judd944

Situation: my 85.5 944 is running but I am getting no Tach or speedometer. The car does run and to my surprise the computer in the car is part # 944.618.111.01 This is for an Early 944 not a late car.

Is my speedometer not working because the computer is made for a car that gets it's speed from the front left hub mechanically? This would explain why I cannot get it to work.

When I put the computer in the 85.5 from my 86 (part # 944.618.121.04) the car starts but quickly dies. (the tach does show RPM while working)

per clarks garage I tried checking the DME relay, that works fine although when I jumper pins 30 and 87b it just cranks. (I can hear the fuel pump working)
The fuse is good I checked that.

The 86 computer is good because my 86 runs fine.

when I have the early computer in the 85.5 the car runs and drives but no tach or spedometer.
This leads me to believe I have:

* DME Control Unit Working-From 86
* DME Relay Working-From 86
* Security System Control Unit I will try to remove this
* Fuel Pump Working
* Fuel Pump Fuse Working
* Distributor Cap, Rotor, Coil, or Primary Coil Wire Working
* Engine Speed and/or Reference Sensors correct resistance and the car runs with the early computer???


What the heck else should I try?

AznDrgn

Check your AFM, you can use either late or early DME's if you match them to the proper AFM. The problem with this as you're seeing is the early dme doesn't have provisions for the speedo but I would think the tach would still work.

judd944

The AFM's are both the same part # (ending in 064)
I tried removing the security system stuff. the car just cranks no surprise there.

I just gave it another try with the DME relay jumpered in three places (87,87b,30) when I tried to start it once again it just died right away. Then I tried to start the car and give it WOT. it stumbled for a couple seconds and died. I think I am killing both of my batteries. they are jumpered together now.

AznDrgn

does the '85.5 DME run the '86 properly?

judd944

No, the car will not start. I have not tried again after someone here said that doing that will fry the early DME

judd944

I just removed the distributor cap and it looked fine. no sign of arcing.

Legoland951

Is your AFM connected? Early DME should not work with the late AFM unless someone tweeked with it.

AznDrgn

The main difference is the signal from the AFM I believe that the early goes from 0-5v and the late goes from like 0-7 or something like that. If you have an early DME you have to run a early AFM or else it won't run right. Have your AFMs or DMEs been opened and tampered with?

judd944

I opened my AFM and tampered with it when I was having some idle problems earlier. maybe I will try to put my AFM from my 86 in the 85.5. I have not opened that one yet.

Lego, my AFM is connected. I tried to disconnect it and start it. no dice.

AznDrgn

What exactly did you do to it when you opened it?

Legoland951

The AFM idle adjustment is OUTSIDE the plastic cover. I think you messed with the main air/fuel adjustment, which will cause the car to run bad or not run at all if its not adjusted properly. The idle is in the little hole covered at the factory for a reason and can be turned with a 6mm allen if I remember right.

judd944

Lego I owe you a beer! The car idles fine with the computer and AFM from the 86 in it. I am going to take it for a drive. I will be back in a few.

I opened up the AFM on the 85.5 earlier and moved that little arm around. I also moved the adjustment screw lego referred too.

WAHOOOOOOO

judd944

alright, so the Tach works fine now. but still no speedometer??

AznDrgn

bad sender on the trans or a bad connection to the sender?

judd944

Right on AznDrgn! I looked at my sender on the transmission and it had corrosion all over the inside of the connector. I cleaned it up but it still did not work. I then swapped the sender from my 86 and that fixed the Speedometer! everything is working now on the 85.5!!!!!
You guys are great! beers for everyone!