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-   -   starting problems (http://forums.pelicanparts.com/porsche-911-technical-forum/431526-starting-problems.html)

limble 09-21-2008 09:51 AM

starting problems
 
I need to point out that I overfilled the oil for a trip from Minnesota to Indianapolis last weekend.
The oil finally burned off and car was starting and running fine all week.
This may or may not have anything to do with the problem I'm currently having.

The facts:
79 SC stock CIS injection
location Minnesota
Summer time car would start on the first turn.
Began taking several spins to start
Average day time temp 60-70's
drove car 2 hours. parked over night.
Car started easily in morning. 70 deg's
Filled up with regular gas.
Drove 5 minutes
Car sat 30 minutes.
Started up easily
Drove 15 minutes to breakfast.
Car cranked 15 seconds before it started.
Once started car ran a little rough but smoothed out.
Drove one hour, turned off car, sat 10 minutes then started easily.
temp 70 deg
drove one more hour stopped for lunch, car sat one hour, car started easily.
Drove one more hour, stopped for 30 minutes.
Car cranked for 30 seconds before finally starting.
Drove two hours, parked car 30 minutes.
Car started easily
Drove 1 1/2 hours
Car sat 2 hours.
Temp 60 deg's
Car cranked 15 seconds before finally starting.

It sounds like it's trying to fire but takes awhile tostart.

This afternoon car starts easily.

Any thoughts?

Paulporsche 09-21-2008 09:58 AM

I would check your control pressures, especially the warm cp w/ a fuel pressure gauge. I would also check the mixture , and the residual fuel pressure, which will help detarmine if the fuel accumulator and check valve are OK.

limble 09-21-2008 12:07 PM

More data...
Took a fifteen minute drive, sat for 10 min
Cranked 10 seconds and finally started.
Drove another fifteen minutes sat for 20 mins
cranked 15 secs started, drove home and into garage, immediately started several times.

ossiblue 09-21-2008 05:03 PM

Follow Paulporsche's advice as your first steps. Several possible culprits and pressure check where you should begin, IMO.

limble 09-24-2008 04:31 PM

From the Bentley Manual:

I checked my fuel delivery by pulling the line from the bottom of the fuel accumulator and attaching a hose to the line. Then put the hose into a liter bottle jumpered the fuel pump. Ran the pump for 30 seconds. This should fill the liter bottle. I only got .4 liter. So should I assume that my pump is bad?
I still might get under there and check the current draw on the pump.

Mike

boyt911sc 09-24-2008 05:24 PM

FP check test........
 
Quote:

Originally Posted by limble (Post 4199631)
From the Bentley Manual:

I checked my fuel delivery by pulling the line from the bottom of the fuel accumulator and attaching a hose to the line. Then put the hose into a liter bottle jumpered the fuel pump. Ran the pump for 30 seconds. This should fill the liter bottle. I only got .4 liter. So should I assume that my pump is bad?
I still might get under there and check the current draw on the pump.

Mike

Mike,

The bottom port of your fuel accumulator is the drain line. What you actually measured was the fuel return from the fuel distributor and WUR via the pressure regulator valve. Why don't you check it before the fuel accumulator (top fitting). This will show the FP's rate unimpeded by the pressure regulators. Just my two-cents.

Tony

limble 09-24-2008 06:45 PM

Tony,
The Bentley book claims the rate should be 2 liters/minute using this method. But as I mentioned I only get half this. Is the Bentley book wrong? What should the rate be using the method you mentioned?

boyt911sc 09-24-2008 07:21 PM

Fuel pump check test........
 
Quote:

Originally Posted by limble (Post 4199908)
Tony,
The Bentley book claims the rate should be 2 liters/minute using this method. But as I mentioned I only get half this. Is the Bentley book wrong? What should the rate be using the method you mentioned?

The book says 'Disconnect fuel line from accumulator on left side of engine (arrow)'......Bentley SC Manual page 201-6.......The instruction is not very clear or specific. But it refers to the delivery line of the fuel pump. What you did was measured the flow rate using one of the return lines instead of the fuel delivery line.

Bentley book is correct. Its the interpretation or implementation that's different. Disconnect the FP delivery line that is connected to the top of the FA. Not the one going to the fuel filter or the bottom. Not unless your fuel accumulator was installed up side down which I doubt. Keep us posted.

Tony

limble 09-25-2008 04:57 PM

Tony,
I hooked up the line as you described. The flow is more than adequate. I installed a new filter. I may drive it for a few days and see if that cured it. If not then a new fuel accumulator might be the next purchase.
Thanks for the help.
Mike

boyt911sc 09-26-2008 04:43 AM

CIS troubleshooting........
 
Mike,

Do you have a fuel injection pressure gauge? Hook one and it will tell you a lot about the condition of of your fuel system. It will save you time and money, just for a $60 investment. Now is the best time of the year to get your car running good before the winter storage. And the car will be ready for sping driving. BTW, your Bentley manual is an excellent reference book to have.

Tony

limble 02-15-2009 02:16 PM

I found out what the problem was/is. The check valve is bad see picture . The spring that holds the valve closed is broken. I found this after replacing the fuel filter, the fuel accumulator and pulling the fuel pump off. I was given information that this pump (1979) has an integral check valve so I bought a new pump. Not so. I may put the old pump back in if I can return the new one. If I can't return it then I'm putting it on EBAY. Anyone need a new unused pump?
Lesson learned? Look for all cheap solutions first.

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