i have a bigport 4age in an ae71 with stock computer

 

when i bridge/short out the diagnostic port/check connector the idle doesnt change and the timing doesnt either.

i have two ecu's one i set the timing at 18 degrees with diagnostic port shorted or not and it makes the extractors very very hot.

when i plug in the other ecu it say 10 degrees with the diagnostic port shorted or not and still makes extractors very very hot.

 

i looked at the wiring diagram and the diagnostic port is pin "T" then to ground, so i opened the ecu and and grounded the "T" pin and it still didnt change.

 

so I'm a tad stumped at this point if anyone can shed some light that would be great :dance:

Edited May 2, 201016 yr by Damon550

played with the timing last night and its set to 28 degrees advanced.

it is alot more resposive it doesnt get as hot and doesnt ping thats a big strange i think.

 

timing light is fine i have checked it on other cars too

Are you sure you have identified the check connector correctly?

 

Post a pic of what you have.

i thought it was T1 and E1 you short??

Could be wrong, it's been awhile.

here are some photos of plugs

the one I'm holding with port written on it is the one i traced from the ecu

 

 

 

though i might ad this,

probably the first plate like this i have seen in a rolla in tas

 

 

also i was talking to a friend who has done a bit of work on 4ages lately,

he said the crank pully/harmonic balancer sometimes slip and move the timing marks,

so thats why my timing may be so whacked out.

does anyone know how to fix this? i don't really wanna pull the pully off and make the problem worse

Edited April 28, 201016 yr by Damon550

well i changed the crank pully over and the marks were only about 1mm different when you lined up the keyway,

still no different in timing department.

 

played with the timing light

it was going from 27 degrees at idle

to 35 degrees at 5500rpm.

does the advance sound right?

27 is too much at idle. Sounds like you could be out a tooth on the dizzy. Set the motor and 10 deg BTDC checking you can see the notch through the oil filler on the cam and you're truly at TDC. Insert the dizzy with the cap and rotor removed so you can see the number 1 tooth (the one the rotor button points at) teeth on the 4 tooth wheel perfectly aligned with the upper pickup in the dizzy.

i have done that a fair few times in frustration.

when its a tooth either way the engine isnt happy.

i have that part down pat its just when i set it to 10 degrees its to retarded and runs hot.

but it sounds and feels happy about 27. where in the real world it should be pinging its face off.

 

I'm starting to run out of ideas?

 

a very appreciated reply thank you beerhead

Edited May 3, 201016 yr by Damon550

Stupid question, but have you checked the cam timing?

It's fairly simple to do on a 4age, just pull the top cam cover off, line up TDC mark on the crank and see if the cam marks line up.

 

MR2_AW_1988_REPAIRMANUAL.pdf

yeah i checked the diagram first

then got 2 different mechanic friends that done a fair bit of work with twin cams to chech for me

the cam timings all good

 

thanks TRD ke70, every little bit helps

Edited May 4, 201016 yr by Damon550

i was wondering if anyone has a photo of a 4age crank pully.

showing the keyway and the timing mark.

because mine arent lined up at all and was wondering if they are ment to be close?

The crank keyway will be at 12 o'clock when the timing mark is at 0 degrees.

to me it sounds definately like the timing marks arent showing the true ignition timing of your engine.

 

though it is weird that shorting the diag port doesnt change anything.

 

if at the "proper" timing (10-15 on your light) the extractors are getting hot, it shoudl run like a dog, have no throttle response etc. if that is the case then it is definately retarted timing.

 

also double/tripple/quadruple (spell?) your cam timing. mine was out for ...quite a while...before i realised....make sure you use the timing marks on the rim of the cam gears. i used the marks that are closer to the centre of the cam gear....bad medicine.

 

does the diagnostic mode work at all? you will need an check engine light hooked up to test this, but you sound like you know what you are doing so you should be able to sort that out.

 

maybe get it into proper diagnostic mode (ign on, engine off, diag port shorted) and see if you get flashes on the check engine light. i think it still flashes something if everything is working fine. code 1 maybe?

 

also i have "heard" that some 4age's have different timing marks, maybe it was the MR2 4age that had different riming marks?

 

did you wanna take a quick pic of the timing marks you are looking at on your engine? there should be a few marks on the plasic timing belt cover, i think the mr2 has something weird? maybe you have a combination?

 

if you are sure that your cam timing is correct, and your dizzy is in the right spot. you could just advance it untill it sounds/runs good and leave it? or do it the old fashion way, advance it untill it pings, and wind it back a bit!

Just had a read of this thread, You need to connect VF to terminal T.

 

VF is the 2nd one from the left on the bottom of the 18pin plug.

 

T is the 6th one from the left on the top plug of the 18th pin.

 

Dave, Yes the AW11 and AE82 have a different timing mark, The AW11 has a single pin to show TDC.

Easy way to test the timing mark is to pull out the spark plug on cyl 1 and put a long screwdriver in the hole. Wind the motor back and forward a bit and make sure the timing mark is lined up correct when the screwdriver is at its highest point

Edited May 6, 201016 yr by beerhead