Delorean rough cold starts till the Frequency valve kicks in.

[Some guy]

Hi I just want to so thank you to this site. By D would still be in the garage if it was not for you.

So here is where i am at. I am having a problem with my cold starts, and after it has been sitting for a while. I start it and then i just dies out. If i play with the gas peddle it will sputter for me(about 1 minute) then once i hear the frequency valve kick in, the car start running correctly.

I have replaced the fuel pump, accumulator, fuel filter, o rings in fuel distributor and even added a second check valve by the fuel pump. I Cleaned the warm up regulator. I even took it apart and clean the o ring diaphragm inside. Put it back together and that helped a little. Then i tried adjust the mixture control valve right next to fuel distributor. (1/6 turn cw) This helped when the moter was warm, but made it worse when the motor was cold.

The car had been to a garage once to have the mixture adjusted and this made it pass CA smog. So i think the distributor is ok with its settings.
I clean the idle speed motor and made sure if was free moving. Then i tested it and made the flap inside move.

I am not sure where to go from hear. Should i clean/replace the frequency valve? Or is it the lambo board not sending a signal to the valve?

Thank you for the help

[David T]

The frequency valve should be buzzing when the motor is running, hot or cold. Try removing the plug on the frequency valve and reconnecting it several times. That may be enough to clean the contacts up and make it work even when cold.
David Teitelbaum

[Bitsyncmaster]

1/6 of a turn is quite a large change. Typical you get less than a 1/4 from full rich to full lean (frequency valve changes from 10 to 90% duty cycle).

[Elvis]

Hey nameless guy - why don't you tell us your name ?
I think this is the minimum you gotta do when you ask for help.


OK you checked the idle motor ? but very often the idle ECU goes bad, too.
I have repaired 5-6 of them in one year.
>50% it's just the power stage (BD335).

[DMC5180]

This sounds like leaking injectors to me. It only happens after the car has sat a for long time. All that fuel system work did not mention having the injectors cleaned. It would make since that the engine runs smoothly after about 1 minute once the injector lines have purged the air out. In my experience it takes more than 2 minutes @idle before the the lambda kicks in from a cold start. I've timed it several times.

[Some guy]

Hi My name is Mark 10408

Leaking injectors make sense, what can i do to fix that? is it just cleaning them or do i have to buy new ones?

Is it a new fuel distributor i need?

[DMC5180]

Hi My name is Mark 10408

Leaking injectors make sense, what can i do to fix that? is it just cleaning them or do i have to buy new ones?

Is it a new fuel distributor i need?

At the very least get them cleaned and check the spray pattern. They can do for you at DMCCA or any vintage european auto repair facility. Replace IF needed.

I would not worry to much about the FD at this point. That said, It is a Rebuilt HERVEY unit. All bets are off.

[Some guy]

Ok so the problem with the frequency valve was a bad RPM relay. I just cleaned the contacts on the inside of the relay till i get the new one in the mail.

I turned the mixture adjustment back to were it was.

It still has a "sputtery" start. but now it sputters for a shorter time. the plate at the air intake takes some pressure to push it down. So i think the lines to the fuel distributor are ok.

Is it posiable the seals on the fuel injector lines are letting air in. ( i have never messed with them)

[David T]

Leaky injector seals are a real possibility. So are many other places including the air tube for the idle motor that sticks into the bottom of the mixture unit. Cleaning and testing the injectors will probably help. You could also try some Techron injector cleaner. You are plugging the hole over the mixture screw after messing with the adjustment right?
David Teitelbaum

[Some guy]

i am plugging the hole after i adjust it.

I have tried some other fuel injector cleaner.

I will try cleaning the fuel lines next.