ECU problem car won't start

1. arroyocorrales Newbie Joined: Sep 2011 Posts: 5

   #1 7th September 2011, 08:54

   My Saxo 1.1 won't start. Broke down and AA towed me to a garage. He said it was almost certainly the double action relay(?) - garage bought the part and fitted it, but car still won't start. They now think it's something to do with an ECU(?) - not quite sure what that is, but something that controls the whole car. They have only spent an one hour trying to solve it so far, but gave me the impression that replacing this part will be so expensive it won't be worth doing.
   
   What is an ECU exactly? I can't afford to buy a new car so I must try and get this fixed if possible.
   
   Any advice please. Thanks
2. Wee_monkey1987 Regular Poster Joined: Sep 2011 Hertfordshire Posts: 250 2000 Saxo Woodland Green VTS, 2002 Mazda MX5

   #2 7th September 2011, 11:15

   ECU = Electronic Control Unit, it is the Engine management system to the vehicle and is responsible for controlling ignition and fuel delivery to the engine without these two fundamentals your going nowhere!!! approximate cost of an ECU can vary from £500-750 depending where you go!
   
   Ask the garage to plug into the ECU and identify if there are any faults on the ECU using a scanner! you can also buy software and cables to plug into the ECU yourself using your own laptop this will give you the read outs from various sensors!
   
   All ECU require two functions to operate these being engine load (throttle position/Manifold absolute pressure aka the amount of air going into the engine) and engine speed (via the crankshaft) if one of these is faulty the engine won't start at all! get the garage to check all these sensors are functioning properly by doin resistance and voltage checks using a multimeter on both of these!!!
   
   Hope this helps!
3. Wee_monkey1987 Regular Poster Joined: Sep 2011 Hertfordshire Posts: 250 2000 Saxo Woodland Green VTS, 2002 Mazda MX5

   #3 7th September 2011, 11:19

   Also if the coolant temperature sensor is faulty it will cause the ECU to deliver low quantities of fuel because the ECU thinks the engine is hot! to bypass this try cranking the engine on full throttle! this tells the ECU of a sudden increase in air entering the engine thus causing the ECU to dump lots of fuel into the engine!
4. P311ATT Regular Poster Joined: Apr 2010 Kent Posts: 260 saxo furio, saxo vts

   #4 7th September 2011, 14:40

   I'm going threw the same problem with my Vts.. bad times
5. arroyocorrales Newbie Joined: Sep 2011 Posts: 5

   #5 8th September 2011, 07:52

   Thank you for your messages. Garage says it was the ECU and has now sent it off for testing. Could take about 3 weeks and then they will test it to see see what's wrong and if they can repair it. Knowing my luck they won't be able to. Buying a new one will be expensive I think and was told even if I did buy one has to go to Citroen to be fitted because of all the codes or stuff? Unless I can buy an unlocked one (plug and play). Is there such a thing as buying a second hand ECU?
6. deks36 Saxperience Forum Bum Joined: Aug 2008 Herne Bay. Kent Posts: 3881 Peugeot 307, Nissan Juke, 206 Grand tourisme

   #6 8th September 2011, 08:40

   you can buy second hand ECU'S make sure its been unlocked and both you and the garage know how to fit it to your car
   by unl;ocked it means the immobilser has been by passed and your car will need to have the immobilser unit removed or it will just lock the ecu when fitted
7. arroyocorrales Newbie Joined: Sep 2011 Posts: 5

   #7 15th September 2011, 13:19

   Where can I get a second hand ECU unit and what info would I have to provide? I have a Saxo 1.1 S reg
8. arroyocorrales Newbie Joined: Sep 2011 Posts: 5

   #8 16th September 2011, 10:18

   Will have to scrap the car. A new ECU with fitting will cost around £900 - car not worth it. Citroen said even if I bought a second ECU how would I know it would work even if it were "unlocked". Not being very technical with the car it doesn't seem worth all the bother.
9. user_43205 Saxperience Forum Bum Joined: Apr 2010 Ilkeston Derby Posts: 3697 Red Mk1 R Silver Mk2 S & Mk2 Seat Leon.

   #9 16th September 2011, 11:16

   I've got a professionally unlocked ECU that i don't use anymore as i've changed engines, but i had the same problem.
   Worked a treat on my old engine.
   It's worth looking into.
10. Ben_SaxoForte Saxperience Forum Bum Joined: Mar 2009 Stoke-on-trent Posts: 2640 Mk5 Golf GTTDI Mk2 VTR Project

    #10 17th September 2011, 12:01

    you should give these an email/message http://www.ebay.co.uk/itm/3023-UNLOC...item3cbb153a28
    
    I know its not exactly cheap but compared to 900quid could sort out ur problem
11. arroyocorrales Newbie Joined: Sep 2011 Posts: 5

    #11 18th September 2011, 11:37

    Thank you all for advice but car being scrapped tomorrow. As I'm know nothing about the inside of a car, I was getting so much conflicting advice from garage and Citroen about buying a second hand unlocked ECU. Citroen wouldn't advise it naturally, garage not keen on fitting a second hand one and I wouldn't know what I was getting if I bought one. A disaster - poor ol' thing gets scrapped tomorrow.
12. coleman258 Established Member Joined: Nov 2008 Eastbourne Posts: 2474 Astra van daily Black Saxo VTR 16v'd kent PT51

    #12 18th September 2011, 11:40

    Scrapping the car seriously? You can buy a second hand ecu for £50-£100 max.
    
    And what are the chances some numpty will sell you another broken ecu, very unlikely.
    
    Also more info on why the car wont start,
    
    Fuel pump priming?
    Got spark?
    Immobiliser light flashing?
13. Tom5190 Saxperience Post Whore Joined: Sep 2007 Someones Bumhole Posts: 5721 Mk2 16v Desire

    #13 18th September 2011, 11:45

    Were do you live and how much have you been offerd scrap?
14. user_43205 Saxperience Forum Bum Joined: Apr 2010 Ilkeston Derby Posts: 3697 Red Mk1 R Silver Mk2 S & Mk2 Seat Leon.

    #14 18th September 2011, 11:49

    O dear,
    I hope you're not scrapping it on the basis on what citroen and the garage said.
    Because that'd be fucking ridiculous as they're both looking for alot of money that's why.
    
    This statement made me laugh ..
    

    Quote:

    Originally Posted by arroyocorrales garage not keen on fitting a second hand one

    Tell your mechanic to stop talking bollocks as its a 30 second job.
    
    And as said you can get a ECU for £50-100 as i'm selling my professionally unlocked one for £65!
15. danny-vts Saxperience Post Whore Joined: Dec 2010 Chesterfield/Nottingham Posts: 7147 dead vts. twisted 106 gti. '03' vtrrrr

    #15 18th September 2011, 12:02

    your seriously scrapping a car because the garage and citroen say so lol.
    
    where abouts are you from, if your not too far away i will buy your car off you?