I recently installed an Apex'i Power FC in my FD. My car has been running much, much better but I've only had one issue, and that is that the knocking shown on my power FC is extremely high. Note, the car feels like its running in a stable condition, and nothing seems out of line (except a little more than normal backfiring).

Now, the knocking is on average around 40-80, depending on my driving, and even when trying full boost, the knocking stayed down. It's been at random times switching gears, or sometimes going 3/4th throttle that my knocking goes up to 131. In essence, it seems random.

My question is, do you think this is an issue with the actual knock sensor, or my car is running too rich / too lean ?

FYI, I'm running on an rx7store tuned map for the following modifications:

Non-sequential setup turbos
Rotary Extreme Monster V-mount
FPD replaced
Pineapple Racing Rebuild w/Mild Street Port
Full Silicone Hose Job in the "Rat's Nest"
Fluidyne Radiator
Evans Coolant
Racing Beat Plug Wires
NGK 9's all around
Rebuilt Turbos
HKS SSQV BOV
HKS Racing Suction Intake
Racing Beat Single Tip Exhaust
M2 Downpipe (Jet-Hot Coated)
N-tech BMK
Supra TT fuel pump
Fan Mod
Fuel filter changed
O2 Sensor changed
Redline Oil (I believe a gasket may be leaking)
Fumoto Oil Drain Valve
Neo Diffy fluid
Neo Tranny fluid
MMO used as premix every fill up

Thanks a bunch !
let me know if you need more information to assess this.

eugene

 

is your knock sensor loose

 

**** mine was knocking around 60-68 and the guy would not tune and dyno it just because that.i dont know.but it happened after the pfc install.let me know what you figure out.i am just as lost as you and where is the knock sensor located? thanks and good luck, jason

 

The knock sensor is located on the front housing above the trailing spark plug. You cant miss it.

 

This topic has been thoroughly covered and discussed, recently even. Please use the search function. Knock readings that occur in conditions other than continous WOT don't mean a damn thing and are nothing to worry about.

 

That makes zero f-ing sense, whatsoever. That's the whole point of tuning the car!!!

 

Here is something interesting for you.

When I had my PFC installed I had max knock values of up to 190. First I thought that it was because the car was running lean at the upper end. So, I maxed out the PFC fuel map settings to give me about 11.3 AFR at the top boost, high RPM. The knock values did not appreciably change. I was paying close attention to the PFC knock graph and noted that the max knock values occured only for a split moment, mostly during the initial phase of acceleration. After that the values fell and stayed at normal levels.

I pretty much given up on it after realizing that it was only a momentary spike.

A while later I changed my stock fuel pump to a Walbro and realized that I needed to lower the fuel map setting back to what they were at the PFC installation because now the car was running far too rich. The stock fuel pump was failing at high RPM adn boost.

As a side benefit, for some reason, the knock values now never exceed 40. Something in the fuel pressure was going wrong even at the initial moment of acceleration to cause a lean knock for only a moment with the stock pump.

Albert

 

When listing engine mods, only list those that are relevant to the dicussion.

Do not list every friggin thing!

 

please excuse the few words that may have tired your brain.

i just cut and pasted that from a list that i had compiled, and had not considered your mental well being.

on another note, thanks for the input everyone.

axr6, it seems that you and i apparently had the same issue. i believe it is the knock sensor, and i'll check it out soon.

i'll let you guys know what happens.

 

yeah check the knock sensor as julian said.

 

The above is all we needed for you concern.

We as a group have respect for people who show more initiative, and are less lazy than the average Joe. The RX-7 (especially the FD) is also due this respect because of it's power. It can bite you if you do not respect it's power as many young newbs have found out.

We expect a higher standard of competence here in this forum, and the single turbo forum than the 3rd gen forum.

 

chill matey. chuck i'm sure doens't mean it in a negative manner. those been around here knows the wealth of information he has passed on to other pfc owners. take a chill pill.

 

I've noticed knock to occur during gear changes/coming off the throttle.

I was there for the tune and it 100% didn't knock, ts fairly difficult to replicate on a dyno the driving conditions of coming off the throttle when going for the next gear.

So after a map trace I discovered there's a couple of lesser load points that required a few degree's to be pulled out, that was done and no more knock on anything less than a slap of a gear change.

If thats not the problem then it may have something to do with the Inj vs TPS1 setting or one of the settings that ensure sudden throttle input lean out does not occur.

 

you got me.if i knew how to tune and had a dyno i would have. as soon as i find a person or shop that is expierenced with rotories it will get tunned again.but i figure i will just change my knock sensor, the fuel pump and injectors. to be safe. there isnt that many fd owners where i live.maybe a hand full but no 1 in my area will give anykind of damn help so here i go throwing my $ away on people guessing.but thanks for the lesson, jason

 

Some cars have high knock levels under non boost driving that can be cause by: drive train slack, loose suspension components, exhaust rattling, or parts hitting parts. If these random noises are high (above 60) and continue after getting on boost; I would not tune that car either because you do not know which is noise and which is real knock. Such a car has a problem and needs to be fixed first. If the noise goes away after the car settles down under boost, then I would tune it.

My car was noisy when driving normally and shifting. My knock would be between 20 to 140. This was caused by my transmission and the rest of the drive train. Once I got on the throttle and the drive train slack was taken out, knock dropped to normal sub 20 values. Thus I could power tune safely. Since installing a rebuilt transmission, most of my noise have gone away.

 

Thanks for the information everyone.

So far I've decided to drive on this knock issue, despite my concerns because it seems to be something other than actual knock, as most of you have stated. I haven't heard anything suspicious other than a high amount of backfiring after easing off the throttle, mostly in third gear. Other than that, the car seems to be running fine.

I know the actual issue itself can be caused by one of many issues, and this i will try to discover when i have time to jack up the car and take a look.

As in cewrx7r1's case, my car's knock is going up to about 130-40. If this is a transmission problem, then can this possibly have any correlation with my 5th gear synchro going out ?

Cubes, I will check the setting of my PFC and refer to my friend's PFC (his car has similar modifications to mine) and see if there are any big discrepancies.

Once again, thanks everyone for the good feedback.

 

If theres one thing i hate more than the incompetence of listing irrelevant modifications it must be the inability to spell the word 'discussion' properly

Come on we must be 100% accurate

Faliure is not an option

 

HaHa!

 

You forgot the ( ' ) on theres. If you want to be 100% accurate.