Mfi Issues

[denson]

Had my MFI pump re-built 14 months ago through a local repair shop. They claim to have sent it to a MFI guy in CA, but I do not know his name.

The idle will not go below 1150 rpm and the adjustment screw that you push in and is supposed to connect to an internal adjustment fork yields no changes when turned. Because of this, the car is running very rich and is dumping gas into the oil. When started cold it shakes a bit until warm and then idles fine at the 1150 mark.

Does anyone know what could be going on here? Can I harm the engine by driving it and knowing I am getting moderate gas into the oil, is the adjustment diferent than I stated and do you guys know who an MFI guru may be.

The car is a 1970 911S.

Thanks for the help, I gotta get this done asap.

Regards,

John

[Chuck Miller]

John,

Before you get into anything drastic, check the pre heater inner and outer hoses that run from the front of the pump to left side sheet metal. Most MFI's are VERY sensitive to this closed system. Check the both hoses for tears and leaks, then see if the clamps are tight.

Hope this first step helps,

Cheers,

[kenikh]

If California, it probably went to Gus at Pacific Fuel Injection:

Gus Pfister
153 Utah Avenue
South San Francisco, CA 94080
650-588-8880


Follow Chuck's recommnedation first.

[pu911rsr]

An overly rich engine can certainly dilute the oil and do great harm to your engine.
Phil

[rvdv]

Oh boy, not a nice problem to have. This could be a number of problems. I don't think that anyone can pinpoint the problem for you as the MFI has to be set up in a certain sequence. It could be the fuel enrichment hoses as Chuck mentioned, the length of the rods on the throttle bodies and the rod length going to the pump and cross shaft are very critical. Your best bet is to download the "Check Measure Adjust" factory service manual from here:" http://www.pelicanparts.com/techarti...MFI/TipMFI.htm and follow the setup procedure outlined in the manual. Be prepared to spend some time.

Rudy

[tfiv]

John, As Rudy mentioned, read "check measure ajust" from start to finish and then decide if it's within your capabilities. The pump is just one of the expensive wear items in this system. Good luck!

[spydr32000]

John, you could have more than one problem. Firstly I would be checking the thermostat hose as stated previously, then remove the cap on the end of the thermostat housing, and make sure there is no rubbish, leaves,or excessive dirt in there.The housing is spring loaded so make sure you keep pressure on the cap while undoing it. Make sure the the washer pack and pin move freely in the housing.
The other possibility is you could have a lazy distributor causing the idle speed to stay up high, to check that you can simply load up theengine at idle by partly releasing the clutch enough to reduce the idle speed, if the idle stays low then start looking at your timing and chek the timing returns to its correct adjustment at idle.

[304065]

90% of the time its NOT the pump.

Until the engine oil temperature reaches about 180 degrees WITH a clean thermostat with 25 pairs of discs in the correct orientation and the proper inner and outer paper hoses, the engine is going to run so rich it will make your eyes water.

Once it's at operating temperature and the thermostat is off, then and only then does the idle mixture screw take over.

A high idle is not the pump, either. It's either the distributor, too much advance at idle, which happens to old distributors as the springs wear and everything loosens up, or the airflow through the stacks, which can be caused by incorrect correlation or worn throttle bodies in the worst case.

But the only, only only way to figure any of this out is to follow Check Measure Adjust.

Any
Competent
Porsche
Driver
Tracks
Faster
If
Brakes
Come
Smoothly

Air filter
Compression test
Plugs
Dwell
Timing
Fuel pressure
Injectors
Belt (MFI pump timing)
Correlation
Smog

http://forums.pelicanparts.com/showt...c&pagenumber=2

[denson]

Fellow S owners:

Thank you BIG time for the tech responses. Going to the check measure info that was forwarded. Hope to have a solution to this soon. Need to learn more before giving it to the mechanic.

You guys think its any issue to drive it ? While it is rich, its running great and not burning any oil.

Thanks,

John

[304065]

Be careful. Even though the oil level may not be dropping, it may be that the oil tank is filling up with fuel. Then when you get it hot enough the fuel evaporates and the engine seizes.

I would CMA first and drive once you have a sense of where the mixture is.