Electrical non-starting issue - few weird things

[Sean.R]

Hi all,

I have recently go a project car - this is a non-runner and a bit of a gamble, it has some issues, and I will try and explain the best I can - I would like to try and fix this issue before calling out an auto spark.

The car 2010 CUP - forged F4r running a Meg 225 wiring loom spliced to Clio loom & meg ECU

The car has not been on the road from about 4 years - it apparently started to have an issue where it would not crank this fault was intermittent and would clear (whatever it was) and the car would crank and start, however eventually it got that bad it would not start - so it got flung in a unit as sat until I got it. (save another Clio from the scrap heap)

symptoms
everything electrical in the car works - stereo, fans, wipers & steering lock
no warnings in the dash expect from the EDC fault and airbag (seats out)
red dot light on the dash blinking when first open the door
the fuel pump is not priming
car wont crank over
unable to read the fault codes - the OBD reader is connected to get power but unable to make a connection with the ECU (it is a cheap one but this connected to my other Clio with no issues)

Go to start
turn the key to stage 2 - fuel pump wont prime & the red dot light goes solid and will not go out
turn the key to stage 3 ignition - nothing happens

what I have done so far
New 12v battery
new batteries in the keys (2 different style keys)
jump lead from the gearbox to earth
starter motor removed and checked working ok
replaced key transponder around ignition barrel
cleaned out the UCH connections (some furring)
checked various red wires in the engine bay to prove 12v

Previous owner also sent the ECU & BCM away to be checked over - all ok


I think that is everything I have done so far, so looking for some further advice or has anyone seen something like this? I am thinking a possible imob issue linked to the ECU
any help / guidance is much apricated before I pull this loom and start fresh (will probably end up going down this route once I know the car can start)

cheers

sean

 

[aaron-rs197]

sounds like an issue with computers on the multiplex network not handshaking properly? you'll need a copy of the service manual and access to CLiP software to investigate this further. i'll try attach some screensnips from the manual relating to this issue which may help you.

 

[turkie172]

I know you checked voltage on the can bus which should be 2.4V and the other 2.5V you were getting higher than that so it is how the modules in the car are talking to each other and more likely the wiring. You also need to check the resistance the can bus system has two 120 Ohm resistors in it when the system is linked you get a 60 Ohm reading at pins 6 and 14 at the diagnostics port with the ignition off is when you test this reading one resistor is at the diagnostic port and the other in the ECU, there are some videos that seem useful I'll see if I can link them but there is no magic video for your exact car and problem. You will hear in the second video as the guy goes through the different ways Canbus can be shorted out you can make out the car chimes and wipers going as the network messages get messed up.

 

[turkie172]

This is the area you should be looking at
1337 Power switching unit
756 AIR BAG/PRETENSIONER COMPUTER
419 AIR CONDITIONING CONTROL UNIT
1232 ELECTRIC POWER ASSISTED STEERING SYSTEM
645 PASSENGER COMPARTMENT COMPUTER
653 CLOCK/EXTERNAL TEMPERATURE/CARPHONE DISPLAY ASSEMBLY
1714 MULTIPLEX LINE INTERFACE UNIT (MULTIPLEXING) I think the Radio or stem controls interface

 

[turkie172]

Another Video

 

[Sean.R]

sounds like an issue with computers on the multiplex network not handshaking properly? you'll need a copy of the service manual and access to CLiP software to investigate this further. i'll try attach some screensnips from the manual relating to this issue which may help you.

Hi, thanks for posting mate
really needed something like that to point in the right direction

Now I need to find some one with a CLiP in central Scotland
thanks again

 

[Sean.R]

I know you checked voltage on the can bus which should be 2.4V and the other 2.5V you were getting higher than that so it is how the modules in the car are talking to each other and more likely the wiring. You also need to check the resistance the can bus system has two 120 Ohm resistors in it when the system is linked you get a 60 Ohm reading at pins 6 and 14 at the diagnostics port with the ignition off is when you test this reading one resistor is at the diagnostic port and the other in the ECU, there are some videos that seem useful I'll see if I can link them but there is no magic video for your exact car and problem. You will hear in the second video as the guy goes through the different ways Canbus can be shorted out you can make out the car chimes and wipers going as the network messages get messed up.

thank you for taking the time to help and stick all the drawings and links up really helpful

I will test the pins next and report back, previously I have been testing with the ignition on

appreciate the help mate

thanks

 

[Sean.R]

So these are the results

1st test across pins 6 & 14 for resistance

 

[Sean.R]

2nd test
Voltage on pin 6 & 14 with the ingition on