because if the ECU does not know the engine is turning you will get no code. Now you are saying you are getting misfires but you evidently you do not get a misfire code.

So the same thing applies. Check or replace the crank sensor.

 

[PuntoHowTo]

U1601 is a canbus communication fault, and should not affect running or starting

 

[koalar]

When it started on easy start but not on petrol, it can't be a crank sensor, no signal, no spark

P0204 is just due to the injector being disconnected

U1601 is common with low battery, battery disconnected, bad earth and sometimes just a random glitch, rarely needs dealing with

You can't normally test the injectors easily with a test light, the are ground switched, if you put one side on ground the other on the injector, the bulb will be on, as it fires the wire will drop to 0V but it will be too quick to see, it's easier to listen to the injector click by putting a screwdriver to your ear, if that's all that's available to you

Post 1 P0303 misfire cyl3 and swapped leads
Post 6 P0301 misfire moves to cyl1

There's got to be a clue in there somewhere,l

If its constantly misfiring at idle I normally start like this

Koalar random thoughts | FIAT Panda (Mk3)

You can tell if the coil pack is getting a control signal and giving a good spark like this If one is weeker and the spark does not jump as far than the others it's suspect It is possible to get a jolt if you do something wrong, probably not a good idea if you have a pace maker As long as the...

www.fiatforum.com

And not rely on the fault codes,

If the coil is faulty, it's not conclusive yet, it's likely to be due to high resistance in the HT path to ground, I normally change the leads and plugs as well.

I not had a Punto for 30 years so will leave it up to others to guide you

 

[judderbar]

The Punto is detecting a misfire by observing the slowing velocity of the segmented crankshaft timing wheel used by the crankshaft sensor. If the car misfires, which is an obvious condition that should be easily detected and yet when there is no misfire code, it suggests strongly the crankshaft sensor is failing and is causing the misfires.

You can use the microphone input of a laptop with some easily downloaded software to display the output of the crankshaft sensor. Or you can get it to pulse a LED. You just have to be methodical.

Testing the crankshaft sensor at the ECU | FIAT Punto (Mk2/2b)

Testing the crankshaft sensor at the ECU Plug I thought this would be an interesting thing to do. My sensor is the two wire inductance or coil of wire type. A three wire sensor would need a different testing arrangement because it has built in electronics which have to be fed with a...

www.fiatforum.com

 

[koalar]

It's getting over complicated

We have no symptoms of a crankshaft sensor

It's not cutting out at high revs, ECU is always getting a signal for it to still start on easy start

The misfire cylinder changes when coils were swapped got to be a big hint here, yet we are ignoring it

Running with misfire is dangerous if it's a short in the coils, high voltage can and does back feed into the ECU, sounds like the original poster has got away with it for some time, not to mention the dangers of bore wash

We haven't asked basic question

What are the spark plugs like, colour, gap, when were they last changed, are any a different colour, are any damp with fuel, oil or carbon fould

Is the MAP sensor covered in oil

What are the fuel trims

What's the pre cat and post cat 02:readings

And so on.

I am going to guess, the fuel trims are maxed out
And the spark plugs are sooty

The pre cat is switching correctly between 0.2V and 0.8V

Due to a slug of unburnt air from one of the cylinder reaching the 02 sensor, and the ECU incorrectly adding more fuel

But this is a guess


It's easy to see which cylinder isn't firing you don't need any fancy equipment

Just unplug one injector at a time, the one that makes no difference is the cylinder that isn't firing

I use the HT leads and understand the dangers of bore wash, as long as you only run it for a few seconds it's quicker

Here's my panda running on 4,3 and 2 cylinders

Smooth on 4 cylinders, slight vibration on 3 and a pop pop sound especially from the tail pipe and very rough on 2

 

[judderbar]

isnt that 118 micro second charging time showing a short on the coil for 3/4?

 

[koalar]

isnt that 118 micro second charging time showing a short on the coil for 3/4?

Am guessing it's the same layout as the 2006 panda with the same
engine


First coil does cylinder 1 and 4
Second coil does cylinder 2 and 3

Post 1 P0303 misfire cyl3 and swapped leads
Post 6 P0301 misfire moves to cyl1

When they swapped coils the misfire followed the coil as reported by the ECU

It's got to be a hint

there isn't any coil that does cylinder 3 and 4
There isn't a coil 3 or 4

More likely a quirk of the scantool


I wouldn't rely on a P030? Code, it relies on timing, even a faulty alternator bearing can mess up the results, just test as per post 14, swap the coils, test again if it truly follows the coil you have your answer

If it doesn't you wasted 5 minutes of your life but cost nothing

 

[judderbar]

Related to the problem the OP is having with his poor running no obvious codes car here is a funny Diagnose Dan video where he has a no start no codes car.

 

[koalar]

No signal, no spark

Car always runs fine on easy start

99% not the crank sensor

Let's not confuse the situation

 

[judderbar]

No signal, no spark

Car always runs fine on easy start

99% not the crank sensor

Let's not confuse the situation

?

In the video you see Dan *systematically* going through a diagnosis.

 

[koalar]

?

In the video you see Dan *systematically* going through a diagnosis.

Not similar to the original poster

They have an error code

The ECU is seeing a signal

It runs fine on easy start

No crank signal, no spark, no running on easy start

Let's not confuse the situation by diagnosis of thing that's it's almost certainly not