Cold starting problem 1996 406 Petrol

[406owner2]

Ok i did some research on this site about starting and idling issues and found a lot of useful information, especially in the "FAQ - 406 D8 petrol (Excl. V6) running and starting prob" posting.

I feel i need to describe my problem exactly so that anyone knowledgable could possible pinpoint
the most likely solution to my problem. I only have this problem when the car is starting cold.

I will describe my problem as best i can.

When i try and start the car in the mornings it mostly only starts after the 3rd or 4th cranking attempt, the way i start is to not hold it while cranking ie just
hold it in the starting position for 2 seconds then stop, then crank it again for 2 seconds stop...etc.. for 3 or 4 times, until the car starts (i find that cranking it for longer for 2 seconds doesn't help at all that is why i stop after 2 seconds to try again.

Then after it starts, if i don't put my foot on the accelerator slightly it will die, then shortly after that i need push in deeper or it would die, then the next sequence is to push and release my foot on the accelerator in quick succesions, because simply keeping my foot on the accelerator will lead to the engine dying, so i found pushing ,releasing about 10 times helps keep the engine running, until the car is warm and all is fine.

While all the above mentioned is going on
At the same time, i can smell the exhaust, the engine is running rough and sounds like it runs on 2 cylinders.

Once the car is warm everything is fine, the revs stays at 900 rpm almost exactly (very steady) no exhaust fumes are smelled all is fine.The rough idling is gone, and the car has full power, starting the car when it's warm is also a non event, i barely turn the key and it instantly starts.

Also if the car has stood in the sun without starting it in the morning it starts up just fine.

Now my question where should i start and where should i end.

I have read one needs to start at the idle/air control valve (this i can confirm has been cleaned in the past and did not make a difference)

Then what should be next (map sensor, stepper motor ? )
From what i read on this forum i have not seen anyone posting that they solved the problem by only cleaning the stepper motor....?)

Then, there is talk of the lambda sensor and even suggestions or a hint of disconnecting it altogether to try and solve the problem. And then also talk about the injectors...?

My question if you read carefully the exact sequence of events above while starting my car in the mornings, what do you think is the most likely cause, where do you think i should start
and what would be the second 3rd and 4th step be ?

i read many people on the site changing so many parts and still having problems.

[Rolebama]

The smell and the rough running seems to indicate that it is getting extra fuel for a cold start, but it does not seem to be getting the extra air to raise the engine revs. I would check the current supply to your air bypass valve, and that the valve is actually working. You should be able to do this by taking it out and doing a visible check.

[406owner2]

Thanks Rolebama, is there perhaps any illustration somewhere on how to take it out and test it ?

[Bailes1992]

Check the gap on the spark plugs.
The Focus started doing exactly as you describe when I was about 5 years old and new spark plugs cured it!

[Harshan]

I would suggest the spark plugs and the wires to start...

hold on ... one more test to be done.. switch on the ignition... let that humming noise (fuel pump) to load the rail.. switch off the ign key without cranking. Repeat the procedure about four five times and crank the engine. does it give any difference ? if so fuel pump or pressure regulator may be at a fault.

[Harshan]

Check the gap on the spark plugs.
The Focus started doing exactly as you describe when I was about 5 years old and new spark plugs cured it!

yeah.. you beat me to it.. I would've checked the plugs before going any further..

[406owner2]

I replaced the spark plugs 2 weeks ago, still doing the same on a cold start, the fuel pump seems to be working fine as i have taken it out and bench tested it throughout december where i was guided by Lozz and Steve.

I will however try the ignition suggestion in any case, you never know, and will report on what it does thanks.

If it still is doing the same, what would be next to test, this only happens when the car is cold, if the car is warm, it instantly starts and idles well.

Like mentioned the car very much sounds like it runs on 2 cylinders when it does start and i manage to keep the engine going when working the accelerator with my foot. i even once tried to put the car in gear and drive like that but the car did not have much power, after 2 minutes i can keep the car running without working the accelerator, only pressing it in slightly with my foot, and then only when it has idled for about 4 minutes, it is as if all four pistons comes to life and the car has power and idling goes to normal without any foot pressure on the pedal.

[Rolebama]

I have Googled and found a lot of little bits of info, so it may just be a matter of reading and looking at a lot of pix to see what needs to be done.

[406owner2]

Thanks, will do so

[lozz]

Car is overfueling,

Think back afew weeks... you opened fuel relay didnt you?


iwill leave the rest to work out for yourself,

[406owner2]

Hi Lozz...

thanks, don't think it's the relay because i don't have it manually pressed in, it works by itself, and i had this problem before the whole water problem in December, it always smell of fuel and doing what it's doing as described above when cold starting in the morning.

I'm thinking of checking the temp sensor first, then i guess it would be on to the map sensor ?

Do you know where i can find the ecu temp sensor and is there a way to check or clean it ?

[lozz]

ok.. good luck,

[steve_earwig]

Looking in Haynes it says all 3 are on the thermostat housing, you're looking for the one with the green connector. Although Haynes says it should bring up the engine light on the dash if it's faulty

[mjb]

What engine is this?

My first thought was a duff ICV, but with it starting off the bat in the sun, it's definitely weather-related so could well be condensation, possibly a cracked throttle pot letting moisture form inside. My approach would be with a warm car, see if unplugging anything causes the cold symptoms.