2015 PIU won't start?

[widewave]

This morning I drove the car no issue. But at afternoon, it won't start.
At the first time trying, it acts like it will start but won't complete starting cycle.

About two months ago, it won't start several times when the weather is very hot. It would start when not hot.
But this time, the temperature is not high now, it still won't start.
No code. Just 'dadada' sound like trying to start.
I measured the voltage of battery, 13.7V.

Urgent, thank you very much!

 

[fosterzcj]

Will it start if you give it a little throttle while cranking? Is there a check engine light at all? I'd guess a fuel relay if it's only when hot.

 

[widewave]

Will it start if you give it a little throttle while cranking? Is there a check engine light at all? I'd guess a fuel relay if it's only when hot.

Thank you for reply.

I pushed gas pedal when turning key to start it but no luck.
No check engine light on, no other lights either.

Before It won't start several times only on very hot day.
But today it still won't start after totally cold down.

 

[fosterzcj]

So what ever problem you had when it was hot only got worse as now it happens when cool. My bet is a relay those usually act funny hot at first and then start to malfunction more even in cooler temps.

 

[widewave]

So what ever problem you had when it was hot only got worse as now it happens when cool. My bet is a relay those usually act funny hot at first and then start to malfunction more even in cooler temps.

Wow!
I will try to test the fuel relay tomorrow morning!
Thank you very much!

 

[widewave]

So what ever problem you had when it was hot only got worse as now it happens when cool. My bet is a relay those usually act funny hot at first and then start to malfunction more even in cooler temps.

I replaced several fuse and relay this morning:
13 Starter motor relay
15 Fuel pump relay
19 Starter motor fuse
65 Fuel pump fuse
87 Run/start relay coil fuse
88 Run/start relay

Nothing changed.
Is there more related relay/fuse in another box?

 

[fosterzcj]

Do you by chance have Forscan or any way to measure fuel pressure?

 

[widewave]

Do you by chance have Forscan or any way to measure fuel pressure?

I have a cheap obd 2 reader.
Is Forscan tool a any bluetooth obd 2 tool with forscan software?
How to measure fuel pressure?

 

[fosterzcj]

Forscan would hook up to your car via laptop and dingle and give you fuel pressure among other things. The high end of the fuel line sits at 680 so I wouldn't mess with it. Does the fuel pump prime when you open the drivers door? You ahold hear a winning when the door is opened.

 

[peterk9]

This morning I drove the car no issue. But at afternoon, it won't start.
At the first time trying, it acts like it will start but won't complete starting cycle.

About two months ago, it won't start several times when the weather is very hot. It would start when not hot.
But this time, the temperature is not high now, it still won't start.
No code. Just 'dadada' sound like trying to start.
I measured the voltage of battery, 13.7V.

Urgent, thank you very much!

Have you tried to see if it will start with a boost?

Peter

 

[widewave]

Have you tried to see if it will start with a boost?

Peter

Not yet. I will try later after I replace the starter. Thank you!

 

[widewave]

Forscan would hook up to your car via laptop and dingle and give you fuel pressure among other things. The high end of the fuel line sits at 680 so I wouldn't mess with it. Does the fuel pump prime when you open the drivers door? You ahold hear a winning when the door is opened.

I used a scan handhold, turned the key on and got some live data pictures:

 

[fosterzcj]

The IAT being negative 40 when I don't think you're at the north pole could be a problem as you'd run super rich upon start and run. What kind of fuel are you running. From what i gather it says ethanol but then says 9.8 percent. Are you using flex fuel?

 

[fosterzcj]

Your intake air temperature sensor is built into your mass air flow sensor. That part may need replacing and that part would cause a no start or very poor running condition.

 

[widewave]

The IAT being negative 40 when I don't think you're at the north pole could be a problem as you'd run super rich upon start and run. What kind of fuel are you running. From what i gather it says ethanol but then says 9.8 percent. Are you using flex fuel?

I detached air intake to access starter. The sensor was detached too...

 

[fosterzcj]

Well with no values for temp and air it's not gonna run. Did reattaching the sensor fix it? I wonder how long that's been severed.

 

[widewave]

Well with no values for temp and air it's not gonna run. Did reattaching the sensor fix it? I wonder how long that's been severed.

Because it won't start, I detached air intake to check starter.
I will replace starter and put them back to test tomorrow.

 

[fosterzcj]

I wish you the best of luck on it firing up tomorrow. Fingers crossed. I'd still look back and see what could have happened to disconnect the maf iac sensor. Those don't usually disconnect on their own.

 

[fosterzcj]

Sorry to double post but with a disconnected sensor a check engine light should have been on.

 

[MAS Tequila]

Are you sure it's getting fuel?

I had one not start for a few minutes then start.

Not long after, the fuel pump completely died.