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-   -   Picture of 73 MFi cold start system please! (http://forums.pelicanparts.com/porsche-911-technical-forum/353536-picture-73-mfi-cold-start-system-please.html)

AndrewWolfeUK 06-23-2007 07:51 AM

Picture of 73 MFi cold start system please!
 
hi guys

I've been looking throught the tech articles, pdf's and my tech manual. I cant seen to find a picture or a diagram of the cold start system, can any of you guys help me out with a pic or a link to a diagram please?

Many thanks

Andy

rs dreamer 06-23-2007 10:26 AM

Cold start solenoid #2
http://forums.pelicanparts.com/uploa...1182618839.jpg


Fuel line #15 from cold start valve to 'T' #46 in next picture
http://forums.pelicanparts.com/uploa...1182618934.jpg



Cold start fuel lines to throttle bodies #26,27,46,47
http://forums.pelicanparts.com/uploa...1182619016.jpg


Last should be the thermotime switch. Gary

AndrewWolfeUK 06-23-2007 12:08 PM

OK Thanks Gary, I've checked it out and i appear to be missing all the parts, i have part number 2 from 1st pic, but nothing else. I cant see an entry point on the throttle bodies either.
I could really do with an 'real life' photo.

pwd72s 06-23-2007 12:56 PM

Andrew, I really suck at searches here...but a couple of years ago (?) there was an excellent thread on replacing fuel lines on MFI cars. Grady Clay did some great work on this one, and this thread has pics, diagrams, etc. covering the entire MFI fuel delivery system, including the cold start. IF you can find it, this thread should cover everything you want.

rs dreamer 06-23-2007 02:17 PM

On the left side of each stack (plastic stacks '72-'73 years) are three plastic pipes - two 'tees' and one 'L' shaped. #48 has a dashed line going to the plastic 'T' at the back of the stack. The fuel line from the cold start solenoid goes to a 'T' piece #46 , and from there a fuel line #47 and #48 goes to the 'T' that is closest to the firewall on each stack. Then short fuel line pieces #26 connect that 'T' to the 'T' in the middle and then from there to the 'L' shaped piece which is toward the rear of the car. #27 are clamps. I looked for pictures of stacks but was unable to find one. Sorry, Gary

svandamme 06-23-2007 02:52 PM

careful when messing with this
it'll flood your engine before you can say wooptido

it delivers huge amounts of fuel, and dumps it raw in the intake stack...

don't test it with the cold start injectors connected
put a tube on the connection and route it to a big glass bottle instead...
only when it does what it is supposed to do , should you connect it to the injectors in the stack...

when you do connect them, tripple check for leaks
those plastic thingies are brittle, and there are like 10 connections to the hose... if even just has a decent leak, you'll have more fuel in the engine compartment then you care for

AndrewWolfeUK 06-24-2007 04:38 AM

Thanks guys.
RS dreamer I can see from the diagrams exactly what is missing, i know exactly what you mean in your post.

I would like a picture of one bank of stacks please, i can not find a point on my stacks for the two 'tees' and one 'L' shaped to enter the stacks.

pwd72s I'm off to search it out now, thanks again.

svandamme As it happens I have seen the speed it delivers fuel, but thanks for the warning a potentially messy/dangerous error if your not in the know...

svandamme 06-24-2007 04:43 AM

sorry for the bad quality, but it's the only one i have
i think you can see the location of the nozzles though

http://forums.pelicanparts.com/uploa...1182685364.jpg

AndrewWolfeUK 06-24-2007 05:55 AM

Ok here is a close up of my left hand stack, can someone point out where the plastic elbow and t's go please?

http://forums.pelicanparts.com/uploa...1182689665.jpg

http://forums.pelicanparts.com/uploa...1182689646.jpg

AndrewWolfeUK 06-24-2007 07:35 AM

I've been sucking the life out of the search function for nearly 2 hours now and I've not managed to find a close up picture of the cold start parts on the stacks.
Anyone got an cold start system on their stacks they could take a picture of please?

Andy

svandamme 06-24-2007 07:36 AM

i suspect that's an older then 73 Stack
there should be a metal airfilter housing, with fuel rails inside to provide the cold start enrichment at the top of the stack

svandamme 06-24-2007 07:42 AM

http://forums.pelicanparts.com/uploa...1182696087.jpg

this shows the older airfilter housing, with connections for the enrichment system

from your picture, i can see some rust on your air filter housing, which you would not see on the newer system, since that has a plastic housing instead...

svandamme 06-24-2007 07:49 AM

i've colored in the enrichment parts of the newer system.

http://forums.pelicanparts.com/uploa...1182696546.jpg

rs dreamer 06-24-2007 08:43 AM

Andrew, You don't have the stacks that came in 1972 and 1973 cars. Those stacks are plastic and have the cold start lines on the sides. You have 1971 and earlier metal stacks. My understanding is that the cold start enrichment was fed into the tops of the stacks. Gary

pwd72s 06-24-2007 10:13 AM

Quote:

Originally posted by rs dreamer
Andrew, You don't have the stacks that came in 1972 and 1973 cars. Those stacks are plastic and have the cold start lines on the sides. You have 1971 and earlier metal stacks. My understanding is that the cold start enrichment was fed into the tops of the stacks. Gary
Yes...and it was a fire trap. Many owners of such earlier than '72 systems unhooked them. Wisely so, IMHO...my (purchased new)70 'T had such a system above the carbs...I suffered an engine fire.

AndrewWolfeUK 06-25-2007 04:05 AM

Many thanks guys.
Your posts reminded me of a thread i started a good few years back, in order to determin what engine and which ancillaries i have on my car.
You guys were correct and i think it was kurt or grady that pointed out I have a 73 motor with 70 MFi.
I fitted and timed new pump drive belt a few days ago and i also made and fitted a manual enrichment device. Now the car will start with 3 turns of the key, much better than the 10 or so i was having to do. I have yet to drive the car but the enrichment device seems to have done its stuff, once it had run for a few mins i adjusted the enrichment device a little, then a little more, etc... Now once warmed up I get a crisp throttle responce and it revs very freely.
As far as a cold start system goes i think i'll wait to the winter and see exactly how hard it is to start, the method of tubes in the airbox sounds like a bad idea as I often here back fires from the stacks when the car is 1st started.

here is a pic of the bodged enrichment :D
http://forums.pelicanparts.com/uploa...1182769469.jpg

svandamme 06-25-2007 05:02 AM

i had a similar setup at some point, but have to say , i was so much happier after i had canned it and went back to the thermostat with warm air hose...

AndrewWolfeUK 06-25-2007 05:45 AM

The heat exchanger cover is non existant. Maybe go back to thermostat when i replace the heat exchanber!

svandamme 06-25-2007 06:00 AM

i did that, didn't regret it... SSI's flow nice with mfi...

Rot 911 06-25-2007 06:49 AM

Andrew, I'm a bit late to the thread, but the others are right, you have pre-72 stacks. Here is a picture of my '72E engine showing how the cold start lines fed into the bottom of the stacks:

http://forums.pelicanparts.com/uploa...1182779229.jpg

Here it is finished with SSI's:

http://forums.pelicanparts.com/uploa...1182779317.jpg


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