Replacement DME

[eomalley]

A flood in my 96 ti's computer appears to have rendered it nonfunctional. The fuel pump does not prime so the engine cranks but does not fire. The relay seems okay and when power is applied directly to the fuel pump it hums in a normal sounding way. Initially, rapping the DME during cranking caused the engine to intermitently fire and run. Now, no matter what I do, the fuel pump foes not prime and the engine does not fire. I believe the DME is not sending the necessary signal. Does anyone know where a new DME might be obtained for less than the pound of flesh that BMW exacts?
Ed

[J!m]

1) get one from a scrap yard from a RUNNING engine. try to get the same options as your car to avoid problems (cruise and traction control in particular), as well as getting as close as possible to your build date (early and late '96 can be quite different- first year of OBD-II)

2) plug that succer in (assuming root cause of failure has been identified).

3) Engine should NOT start. Not even try. This is normal, and confirms the driveaway protection is functional.

4) tow car to dealer to have EWS and DME allignment done. Should be 1 hour labor- about $95.00. Bring old DME with you, to prove ownership of the car in case of any questions. Have dealer do a full diagnostic as well- that water may have damaged something which damaged the DME, the water may not have directly damaged the DME.

5) drive home $95.00 poorer (or more if more work is needed), with car working perfectly.

NOTE: mileage may change if 'donor' car DME has higher mileage on it. Higher mileage always prevails to prevent odometer 'roll-back'.

[fourbanger]

hey jim, what about OBD-I cars?

Because i saw a '95ti ECU w/ chip sitting in the Turner used parts bin.. I was going to snatch it, but the doubts have prevented me from doing so. Thing is it's a close production date match soo...

[J!m]

If you convert to OBD-I, you will need the entire engine wiring harness as well as the DME. This is for any conversion, not just for what you want to do. Converting will loose 'driveaway protection' if you have it now. I like this feature, as noisy alarms only annoy, and don't stop a theif.

I'll bet dollars to donuts the wiring harness between OBD-I and OBD-II is quite different, even with close build dates. Also, the options on your car, such as cruise, OBC and traction control may not be present in the OBD-I DME. Before I tried it, I would need wiring diagrams from both cars (available at the dealer, if they feel like sharing them).

It might work fine, and it might not. Feel lucky???

Personally, I think my original reply is the better way to go. A chip will not do all that much for you. I never chipped my car before I did the engine swap because the gains did not justify the cost to me. A supercharger, which can be used on either engine, will get you what you want. If a six can be had cheaply enough, the 3K you were to spend on a blower can go toward the six. This is where I started to think it over...

[fourbanger]

Well jim, i wasn't really thinkin about swapping anything but the DME :P

Chipped DME '95 ti + '95 ti = Chipped '95 ti right?

That was my basic question :P

[eomalley]

Jim,
You were right on. I found a used DME at Stocktonauto.com for $250 + $25 shipping. The first couple of dealers I spoke to said they would not flash a used computer, rather they would order a new one and flash it for around $1600. My local dealer, JMK in Mountainside, NJ did flash the used one and charged $300, (three cheers for JMK). My car now runs fine but the check engine light comes on all the time. JMK warned me of this and said it's because the replacement computer came from from an automatic trans car and mine is a five-speed. They noted they could order an eprom chip to correct it.
Thanks again for the advice.
Ed