Unstable idle

Discussion in 'Clio 197 Area' started by FishFart, Jun 18, 2018.

  1. FishFart

    FishFart Paid Member

    Clio 197
    @Foxspeed it has been mapped and had this issue but then stock map was placed in for test purpose but it is still there. Was massive flat spot from 2500-3000rpm (even after remap) which is known to happen when precats are deleted or cats are removed, specially with Toyosports manifold (and I also have Akrapovic evolution).

    I would assume that stock map would be behaving like this or a remapped one (if maybe missed something) would do the same, so either map inside would cause it anyway, as it does now. Same problem. The car has rly modified breathing mods and stuff, here is a list:

    Flat spot (2500-3000rpm) and also this "bad idle and rpm drop / choke" appeared after the engine rebuild when modifications in "bold red" were added:

    -V6 Airbox + K&N panel filter
    -Vemo AIT sensor
    -Ported+Polished intake manifold
    -Ported head (exhaust and intake, intake not "mirror polished")
    -CatCams '402 (limiter at 7800rpm)
    -Lightweight flywheel (KTR)
    -Lightweight crank pulley (by Raptor)
    -Toyosports exhaust manifold

    -Akrapovic Evolution

    Before the above marked "red bold" the car had remap at same tuner but everything was fine.
    After rebuild and above "red bold" mods, the remap was done again by same tuner.

    My questions / guesses here:

    1) Could only Toyosports make my problem when mixed with all mods together? (wouldn't even worry about mentioned flatspot, but the idle choke and car turning off is what worries me, also sometimes it has struggle to start the engine in the first place). Also more AC power level I add, car will more likely turn of on RPM drop.

    2) Headwork problem possible? But this wouldn't cause too much petrol being bumped to engine...

    3) Faulty flywheel giving crank sensor wrong information and messing it up?

    4) Map? (will be tested by the end of this week).

    5) ECU just went to hell overall somehow?

    Most powerful indication and actually the only one (since on diagnosis it usually shows nothing, and sometimes missfire but with no cil num defined) is all 4x sparks are black and wet.
    Last edited: Sep 12, 2018

  2. FishFart

    FishFart Paid Member

    Clio 197
    Ok so another map sensor was placed in (yes, previous "good" one used didn't work), and together all the electric connections were cleaned at the same time, and now the car turning off while RPM drop is not happening anymore, but another problem happened a moment later.

    I just took the car out from mechanic's garage, drove it home like 5 miles and on the 2nd traffic light before home, idle dropped down to 600 rpm as I was waiting at the intersection, and nothing happened.
    Took off normally, and then on the last traffic light before home it happened again but now I got "ENGINE OVERHEATING" message and "STOP" light on the dash, as well as my engine temperature going up from 12 to like 1:30 or 2 o'clock position (as the 12 is 90degree I guess this was like 110 degree), just like that. I was checking the temperature half way to home, nothing happened, but then it just got raised).

    I stopped in my garage and turned car off, bit later checked the coolant fluid and it was just right (a little bit under the maximum). I see no leaking / fluid around the engine.

    Will bring car back to the mechanic tomorrow morning.

    Any ideas?
  3. Foxspeed

    Foxspeed "the new red baron" Moderator

    sat behind a laptop over-moderating...
    ford mustang shadow gt v8
    thermostat have be known to go faulty
  4. FishFart

    FishFart Paid Member

    Clio 197
    Thx @Foxspeed , thermostat failed already about 1 year ago, and was replaced (had problem with engine showing as if it never gets properly warmed up).

    Is it possible that the new one fails so quick again? Haven't done more than 4-5000 miles since then.
    Also can it cause this slight idle drop to 600 while being in idle at traffic light?

  5. FishFart

    FishFart Paid Member

    Clio 197
    Some new things came up.

    The problem with overheating was dead cooling fan.
    As I described above, the idle (with and without AC) worked perfect, no RPM drops, no choking. After 15 minutes drive on way to home, engine overheat happened.

    So today I took the car to the garage again, really slowly, and while I came there and we tested the car on throttle a bit, overheating started again. So obviously the fan was broken, then replaced and all was good, regarding overheating.

    But, the idle problem came back.

    From here, I got some advice from friends that this might be caused by alternator or battery slowly failing.

    As there is not enough power from them (whichever one is failing, which both fan and alternator are using, and AC as well), these symptoms which I had could appear:

    1) Sometimes engine wouldn't start
    2) Idle RPM drop to 500 rpm or car shuts off
    3) More AC level power, worse idle gets
    4) Fan is off (dead), idle works perfect
    5) No error shown on diagnosis
    6*) Not sure about wet/black sparks tho

    Any thoughts?

    The car will be inspected again on Monday/Tuesday next week
  6. majki

    majki Paid Member

    Samobor, Croatia
    CS197 - Rouge
    I had similair problem when my flyhweel broke the gearbox. The problems were 1, 2, 3, 5.
    The camshafts went out of phase. Check the timing belt etc.
  7. FishFart

    FishFart Paid Member

    Clio 197
    Problem seems to be resolved now, and car works fine!
    After the radiator fan was replaced and all the above, after some days I went to get my map back and got it fine-tuned.
    Was driving the car on track this Sunday and everything worked perfectly.

    Let's consider this issue resolved, and hope the health will last!

    Thanks everyone on here who helped out! Cheers!
    Big Ben likes this.

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