4AGZE loses power at 5500rpm

[PsyCo]

Hi all.

I recently bought a Ae92 with a DLI Map sensored GZE.
I have noticed a problem. It seems to suffer an ignition breakdown or similar sort of feeling at around 5500 rpm. Pulls like a freight train up until then.

I have only experienced it the first couple of times I hit this sort of rpm in a drive. I travel 9km to work each day and it may do it once or twice till i'm about half way to work then it revs out freely. I have changed spark plugs from 1.1 to new .8 gapped ones (thought it might have been blowing spark out). Also fitted a new set of leads but to no avail. New fuel filter fitted as well.

I'm going to check caps in the ecu just to rule out another thing but would appreciate any idea's of other things to look for as possible causes.

Cheers


Brad

[trdee]

sounds like the powerdrop issue (knock sensor picks up harmonics at 5500rpm and cuts timing), though that normally happens with the AE101 gze???

[PsyCo]

I think the donk is out of a 101. I'm GZE noob remember Vito
JP said the same thing about timing cut. I assume this is right but would it only happen for the first few times I try to rev it out.
Fuckin knock sensors. I hate them. The ones on my LS1 are being arseholes too atm

I'll hunt the powerdrop issue and see what i can find out.

[Hiro]

The 5500rpm drop is fairly well known on Twincam...

[PsyCo]

The 5500rpm drop is fairly well known on Twincam...

Plenty of info on it Hiro, Thanks.
Can't seem to find anyone who as actually fixed it though which is concerning.

[Hiro]

I think Terra had a go at some stage at swapping the knock sensor for one from a different car, can't remember if he succeeded or not

[PsyCo]

I think Terra had a go at some stage at swapping the knock sensor for one from a different car, can't remember if he succeeded or not

Yeah TERRA's done a 92 GZE ECU swap as well.
Gimme back my problem free 1J i say

[TERRA Operative]

Pow! Welcome to the fun of the AE101 GZE.

My AE101 GZE runs without the powerdrop 90% of the time, the other 10% it's barely noticeable, and it's usually on a hot day, when I'm wearing odd socks or the planets are aligned.
So far, I've installed a 7MGTE (IIRC) Knock sensor, an AE92 ECU (less sensitive knock circuit) and that may be it... You'll also need the plug for the 7MGTE knock sensor as it's different to the 4AGZE one. Oh, and the AE92 ECU has a slightly different pinout, but my site in my sig has the details.

I'm planning on maybe building a filter circuit that filters out all but 6400Hz (knock frequency in the 4A engines) to minimise extraneous noise from reaching the ECU to help prevent it from freaking out.mIt would be an inline module that you hook in with a power and ground too, Basically an active bandpass crossover.

It seems that in the AE101, the knock sensor circuit was made more sensitive due to the higher compression and boost, but due to harmonics from the supercharger (it is believed) the preamp in the ECU overloads at 5500RPM from the extra noise and the ECU freaks out and pulls timing. Kind of like yelling into a microphone (the knock sensor is just a piezo mic).

I would like to get my hands on an AE101 GZE ECU, so I could trace out the knock sensor circuit and compare it the my AE92 GZE ECU. That way, it might be possible to insert a gain control like on an audio amplifier to cut down on the overloading. Or maybe have a zener diode to shunt any over voltage to ground... hmmm.
I just need an AE101 GZE ECU for a few days...

[trdee]

Yeah TERRA's done a 92 GZE ECU swap as well.
Gimme back my problem free 1J i say

I wouldnt mind a 1J to replace my GZE either, fkn fail engine.
I'm afraid terra is the only one here who has some workable solutions, the only other solution is to replace the ecu with something aftermarket, which is what most people do.

[PsyCo]

Pow! Welcome to the fun of the AE101 GZE.

...

I'm planning on maybe building a filter circuit that filters out all but 6400Hz (knock frequency in the 4A engines) to minimise extraneous noise from reaching the ECU to help prevent it from freaking out.mIt would be an inline module that you hook in with a power and ground too, Basically an active bandpass crossover.

I would like to get my hands on an AE101 GZE ECU, so I could trace out the knock sensor circuit and compare it the my AE92 GZE ECU. That way, it might be possible to insert a gain control like on an audio amplifier to cut down on the overloading. Or maybe have a zener diode to shunt any over voltage to ground... hmmm.
I just need an AE101 GZE ECU for a few days...

Yaaaay i was hoping you'd join in TERRA

Don't plan on maybe building this filter. Just do it. You're clever. You can do it. All us GZE owners beleive in you

I could probably lend you my ecu for a 2 day period if I planned it in advance. Do it on my days off from work (2 days) and I wouldn't need my car.

Mine still only does it the first few times i give it stick. From my place this morning it did a few times the last one being as I turned off wembley rd onto kingston, but as soon as i turned into moss st, it reved freely 3 or 4 times

I repeat again. I hate knock sensors. At least they aren't buried under the valley cover on the gze like my LS1 Homo holden mobile

[TERRA Operative]

I'll get back into designing that circuit then. I should even be able to get the PCB's made at work too.
They will probably be sold as a complete unit (I'll build them) due to the parts used (PIC's etc) so all that needs to be done is to install the box.


The retard problem takes five times to fully disappear. Ie. if you get the power drop at 5500 RPM once, you have to rev past 5500 RPM 5 times for it to return to normal. Each time it adds a bit more timing back. If at any point, it detects knock, it pulls all timing and starts over again.

[PsyCo]

Hmmm.I wonder if mine is triggered on startup then....?
I have to take the thing for a longer drive. I have only noticed it when i start driving and then once it goes it's gone.
Just have to caned it out of my estate and enjoy the drive to work

Keep me posted on the filter cicuit. I do not appreciate being chopped by CE lancers on my way home from work due to short shifting

[the_random_hero]

If you guys were keen I could make the filter circuit for nothing, I have plenty of free time at the moment. If Terra wanted to make the PCB and sell it that's fine by me.

[PsyCo]

If you guys were keen I could make the filter circuit for nothing, I have plenty of free time at the moment. If Terra wanted to make the PCB and sell it that's fine by me.

Is that you drew?
I hear talking but I dont hear making

[the_random_hero]

Is that you drew?
I hear talking but I dont hear making

Shoulda guessed from the username, avatar and car
I'll see what I can do mate.

EDIT: Shit it's been some time since I did proper electronics, this is harder than I expected.