Im Getting Desperate

[davehg]

what is a normal knock level when accelerating or accelerating under boost???

[rx7veilside]

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

[rx7veilside]

out of interest where is the knock sensor..picture if poss

[Oedipus Rex]

Originally posted by davehg
what is a normal knock level when accelerating or accelerating under boost???

max knock level I see is about 30

[jonrx7uk]

Not a very good picture but gives a general idea, near the front housing spark plugs

Cheers
Jon

[davehg]

well ive checked that all 4 injectors work (didnt flow test them) but they all click on....

im really stuck guys...

[shaunwil]

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

[FD3UK]

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

[davehg]

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

[Spotlamp]

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

[davehg]

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

[20B_boy]

Originally 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)

[Oedipus Rex]

as far as I was aware, anything much over the 11.5 mark is getting on the bad side of lean.

[20B_boy]

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.

[FD3UK]

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.