Guys,

A friend is having a problem with his 7. Spec as far as i know is standard, bar a street port, cat back exhaust, PFC and HKS filters. He is currently running the base map on the PFC, but only switched back to the base map to try and cure the problem he is experiencing.

Basically, at anything above 2.5k, even at constant throttle (i.e cruising at 2600rpm exhibits problem too) the "heat" light flashes on the dash. He has been told this is generally the knock light for th ePFC, but i find it hard to believe his car is knocking on a base map at constant throttle.

The car starts and runs fine. I also notice the air pump is disconnected at the plug, however, reconnecting it has no effect on the light.

Can anyone suggest a way to proceed investigation with this problem? because im stumped. Everything looks connected etc...he has had it at a specialist too who said the car was showing high knock levels, but he had been driving it hard before with the same problem, so i find it hard to believe the car is knocking hard because it hasnt grenaded yet.

Ive told him to get his timing and AFR's checked on a rolling road, apart from that i dont know what to do. Can anyone shed any light on this problem?

thanks all.

 

Unplug the wire to the knock sensor .

 

Im interested in this topic bobfish,,,,, because 4 months ago i bought a PFC,,, thinking i could plug it in and drive,,,, (i had similar problems to your friends,,, cat temprature light flashing on any kind of medium/hard throttle..also noted that my knock levels reached 180 on the PFC commander),,, i was so scared i was gonna damage my engine i removed the ECU and am waiting now till i can get it tunned correctly to reinstall,, (what gets me is i constantly read that the base maps are very safe for a normally tuned car,,, so what gives,,,, i never read of any of the amercian rx7 owners having this problem with there PFC),,,,,,,,,any input greatly appreciated as my power FC is getting plugged back in again soon??????????

 

I'm curious to what year 7 your friend has. I know there are different versions of PFC for different years. Double check and make sure you have the right version. I know for fact 99 PFC wouldn't even plug into 93-95 US version.

Good luck!

 

i had the same problem. I got the car tuned to the right afr's then increased the knock threshold with datalogit. Basically it was my broken ppf.

 

whats a broken ppf?

Whats a normal knock level for an RX7 then? If we can get a reading and make sure its within spec then im sure we can increase the threshold using a datalogit.

Herblenny, my friends car is a 92 '7, unsure of what PFC he is using though. Ill get the numbers off the ECU.

Garco, what happens if we unplug the wire to the knock sensor? Doesnt the car need this to knock retard?

 

It has to be the right PFC - the others simply won't connect (16bit after 95).

I had intakes/catback/dp and got high knock levels and frequent flashing. The cure: tuning! Don't be too quick to dismiss high knock levels as background noise. I had readings 120+. I don't think I've seen anything over 40 since tuning.

The smart idea would be to put it on a dyno and actually check it.

 

ok Dai, will do - thanks for the valuable input.

The thing i cannot understand, is why the light comes on at the times it does. If you drive at 2.6k constant throttle you get the knock light come on. Even on overrun it comes on, and switches off once the revs drop below 2.5k...

 

broken power plant frame. it attached the transmission to the rear differential. When it is cracked, you get severe vibration in your drivetrain that increases with rpm.

my FD's peak knock readings are around 70 or so, and I haven't seen over 100 in a long time. Now that I have my water injection installed the peak knock has settled to aroun 40.

 

so the broken PPF could be causing the knock? Does any one have any pictures of it? or any info on where it usually cracks so it can be checked?

 

Unless you've been launching the car, I doubt the PPF is cracked. Plus, you would definitely hear it---you will get some serious vibration that increases as your rpm goes up.

 

personally, I believe water injection will result in world peace