Cossie ECU Voltage
08-12-2005, 07:54 PM
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Cossie ECU Voltage
With my engine running, my SECS monitor shows around 12.7V. I've confirmed this with a meter. Is this sufficient for the ECU, or should I have more (I gather that the ECU voltage has an effect on the fuelling).
I should also add that the voltage at the battery is 'only' 13.2-13.3V.
The voltage between the alternator casing and the output wire is a tad over 14V. Between the battery earth and the alternator output is the same, so I guess the earth is all good
Am I right in thinking that the only things that can cause this is bad wiring between the alternator and battery +ve, or the vehicle systems drain?
Am I making work for myself, or am I likely to have some kind of problem?
Any pointers would be ace!
Neil.
I should also add that the voltage at the battery is 'only' 13.2-13.3V.
The voltage between the alternator casing and the output wire is a tad over 14V. Between the battery earth and the alternator output is the same, so I guess the earth is all good
Am I right in thinking that the only things that can cause this is bad wiring between the alternator and battery +ve, or the vehicle systems drain?
Am I making work for myself, or am I likely to have some kind of problem?
Any pointers would be ace!
Neil.
08-12-2005, 09:07 PM
#2
Too Low IMO.
Wants to be battery voltage there really, but battery voltage should also be around the 14mark or at minimum 13.7 with electrics all off.
Look at teh battery "Fusible link tails" They look like 2 small crappy burnt out wires.... follow them 6" and learn that they are the main fusebox feeds!! Dead Common.
Wants to be battery voltage there really, but battery voltage should also be around the 14mark or at minimum 13.7 with electrics all off.
Look at teh battery "Fusible link tails" They look like 2 small crappy burnt out wires.... follow them 6" and learn that they are the main fusebox feeds!! Dead Common.
09-12-2005, 01:54 PM
#5
Originally Posted by Neil S
Does anybody else have any input on this?
How can the condition of the fusible links affect battery voltage?
Neil.
How can the condition of the fusible links affect battery voltage?
Neil.
Replace them with a proper bit of wire and a decent seperate huse holder located by the battery
09-12-2005, 05:03 PM
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I meant BATTERY voltage, i.e. measured at the battery
I can see that the fusible links are a likely cause of the drop to the ECU, thing is, this ECU voltage is only about 0.5V less than battery. I repaired them last year, but I'm thinking that your way might be a useful mod
I've run a jump lead from the alternator to the battery positive tonight, this didnt affect the voltage at all. I can't see how the battery voltage is so far down from the alternator voltage
The only way I can imagine it is that the rest of the vehicle electrics are dropping the voltage at the battery, or that the battery is poor...
Cheers for the input Chip
Neil.
I can see that the fusible links are a likely cause of the drop to the ECU, thing is, this ECU voltage is only about 0.5V less than battery. I repaired them last year, but I'm thinking that your way might be a useful mod
I've run a jump lead from the alternator to the battery positive tonight, this didnt affect the voltage at all. I can't see how the battery voltage is so far down from the alternator voltage
The only way I can imagine it is that the rest of the vehicle electrics are dropping the voltage at the battery, or that the battery is poor...
Cheers for the input Chip
Neil.
09-12-2005, 05:05 PM
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look at the alternator as well..
i think mines on its way out..
I have an optima top bollock battery and used to see 13.9's to 14's on my secs..
now im only getting 13.4's
trivial I know.. but i prefer it higher!
i think mines on its way out..
I have an optima top bollock battery and used to see 13.9's to 14's on my secs..
now im only getting 13.4's
trivial I know.. but i prefer it higher!
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09-12-2005, 05:41 PM
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09-12-2005, 06:44 PM
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neil, not sure how relevant it is, and i know shit all about electrics before you ask but mine sees 14.1 at the ecu according to the secs monitor when its running so based on that fact alone....too low lol 
stu, you'll be able to elaborate more on the ecu compensating the fuelling for voltage drop, mine went banana's with the old wiring loom, fuelling at idle was all over the place, voltage dropped a good 2 volts with all electrics on (fuse links smoked and burned out!!). only drops half a volt now since new loom and proper loom fuses. karl did tell me why having a stable voltage was soo much better but im fooked if i can remember his nev like techy waffle
stu, you'll be able to elaborate more on the ecu compensating the fuelling for voltage drop, mine went banana's with the old wiring loom, fuelling at idle was all over the place, voltage dropped a good 2 volts with all electrics on (fuse links smoked and burned out!!). only drops half a volt now since new loom and proper loom fuses. karl did tell me why having a stable voltage was soo much better but im fooked if i can remember his nev like techy waffle
09-12-2005, 06:52 PM
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Thanks Lynne - I had read those earlier this week, and am currently in the process of measuring the current draw
Matt - I think I'm headed towards re-wiring as per Karl and Chip. Any idea what/where Karl did, or could you find out?
Neil.
Matt - I think I'm headed towards re-wiring as per Karl and Chip. Any idea what/where Karl did, or could you find out?
Neil.
09-12-2005, 07:32 PM
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https://passionford.com/forum/viewtopic.php?t=53903
take alook at this neil try the cable between alternator and battery mine was fooked and had the same problem and as stu says the links at the battery
take alook at this neil try the cable between alternator and battery mine was fooked and had the same problem and as stu says the links at the battery
09-12-2005, 09:07 PM
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Alan - I was looking for that post earlier! 
I posted on there at the time as I had recently replaced one of the fusible links.
This time, I will strip the fooker right back and replace them all.
Soldering the large cables is a right ballache
Reading that post brings it all back!
After some fiddling, The residual current with everything off (doors closed etc) is about 40mA. Also I have 13.5V @ the battery at idle with no load. I'm happy with this for now.
Next step is to get the ECU voltage as close as possible to this.
Thanks all for taking the time to read the post and put some thought into it!
Neil.
I posted on there at the time as I had recently replaced one of the fusible links.
This time, I will strip the fooker right back and replace them all.
Soldering the large cables is a right ballache
Reading that post brings it all back!After some fiddling, The residual current with everything off (doors closed etc) is about 40mA. Also I have 13.5V @ the battery at idle with no load. I'm happy with this for now.
Next step is to get the ECU voltage as close as possible to this.
Thanks all for taking the time to read the post and put some thought into it!
Neil.
09-12-2005, 09:14 PM
#20
Neil i can tell you what to do without a new loom, as long as its in good condition.
I have got 14.32 volts to the pump from an alternator creating 14.35
I aint posting ths though will tell you on msn.
So know what I am doing.
I have got 14.32 volts to the pump from an alternator creating 14.35
I aint posting ths though will tell you on msn.
So know what I am doing.
steve's back. 
11-12-2005, 03:37 PM
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OK, I'm pretty clear with how to get the ECU voltage up now thanks to Dingy 
Whilst checking the rest of the lives, I found this:
This is the wiring to the 3 ABS relays, they supply the ABS valve block!
Must have been done before I got the car
Another job!!
Neil.
Whilst checking the rest of the lives, I found this:
This is the wiring to the 3 ABS relays, they supply the ABS valve block!
Must have been done before I got the car
Another job!!
Neil.
11-12-2005, 03:58 PM
#23
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Originally Posted by Matt
this needs a post about fuelling voltage compensation!
11-12-2005, 04:29 PM
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Originally Posted by GARETH T
Originally Posted by Matt
this needs a post about fuelling voltage compensation!
Wot amount should the ecu be compensating?
i think wen mines runing with all the lights etc etc on, 13.4-6volts @ ecu, inj's and fuel pump.
wot % should the fulein be changed if voltage goes down to 12.5volts?
12-12-2005, 08:36 AM
#28
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Originally Posted by fiesta cossie
Originally Posted by GARETH T
Originally Posted by Matt
this needs a post about fuelling voltage compensation!
Wot amount should the ecu be compensating?
i think wen mines runing with all the lights etc etc on, 13.4-6volts @ ecu, inj's and fuel pump.
wot % should the fulein be changed if voltage goes down to 12.5volts?
12-12-2005, 03:51 PM
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Edit it back cos now I look like the penis!
'We extend the injector duration by 500 mega seconds per volt, or 953 years, whichever is sooner'
Seriously though, just messing I always enjoy reading the techy stuff
Neil.
'We extend the injector duration by 500 mega seconds per volt, or 953 years, whichever is sooner'
Seriously though, just messing
I always enjoy reading the techy stuff Neil.
16-12-2005, 05:18 PM
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OK, I've replaced the fusible links and now have 13V at the ECU. Battery Voltage is around 13.2V, so it's a bit better now
What should the alternator output be ideally?
Mine is 14V, sometimes just under.
Cheers!
Neil.
What should the alternator output be ideally?
Mine is 14V, sometimes just under.
Cheers!
Neil.
08-01-2006, 05:53 PM
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neil I have exactly the same reading as you did to start with! exept if i load the electrics i see about a 2v drop in all readings, did your fuseable links look dead mine look ok but i still suspect they may be to blame, what did you replace them with?
08-01-2006, 06:35 PM
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So these 'fuseable link tales'
are 2 wires coming off the battery to the fuse box??
sorry just adding things to my list of checks for my car
over the winter!!
are 2 wires coming off the battery to the fuse box??
sorry just adding things to my list of checks for my car
over the winter!!
08-01-2006, 10:06 PM
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Well check voltage drop.
i test voltage at
alternator (usually 0.2 volt higher than battery
battery,ecu feed and outputs, fuel pump, inj. (all these about the same with in 0.1 volt, except fuel pump wen connected)
if you get low readings on something, put a better + and earth to it.
i test voltage at
alternator (usually 0.2 volt higher than battery
battery,ecu feed and outputs, fuel pump, inj. (all these about the same with in 0.1 volt, except fuel pump wen connected)
if you get low readings on something, put a better + and earth to it.
