givemethebighammer
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| posted on 3/5/04 at 12:24 AM |
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Permanent feed to ECU ?
Sorry about all these electric questions, but I'm nearly finished now.
Do you need to have a permanent feed to your ECU or just one that is live when the ignition is switched on ?
ps.. finally figured out the relay stuff.. once I had established that the switch was a dim/dip one. Addressed the issue of the dip beam coming on
with the side lights, by connecting the low and high beam relays with an ignition fed live connection. Turn the ignition off and the side lights stay
on and the headlamps go out. (Just like my wifes Fiat....at least that's what happens on her car, couldn't say if it was right or not
!)
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Hellfire
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| posted on 3/5/04 at 12:40 AM |
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GMTBH - our's is fed through the fused starter relay so is switched live. Having said that so are our sidelights, horn and headlights. Nothing
works when ignition is off - and ours passed SVA like this.
Stops tamperers too!
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zetec
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| posted on 3/5/04 at 09:19 AM |
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I've gone for switched.
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givemethebighammer
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| posted on 3/5/04 at 11:03 AM |
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thought switched would be better, just wondered if powering the ecu on and off all the time might affect the internal memory chips in some way.
But if others have used this method and it was OK, I'll do the same
thanks
[Edited on 3/5/04 by givemethebighammer]
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Dale
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| posted on 3/5/04 at 02:58 PM |
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Most north american ecu's are learning- sensning how the car is drived and setting up the set points for the fuel / spark advance ect. shift
points if its an auto. Every car I have ever seen with the engine control unit has allways had power to it and you had to disconect the battery from
the car to clear memory.
Dale
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ceebmoj
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| posted on 3/5/04 at 06:19 PM |
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I agree with give me the big hamer most ECU are lerning ans develop ther fule mapping witch is saved internelin hoever most ECU's drop tis map
if the battry is disonected. however the map will be relernt very quickly.
this feature is designed in incase the battry goes flat or for when you put difrent fule in as it will give a slighly difrent bang per unit volume.
ps a new ECU sutch as the one fitted to a VAG (Valtsagen audy groupe) and I suspect many other but do not know will enter in to GYHM Get You Home Mode
if it detects that ther is repeted memory corupion (constantly removing and replacing the power) this means it willstop trying to do clever stuff and
gust use fixed map amongs other things.
Blake
sorry no spell checker to day
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NS Dev
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| posted on 3/5/04 at 09:06 PM |
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depends entirely on what ECU you have. Bosch L-Jetronic and earlier (maybe later too?) Motronic was not self learning. Certainly non-lambda systems
are not self learning!!
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givemethebighammer
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| posted on 3/5/04 at 10:28 PM |
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Mine's a GEMS (now DTA) ignition only unit. Not worried about the learning thing (doubt mine does) more worried about corrupting the
unit's flash memory by repeated connection / disconnection of the power. Just my thoughts ?
[Edited on 3/5/04 by givemethebighammer]
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NS Dev
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| posted on 4/5/04 at 09:55 PM |
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Not 100% up on the GEMS/DTA stuff, I use MBE. With this the main power is just to the relays, i.e the control box "on" relay and the fuel
pump "on" relay. The ignition controlled live then turns the control box relay on. The permanent live is only connected to the switched
side of the relay. The ign controlled live switches the relay on.
Maybe the GEMS is different but I doubt it.
In any case it shouldn't corrupt the eprom in the ecu. Do you have the mapping software? If so for peace of mind make a copy of the map
(chipfile), then you are covered anyway.
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mad4x4
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| posted on 20/5/04 at 11:20 AM |
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Yes you need to have a wire from the battery to the ECU
Have a look here
http://www.xr2zetec.co.uk
Scot's do it better in Kilts.
MK INDY's Don't Self Centre Regardless of MK Setting !
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NS Dev
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| posted on 20/5/04 at 11:02 PM |
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quote:
Originally posted by mad4x4
Yes you need to have a wire from the battery to the ECU
Have a look here
http://www.xr2zetec.co.uk
This is a totally different ECU, the Ford EEC4 etc may well need a permanent live but few if any of the competition oriented ECU's do (I am sue
the GEMS ecu doesn't), as they are designed to be wired via a battery cutoff switch, so it wouldn't be very good if they needed a
permanent live!!!
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crbrlfrost
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| posted on 22/5/04 at 06:19 PM |
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If you run a OEM ECU, then you'll want to have a permanent power circuit to the ECU. The reason for this is that the computer stores trouble
codes and driveability settings (especially newer ECU's that often have a learning capacity to suit themselves to the engine as it wears and
changes, as well as the way the vehicle is usually driven). This is put into volitile memory so when the power is cut, they are lost (want a pain in
the ass, disconnect the Porsche boxster battery without a powersaver connected). With aftermarket ECU this isn't an issue and it can be
permanent or not. Might ask the supplier for their preference. Cheers!
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NS Dev
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| posted on 23/5/04 at 03:01 PM |
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As Givemethebighammer says, he is running a GEMS ecu (now DTA) which is aftermarket, so no need for permanent live. Also like to point out that most
older OEM ecu's do NOT self learn, and do NOT need a permanent live!!
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givemethebighammer
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| posted on 23/5/04 at 10:23 PM |
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Yup NS is right, finally got hold of someone who knew about the gems unit. He said no problem with an ignition controlled feed.
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crbrlfrost
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| posted on 23/5/04 at 11:28 PM |
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Just a very minor point, many ECU post '88 have volitile memory for trouble codes. If you know you'll trigger codes with your set-up, then
always switching it off is probably a good idea. Post'94 and beginning OBDII cab be a little more finicky, and NSDev is right that most anything
that isn't in the past few to five years doesn't self learn, and new ones that aren't from performance cars often don't
either. My past post was just to a generalized list. Cheers!
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