Only start the car on second crank

Hi everyone, just find this great forum !!!

First, sorry for my English, i'm tring......

My wife has a C3 Pluriel 2007 1.6 TU5JP4 NFU with a MA5 gearbox about 100k on the clock, it offer a lot of headache but we just cant get away this amiable little car.

Few months ago, it only start on second crank, no matter the 1st crank just half sec, the second crank will be right start up like normal. And once it get start, I turn it off straightway, it can be start like normal again when i turn the key or even after an hour or two it still can be easily. The problem only come up when it sit for few hours or over night And recently going bad and need few cranks to start up the car.

Background as below:
1. No code (only a P0750 about the gearbox / solenoid A problem, i dont think it affect the start up)
2. New battery, good alternator, new coolant temp sensor.
3. Fuel pressure on fuel rail:
46psi when i prime the fuel pump and it hold 44psi for about 5mins and after 15mins if drop to 40psi
52psi once i started the car, it very steady even I rev it up, it just keep in 52psi and not move at all. (is that normal??)
4. 4 injectors been clean
5. Muffler get one very tiny pin hole. (im going to putty seal it today.)
6. Lexia mentioned "Throttle status" is "value incorrect" - no idea it maybe help to diagnosis
7. Try to prime the fuel pump but didnt help.

I try to locate the fuel pressure regulator, but i cant find it or it dont have one.....

"I wonder whats that in the red circle?" So, any suggestion what should I do next ? Really appreciate for any input!!

Hi, welcome to the forum.

The item you have ringed in the picture is the purge control valve. If only I had a cent for every time I have answered this. It directs vapors from the top of fuel tank to the inlet manifold via the purge canister (or carbon pot). It is controlled by the engine ECU and is typically only open when the car is coasting but occasionally you may her it clicking at idle.

The fuel pressure regulator is part of the fuel pump submerged in the fuel tank. The regulator is set to 3bar or 43.5 psi so 52 sounds a bit high but at least it' s steady and seems to show fuel regulation of some sort.

When you first turn the key to ignition, do you hear the fuel pump running ? It's in the fuel tank under the rear passenger seat. As a test, can you simply turn the ignition key to the ignition position and listen for the fuel pump to run for about a second? If you can hear the pump run will the car start straight away or not?

Thanks Ozvtr! I been dig for so long to found out what is that, but still no cure.

Yes, I'd tried to prime the fuel pump but whatever how many times I prime, it still decided to start on second crank.....

How long do you crank the engine the "first time"? Are you saying that no matter how long you crank the engine, it wont start the first time? So if you sit there for 5 minutes cranking the engine it wont start? Or are you saying it's just hard to start the first time?
I can not think of any thing that would stop the engine from starting at only the first go. The whole point of the fuel pump running is to prime the system as you said but if it wont prime then the fuel pump wont run and clearly it does. I can only assume there is some bazar problem with the fuel pump.

Yes, I mean if it sit for few hrs and I crank it for 10~20sec it wont start. But when the engine was started on second crank, then even i turn it off straightaway and turn the key again it can start up right away. Seem like a cool start problem, but a long first crank not work for me, it always need to be second.

I primed the pump when I listen and look at the gauge, it sound and look like normal, as I said it got 44~46psi and hold 44 psi for few mins.

Out of curiosity, as you've seemed to eliminated the fuel side, is the ignition circuit ok? plugs/leads/coil packs (can't remember if these were fitted to that model) I've known problems like this be caused by a faulty water temperature gauge, as this sends information to the car's ECU to adjust the cold start fuel/air ratio, bit like the old fashioned chokes

Hi DrDiesel, spark plugs just about 2000km old and it do have a ignition coil and i'm going to give it a test tomorrow, let see how is going. thanks!

is it the same thing of water temperature gauge and coolant temperature sensor? I just put a new one on but no luck...

Kay006622 wrote: ↑Fri May 01, 2020 7:35 am Yes, I mean if it sit for few hrs and I crank it for 10~20sec it wont start.

I'm sorry to harp on about this but can you use the stop watch on your phone to crank the engine for an actual 10 seconds?

Apart from the fuel system bleeding off pressure I have nothing. Things should work, not work or be random. Not work EVERY second time.
If your fuel pump is "priming" then you are getting power to the engine ECU, purge control valve, injectors and coil pack. Your engine light would not go out. So it's not a faulty relay in the BSM.
It's possible some of the injectors are sticking closed but why do they dislodge only on the second start? You would have to have more than one injector to stick for the engine not to run. Then they all unstick at the same time and the engine runs perfectly?
Do you have any other clues?

I just back home so have to wait overnight and try to crank it for a good 10sec, see how is going.

I'm thinking the same about the injector and also it too expensive to replace them. So I want to leave it to the least.

My friend told me look into the fuel pressure regulator and crank position sensor.What do you think?

Also, the fuel pressure from 46psi to 40psi after 10mins it primed and engine off . Is it bleeding too fast?

Kay006622 wrote: ↑Sat May 02, 2020 10:58 am Also, the fuel pressure from 46psi to 40psi after 10mins it primed and engine off . Is it bleeding too fast?

I honestly couldn't tell you but the theory is that as soon as you turn the key to "ignition" the fuel pump runs for about a second and stops. So no matter whether there is or isn't fuel in the lines, after priming there should be. As you say, priming the system and you should have enough volume/pressure to start the engine. My theory is that the pump may be on the way out and provides enough pressure/volume to run the engine but not enough to prime it, it takes two goes to prime it. Again that's only a theory. That's why I want you to crank it for a longer time to see if it does start. By the way do you turn the ignition to 'off' before trying to start the car the second time?

The crank angle sensor thought has merit. The reason why the fuel pump only runs for a second and stops when you turn the key to ignition (why not run all the time?) is for safety. Say the car had an accident and the engine stopped running but a fuel line was ruptured? If the fuel pump was only controlled by the ignition key it might keep pumping fuel out of the fuel line. Not a good situation! So the engine ECU controls the fuel pump. If the engine is not "turning over" the ECU cuts power to fuel pump. The only way the engine ECU knows that the engine is running is pulses coming from the crank angle sensor. Unfortunately I cant explain why the crank angle sensor would only work on the second start.