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NEW 944-Spec Legal DMEs!
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TOPIC: NEW 944-Spec Legal DMEs!

Re: NEW 944-Spec Legal DMEs! 2 years, 1 month ago #21264

  • reflexr
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  • Senior Racer
  • Posts: 146
I don't know, we have found a difference in DME connector to engine harness between late and early. 28 pin for late, and 24 pin for early.
Joey Genitempo
NASA SoCal
88 944 Spec
No. 42
Blue track map camouflage

Re: NEW 944-Spec Legal DMEs! 2 years, 1 month ago #21265

  • AgRacer
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reflexr wrote:
I don't know, we have found a difference in DME connector to engine harness between late and early. 28 pin for late, and 24 pin for early.


You are referencing the number of pins the chip has internal to the late DME. The 85.5 to 87 DMEs have 24 pin EEPROM chips which contain the engine tune. The 88 DME was changed to a 28 pin EEPROM chip with the tune which has a 150 rpm higher rev limit. The 28 pin chip has other benefits not taken advantage of with the stock hardware from the factory.

The early DME with the screw on cover has no removable EEPROM chip like the late DMEs as its tune is imbedded in several chips on the board. There are people who have modified the early DME to accept a removable chip, but that is not legal for 944Spec.

This new DME has the 88 tune with 150 RPM higher rev limit embedded directly on the board like the early DME.

I have found no reference anywhere to differences in DME main connectors to the engine harness which allows them to be plug and play across all years so long as you match an early DME with early AFM and late with like likewise.
J. Stanley
NASA-SE Region 944 Spec Series Director
Yellow #60

Re: NEW 944-Spec Legal DMEs! 2 years ago #21268

  • dpRacing Dan
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  • 944 Spec National Director
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Thanks for taking care of much of this clarification Stanley.

Correct, there is no difference between early DME and late DME connectors to the wiring harness of the car.

It DOES have the FQS

Charlie, the "better performance" literature is from F9techs verbiage, and is purely a reflection to the failure of OE DMEs.

I have had 4 or 5 DME failures in my time racing 944-spec cars. The failures seem to be directly related to 2 issues- big curbs (like at Road America) and moisture. 2 of the DMEs I've had that failed have been corroded from the inside out, a common issue in the midwest with high humidity.

I have switched several times from early to late DMEs and AFMs. Saying that cars with only early AFMs and DMEs arent easily updated to use this component is rediculous. I have about 8 AFMs in my many boxes of parts I've accumulated over the years of buying these things, and scowering junkyards. The late AFMs are not difficult to find. If you havent felt the need to update your car to the late stuff up to this point, then this makes no difference.
Last Edit: 2 years ago by dpRacing Dan.

Re: NEW 944-Spec Legal DMEs! 2 years ago #21272

  • tcomeau
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Also, keep in mind that there are 3 components to the air/fuel/injection process.
The DME, the AFM ......AND the injectors. The early 201 P/N injectors flow more than the late 158 P/N injectors.(last 3 digits of the part number on the injectors). The AFM's end in 028 (early) or 064 (late).
If any of you guys have bad DME's, contact me for repair. I've learned/taught myself how to repair these units. Works almost every time. We test them by starting, idling, and pulling to redline under load.
Tim Comeau
SoCal 944 Spec #22 since Feb 2003.
Let's keep building it!

Re: NEW 944-Spec Legal DMEs! 2 years ago #21274

  • KJZ78701
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  • Comp School
  • Posts: 27
Thanks Tim

Could you please add a bit more information if you have it. If I replace my early DME/AFM combination for the newer DME/AFM, but leave the early injectors in there, am I going to have trouble tuning the car to get the target AFR?

Also, would you be willing to share what you have learned about repairing the DMEs?
Last Edit: 2 years ago by KJZ78701.

Re: NEW 944-Spec Legal DMEs! 2 years ago #21275

  • tcomeau
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No, you shouldn't have trouble tuning. Just be aware that you're injecting more gas all the time with the early injectors.
I get paid for what I know. I charge for this DME service so I can't afford to share eveything I know, though I'm known for my generous technical help. This wasn't supposed to be an ad for my services. I'm just saying don't junk them.
Tim Comeau
SoCal 944 Spec #22 since Feb 2003.
Let's keep building it!
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