View Full Version : Knock Problem
Hi Gary/Christian,
The latest weeks i got a knock reading up to 40 when i drive on the highway (120-130Km/h). But today i even got a 60 :eek: And i still got the problem that my car judder when i stop accelerate, it feels like my car have asthma :wack:
Regards, Nick :)
All sounds pretty normal probably just the fact the boost is dumped and the turbo takes a bit to spin again and the air flow readings are not quite right.
The knock readings are likely to be poor quality fuel, ive had a 60 after putting some rubbish bp in and a bit of 95 that had to tide me over. Im more careful with throttle and rubbish fuel now (go easier when im running it). High knock reading dont necessarily mean det too I believe.
All sounds pretty normal probably just the fact the boost is dumped and the turbo takes a bit to spin again and the air flow readings are not quite right.
The knock readings are likely to be poor quality fuel, ive had a 60 after putting some rubbish bp in and a bit of 95 that had to tide me over. Im more careful with throttle and rubbish fuel now (go easier when im running it). High knock reading dont necessarily mean det too I believe.
Thanks for your help mate :) I always use the best fuel available and this is Shell 'V-power' 98Ron. While accelerating everything is fine but the moment i take my foot off the throtlle or even a bit, i got these high knock peaks :confused:
i get a similar stutter when you back off :nod: is this with a SAFC 2?
My knock reading are also high on idle when its been running for around 40mins, i think as long as you dont see any peaks when your accelerating your ok :confused:
You have got the power FC which is good, you will know if you get an above 60 when accelerating by looking at your engine check light, it will flash. When mine flashed under hard acceleration with rubbish fuel I heard no det (wont do that again to be safe though). Your car should be ok on 98 ron and it looks like you have a pretty high specification for the turbo size.
i get a similar stutter when you back off :nod: is this with a SAFC 2?
My knock reading are also high on idle when its been running for around 40mins, i think as long as you dont see any peaks when your accelerating your ok :confused:
I use a Power FC :)
You have got the power FC which is good, you will know if you get an above 60 when accelerating by looking at your engine check light, it will flash. When mine flashed under hard acceleration with rubbish fuel I heard no det (wont do that again to be safe though). Your car should be ok on 98 ron and it looks like you have a pretty high specification for the turbo size.
Hi Ian,
Today i did a bit of test drive, and the 'engine check light' flashed while accelerating above 5000rpm. :( But why do i get 40 knock reading when i take my feet off the throtlle? Maybe i should try another fuel brand :confused:
Yeah i know that my turbo is :ghey: but i got it before i need to do my engine rebuild. After i sort suspension mods i buy something bigger ;)
That is strange the only thing i can think of is that belgium optimax is not as good as english stuff. (I think in this country some people have found some places selling 95 as 97) Maybe best to get it on a RR and get a slight timing alteration. That is if your knock mics not playing up and over reading.
I´ll try to go back to APT asap :nod: Nobody here in Belgium works again on my car, they did already damage enough. Thanks for your advice mate :)
Thats a long way to go to get things checked (it costs me about 140 quid to get to norwich and back so it must cost you a fortune, you might want to at least save the journey for a major tuning event) maybe he can pm you how to change a few points on the powerFC or even increase fuel a bit to make things a bit safer (i wouldnt know where to start so cant advise). What levels of boost are you seeing too? Do you hear any det, pinging? Check your spark plugs condition too
I´ll try to go in my summer holiday period :nod:
I fitted new spark plugs last week, but i noticed some blue corrosion on the coilpack connecting plugs maybe this is the problem.
Papa Lazarou
16-04-2006, 15:02
Do you drive far in it? Mine started getting higher knock readings for a time (no real concern, just like 42-43 during the spool up rpm, enough to trip the warning which is set at 40 on mine). It started happening after I adjusted one of the IC pipes to get a better seal, so I thought it was related to that.
I had been using the car for short journeys, the odd short blast, but not really hammering it. Pretty sure I'm not imagining it, but after taking it for a good 70 mile drive, the knock values seemed to lower slightly. Now I rarely see over 33, even on Tesco SUL (a lot cheaper than Optimax and supposedly not as high octane).
Just a thought anyway. I think what happens is that short journeys/slow city driving will increase build up of carbon deposits in the chamber, which may make it more prone to knock. Clearing it out with a good long spirited drive may help (obviously keep an eye on knock levels). This is also known as an "Italian tune up" ;)
:nod: most of the time i do short journeys/slow city driving. Tomorrow i do a longer 'pleasure' trip and see what happens. Thanks Papa :)
Hi Gary/Christian,
I still got a knock reading of 40 when i drive on the highway. The knock bar is always between 30-40 when i´m keep the same speed. But when i´m accelerate the knock readings are around 20-25. And the stutter when i stop accelerate is also :annoyed: i got this from the first day after mapping.
Greetz, Nick :)
You could try tightening up the HKS SSQV to reduce the stutter (I dont know if its clockwise or anticlockwise). 40 on the highway may just be picking up noise from other cars, 20 on acceleration sounds good :) if you have changed any settings or just changed the fuel it seems to have done the trick.
The HKS SSQV is the only second hand part (from a Subaru:wack: ) on my car, so maybe this is the problem for the stutter. Thanks again mate :)
I never change settings and i used always the same fuel since my mapping. The Shell V-Power i use should be better then the Optimax :nod:
You can turn it into recirc mode also may have less problems with it. I think maybe with you having a small turbo it spools a bit quick which means for greater fluctuation in the lower rev range. A recirculation setup or a Djetro powerFC should lessen then problem I think. Also tighten the spring up so it actuates less easily. Shouldnt be a problem second hand I dont think.
A bit strange that you car has gone from high knock to low knock without changing any settings, maybe your intercooler was heatsoaked or something when you originally has the engine warning light flash.
I got the D-Jetro version ;) The knock readings are weird, when acellerating everything is good (20-30) but when i drive the same speed on the highway i got knock readings of 35-40. I´m only affraid for my engine, i dont have the money and desire for another engine rebuild :no:
Nick, we sometimes see vast differences in the readings produced by different knock sensors. If your plans are to make a trip to us in the Summer, that would be a very good idea, by which time we will have our Rolling Road in use. Until then, it may be a good idea to either take it easy, use Octane booster or discuss with Gary removing a couple of degree's of timing from the Map. I wouldn't normally encourage fiddling with settings to that extent as pressing the wrong button could do some serious/costly damage, but we can help you.
Hi Christian,
Today i got again 50-60 while accelerating on third gear :( I´m coming over in the summer. Does it makes a difference that the car is mapped with Optimax and that i drive with Shell V-Power. Maybe i can take a jerrycan with V-power with me for the mapping.
I got holiday from 21 July till 15 August are you guys working in this period ?
Greetz, Nick :)
Sometimes i got some weird idle, it goes always from 150rpm. to 1600rpm. :confused:
Whats going on with my car ??
Again could be a loose set dump valve or rogue air signal. Sometimes if I am not quick with changes the engine will virtually stall with the backup, some people get these things worse then others.
Its no stall :no: When i´m waiting for a traffic light, my rpm's drop to 100-150 and up to 1500-1600 for the whole time i stand still on the lights ! If it was the dump valve, why do i not have it always :confused:
I´m really disappointed, after 5 years of problems and 2 engine rebuilds i went especially to APT because they are THE mapping 'gods'. And now i still got problems with my car :(
The first weeks the car runs fine but for some reason i got always more and more problems :cry:
well it sounds like an airleak of some sort, its just most common its the DV
I will look for another dump valve :nod:
I would try blocking it off or puting back the original to try seeing if it makes things better before making a financial commitment, it might be that a hose jubilee elsewhere might be letting air past or a loose vacuum hose.
Gary@APT
28-04-2006, 19:50
nick when you get the time give me a call and we can go though a few options to see if we can sort over the phone.
if you can be near car when you call
I would try blocking it off or puting back the original to try seeing if it makes things better before making a financial commitment, it might be that a hose jubilee elsewhere might be letting air past or a loose vacuum hose.
I still got my Bailey dump valve, tomorrow i try with this one :)
nick when you get the time give me a call and we can go though a few options to see if we can sort over the phone.
if you can be near car when you call
Hi Gary,
Thanks, but first i gonna try my other dump valve :)
Are you working between 21July and 15August ? I´m gonna try to find the money for a better clutch and turbo, i need a re-mapping anyway then ;)
SteveSadler
29-04-2006, 15:20
Hi Gary/Christian,
I still got a knock reading of 40 when i drive on the highway. The knock bar is always between 30-40 when i´m keep the same speed. But when i´m accelerate the knock readings are around 20-25. And the stutter when i stop accelerate is also :annoyed: i got this from the first day after mapping.
Greetz, Nick :)
did you map the car on the road or the rollers? or a combinations of both?
usually you only get high knock readings if youve noisy lifters (ive experienced this) or some time too much ignition )
you really need to datalog the power fc logs and analyse them properly. This is what I do all the time when tuning power fc's. From the data logs you can then establish which cells are giving you the high knock readings and adjust the fuel or in more cases the ignition easily and quickly.
Apexi have the warnings on most Nissans and Mitsubishis set at 60 anyway as a near max (on 4 cyl motors). But what you will find is that when analysing the map the 60 may only be with specific reference on one cell of the map. doesnt mean at all in anyway that your getting 50-60 knock on your map. the rest of the cells on your map may only be seeing 10 - 30 knock.
did you map the car on the road or the rollers? or a combinations of both?
usually you only get high knock readings if youve noisy lifters (ive experienced this) or some time too much ignition )
you really need to datalog the power fc logs and analyse them properly. This is what I do all the time when tuning power fc's. From the data logs you can then establish which cells are giving you the high knock readings and adjust the fuel or in more cases the ignition easily and quickly.
Apexi have the warnings on most Nissans and Mitsubishis set at 60 anyway as a near max (on 4 cyl motors). But what you will find is that when analysing the map the 60 may only be with specific reference on one cell of the map. doesnt mean at all in anyway that your getting 50-60 knock on your map. the rest of the cells on your map may only be seeing 10 - 30 knock.
Steve, we do datalog the PFC maps whilst making adjustments. I do not think it is appropriate to discuss publically our mapping procedures, but suffice to say that we do take measures to fully see even parts of the map that the end-user will almost certainly never see, both from a Fuelling and Ignition point-of-view. Fine adjustments can be made to individual cells as you describe and we certainly do make those adjustments, it would appear in this case that there may be some other variables involved.
Whilst mapping, we are concerned with a value of 60, even if it is on one cell only. OK, so this may not present a major risk, but from a commercial point-of-view we must consider the long-term safety of the engine and the situations that it may find itself in.
did you map the car on the road or the rollers? or a combinations of both?
usually you only get high knock readings if youve noisy lifters (ive experienced this) or some time too much ignition )
you really need to datalog the power fc logs and analyse them properly. This is what I do all the time when tuning power fc's. From the data logs you can then establish which cells are giving you the high knock readings and adjust the fuel or in more cases the ignition easily and quickly.
Apexi have the warnings on most Nissans and Mitsubishis set at 60 anyway as a near max (on 4 cyl motors). But what you will find is that when analysing the map the 60 may only be with specific reference on one cell of the map. doesnt mean at all in anyway that your getting 50-60 knock on your map. the rest of the cells on your map may only be seeing 10 - 30 knock.
APT did the mapping mate ;) thanks for the advice anyway :)
SteveSadler
29-04-2006, 19:03
Steve, we do datalog the PFC maps whilst making adjustments. I do not think it is appropriate to discuss publically our mapping procedures, but suffice to say that we do take measures to fully see even parts of the map that the end-user will almost certainly never see, both from a Fuelling and Ignition point-of-view. Fine adjustments can be made to individual cells as you describe and we certainly do make those adjustments, it would appear in this case that there may be some other variables involved.
Whilst mapping, we are concerned with a value of 60, even if it is on one cell only. OK, so this may not present a major risk, but from a commercial point-of-view we must consider the long-term safety of the engine and the situations that it may find itself in.
Guys, i didnt say that you didnt datalog the maps ;-) I just said that they need to be analysed, and i can understand and respect fully if you do not wish to discuss mapping procedures of whatever kind, I wouldnt expect you to.
And of course, like yourself, when tuning a customers cars any high knock value is of concern as is the long term safety. I agree
SteveSadler
29-04-2006, 19:04
sorry if you felt offended in anyway, no harm intended ;)
No offence taken Steve, I just wanted to clarify that in the instance of Nick's knock readings, as with all our maps they are written with a number of things in mind. These include maximum power, good quality driveability, off-boost economy etc.
When I said that we datalog our PFC maps, perhaps I should have been more clear about the fact that our datalogging process involves analysis of the results, or else what is the point in datalogging?
We have concluded in some instances that there are variations in the knock sensors on different cars and this can make for starkly different results. This may or may not be the case with the car in question here. I am sure that we will rectify these issue's upon Nick's return.
Of course, when we are mapping on the Rolling Road, we can use different approaches to those that we currently employ. It is not to say that we consider road-mapping to be inferior, I actually think that a proportion of our mapping will still be implemented this way, more that we can make use of some of our more specialised equipment, such as our 6-Way Det Cans, Exhaust Gas Analyser, Timing monitoring equipment etc and will have the ability to load the car up in different ways. Sometimes there is no substitute for extensive equipment, hence our massive financial outlay. By the time Nick returns we should be fully up and running.:thumbs: :Plug:
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