Guys,
i need your expert help, i have a FD just just been rebuilt but it keeps knocking, we have checked the plug leads, coils, oil injectors and wiring loom, the knock goes mad when you let off the throttle or change gear but it also knocks when you accelerate at anything other than a snails pace.
any help would be appreciated.
Dave
When you say knock.. do you mean just a clunk type knock or you on about something more serious like pinking/knocking????
if its a clunk type knock then check engine mounts Id guess??? does it do it when the cars not moving if u rev the engine???
Did you rebuild or was it a garage? If it was a garage, i suggest you get on the phone to them!
If not then, have you checked the wiring to the actual knock sensor itself, maybe a loose connection or broken cable..????
Hope you get it sorted...
Sorry not very clear, i mean knock as in pinking etc, the guy who built it has been very helpfull but we just cant find the problem, the knock sensor has been replaced.
i thought that someone may of had a similar experience.
at this rate i wont be making rotorstock :mad:
Might be worth phoning one of the tuners, they might have come across this before...
If the rebuild was done by a garage then if it was me it\'d be straight down there.... left with them and told to sort, if they cant sort it take it too a 3rd party and get the bill forwarded onto the garage who did the rebuild...
personally wouldnt be touching anything yourslef otherwise the garage could claim youve been messing and invalidating the warrenty....
thats my take on it anyhow... you may or may not find it helpful but there you go :)
I cant fault the person who built it as he has check everything out ie wiring loom etc. it just one of those things that puzzling....
Not saying lay any blame but in all honesty if he cant fix it and the fault has come about from any work he carried out on the car then youve got to fix it somehow... if neither of you know how then look at a 3rd party.... its the only route to take IMO... unless anyone obviously comes up with suggestions here...
do you know anyone nearby with an ECU??? could be worth swapping them over and seeing if thats the prob? just a thought
The Ecu would be a start. Is it a standard ecu or an aftermarket?
also if it a new knock sensor, was this done because the other one was broken? If not why not try the old one, brand new things can be faulty sometimes...
Is the knock sensor tightened properly?
i replaced the sensor to see if the old one was working. ive been talking to a specialist and he thinks that it could be fuel pressure. if the pressure was low could you still get the correct afr at low revs???
the ecu is an apexi and has been checked out
Did you do any other mods when you where rebuilding? when i did mine i had uprated turbos intercooler injectors so i got a better fuel pump too....
Just to get a better picture, are you talking about knock you can hear or just the readings that you are getting off the PFC Commander?
Kev
No no mods at all, it was already street ported and a single turbo, the only thing that was done was to clean up the ports slightly. :confused:
Isn\'t the knock level adjustable on the pfc, the manual says it only flashes when it goes over 60 on the reading. I think pip said you can adjust this when tuning, so the ratio is different on the readout. mine is flashing at the min, so taking it easy, but the reading has gone to 71 on the knock readout.
I noticed it said in the manual that the figure don\'t mean that knock is happening.
Hopefully one of the tuners can give you more advice on the fact. Better one of them explaining it first hand.
I may be completely wrong, got told about 8 months ago at oulton park ! But may just be settings in the pfc.
Whats the max reading you getting on the commander ?
Shaun
Easiest way to check if it is pinking is to check the knock value under part throttle. Mine reads up to 100 sometimes just tickiling the throttle at about 3000rpm. Might just be a vibration near the knock sensor, or knock sensor not tight. Apparently a dab of superglue on the knock sensor threads can cure an over-reading. I got Pip to raise the Knock Threshold to 75 when re-mapping my PFC a couple of weeks ago.
As mines not doing it under "balls out" acceleration, i dont think its anything to worry about...
Cheers
Jon
what is a normal knock level when accelerating or accelerating under boost???
i think the cat warning light is better guide mine has flicked on now and again but knock reading on pfc varies..have seen only abot 30 giving it stick but low on fuel and pushing it registered 89 but no cat warning light
out of interest where is the knock sensor..picture if poss
QuoteOriginally posted by davehg
what is a normal knock level when accelerating or accelerating under boost???
max knock level I see is about 30
Not a very good picture but gives a general idea, near the front housing spark plugs
Cheers
Jon
well ive checked that all 4 injectors work (didnt flow test them) but they all click on....
im really stuck guys...
Sounds like you need to get it on the dyno and at least see if it needs some tweeking to stop giving you greef. Just been out tonight, and mines flashed a couple of times. Its going to pip next friday, so hopefully it should all be sorted.
Shaun
As I asked earlier, are you talking about knock you can hear or just the readings that you are getting off the PFC Commander?
Remember the knock sensor is only a mic and can pick up noise from changing gear, ticking metal after boost run, etc. If you are getting high readings on full boost then you have to get off the throttle and have it checked out. But high readings cruising or changing gear is only noise.
Hope this helps.
Kev
to be honest i havent chanced in on high boost, it worries me too much as it popped after only 700 miles before and we cant find the cause of the knocking
It does sound unusual, I\'m not sure what state it was in pre-rebuild but if you\'ve done some work to the ports it could be running more lean than before which would cause knock, however if you\'re on light throttle and no boost I wouldn\'t have thought it would make enough of a difference.
First suggestion would be to get a lambda sensor on it and measure you air/fuel ratio. This will give you a really good idea of whether you\'re getting enough fuel. Anything above 11.5 is on the safe side for a rotary. 10.5 for maximum performance, any less and you\'ll be running lean.
It\'s odd though that it happens on tick-over. At the end of the day the knock sensor is a microphone, so if something\'s loose very near it that may cause it to get readings. Another possibility (although I haven\'t worked out how or why) is that something may be loose in the engine, one of the bearings perhaps?
May give you some ideas.
H
thanks for the reply guys
ive booked it in to be looked at on wednesday so ill let you know the outcome.
fingers crossed for rotorstock
QuoteOriginally posted by Spotlamp
First suggestion would be to get a lambda sensor on it and measure you air/fuel ratio. This will give you a really good idea of whether you\'re getting enough fuel. Anything above 11.5 is on the safe side for a rotary. 10.5 for maximum performance, any less and you\'ll be running lean.
Bit of confusion here i think H. :)
ROUGHLY (i.e. open to the individuals interpretation and experiences and what fuel/additives u are running - you could add or subtract half an AF easily):
12:1 lean (power)
11:1 in the middle
10:1 rich (bogging)
as far as I was aware, anything much over the 11.5 mark is getting on the bad side of lean.
Like I said, it all depends who u r, what u think and what you are feeding the engine on fuel and additive-wise; most tuners will leave a considerable safety margin when tuning customer cars to account for a bad tank of gas, may be tuning to 11 or even <10.5 under boost - that doesnt mean leaner than 11.5 is instantly death on a stick tho. On the contrary, with good gas and/or water theres lots of power there potentially. Just for most people its not worth it.
From what I undestand you can get more power from running at 12 - 12.5 AFR but there is a higher risk of detonation, which we know is bad for rotaries. They run at about 10.5 - 11AFR to help with cooling. That is why a well set up water injection can net more power using water instead of fuel to reduce detonation.
Oops, sorry, my bad :)
Thanks for the correction.
H
QuoteOriginally posted by 20B_boy
Bit of confusion here i think H. :)
ROUGHLY (i.e. open to the individuals interpretation and experiences and what fuel/additives u are running - you could add or subtract half an AF easily):
12:1 lean (power)
11:1 in the middle
10:1 rich (bogging)
Quoteas far as I was aware, anything much over the 11.5 mark is getting on the bad side of lean.
That\'s my understanding too - which is why it\'s worrying that mine had a reading peaking at 65 at low revs when i took mine up to WGT!! Going back up this week to get that sorted now!!
So how does it all relate to the figure shown on the pfc ???
Shaun
QuoteOriginally posted by nikp
That\'s my understanding too - which is why it\'s worrying that mine had a reading peaking at 65 at low revs when i took mine up to WGT!! Going back up this week to get that sorted now!!
Woooh, we are talking about different things here; H was referring to A/F ratio measurements not Commander knock readings!
Spurious \'Knock\' readings on the commander vary very much from car to car, some suffer, some dont. If you are getting \'high\' knock under full load (i.e. full boost, rpm-regardless) then take it seriously! If you\'re getting the flashing light on lift off or cruising then its not likely its much to worry about I would say. The max I\'ve seen on one car was 207 on lift off - along with lots of 180\'s - but under load its f/all and the car runs great with no problems ever. I\'m happy the tune is perfect and very safe - and given the life it has it would\'ve **** itself long ago if it were a problem - its just an annoyance ofdten more apparent on older cars. I still keep an eye on knock readings periodically on the commander under high load but otherwise I\'m not worried by the peak readings.
One of THE Datalogit guys used to report and completely ignore 130+ knock readings for whatever that may be worth...
Basically, dont dismiss PFC knock levels but pay attention to when they peak and if still unsure take it to your preferred tuner to get checked out on their wide band lambda gear...
Nope - I was referring to A/F ratio too! Mine was massive! I have a graph to prove it - kindly supplied by WGT!! :p