advice needed for 197 - stalling issue

[aaron-rs197]

looked for some advice on where best to start looking in to this. the issue is when the clutch is disengaged and rev's allowed to drop to idle, it will drop right down to about 400rpm, struggle and stutter for a split second then return to idle of around 800-900. occasionally it may stall completely. this is not good for driving around town. any help much appreciated. thanks.

 

[aaron-rs197]

just to add: i've put my obd scanner on, no fault codes logged. i've taken the throttle body off and cleaned and checked it thoroughly and cleaned plug with contact cleaner. new spark plugs coming next week. checked coil plugs are secure, checked map sensor secure. haven't checked crankshaft position sensor yet (some searches say this could be the cause but i have no trouble starting...) i'll have it on the ramps tuesday so will check/clean crankshaft position sensor then. if its not that, anything else I could check?

 

[Foxspeed]

check live data for lambda signal...could be fuelling issue due to faulty lambda readings

 

[aaron-rs197]

hi @Foxspeed thanks for the reply. what would you consider to be a normal signal for lambda data readings?

 

[Foxspeed]

should be a constant fluctuation of voltage reading if its doing its job, theres plenty of info on line for lambda diagnosis

 

[Abdulla Ali Al Ali]

probably worth cleaning the lambda sensors ends if they are pretty old and may be clogged (or replace them)

 

[aaron-rs197]

so i checked voltage returns from pre and post 02 sensors. pre is fluctuating fairly consistently between 0.2v and 0.8v. when i increase revolutions for a moment and let it come to idle it will hold low for a few moments before fluctuating again. post is held at 0.4v-0.5v. i believe these readings are considered normal?

 

[aaron-rs197]

i do have a fault code relating to the knock sensor - P0325 Knock Sensor (KS) 1, bank 1 - circuit malfunction

Could that be related at all?

 

[Foxspeed]

i do have a fault code relating to the knock sensor - P0325 Knock Sensor (KS) 1, bank 1 - circuit malfunction

Could that be related at all?

mmm not sure stalling would be a cause of the knock sensor circuit....unless its pulling the timing back when the revs drop and causing the stall... as you can use timing advance to improve and lift engine idle revs

investigate it and sort the error if just might cure it

 

[aaron-rs197]

this has turned in to something a bit different now lol. i changed the plugs last weekend (ngk iridium heat rating 7 from engine dynamics) to see if that would sort the low idle, which it didnt, it stayed the same and running ok otherwise. I ordered new knock sensor to fit this weekend as that had a fault code stored in ecu so thought i'd change it anyway. started the car yesterday evening as hadnt been started all week and the idle went completely the other way and now just wants to sit there slowly creaping up to 2k on its own with what sounds maybe like a slight misfire every so often. so i've changed the knock sensor anyway and started the car up again, still high idle. I can now also read codes p0351 and p0352 which are relating to the coils packs p0351 for 1 and 4, p0352 for 3 and 4.

what on earth could of gone wrong here? all four coils couldnt of gone bad within the space of a week surely?

 

[turkie172]

Pictures of the old plugs please they can tell a story.

 

[aaron-rs197]

i'll get some pics of the old ones in a bit. the high revs was sorted. took throttle body off, it was seized up. cleaned up with some wd40 and now ok (ish) does get stuck for a bit if i open the butterfly right up and hold it there. thing is, i took it off a couple weeks ago and cleaned it up so not sure how its managed to seize up in such a short time... anyway im back to square one with the almost stalling thing. going to book in to see the clio man. hopefully he can figure it out. oh and the coil codes seem to have disappeared too....

 

[aaron-rs197]

 

[aaron-rs197]

the 2nd and 3rd time i gently blip the throttle to 2k rpm and let it idle, it goes way down then struggles to keep itself alive and then eventually idles out at 800rpm ish. maybe one time out of 20 it will stall completely.