ECU Grounding.
08-28-2010, 10:56 AM
#2
Been a while since I've had my ecu open, but I recall that it does ground through the housing. The casing is NOT isolated from the bracket or the floor plan where it is mounted.
Curious.....Why do you ask?
Curious.....Why do you ask?
08-28-2010, 11:15 AM
#3
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Join Date: Aug 2009
Posts: 96
A few months ago I had a heater pipe leak in to the ecu. Damage was contained to a small area (around pins 60-57, 50-47 and a few components) The ecu is just showing a red LED and wont go in to diagnostics mode, engine wont start and conzut doesn't puick up the ecu.
Pulled the ECU, cleaded it and tried it again but nothing.
Have been really busy with no time to work on the car till recently so has been left till now.
I left the ECU outside it's chassis so was wondering if it grounded through it. Just put it back in chassis (not screwed in) and still the same single red light problem
.
Can't get an ecu over in the UK for love nor money (well you can for £2100 from nissan !!!)
Pulled the ECU, cleaded it and tried it again but nothing.
Have been really busy with no time to work on the car till recently so has been left till now.
I left the ECU outside it's chassis so was wondering if it grounded through it. Just put it back in chassis (not screwed in) and still the same single red light problem
.Can't get an ecu over in the UK for love nor money (well you can for £2100 from nissan !!!)
08-28-2010, 12:55 PM
#4
My 91 foldout shows 9 ground pins at the ECU connector. VG of course, but I guarantee you the VE ECU does not ground out at the enclosure either. You kind of need the foldout to see everything clearly. If you can, print out all those pages from the PDF and line them up to get the full view. They should all be black wires, but that's not always the case with grounds.
Last edited by Hectic; 09-05-2010 at 04:59 AM.
08-28-2010, 11:04 PM
#6
08-29-2010, 07:30 AM
#7
I'll say you've shorted this ecu despite your ability to clean it and dry it.....especially if coolant got into the board...it's done. I wouldn't trust it at this point even if I could get it to work....know what I mean? I along with several others have additional ecu's you could use. Just email some of us or post a WTB thread in the 4 Sale forums.
Regarding the pins. I reviewed my tracing, and I can only find 7 that connect to ground points (89 VG). Not to dismiss the ecu is using these to help ground, all the points appear to be used to either obtain sensor signals/readings OR to sheild other wire signals (ie: if you've ever re-wired a MAF, there are ground sheilded wires inside). So, without cracking one of my ecu's, I still stand by my memory that the board does ground through the casing (This will drive me nuts, so I will be cracking one asap!). As Hectic mentioned, though, there are differences in the VG/VE ecu schematic. Sadly I cannot offer specifics on the VE as I do not have that foldout.
Hectic, just in attempt to figure out what you are identifying as ground points and hopefully learning something........the ONLY grounds I see running into the ecu are at points: 107, 108, 116, 10, 20, 50, and 60. And these all connect to F28 and F31 (engine ground points)respectively. Additinally, these are all black wires and there are NO other black wires listed off the ecu. This of course should compare VG to VG since that seems to be what you are referencing as well. However, what year foldout are you looking at? Again, mine is from an '89.
Regarding the pins. I reviewed my tracing, and I can only find 7 that connect to ground points (89 VG). Not to dismiss the ecu is using these to help ground, all the points appear to be used to either obtain sensor signals/readings OR to sheild other wire signals (ie: if you've ever re-wired a MAF, there are ground sheilded wires inside). So, without cracking one of my ecu's, I still stand by my memory that the board does ground through the casing (This will drive me nuts, so I will be cracking one asap!). As Hectic mentioned, though, there are differences in the VG/VE ecu schematic. Sadly I cannot offer specifics on the VE as I do not have that foldout.
Hectic, just in attempt to figure out what you are identifying as ground points and hopefully learning something........the ONLY grounds I see running into the ecu are at points: 107, 108, 116, 10, 20, 50, and 60. And these all connect to F28 and F31 (engine ground points)respectively. Additinally, these are all black wires and there are NO other black wires listed off the ecu. This of course should compare VG to VG since that seems to be what you are referencing as well. However, what year foldout are you looking at? Again, mine is from an '89.
08-29-2010, 02:32 PM
#8
Hectic, just in attempt to figure out what you are identifying as ground points and hopefully learning something........the ONLY grounds I see running into the ecu are at points: 107, 108, 116, 10, 20, 50, and 60. And these all connect to F28 and F31 (engine ground points)respectively. Additinally, these are all black wires and there are NO other black wires listed off the ecu. This of course should compare VG to VG since that seems to be what you are referencing as well. However, what year foldout are you looking at? Again, mine is from an '89.
08-29-2010, 09:03 PM
#9
Wow, I did miss some. Those charts make my eyes go cross-eyed! Hectic, Much appreciation for pointing out the other black wires coming off the ecu. I know why I missed them now...... because I never marked them given they are not grounds. I originally needed a ground pin when connecting my Apexi AVC-r to the ecu, so I ignored all other "B" wire pins. But, there are definately other "B" wires! 
The pin 104 is black and is a ground, but not for the ecu. Again, it's one of the many that are used to read signals/operate components. For example, 104 specifically runs to the fuel pump relay and fuel pump. Then 26 goes to the Airflow meter. Finally 30 goes to the Throttle sensor.
Still, my information is dead on correct pertaining to the pins I identified being the only ones which lead to an actual "ground" at F28 and F31.
So, Woodface, all the ground pins have been pointed out. Good luck....replace that ecu!
The pin 104 is black and is a ground, but not for the ecu. Again, it's one of the many that are used to read signals/operate components. For example, 104 specifically runs to the fuel pump relay and fuel pump. Then 26 goes to the Airflow meter. Finally 30 goes to the Throttle sensor.
Still, my information is dead on correct pertaining to the pins I identified being the only ones which lead to an actual "ground" at F28 and F31.
So, Woodface, all the ground pins have been pointed out. Good luck....replace that ecu!
09-05-2010, 04:00 AM
#10
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Join Date: Aug 2009
Posts: 96
one from a 91 should be fine shouldn't it? ie, this one http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT
Just want to double check as I don't want to wait 3-4 weeks and pay loads of import duty to find out it doesn't.
Just want to double check as I don't want to wait 3-4 weeks and pay loads of import duty to find out it doesn't.
09-05-2010, 04:33 AM
#11
one from a 91 should be fine shouldn't it? ie, this one http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT
Just want to double check as I don't want to wait 3-4 weeks and pay loads of import duty to find out it doesn't.
Just want to double check as I don't want to wait 3-4 weeks and pay loads of import duty to find out it doesn't.
09-10-2010, 05:54 PM
#12
The pin 104 is black and is a ground, but not for the ecu. Again, it's one of the many that are used to read signals/operate components. For example, 104 specifically runs to the fuel pump relay and fuel pump. Then 26 goes to the Airflow meter. Finally 30 goes to the Throttle sensor.
Still, my information is dead on correct pertaining to the pins I identified being the only ones which lead to an actual "ground" at F28 and F31.
Still, my information is dead on correct pertaining to the pins I identified being the only ones which lead to an actual "ground" at F28 and F31.
True that, but 7 of the 10 are source grounds. Regardless, the ECU was exposed to water so it is no doubt fried, so I guess it doesn't matter. It is strange there are 7 input grounds though.. I guess there were layout/space restrictions preventing distribution on the mainboard.
Last edited by Hectic; 09-10-2010 at 06:15 PM.
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