low fuel on cold start,

[w113dude]

On my 1970 280se engine the car has lots of power, drives great & very responsive but during cold start the engine sputters as if it's not getting enough fuel, when it warms up it's a bit better but there is a bit of engine mis that I can not figure out. I have check every thing along the way, WRD, linkage, fuel and air ratio are all in order. It seems to me when it's asking for more fuel during cold start the pump is not able to supply the extra amount therefore it starts sputtering.

Is it possible the injection pump tips have adjustments, meaning by loosening or tightening will allow more or less fuel? one other thing the fuel line were all CAD plated recently but have taken them out and made sure were clean.

Any Ideas how to verify fuel amount going in to each cylinder or any torque setting?

Thanks
Shaun

[ja17]

Hello Shaun,

Does the car "caugh" (back fire through the intake) during acceleration when cold?  If so, the mixture might be too lean. 

[w113dude]

Hi Joe,

At first it was lean, but after adding shims to barometer fix the lean problem, split linkage test also checks on warm engine. after driving for a while the mis is hardly noticeable but still there. Do you think it's still too lean?

[ja17]

Shaun,

What is the status on the spark plugs?  What brand and how fresh?

[w113dude]

Hi Joe,

I have a set of new NGK BP5ES, I did play around a bit more with CO meter, at around 4.5% the car idles great but sluggish on all ranges, when I richen it the car drives great but idles poor with the plugs turning black. The wires are new carbon, 051 dist, with Pertronix set up, the coil is black flame thrower that comes with Pertronix, I also tried with a set of copper wire set  I didn't notice any changes.

Shaun

[ja17]

Hello Shaun,

Sounds like the timing may be a bit retarded.  Check to see if it is at 30 BTDC at 3,000 rpms.  Also check to make sure that the venturi throttle is all the way open when the accelerator pedal is on the floor.

[w113dude]

Last we checked timing (couple of weeks ago) was 30 BTDC at 3000rpm , the throttle body checks, on the weekend I'll play around with timing maybe advancing it.

Thanks Joe,

Shaun

[w113dude]

An update,
I did advance the timing from 30 to 36 at 3000 RPM, much better. after checking fuel/air ratio with split linkage at 3000 rpm it's still too lean but at about 2000 to 2500 rpm drives great and very responsive. currently I have two thick washers under the barometer which is over 4. ml, so my question is if I add more washers to increase fuel what happens to the mixture at 2000 rpm will that increase as well? or should I use the screws at the back of the pump to adjust more mid and higher range?
I have to admit adjusting the washers is a much easier choice.

Thanks
Shaun