4AGZE map lagging a little more than expected!! NOW FIXED!!!

[4AGZE_rolla]

well i guess then it could be the knock sensor i will be dropping into a tuner anyhow for a few tests!!
question though witzl you say if that is the prob then i hav limited solutions which are ethier rebuild the engine or aftermarket ecu.. is the rebuilding solution only too try and eliminate any vibration so that a faulty/sensitive sensor wont pick up these and give false readings?? only coz the internals seem to be fine so would prefer not to dismantle a good engine!!
if i was to choose aftermarket engine management,, what would you suggest(keeping cost in mind im not a millionare, and i want to go turbo in like 6months) ??
would this fix the prob without rebuilding,, because it wouldnt be using the knock sensor??
thanks again guys heaps off great feedback!!

[mic*]

Before dismantling the whole engine, ring around to a few dyno places and find someone who will charge a reasonable price for a test which would take 15 minutes tops.

Like has been said, you want a wideband AFM up the bum to see what is happening to mixtures at top end. If its leaning out, you would be looking at the fuel system - injectors are rooted, pump is rooted, filter is blocked, knock sensor is too sensitive (EDIT: last one is not a leaning out prob, but a problem if your mixture is ok and ECU is still sensing knock)... If its not leaning out you should start looking at what could starve it for air. I would start with the S/C pulley bearings or lobe shaft bearings (too much crank loss up top) and your air filter for furry animals .

Its also worth noting that the flat torque curve can be very deceiving in terms of how an engine "should feel" even when you have one running at its best.

[oldcorollas]

in the cases where the knock sensor has proved a problem, has a new one solved this issue?
or is it a case of the engine developing more internal noise as it goes along?
could a simple resistor be used to reduce the amplitude of the piezo signals?

[mr2gze]

could a simple resistor be used to reduce the amplitude of the piezo signals?

Greddy actually make a knock sensor suppressor. We tried one on a ae101 gze conversion into ae82. While it didnt totally stop the 5500 power cut. It 'sometimes' pulls past it right through to redline. Feels like another engine.

Although even before the suppressor the engine occasionally pulled past the 5500 power cut. Probably too many variables to directly link the two....

[4AGZE_rolla]

Greddy actually make a knock sensor suppressor

anywhere in sydney area i can obtain one if the knock is in fact my prob?? or do i hav to go online and purchase??
thanks again guys heaps of good feedback!!
i drove the car this morning i feels so good unless you try to give it some!! runs smoother if you dont put the foot down much but then you cant accelerate hard!!
is it really bad too be driving it round with the prob?? or is it just i wont hav the desired power?? keep in mind unless i try to go hard it is fine, smooth and reliable,

[inertia]

We had similar low performance issues with my GZE when it first when in... then we noticed that the exhaust manifold was glowing after a very short time...

Turned out to be the cam timing, in particular the exhaust cam was one tooth off. We had doubled checked the timing marks all aligned during the installation of the new timing belt so we didn't think it would be the problem, but alas Toby of meridian motorsport believed the problem, from the symptoms described, to be cam timing and was proven correct.

Car was so much more responsive and powerfull I couldn't stop smiling lol.

Give it a check, can't hurt.

[rusty82]

sounds like the fuel pump to me i had a similar problem when i converted my ae82 to 101gze with the stock pump.

it would idle fine but run quite rough if you tried to give it a few revs on load and didnt want to rev at all.

ended up getting a walbro $170 job and it has been sweet as ever since

i wouldnt bother with a knock supressor as i have one installed on my car and noticed little difference if any after it was installed. i might uninstall it and check this though.

i have noticed that after about 15mins of driving the 5500rpm power cut disappears and the car revs hard to 7000rpm. just my experience though dont know if anyone has had a similar experience with map gzes.

[inertia]

Mine power drops at 5500rpm but not always, i'm living with it, only appeared after i put the powerup pulley on there...

I believe some people have had success using an aftermarket knock sensor, though the part numbers have never been revealed in any posts I have found.

[rusty82]

from the box it says:

15900903
E-manage Knock Sensor Adaptor 1

cost was around $20 from memory.

if anyone else has had experience with these it would be interesting to know if they noticed any effect on the power cut.

i have also heard of people using 7mgte knock sensors with mixed results. it seemed to get rid of the power cut most of the time.
when the power cut did happen the car would be put in nuetral and given a few quick revs and the power cut would not effect the car for that period of driving again.

this is second hand information though so it may not be 100% accurate.

[inertia]

Will try and track down an adaptor and see if it makes a difference...

Replacing the ECU is not really an option for me as I want to keep the car legal.

[mic*]

4A-GZE Rolla,

Just a thought, but if the ABV (air bypass valve) was not closing, this can limit boost somewhat and make the car feel a little piggy.

I am not highly familliar with the 4A GZE (i have a 1G-GZE) but when you find it, start the car, then pull the vac line off it. You should feel a weak vacuum. When the charger is on, the ECU closes a solenoid stopping the vacuum signal and closing the ABV.

You can mimic a permanently closed valve by pulling off the vac line and plugging the end of it. You dont have to plug the ABV nipple, except to stop dust etc entering it.

I guess its a 15 minute do-it-yourself test that cant hurt. If you cant find the ABV, post up a pic.

[The Witzl]

the problem with the knock sensor "supression" products is that they reduce the WHOLE signal from the knock sensor...

... the problem here is that the 4agze ecu is too smart and cracks the shits if it's not reading a NORMAL signal from the knock sensor, and uses what is theorised as comparative logic rather than case logic. (ie comparing knock signals against normal signals - NOT just seeing if a knocking signal exists)

A new sensor might help, but from stories that Ant Kellam has passed onto me from his experience this only works for a little while and then the problem creeps back.

An aftermarket ECU avoids these problems, of course

[oldcorollas]

oh.. just a thought

have you checked that the boost/vac reference line from manifold to the fuel pressure reg... is there and ok?

if not, when you hit boost, you are reducing the amount of relative rail pressure etc..

an extra 10psi is not much extra for a normal fuel pump to cope with after all..

[4AGZE_rolla]

cheers again for all the feedback,, dropping it in today!! i hope it is as simple as the cam timing being out!!
dont really hav the funds for aftermarket engine management yet
thanks... wish me luck

[The Witzl]

MEGASQUIRT-2. problem solved