Simple '74 2.7L Engine Warm Up Question

VDD · 12-11-2008, 07:01 AM

New to this blog - thanks for the help:

Facts: 1974 911 2.7L engine. High quality rebuilt engine (including new inserts to solve the stud pulling problem) with 30k miles on it. Engine runs great when it’s warm.

Problem: In California it seldom gets below 40 degrees, but even between 40 and 60 degrees it takes a very long time for the engine to warm up to accommodate virtually any load (10 mins +). How do solve this problem?

kodioneill · kodioneill's Garage

do a search on " control pressure" the most likely culprit it the cis control pressure. this can be adjusted. it's running lean upon start up and you have to lower the pressure that controls the fuel mixture via "the fuel distributor" to richen fuel mixture when cold. sort of a complicated choke. this is done by adjusting the control pressure regulator. read up on the cis system. buy or borrow a fuel pressure gauge . there is plenty of info on this forum. use the search function and you will see. all new commers must include pics of their 911.

VDD · 12-11-2008, 07:47 AM

Very helpful. Thanks. I'll send a pic later what I have is not in a .jpg or .gif format.

don gilbert · don gilbert's Garage

vdo, you control pressure reg is not adjustable unless you do a simple modification to it, search threads on adj. wur. Before adjusting, turning, or twisting anything, you need to put the gauges on it to determine cold and warm pressures. sounds like your a little lean, might want to turn you mix up 1/4 turn and see if that helps.

kodioneill · kodioneill's Garage

pressures first, mixture later!!!!

don gilbert · don gilbert's Garage

it wont hurt anything to richen it up a little, might solve his problem and make him happy not to have to buy gauges until the next problem

RWebb · RWebb's Garage

blog??

are you letting the car sit to "warm up" the engine?

if so, DON'T -- drive off asap and keep the revs over 2,000 but below 5,000

VDD · 01-15-2009, 06:22 AM

All, sorry been off line for a while with insane year-end work. Just to get back to you, the problem has been solved and you guys were amazingly helpful. As it turns out it was the warm-up regulator and for some reason it was not getting any voltage. To be honest, I've had the car now for 10 years and it has NEVER run better! Thanks