Charlie944

Ditto on what Michael asked. For now I am going to run early injectors cause I want to see if this late DME/late AFM cures this wicked intermittent no start problem of mine.

dally_de, If the flap spring was moved (and I cannot understand why) that could cause a false readin AFM (especially if the flap is open further that what it needs to be hence dumping more fuel). I know the wiper track arm can be bent to cover a new set of tracks on that black electroconductive film.

For used look around here for folks parting out cars or check on ebay, or PCA classifieds (if you are a member). Also look on Pelican Parts Classifieds.

UncleMaz

Thank you. Is the difference between early vs. late flow ratings (236.5 cc/min vs. 229 cc/min @ 3 bar) significant enough to warrant concern in terms of DME management?

Charlie944

What sort of problems were you having? Starting, running, etc? I know most injectors over 55lbs/hr are low-impedance and anything less is usually high-impedance. But I cannot imagine the NA injectors being anywhere near 55lbs/hr.

Jeff, I am running the TEC2 of my Callaway turbo, but all this DME swapping and intermittent no-start problems is what plagues my 84' 944 NA which is my daily driver.

Charlie944

Well according to Clarks the resistance values are the same so that is good!
I wonder due to the addtional pressure for more fuel conservation Porsche went with a bit less injector and tweaked the fuel maps more. Did it backfre through the intake or exhaust?

UncleMaz

So, it sounds like when they go, replace them with late injectors. For now, the car is running... Won't jinx it.

dally_de

yes,someone took the black cover out..and moved the spring..i do not know in witch way..i have removed the the wiper pick up to a different line..i have excellent reading on the gas analyzer..good fuel/air mixture..but that it is on idle...do not know what the nr should be on different rpm..i have a big fuel consumption 16l/100km in the city..and it is big (from what i know) for my car (85.5 ,2.5l ,163 hp).i have changed pretty much everything ,and all that i think it is because of the AFM,that if u move the spring ,the AFM will have different readings on the rpm range..not on the idle..
i also pretty unsure for a used AFM...and a new one ( ...it is pretty expensive.
inside there is a plastic toothed wheel with numbers marked around the edge to indicate the spring tension but all the marks are 500 ...
can it be a way to bring it to factory settings??

M758

The fuel rails don't make difference at all. You can use any fuel rail. As for the injectors... well I had access to the late injectors and generally perfer to keep to all late parts or all early parts where reasonably possible. Fewer chances of potential issues down the line. Even so my 84 944 is really bastard of parts from 83, 84, 87 and 88 and still runs great.

Rock

You dont need to change the injectors. The injectors dont give a flying crap.

Think about how simple the injector is. It opens when the DME pulses like 12 volts to it. How is the injector going to know if its a late DME pulsing it vs an Early DME? The both send the same voltage. You shouldn't have any problem with your injectors.

rberry951

The 85.5-87 performance chips we're testing now are being run on a 1984 944 with a 87 DME/AFM. No issues. Have also run with a 88 DME, still no issue. Management is different than stock, but Porsche built in enough protection that the injector size difference will not harm your car. They had to ship cars all over the planet, not knowing what kind of crap fuel someone might have access to. So stock management would be safe.

Regards,
Russell

Rock

I berieve Stock vs Stock 84, up to 87 N/a injectors flowed the same rate and ran at the same fuel pressure ~36lbs?