4agze engine cuts off at high rpm

[AE_92GT-i]

Hi I am a newbie here (love the forum guys great stuff )

I have a 1989 corolla gti (FX) and i have done a 4agze conversion on it.
It has a 4agze engine off a jap spec AE101 (i think its a late spec motor) the only mod i have done to its is a overdrive supercharger pulley now the problem is at high rpm about 5k to 6k the ignition cuts off and the engine wont rev any higher the weird thing is it only happens sometimes like some days i would drive the car and it perfect no problems and some days it does that iam confused please help

Thanks

[Laruso]

I had the same problem with my regular 4age. It turned out to be a faulty alternator that would fail under load. Check to see if your charge light comes on when the limiting occurs. And perhaps make sure your alternator belt isn't slipping at high RPM either.

[AE_92GT-i]

I had the same problem with my regular 4age. It turned out to be a faulty alternator that would fail under load. Check to see if your charge light comes on when the limiting occurs. And perhaps make sure your alternator belt isn't slipping at high RPM either.

Hi mate nope no charge light

[-GT-]

Do a good search through the forums tech section, i've heard of this and i'm sure there's an acknowledged fix - can't remember what the fault/fix is as i'm not a gze owner, but it's common enough it's ringing bells with me so i'm sure there's been a few threads on it.

Somebody else might come along soon who's nice enough to link to one.

[oldcorollas]

knocksensor from memory.. witzl had posts abotu it?

[Poggy]

Does it rev slowly past that if you push it? or just stay on the same rpm?

[AE_92GT-i]

hi mate stays at same rpm

[Adsport]

ive heard of this being casused by the knock sensor pickup up vibrations from solid crank pulleys and the ecu pulling out timing to compensate.

Greddy did a knock sensor numbing device, we put one on an ae82 with 101 motor and it seemed to make it a lot better . i had a couple of them laying around somewhere i think still..

its a weird one that seems to occur on some swapped motors either fwd or rwd. ive come across it a few times and im convinced that there is something that people sometimes miss when wiring the cars up.

[TERRA Operative]

My stock AE101 4AGZE had the power drop.

I have swapped the ECU to an AE92 GZE ecu, swapped the knock sensor with one from a Supra, serviced the supercharger (cleaned oil chamber and filled with ner supercharger oil), cecked timing etc etc etc.

Apparently, the knock sensing system was made more sensitive due to the higher compression used in the AE101's, and it picks up the whine of the supercharger and thinks there's knock, so pulls out timing.
The ECU then remembers the knock event and progressively adds timing over 5 'passes' of the event on the rev range. If at anytime it picks up the 'knock' it's back to square one.

About the only way I can see that the problem can be solved is to deaden or remove the knock sensing system, or install an aftermarket ECU.

Another cause *may* be a dead knock sensor. I have seen ATS racing have a GM knock sensor and adapter that's much more resiliant and way cheaper, but I've never tried this mod to see what change it makes.
Apparently the stock Toyota knock sensor os relatively fragile and a big knock event can kill it.

http://www.atsracing.net/ats_racing_knock_sensor.htm

[TERRA Operative]

double post.

[AE_92GT-i]

What if I take the knock sensor out but still have it conected will that work??

[TERRA Operative]

You won't have any form of knock detection, but it will tell you for sure if it is the knock sensor causing the problem.

Just be sure to earth the case of the sensor to the chassis. Cable tie the sensor to a loom to keep it away from the engine then wrap a wire around it and wrap the lot in tape to keep it in place. Then simply earth the wire to the chassis or engine on a convenient bolt somewhere.

I've got a spare knock sensor that I've been meaning to hook up and try this with. I might give it a go after work tonight.



Remember though, you will have no knock detection. So don't leave it disconnected too long.