1jz-gte adjusting cam timing

[snoarer]

I have a '91 Toyota TT Soarer with a 1JZ-GTE engine.
Has anyone had experience in varying the cam timing? I hear/see lots of people doing it but not discussing it.
The engine has 2 cam sensors (non-adjustable as far as I can tell) and 1 crank sensor (adjustable).
After adjusting the intake cam timing with an adjustable cam sprocket the car gives an electrical error efi 13, which is supposed to be the rear cam sensor, and the engine goes into limp home mode.
An ecu reset does not solve the problem.
Checking the ignition timing (connecting the correct "timing set" pins on the diagnostic port) reveals the correct 10deg. btdc initial timing. The ecu has learn't that the cam has changed timing but it still knows what cyl. should fire at 10deg. btdc.
Intuitively I should adjust the cam sensor but it seems to be bolt on only with no adjustment. The error code for just 1 sensor leads me to believe that each cam has its own sensor although they are both mounted on the intake side of the block.
Any hints?

[Smiffie]

welcome to the site Dave,
I think you will need to speak to either Birmingham Bill or Iain about that, both went to the same school of "let's try this to see what it'll do" as you obviously did.

[BlakeNZ]

Dave,which are the "timing set" pins in the diagnostic port,and how did you become aware of them.It is an interesting dilemma you have,as the very few 1JZs that have had adjustable cam timing installed usually already have an aftermarket ECU,hence no error codes or limp home modes.Sorry I can't shed any light on the matter.

[London Bill]

Dave;

Smiffie has just posted an article about cam/crank sensors, appears the inlet cam has two sensors (I dont why either), Error Code 13 will display if the ECU detects any mis-timing between crank and cam, a TT with a worn belt tensioner will display an error (Code 13) if the belt is slack (clever bugger).

I really wish the Soarer ECU could be less complex which would allow the normal draft of engine mods, some of the Oz guys are using the Motec M800 management system, results looks good as it allows boost, ignition and fuel re-mapping but the price is sky high.

[London Bill]

Just discussing Error Code 13, it looks like the ECU can detect even small variance in the cam/crank timing, certainly less than 7.5deg, if you want to retain the performance cam pulleys you could reshape the camshaft timing lobes to match, so if your inlet cam is advanced 5deg you could retard the timing lobe by 5deg possibly by grinding off the leading edge of the lobes, if this makes the lobe too thin (so the sensor cant detect it) you would have to weld on a small filliet to the rear edge of the lobe.

[AussieMug]

I posted elsewhere that I didn't think the ECU would detect small variations as an error. Obviously it does! (Which is interesting info indeed.) Now that I know this, I imagine it is looking for the camshaft pulses to be relatively "co-incedent" with the crankshaft sensor.

That it is sensitive enough to sense the belt has worn/stretched is indication enough. It would also be a diagnostic aid that cross checks the crankshaft sensor. (Which, according to some people is adjustable.

It may be possible to reposition the sensor back slightly, and a moveable "magnetic yoke" might then be fitted to the tip of the sensor. (Soft iron)

Of course, the other alternative (apart from what Bill suggests) is to remove the sensing lobe from the cam, and manufacture an adjustable "clamp" in its place, with an airon extension to come near to the sensor. Clamp would be fine in aluminium or brass.)

[snoarer]

Thanks to everyone for the input!

I think I have enough info to start modding.

Bad luck about two of them, but now that I know they're both off the inlet, they are probably used to make timing adjustments with increased resolution.

Steve, the two "lugs", were they 180 deg. apart?

[Smiffie]

Just checked, and yes they are.

[AussieMug]

Bugger, wish I had of read that before all the bullshit I wrote elsewhere, howver, it only serves to re-enforce the bloody dissertation.

[adi]

Originally posted by London Bill
Dave;



I really wish the Soarer ECU could be less complex which would allow the normal draft of engine mods, some of the Oz guys are using the Motec M800 management system, results looks good as it allows boost, ignition and fuel re-mapping but the price is sky high.

I know of someone whos experimenting at the moment with an E-manage on his 1JZ supra, mainly for the timing, but also for the mapping and boost control as well...
If it works sucessfully its a good compromise between the norm and a standalone system. E-manage can be bought for good prices too ! If his works i'll certainly be considering it..

it'll be at billing so i'll have to wait till then to find out

[London Bill]

Adi;

E-Manage on a manual or auto 1JZ?

[snoarer]

The E-manage, does it ignore certain inputs such as the cam sensor or cam sensor vs crank trigger angle?

As for the original ECU, I have a proposed solution, just that I don't have time to pull the cam out of the motor for a couple of months. I bought the car as a driver! I'll post the results.

I'm of the mind set of keeping things, not so much low buck but, as factory as possible. I'm already faster than others who have just run out and bought all the brand name gear (trinkets). I like a car whose raceday settings are the same as the work day settings.

I've done this with my previous car, a few smarts really hurt those with big wallets. I feel a $1000 (or probably more) is better spent on suspension and tyres than an ECU. You've got to get the power to the ground eventually. From what I've seen/read these babies can produce 400hp with stock fuel management. I see a lot of sky high power figures around, but if you really have 400hp (engine) and can get that (whatever it is at the rear) to the ground without wheel spin, not much on the street is going to catch you.

Anyway, this forum along with this car is a great distraction!

[adi]

Its on on auto Bill, but that shouldnt make a difference should it as its a piggyback unit anyway? I havent heard much from him recently though to report the progress..

The e-manage doesnt ignore inputs snoarer, as its just an interceptor so it only changes what you want it to change..
To be honest im not sure how it changes the timing... presumably it intercepts the cam position sensor input and alters it to fool the ECU into thinking something is different? Im eagerly awaiting the results as it could mean the end to the slow launch on the JZA70 (if the theories are correct) and also get some good results on high boost.