TurrFinn

Are early model 944 AFM's the same as late model AFM's?

pjs.oregan

No.

But if the AFM and DME match you can swap them from early to late -- e.g. late DME and AFM in an early car. You just can't mix them up.

TurrFinn

Appreciate the answer. I've got a 1984 944 and my ECU/DME I'm pretty sure has an issue from corrosion. I replaced my AFM because the temp sensor in it was bad and the meter is an 87 but I want to switch to a late model ECU/DME. Are there only three types of ECU/DME pre 1985.5 and then after? I know the early models were different then after 1985.5 they switch to 24 pin that could be a made 28 pin and then late years they are 28 pin. Do you know which model DME fits an 87? Instead of switching DME's can I pull the temp sensor from the 87 AFM and put it in the 84 so I don't need to buy a late DME? Sorry to bombard you with questions lol.

pjs.oregan

My understanding is it is just divided into early / late with the transition in 85.5 (ie oval dash = late AFM/DME).

Later (I think 88+ but not sure) DMEs had a 28-pin chip socket but no other compatibility changes i.e. they should be compatible with any "late" AFM. But that's just my recollection.

Unfortunately I don't think changing that temp sensor will help.

TurrFinn

https://rennlist.com/forums/924-931-...-no-start.html
That's the link to the thread about the car and what my issues have been, the car is hard start no start currently. If you could tell me what you think about my issues that would be greatly appreciated. I'm losing my mind a little.

pjs.oregan

Just checked out the thread. It might be helpful to post a video of what the car does to see if anyone notices something.

I suggested before you double/triple/quadruple check the spark plug leads are going from the right socket on the distributor to the right cylinder (you'd be amazed how easy it is to mix them up) - did you get around to doing that?

I also saw the picture of the DME you posted -- it looks like there's a 28-pin chip in there? In which case you must have a late DME (and therefore your late AFM should work, and your problem lies elsewhere)

edit: I see you've got a fuel pressure tester. What happens to fuel pressure when the car is (briefly) running? Might be worth getting a video of that too

TurrFinn

I checked the wires but I will do it again. I didn't have the DME in the car when I fuel pressure tested it, I have an ftech9 relay with a 3 second prime so I just went with that because the car will puff. I'll see if I can catch a video of what the car us doing and post that to the thread.
Edit: I just counted pins on the chip and your 100 percent right, its a 28 pin chip, thats helps if i ever want to do a maf conversion kit. Thanks for noticing that and telling me.

TurrFinn

I belive the wires are in the correct order according to Lindsey racing photo

TurrFinn

This is the final response to this thread. Today I can confirm you cannot mismatch AFM's and DME's from different years.

DO NOT MIX AFM'S AND DME'S FROM DIFFERENT YEARS, YOUR CAR PROBABLY WONT START.

I speak from experience

Link to origin thread: https://rennlist.com/forums/924-931-...-no-start.html