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-   -   DME Gone Bad? (http://www.318ti.org/forum/showthread.php?t=44829)

robnhod 03-19-2020 07:06 AM

DME Gone Bad? Anyone got one?
 
Short version:
96 318ti stick. Replaced head and battery. Start car and runs great. Next day car doesn't start, but can jumper starter and car runs good. Check engine light does not come on when first turn ignition, but bulp works. Disconnect battery and DME then reconnect. Turn ignition so the check engine light comes on. Start car then the light goes out like it is suppose to. All is good. Next day, car wont start via key/ignition and cluster works except for the check engine light.
I'm looking to put in a new DME, but could use some advice on acquiring what I'll need regarding delete chips, performance chip, cut wire to avoid EWS, etc.
If you can think of something I'm missing or want the long version, see next post.
Thanks for reading.

robnhod 03-19-2020 07:08 AM

I put a new head on my 96 318ti manual. Once put back together, started right up, drove 5 miles, parked and started it up a couple more times. The lasted time I started it, it was slow to crank over. After that, nothing when I turn the key. HI have lights, full cluster, but no ignition or click from the starter. Also, new battery and verified clutch switch is working. Eventually was able to jumper the starter(push button on alligater leads) and it fires up. I've put a couple hundred miles on it and was going to get it smogged while I work on the ignition troubles. Couldn't get it smogged because the check engine light (CEL) did not come on when the key is first turned on. The rest of the cluster comes on, but not the CEL. I know the CEL is working because I did throw a knock sensor code early on in the running the car. Everything I found regarding the CEL points to the DME. I pulled the DME and checked the relay but didn't find anything. Reinstalled the DME and the car started on the first try. Started 4-5 straight times. Started the next day, but second time I started it, it barley cranked over, then back to not starting with the key. Still runs great when jumping the starter. I did disconnect the battery for something unrelated and when I reconnected the battery, it started one time only. Regarding the (CEL) after unplugging/plugging in DME, at times it did illuminate when first turning on the key and then going out once engine starts, but now back to note coming on at all.
I believe the DME is somehow losing something after first getting re-energized and would like to replace it as I understand there are several option for another DME. Anyone have any thoughts on this diagnose or acquiring a DME?

BRADESTAR 03-20-2020 03:35 AM

If you change DME, you need a matching ews box and key chip. All 3 need to be from same car. Can get a ews deleted DME and it should work.

I wonder though.....If the car does runs under any circumstance it seems like the DME is good as it is controlling the engine properly. Though if it doesn't turn the 'check engine' light on that is a problem.

Have you checked all the grounds? I think there are three.

robnhod 03-20-2020 08:27 AM

Thanks for the thoughts Brad.
I see your point regarding the car running good once started. Could be something with battery or even the ignition, but the CEL does point to the DME. I've checked 2 grounds. Battery and passenger side wheel well. Didn't know of a third. CEL is the main issue because I can't get it smogged in CA. DME seems next logical step. I see a lot of cheap DME's, but best I can figure is I need a M44 unit w/ manual trans. It either needs a delete chip or would even be ok with cutting wire to ems. Does that sound right?

BRADESTAR 03-21-2020 03:56 AM

cutting the wire doesn't sound right. You can jump the ews terminal by connecting the two large wires at the ews box location. The DME will still want a matching box and key unless the ews is programmed out of the DME. And if it's programmed out you could just leave your old box in there....

robnhod 03-24-2020 02:58 AM

You are correct Bradestar. I was reading a post discussing the earlier 282 DME where they cut a wire at the EWS. So I either need a programmed DME from the dealer, a matching DME, EWS, and key, or a used DME with a delete chip?

Does anyone have a DME that might work for me?

I thought about disconnecting the DME for awhile, plugging it in, and then immediately getting it smogged, but I think I need to run the car awhile after reconnecting the battery. By then, I'm afraid the problem will resurface.

BRADESTAR 03-27-2020 06:31 AM

I looked around and couldn't find my EWS box from my '96. Have the DME and key chip, but that wont work.

The computer needs a while (70 miles) to 'ready' all the systems for emissions testing. I'd recommend registering in another state if possible. A lot are doing away with emissions. Otherwise you'll have to fix the problem.

I still wonder. If your DME was shot the engine wouldn't run under any circumstance. Even if it was an EWS issue it still would never run.

robnhod 04-03-2020 03:01 AM

Bradstar, I can't disagree with anything you said.
I was thinking there were a lot of old DME's out there that would work (incorrect assumption) and both of my issue's could be attributed to an DME going bad. A used DME sounded like a good place to start.
The fact that the car starts just fine after the battery has been disconnected and then the next day it's back to not working is discouraging. It's like a "capacitor?" somewhere is shorting out. It works at first and then slowly drains. (Pardon my lack of electrical terminology. I'm definitely more mechanical than electrical). Everything I've tested and checked off may still be the problem if I checked it after recently connecting the battery. Would the relay by the DME possible work at first and then run down the longer it has power to it?

robnhod 04-03-2020 03:27 AM

You also mention there might be a third ground beside the one in the pass. side wheel well and the main battery ground?


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