Diesel ecu?

[bigblue75]

What I thought was an under bonnet fuel pump problem seems to be something else.

I had planned on using the Cdti auto to travel to and from Plymouth every month for work so gave the car a good once over and installed cruise control to make the motorway miles a little easier. I had no problems with the car during the fortnight before the first journey- cruise worked as expected without t4 configuration and the car had been pretty much faultless for the previous 18 months of ownership.
First run down ended abruptly with classic signs of fuel pump failure so car was recovered to home and the journey completed next day using a hire car. Nine hours journey time door to door which will in future be done via plane and coach or train... I know they are comfortable cars but that is a monster journey to make twice in four or five days.

Fast forward to this weekend. I got home and put the car battery on charge and changed the UBP for one from DMGRS. Today the battery was returned to the car and the new pump and battery made not one difference. all ok til posII- no fuel pump noise or vibration. Trying to start it the engine did turn over but no joy- EP then showing where gear selection does.

In desperation, connected to toaf to retrieve any fault codes but the engine module is not showing when car is scanned ( all other modules are). When selecting the engine module toaf shows 'reading keys...' where 'connect successful' usually appears at the bottom of the window- but remains stuck at this point.
The car locks, unlocks, engine turns over but does not catch.

I would appreciate any advice regarding testing for ECU failure, the car is sitting dead and parked at the minute and I am southward bound again tomorrow evening.... by plane.

I will check back for replies tomorrow a.m as away from computer tonight. Thanks in advance.

[trikey]

Switch ign on, see if you have an oil light, report back

[BigRuss]

First thing to do is to check for power to the ECU if you have a multimeter.
The thick yellow with red trace wires in the plug nearest the driver's side on top of the ECU should read 12 volts

If they don't then disconnect the battery and undo the underbonnet fuse box unlatch and relatch the connectors and then check once the battery is reconnected to see if that solves it.

If you suspect it is the ECU that's at fault I can test it for you. If it is at fault and isn't repairable I always have suitable replacement ECU's in stock.

Russ

[sewerman]

May be oblivious but have you checked the plenum isnt flooded?

Sent from my SM-G950F using Tapatalk

[bigblue75]

First turn to posII resulted in the oil light showing and all else on dash as usual. turning off and waiting around 20 seconds before turning to posII again resulted in no oil light showing but all else as first turn.

Removing the ECU from plenum (bone dry and clear) and checking the drivers side wiring block gave the results below for connections 1 and 8

ign off both 56.8 mV
posI both .408 V
posII both .626 V

The battery readout was 12.64 V.

My time today is very limited but I am hoping I will get time to investigate further when I am home for around five days or so in around three weeks time... Many thanks for the advice gentlemen- I know I would have been pretty despondent without your help. Any further information or explanation would be appreciated immensely- does the low voltage at pins 1 and 8 mean a fault with wiring from the battery or is it (as I fear) more complicated than that?

[COLVERT]

Camshaft sensor ???--

[bigblue75]

Currently in Plymouth for work and having re-read my update post feel I should explain that the readings from the drivers side plug were taken from the female connectors 1 and 8 while the plug was disconnected- I did not take the readings directly from the yellow wires with red trace while it was still connected. Not sure now if this was what was suggested?

The short time at home was gone before I got any real time to look at the car and I was not able to give it my full attention. I will get time to investigate further towards the end of the month when I can try the power off and unlatch, unplug / plug in, relatch suggested by Big Russ. Thanks again for the advice given.

[bigblue75]

Back this weekend for a flying visit and todays weather has been pretty good after the previous few weeks.

On my last weekend off I'd checked the wiring as Russ had advised and decided that the ECU would benefit from his attention. Sent it off as instructed and when inspected by Russ it was found to be beyond repair and so he sent me another ECU coded to my vehicle (with the added benefit of cruise control being configured).
Earlier today I checked the wiring again for signs of damage, removed the glow plug relay/ecu fusible link and replaced the 'new' ECU. After connecting a fully charged battery and crossing my fingers I turned the key to posII and was pleasantly surprised to hear the fuel pump running. After allowing the pump to stop, I turned the key to OFF before turning to posII again and then after hearing the pump run for a bit turned the key to start. The engine started immediately and idled evenly while I put things away/ back together.

Let the car idle for five minutes and then moved it back and forth to free up the brakes and roll the wheels as it's been sitting for around two months.
I did notice a whine when pressing the accelerator which came around 1300 rpm and remained without much change in tone as revs increased. Not sure what this is and can't investigate until maybe later today when I have my better half available as my assistant.

Big big thanks to Russ.

[bigblue75]

Managed to give the car a wee run out to clear the cobwebs and clean up the discs and drums, bit grumbly to begin but after a bit of friction much, much better. I will be removing the wheels to give the brakes a bit of TLC.
After warming the engine I managed to give the car a 5 min run at around 3500 rpm to get some fuel and exhaust through it- quite surprised by how smooth the engine was after nearly 9 weeks laid up.

I think the (more like humming than a whining) noise may be coming from the power steering pump. Not sure how likely this is on a 102000 mile engine. Is there an easy way to check this? Difficult to pinpoint the noise. As usual, any ideas and advice gratefully received.

Glad to have the car back, almost forgot how nice it is to drive- even when it's needing a wee bit of attention.

[bigblue75]

Moved the car to hardstanding in front of garage, removed undertray and cut plenum tube from below. Gave it a wash to clean off ten weeks worth of dirt from when dead and parked... Almost immediately started to rain and so gave up trying to pinpoint noise.
Southbound again but much happier to have it running.