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Discussion Starter · #1 ·
hi all can anyone help i have been given a mint condition 420 sli r plate the car is lovely except there is no spark so it wont run all i know is that he was driving along and all the dashboard lights came on pulsing and it died what would be your recommendations to enable me to get it up and running
 

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that happened to me .......
but as far as no spark, don't know how its connected to that, you don't say what you've been doing to test things out

anyway when it happened to me, it the the alternator.
when the rectifier goes in the back of the alternator .........instriments stop working ....and if you carry on you get a flat battery.

all the best..mark
 

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Discussion Starter · #3 ·
instruments

all the instruments work fine and put new battery on it changed plugs leads coil pack cleaned up crank sensor today but have no power to crank sensor so this being said have tested coil pack wires have two brown wires a white and black wire on coil pack and a plain white wire only have power on two brown wires no power to others even on cranking its very puzzling does anyone know where the crank sensor picks up power so that i can test that



and will change alternator thanks for reply andy
 

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well i can tell you that one of the wires on the coil pack is for the rev counter signal pick-up.

just because you have power on the two brown wires probably means that the coil primary circuit is OK ..

i hear if the crank sensor buggers up .......it wont fire at all.

I'm afraid, i don't know how to test these things other than substitution.

so one of the first things i did when i bought my rover 420 was to get a pile of second hand sensors and a coil pack.

that way i have my own diagnostic kit . :)

lot better than paying some rover dealer £70 an hour, that jumps to conclusions when a machine tells him somethings wrong.

car should still start with a fully charged battery ...even with a duff alternator...so don't go replacing this when it does not need it ..
if you have a friend with a same 420, ask him,can you swap a few things over to your car ..So that you can make a proper diagnoses.

all the best..mark

think its either the coil or the crank sensor.

have a look at the big plug on the ecu as well.

and not sure about this, but check all the fuses .

some 420's have different crank sensors and flywheels ...
 

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Mmmm....Rover..
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The crank sensor is not powered, you will only see the correct signal using an oscilloscope.

The only quick test would be a resistance check with a multimeter.
 

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Discussion Starter · #6 ·
no luck

still had no luck becoming a pain in the neck now does anyone know whether the crank sensor picks up its power from the ecu or somewhere else it looks like the ecu might be naff but have no problems with anything else

should there be more faults if ecu dont work
and
is there a way to test ecu without substitution
 

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Like i said ....if you have no electronics knowledge ...
get a pile of spares to substitute

it will serve you well and save you money in the future.

ecu is coded with alarm ecu ...and key fobs ...

look at cheep things first

buy coil off ebay ...for tenner

look for crank sensor on there ...FOR BELOW TENNER
these components first ...
before you look at the ecu .

and DO NOT BUY ECU ON IT'S OWN.!!!

There are a lot of ecu's sold on ebay this way .......take no notice of them.

because it will cost you a lot of money to have them coded by rip-off main dealer to your alarm ecu .

all the best.mark
 

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Discussion Starter · #8 ·
tried a coil

tried a new coil on there new plugs leads so it has narrowed it down to three possibles

like you say the crank sensor

the ecu

or the immobiliser

so just going to try crank sensor if no joy will have to put it in a garage for diagnostic check to see where the fault is

thanks for replys
 

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Discussion Starter · #9 ·
almost fixed

have solved no spark problem at last bought new ecu and immobileser and alarm with it runs a treat but now have problem with the new fob hit and miss if it works put in new battery but still only hit and miss looks like i need a new fob
 

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I have exactly the same problem. I changed my battery in my key fob, and now it does not work. The manual says that you need to resync the key fob to the car. I am no expert in any shape or form but from threads that I have posted the impression I get is that both the ECU Immobilisor and Key Fob all have to be synchronised and talk to each other. If you have replaced the ECU and Immobiliser I can understand that the Fob would have difficulty in communicating with them as there probably speaking a different language. You may have to get your Fob reprogammed to both. That is what it looks I have got to do.
 

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Resynching in this context simply means pressing the lock button around four times.

If the fob originally worked then it is already coded to the car and that doesn't get affected by changing car/fob batteries.

Peter
 

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have solved no spark problem at last bought new ecu and immobileser and alarm with it runs a treat but now have problem with the new fob hit and miss if it works put in new battery but still only hit and miss looks like i need a new fob
I take it the fob came with the ECU.

If it works sometimes then it is "talking" to the ECU.

To sync=
Unlock car with key(leave door shut)
Remove battery from fob
Press each button in turn for 10 secs
Fit battery to fob
Press lock button,car should lock
Press unlock button,car should unlock
Repeat 5 times,if everything functions fob is now synced and you're away.

If you still think fob is scrap and you're in or near Warwickshire contact
lates600.com he will supply and programe new fob and tell you your KAC (KEY ACCESS CODE). He's worth the journey.
 
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