Pressing the gaspedal before starting

[cschriks]

Hello,

I recently purchased an Esprit S1 with 907 engine upgraded with an electronic ignition system. Before I start the car I have to press the gaspedal 3 or 4 times to build up pressure. Can someone explain why and is there a modification that makes starting the car easier? Thanks!!

Edited March 28 by cschriks

[CarBuff]

With carb'd cars (not just Lotus), it was usually necessary to pump the gas pedal once or twice to make the accelerator pump squirt some gas into the engine to help it fire off.

 

The 'modification' is to YOU, LOL.

 

PUMP a couple times, THEN crank the starter.

 

Has nothing to do with the operation of the electronic ignition.

[jep]

Priming it is called.

Totally correct procedure for twin carb Lotus 9 series engine. It's in the handbook. 

And don't rev it hard until the oil pressure registers.

Justin 

[cschriks]

I feel like an idiot 😂. But a happy one. Thank you for teaching me. 😌

[C8RKH]

As an add to this, I have heard that Esprit's can be a real bugger (I believe that is the correct technical term) to start when the engine is hot. Out of interest, is the starting procedure the same in this instance too?  Thanks.

[Barrykearley]

Pretty sure @C8RKH they can be problematic when hot. Buy a later fuel injected car and the issue ain’t there 😎

[JR]

I have found priming when cold works but priming when hot does not. Hope that makes sense.

[C8RKH]

Just now, JR said:

Hope that makes sense.

Yup. I would assume from the information provided that a hot engine would not need the help of "priming" to ignite, so if you did "prime" it would be too rich etc.

I only ask as I'd love an Esprit, one day, and you old farts may not be around by the time that happens for me to ask and get the advice 

Thanks all.

[Escape]

As above, no need to pump/ prime on a warm or hot engine. In fact, pumping the throttle too often before a hot start can lead to flooding, making it harder to start.

With a cold start, the car has been stood for a while and there will be no fuel vapor left in the intake and less fuel in the internal channels of the carbs. By pumping the throttle you are activating the acceleration enrichment pumps on the carbs. You're not building up pressure but spraying a few drops of fuel in the intake. These get sucked in as soon as the engine turns over and allow it to fire immediately. Once running, normal fuel supply through the carb (idle circuit and cold start circuit if you pull the choke) will take over.

How many pumps you need and under which circumstances differ depending on carb type and can even vary between engines of the same type. The Dell'Ortos used by Lotus typically require 3 or 4 pumps, but most only require the choke when it's really cold. With other brands, 1 pump may suffice but the choke is always needed if not fully up to temperature. For me, that's all part of the charm of driving classic cars: you need be aware of the circumstances and react in the right manner for everything to work as it should. If you do, you will be greeted by an eager engine and are bound to smile because things worked out as you planned. You don't get that satisfaction pushing a button to ask a computer to start the engine for you. 😉

[peteyg]

With a hot engine, slowly press the accelerator pedal down whilst cranking. Don't prime beforehand.

Pete 

[drdoom]

6 hours ago, peteyg said:

With a hot engine, slowly press the accelerator pedal down whilst cranking. Don't prime beforehand.

Pete 

Yes, SLOWLY ! 

[DanR]

Won't work for cold start if the car has SU carbs. 

[semi42]

Fun fact…

In the song “roadrunner” by Jonathan rich man and the modern lovers. At the start of the song the vocals count to six.

because the Plymouth roadrunner had to be primed by pressing the pedal six times before starting.

[pete]

Wow Jonathan Richman,not mentioned much on here

[MPx]

Only just seen this thread.  I too have always used the couple of pumps priming routine in a cold car - indeed as I don't use the car much these days, I usually start with a short crank just to wake it up and start moving some fluids, not trying to start.  Then 2 priming pumps and crank again to start - works for me. 

Also not priming but half throttle and a long crank works for hot engine.   Sometimes needs a pump after a few secs cranking.

However, just to add an alternative view, a while back I was lectured (well not quite - but had it explained to me) by a very well respected Lotus engineer that I shouldn't pump the throttle because the extra fuel washes down the cylinder walls stripping them of any remaining lubricant and therefore causing even more wear at the very moment of maximum wear of an engine.  Likely to lead to premature wear of the rings and their failure which in turn could score the liners.  He didn't go on to explain how to actually start the car though.

[Escape]

I'd argue bore wash is only a problem if there is already enough fuel available for a (very) rich mixture. Which is rarely the case on a cold engine or after sitting for a while. Longer cranking would of course prevent this completely, but that doesn't seem to be very kind to the engine either. Your method of a short crank to get oil flowing and then a few pumps to actually start could be the perfect compromise.

[drdoom]

In operating an early Elan on DCOE's I found that while the pedal pump technique was good for cold start the starter units on the carbs were flat superior, with them the engine would fire about as soon as key turned. Presume the Dellorto's are quite the same.