engine rpm/misfire problem

  1. Administrator Joined: Dec 2002 Warrington Posts: 20561 Blue Saxo VTS Turbo/White Megane F1 R26
    #1
    Guys,

    Ive not used the car in a week, but when I came to on Friday the bloody thing wouldnt run right.

    To cut a long story short, the car wont rev above 2000rpm and if it does it misfires and pops like a good un!

    Is suspecting a knackered coil pack, or engine speed sensor, or fuel relay maybe?

    Any opinions as I cant afford to waste time today looking at un-necessary stuff.

    Any opinions gratefully received.
  2. Administrator Joined: Dec 2002 Glasgow United Kingdom (Scotland) Posts: 26097 Chelski Traktor
    #2
    tps sensor?
  3. Saxperience Addict Joined: Aug 2004 Herts. N/W London Posts: 13578 Project MK4 MoreDoor
    #3
    sounds like the fuel pump matey ??
    lift the back seats up and listen for the fuel pump whirring away?
  4. Administrator Joined: Dec 2002 Glasgow United Kingdom (Scotland) Posts: 26097 Chelski Traktor
    #4
    Is it running lean or anything? if so then i would suspect fuel pump or fuel hose popping off at filter again.

    More inclinded to say map or tps sensor though
  5. Administrator Joined: Dec 2002 Warrington Posts: 20561 Blue Saxo VTS Turbo/White Megane F1 R26
    #5
    Fuelling is fine... i dont think its fuel pump related.

    The car runs perfectly below 2000rpm... on and off boost. But at 2000rpm it feels like the engine is retarded... and the engine is put under load and boost begins to build.

    The worrying thing is how can the engine be put under load of the wheels arent turning.. u8nless something in the engine is catching

    Could be a whole host of things...

    arse.
  6. Regular Poster Joined: Jan 2004 ankara Turkey Posts: 292
    #6
    do you have 2 fuel pumps?
    maybe too mch fuel, do you saf-c or something like it?
  7. Administrator Joined: Dec 2002 Warrington Posts: 20561 Blue Saxo VTS Turbo/White Megane F1 R26
    #7
    I dont think the problem is fuel related... that all seems to be OK.

    I think the problem is timing related... ignition or cam timing.

    I wont have spare time to check anything until this coming weekend, but Im still trying to think about what the most likely cause could be.

    Going down the ignition timing / cam timing route for a moment...

    It could be possible that the belt has slipped one notch? I guess I would be looking towards the exhaust cam for this?

    But what if the belts not slipped, but the pulley has rotated on the shaft? ie, if the 3x10mm nuts worked loose for some reason, I guess the centrifugal force would adjust the timing for me!

    I was thinking about this at work today so just nipped out to the car to take a look at the pulley positions. I know I cant directly infer anything from this without aligning and checking properly, but the exhaust pulley does appear to be on its maximum adjustment??

    If this has slipped (unlikely) would this cause the symptoms I am seeing, or am I barking up the wrong tree??



  8. Regular Poster Joined: Jan 2004 ankara Turkey Posts: 292
    #8
    if the 10mm bolts have loosend and slipped then the symptoms your seeing are right.

    did you check all the sensors?
  9. Administrator Joined: Dec 2002 Glasgow United Kingdom (Scotland) Posts: 26097 Chelski Traktor
    #9
    they actually do look as if they have slipped
  10. Saxperience Addict Joined: Aug 2004 Herts. N/W London Posts: 13578 Project MK4 MoreDoor
    #10
    the one on the right of the first pic more then the other side, but both are slightly of line
  11. Administrator Joined: Dec 2002 Warrington Posts: 20561 Blue Saxo VTS Turbo/White Megane F1 R26
    #11
    They dont have to be aligned centrally.. they are adjustable for fine tuning.

    I can see marks where the exhaust cam timing used to be set.. but I dont know if that was recent or years back?

    I will have to lock the flywheel, etc and check it out.
  12. Administrator Joined: Dec 2002 Glasgow United Kingdom (Scotland) Posts: 26097 Chelski Traktor
    #12
    it does look as if they have move very recently with rust marks etc...

    the bolt top left on exhaust cam definetly looks like it has dragged

    Maybe have a quick go at tightening them up, if it has play to tighten then it would suggest it may have beeb loose enought for it to slip
  13. Regular Poster Joined: Jan 2004 ankara Turkey Posts: 292
    #13
    well why not set them to factory settings , it wont take long, and then try again
  14. Administrator Joined: Dec 2002 Warrington Posts: 20561 Blue Saxo VTS Turbo/White Megane F1 R26
    #14
    Well, Almost 2 months have passed and I eventually started to look at the car again at about 3pm this afternoon!

    Thank fcuk I bought a 2nd car. LOL

    Anyhow, after giving up on it being a mechanical problem I put everything back together on the engine.

    Now sure it was ignition timing related I thought it would be a loose wire, ecu breakdown(a new one was fitted the week before it broke), or a dodgy dastek (as this intercepts ignition timing signal)

    Couldnt find a problem with the wiring, so I decided to link out the Dastek... and it fired up and purred like a kitten straight away!!!

    What a Tw@t!



    So, with the dastek plugged in it screws with the timing, causing the engine to go under load... with the dastek removed the engine runs fine.

    Ive not been on the road yet, as I have quite a few things to put back together.

    Has anyone else had experience with a dastek suddenly failing? Is it possible for the unit to have lost its settings somehow? (unlikely) or is it likely to be fcuked?

    I will need to talk to john to see how much the dastek was doing in my mapping... im summising not a lot, else I will need to replace it or have the mapping redone without it.

    Any thoughts?