MFI 2.4 Cold will start, but with problems..

[pszemia]

Hi there....

I am finally setting up my porsche as it should be. All the previous mechanics where a waste of money, just me, some weekends and all the tools and CMA in hand and there it is

After a cold night, or maybe a week without starting (car stone cold), the car will crank, 3-4 seconds, a little press on the gas and it starts ok. No problem with this.

The problem is that the car will start showing little RPM like 500, and with a little press on the gas, it will climb to the regular 900RPM but after some little time, a matter of seconds, drop some RPM and then shutt off.

If i try to start again, it will start ok, and will happen the same sequence.

Maybe on the third or 4th start and some gas, it will stay idling, with no problem (i think because the engine is not yet stone cold).

Also i found that, if i keep the gas pedal pressed some time, like 1 min or maybe a little more on the first try, the car will keep idling without problem.

I've tried the CSV the easiest way, dissconected from stone cold.. crank some seconds, no start. Reconnect the CSV, crank some seconds and it will start ok. So i assume the CSV is working ok.

Is this cold start a common problem, solved by keeping the hand throttle a little lift at about 1200RPM until i get the engine hotter, or there is maybe some other thing making problems here??

here is a video on how the engine stops: http://www.youtube.com/watch?v=bZWeHcvRvC0

thanks!!

Ariel

[tharbert]

I'm a newbie too. I have a 72 2.4 w/MFI as well. May I suggest you read this thread and if you have any questions, start asking... Basically, there are some very well tested procedures to solve MFI problems. Read on: The Ultimater MFI Thread

[FenderBender]

Yes, the hand throttle sould be pulled up a little until it is warmed up. I read the proper factory sequence some where on the fourm's and I believe the factory recomended a quick rev to 4,000 rpm once our twice after it is warmed up a little to clear out any extra fuel from the CSV.

[pszemia]

thanks mike, so there is no problem aparently with my ignition system

[tharbert]

Cold Engine Start

[FenderBender]

Thanks tharbert, That is the thread, I did not have time to look for it.

pszemia, If that is your only problem I would say the ignition is fine. Do not forget to lube your dizzy at tune up time.

[pszemia]

thanks for the thread.. has a lot of info. And indeed, my start system is ok, just need the hand throttle to work again (i've just bought) the plastic piece to connect it again.. the las one has dissapeared.

Mike, what do you mean with "lube your dizzy"???

Thanks!!!

ariel

[FenderBender]

Lubricate the distributor. You might want look up how to replace the hand throttle. It is a real bear to do, most recommend removing the passenger seat I think. I did not but it was a real PITA.

I found the Dizzy thread. Hope the link works.

distributor lube...

[pszemia]

thanks fender for the explanation, i was reading it.. will add some drops of regular oil or 3 in 1 if i can find in there.

[dlague]

I took a different approach to cold start on my 1973 with a 2.7 engine with MFI. When I bought the car I was told to just press down on the accelerator when cranking. The previous owner was not sure if the cold start solenoid and actuation was working.

Being a long time motorcycle guy, I decided that I wanted to control the cold start procedure of squirting the fuel into the engine. Old bikes usually have a little button or "tickler" on the carb that holds down the float and floods the engine a bit for cold start.

What I did was to install a cold start button on the dash and wire it up with a relay to actuate the cold start solenoid on starting.

My cold start procedure is to turn on the key and let the pump run for 10 seconds or so to build up pressure. Then I press the button for a couple of seconds and then crank the engine. It works extremely well, and I know that I am in control and I am not depending on some crude electronic circuit to feed fuel to the engine.

Once started I try to start driving immediately and put a light load on the engine until it starts to warm.

[Jandrews]

Originally Posted by dlague

I took a different approach to cold start on my 1973 with a 2.7 engine with MFI. Whne I bought the car I was told to just press down on the accelerator when cranking. The previous owner was not sure if the cold start solenoid and actuation was working.

Being a long time motorcycle guy, I decided that I wanted to control the cold start procedure of squirting the fuel into the engine. Old bikes usually have a little button or "tickler" on the carb that holds down the float and floods the engine a bit for cold start.

What I did was to install a cold start button on the dash and wire it up with a relay to actuate the cold start solenoid on starting.

My cold start procedure is to turn on the key and let the pump run for 10 seconds or so to build up pressure. Then I press the button for a couple of seconds and then crank the engine. It works extremely well, and I know that I am in control and I am not depending on some crude electronic circuit to feel fuel to the engine.

Once started I try to start driving immediately and put a light load on the engine until it starts to warm.

+1. I have the exact same manual switching mechanism and follow the exact same process. Works extremely well.

JA

[dlague]

I guess there are at least 2 brilliant MFI owners in the world!!!

Think there are any more???