Having some electrical woes with the cossie, it concked out last weekend and since then I have discovered the cause to be the fused power supply for the ECU under the dash in the passenger side footwell.

Anyway after replacing the fuse it keeps doing it, so I've now got the dash in bits after losing the plot trying to spot any obvious damaged wires or shorts, also I haven't ruled out it may actually be the ecu itself.

Any thoughts on probable causes, I've visually checked the wiring and checked the operation of the relays and not found anything so far.

 

Bad earth somewhere? Or maybe one of the pin outs had a bad connection.

 

Hi mate I had a similare problem my saph 4x4 cut out everybody was saying this that the other so I got an elecy in turned out every saph 4x4 came with a aircon loom even though there wasent aircon mass produced looms anyways the wires were britle and shorted out by bulkhead and burntout my ford alarm relay.The wire is located underneath the turbo the relay is located under the steering wheel GOOD LUCK PAL at the end of this you will kick yourself lol I did.

 

Thanks, I'm possibly thinking it might be related to wiring near my turbo, I had the car on the longest run it's had in years after recently fitting a T4, I made a lot of effort to make sure the wiring was protected but you can never be too sure, will have a look for that mate.

 

Does it blow the fuse as soon as to turn the ignition on?

 

One place to check is the loom plug where it connects to the ecu when you put the cover back on the plug you might have disturbed it or putting the ecu in and out when installing the chip.

 

Yes, as soon as i turn on the ignition before I even start the car it blows the fuse.
It ran ok for ages then just died last weekend, the chip has been in it for about 2 months, i'll pull it apart and have a looksee!

 

Sounds like a short, the easiest thing to do is simply disconnect the ECU connector (AKA hairbrush/scart ) if the problem still occurs the ECU is fine, rather the wiring/relay's etc are at fault, which wouldn't be a surprise anyway!

Martin

 

Yes I did that and it doesn't blow, are you saying it's the ECU thats at fault then???

 

Put a bulb in the end instead of the ecu and see if it blows.

 

I would say so, do you know anyone with another ECU you could borrow to test?

Martin

 

Yes, I will ask them and hope they are obliging!

 

Have you tried removing your chip out of interest?

Only you mention it hasn't been in there long, wondering whether it's that that is shorting, it's worth a try.

Martin

 

I'm not so sure about that,once the ECU is plugged in your starting to complete circuits etc that weren't completed while the plug is off,all this says is the wiring INTO the ECU is ok,not necessarily the circuits that only complete when the connector is plugged in.
You'll need a multimeter and wiring diagram to trace it properly.
Im happy to help but not back up your way until a week Monday?
If you have access to a wiring diagram and can put it online I could guide you through approximate resistances and areas where the fault could be occurring,even basic test procedures if your desperate to get it back on the road?

 

Thanks guys, I tried a totally different ECU with a different chip and it did the same, blows as soon as the ignition is on with the ECU plugged in.
I'm away on holiday tomorrow for a week so thats fine by me mate, no hurry, she's back in the garage again waiting.....I'm off for a week after that but will be at home or nearby.

Got all the diagrams, and already started to trace them so thanks for suggesting that, be good if you could lend a hand and check i haven't missed anything. I was actually thinking what you said about completing the circuits last night when i was working on it, so I disconnected the TPS/SECS/Injectors but had no effect, i'll keep digging and maybe even start right from the column/ignition switch, cant hurt.

 

i would work from the ecu plug, with the ecu disconnected and test the resistance of each sensor and associated wiring and each sensor to earth while comparing it to a wiring diagram. when you find a fault, unplug the sensor and test again, my money is on the loom rather than a sensor
either that or use a pin removal tool and remove the pins from the ecu plug systematically untill it stops blowing fuses.

 

do they have a system test at all like the gtrs? can it be fault code read ?

 

the ecu stores the fault codes but is reset when power to the ecu is switched off, and he cant get any power to it to start with

 

Just a stab in the dark but i remember a thread ages ago now and also recall Tabetha mentioning it . A power lead running from the batterie behind the bulkhead panel causing certain problems and getting very hot under there. May of even been 2wd but thought it worth a mention.

Mike

 

start with all earth connections mate, there should be a strap from chassis to block and afair few other earths. then its check things like the fan switch that are prone to melting etc, wiring around turbo

the ford ecu switches the earths, so once the ignition is on, most stuff is live.

i take it you are still getting power etc to the starter, but the ecu is shitting itself everytime you switch on?

 

No probs rog,will message you on here once I'm back up.

 

No they have a very basic flash code system as standard, it's a bit like morse code but using light instead of sound

You have to use your brain when these go wrong, which is a good thing.

Plus the fault detection is very crude, I think I am right in saying they will only flag a fault if a sensor goes fully open or closed circuit?

In any case, it has to be something to do with the wiring, now you have tried another ECU you have eliminated that possibility.

It won't be the injectors, the ground is switched by the ECU, so if these were at fault it would blow regardless of the ECU being connected or not.

The pin you want to remove/check is pin 30, as this is the 5V supply to the sensors.

Martin

 

Cheers Marty,if he's got nowhere by the time I get back to scotchland I'll need all the advice I can get!!!

 

my guess and this is a guess is that when the ecu powers up it checks the sensors that are plugged in to it and the engine so it fan run the engine if all ok it then turns on bits (like fuel pump) to fire up the engine. the devices that it turns on have there own fuses but the input to their relays will not. so if you hear it starting things up for a split sec it is in the relay for one of these devices or the wiring, if nothing at all probably a short in the sensors. good luck.

 

First... try it without the Amal and ISCv plugged in.

Second... pull ecu out and look right behind at teh back and you will see all the wiring as it snakes around the steel cable, give all that a good tug to move its positioning and try again, if it now stays on, one of the power wires there has likely chaffed through on the metal of the cradle.

 

something is drawing too many ohms

 

You must have whats known as a "ROD"

Short, and causes agro for lots of PF users who also blow a fuse

 

not quite sure what u mean!

Thanks guys, away on hols for a few days but I get back on Friday so I'll be back into it again, took the dash off before I left so all those checks won't take me too long to do. I'll definately report back with what
I find and post some pics for reference just in case anyone else encounters a similar issue.
Away to go a bit mental with the spending on it again so I need it running!

 

Had this on mine yrs ago, was what Stu has pointed out with the ecu cage rubbing throug the loom a tad.

Steve

 

He is referring to Rod on this site, and means you have a short, it's a joke.

Martin

 

My bet is its the ignition barrel as when he turns it to the on position it blows the use

 

Well whatever it is I shall try an have a look this weekend but have a stag doo, hangover and wedding to go to, so hoping I can sort it easily enough, but off work next week so I might tackle it then. Expensive garage ornament if I don't fix it, Ł8k in 6 months I've spent on it once I get my box and diffs, no more!!!!

 

99% of us say that but keep spending

Steve

 

and the other 1% arnt stupid and stop wasting money on the shonky old money pits

 

Right that's me back for a couple of days so I'm away to have a look later on and see what I can find, got some good news yesterday so the gearbox and diffs will be sorted out next week.
Will start with taking the ECU plug apart and see what I can find there, if nothing then i will move on and heed your advice and keep you updated with my progress, thanks again. All your help is greatly appreciated guys!

 

Looking at this today (with a hangover) and I've ruled out the ecu plug by taking the cover off and checking the connections, also disconnected the amal valve and iscv and also made no difference so I'm back to blindly checking the wiring.

 

Not that I am being funny or anything, but I couldn't see it being the amal wiring etc, as they are powered from the fuel pump relay, and so it would be causing problems with the ignition switched on regardless of whether the ECU was connected or not.

I suspect it's something to do with the ECU supplied 5V line (Pin 30)

Martin

 

Rog, pitty im away again fella, would have gave you a hand no probs, cheers for saturday by the way, roll on 2 weeks.lol

 

No worries man, think I'll be away to Cameroon next week, so not sure if I'll be around when you're back.
Marty, I'm with you there, but was worth punt before I started stripping stuff back, car looks messy now, bits hanging out everywhere, and I bet it's some pissy issue! Haven't found anything yet, might call it a day, I have another week before I'm back at work to mess with it.

 

have you checked the lamda wiring by the turbo rog