Charlie944

I have a DME out of an 87' 944 and a AFM out of an 88' 944. I want to put these in my 84' 944 but I read that the late DME's will not fire the fuel injectors due to the different drivers.
This was on Clarks Garage: "Just realize that you can't test an early 944 (pre-1985.5) using a DME computer from a later car or vice versa. They use different injectors. A later DME will not fire early injectors at all. An early DME MAY fire the injectors in a later car but, the current draw will be excessive and you could potentially damage the DMEs injector drivers. Even if you don't damage the injector drivers, they will likely shut down after a few cycles due to the excessive current draw."


I know some of you have done this swap for a later DME and AFM into an early 944 have you had these problems?
TIA!!

Rock

You can swap the DME and AFM.

The Early DME's (pre 85.5) have to go with the earlY AFMS. It uses like a .5 volt signal instead of a .9 volt or some crap like that.

Ive swapped out the DME and AFM from my 86 into the old yeller 84. It worked.

You just have to switch both! The later AFM/DME setup allows you to use chips that can be dropped in, whereas the early DME's chips have to be soldered in.

AznDrgn

Never heard of the driver problem, always was told that you just needed to swap both or else it wouldn't work.

Charlie944

Awesome Rock, I knew the later AFM was required for correct signal to the DME. I am glad to hear no problems with the injectors not firing.

In regards to the O2 sensor did you have to use the later heated style? Right now mine is unplugged because it does not have that much authority (0.25V - 0.75V) and actually runs better.

I am hoping this will help with my intermittent no-start problem. I think my early DME's are suffering from cold solder joints. I have to open them up and look where the ribbon cable connects the two boards (source of probs) and by the transistors as well.

Rock

The O2 Sensor should still work. There is only one signal wire (black) on the o2 sensor if I remember correctly. The later style has that and 2 white wires to heat it up quicker to get it out of open loop mode.

Charlie944

Rock, how you long been running the early injectors with late DME + AFM?

Charlie944

Anyone know if later 944 Fuel Injectors will fit into a early 944 fuel rail? As far as nozzle sizes are concerened.

AznDrgn

All 944's use the same injector seal kit so they should fit fine.

85944na

I'm running a late dme/afm with early injectors, haven't had any problems. I have not heard of the injector issue before do I need to go out and get some injectors?

UncleMaz

+1

V2Rocket

I have 4 spare DME's and an extra AFM, all for early models...:P

TWO HUNDRED AMERICAN DOLLA

M758

my 84 944 has run from the start with Late AFM/DME/Injectors. For time I ran early AFM/DME with the same late injectors. Never any issues.

dally_de

so u guys say that u cant run with a late DME and a early AFM..right??then can someone tell me if i can adjust mine AFM (i have a 85.5 car) because when i bought the car someone has opened the AFM and relocated the spring...can i know somehow what is the right position for it??or i have to get another one(new it's out of the budget ,and used..i cant find ) ?? ...pls help me ,if someone know....i have a very big fuel consumption..and im sure it is because of the AFM
thank u

UncleMaz

No, only late with late and early with early (DME/AFM).

UncleMaz

Do you recommend the late injector set with the late DME/AFM or just stick with my early rail until I need a new one?