WTF with 4age ke70

[kiahn]

ey all I'm not brilliant at mechanical fault finding so here is the problem

4age from an ae86 (RWD manifold) just dropped into a ke70 and it is doing something wierd, if we unplug the injectors the engine doesnt change revs much (maybe 50rpm max)
the idle is alright and at correct rpm, the TPS is set correct and there is plenty of fuel as you can smell its over fueling and see it on plugs too
when you goto rev it the timing changes so much that it doesnt want to climb revs fast, gets up to temp like normal and stays there

we suspect the oxy sensor is to blame but we don't to what degree it effects the performance (obviously mixture is effected but to what extent)

please help as I'm starting to get frustrated and run out of ideas

cheers

[RobertoX]

If you unplug the injectors it keeps running? You unplug all of the injectors at once? Do you also unplug the cold start?
If you unplug them they should stay closed and the engine should stall

They are possibly dirty as when they get crap in them they stay open a bit. Reason is the build up of crud stops them closing properly so a bit of fuel leaks past.
Get them cleaned and see what happens

[kiahn]

sorry unplug them one at a time not all at once

[ke70dave]

im not exactly sure what your asking, but from what i gather your saying its over fueling?

done a diagnostic check?

mine was overfueling across the rev range (even at idle) , and it was the temp sensor. it gave the error code with flashes with the diagnostic check.

After re-reading your saying the timing is advancing too quick? what is your base timing to set to?

[kiahn]

just finished up for the day after finding out with the diagnostics check that the Throttle position sensor and the air intake temp sensor isnt working properly
dad will fix them during the week and then hopefully it will run properly :))
if not then does anyone want the car?
:P joking

cheers

[kiahn]

alright given up and getting a new loom now, red/black top 4age with knock sensor and all.
hopefully this will make it run and if not then im buying a vespa with the engineers cert money i have

[ke70dave]

it amuses me how many people just "buy a new loom" when stuff doesn't work. don't worry your not the first.

if the engine is running, that's 90% of the battle.

some more details may help us help you.

also what does your little avatar pic say? (the one about Christianity) its a bit small to read.

[kiahn]

well here are all the symptoms i can remember:

runs rough
doesn't idle at correct rpm even with idle screw bottomed out and tps adjusted
dies when you put your foot down under load, but not when free reving
the loss of power while flooring it is worse when timing is retarded but when timing is put forward it doesnt want to start due to early detonation
runs perfect when compression braking, no backfires or missing
plugs are black after a few mins of running
sounds like a WRX (the running on 3 sound)


heres the avatar
6120

[ke70dave]

well i cant quite decide if that avatar is a payout on Christianity or not. i guess that depends on weather being a representation of pac-man on a pie chart is bad or not, and also the implications of "wakka wakka wakka".

now as for your engine.

sounds like its running very rich.

now the running on 3 cylinders, find out what cylinder it is, see if the spark plug is firing. and if it is, see if the injector is firing (both clicking and fuel coming out of it). if you pull the spark plug out and turn it over you should get a mist of fuel spray out the spark plug hole (dont smoke near this)

possibilities: dud spark plug (give them a brush up with a wire brush), or you have a blocked injector (get all injectors cleaned and flow tested).

right, now you did a diagnostic check, and you came up with TPS and air temp sensor.

for now unplug your TPS completely, it will run fine without it. i drove mine around without a tps for a while.

the air temp sensor could well be the source of your problem. if it doesn't know the air temp, it wont know the density of the air, and thus wont know how much fuel to put in. and i guess the default is to just dump in lots of fuel (like its doing). and since you haven't said you have changed it, i assume you haven't.

so second step after the above items, is to get another air temp sensor. pull one off a mates 4age and test it.

as for your idle, it will run like a dog if its running rich, so i dont expect you to be able to get a decent idle anyway. but sounds to me like you just have air leaks everywhere. when the engine is running, stick your hand over the throttle body, if the engine doesn't almost stall and your hand is sucked really hard, then you have air leaks. no air should be able to get in anywhere except through the throttle body. (assuming you've blocked off all the funky air pipes that sit under the throttle body, and also your not using an idle up for aircon or power steering)

then report back with your findings! good luck!

[kiahn]

the avatar isnt dissing christianity its just merely saying that the ratio of christians to all other religions in america looks wierdly like pacman

sorry i thought i had posted my update the other day, mustn't have worked
dad found out with the crow that the ground wire from both the TPS and the air temp sensor had a SHITLOAD of noise on it so he ran 2 grounds compared to toyota's 1 and the error disappeared,
we tried different throttle body, map sensor and dizzy of a workng car but didnt fix it.

i have almost had my hand sucked into the throttle body a couple times before and it does die or come close to it.

we have re-shimmed (ground down shims) to make all the clearances right and it still runs rough

the only thing left to really pick at would be the wiring, i have tried both my jap ecu and my adm ecu,

will double check but because im running 91 atm while testing i may have been running the jdm ecu which means the timing things would make sense as it would advance masses to account for the 98/102 octane in japan unlike the adm one which is made to take 91 octane

[Nikkojoe]

I might be looking at it this afternoon and see if I can find what the problem is. The only thing really dodgy on this 4age install is the loom, and from what has been explained to me it's most likely the cause.

[Skylar]

Dave, the loom is pretty fucked. It really needs to get taken off and remade just to eliminate it being a possible problem.

New loom is easier.

[kiahn]

me and dad will check all through the loom this weekend,
if there are major problems ill just throw it out and start fresh, looks like shit atm only because none of the accessories are hooked up like tacho and what-not.

[ke70dave]

ah k

good luck with it hey, let us know how it goes.

[Nikkojoe]

Having seen it now, loom is pretty munted i would say. Will try and hook up my ae82 loom to it and see if it works.

[kiahn]

were gonna run a crow across all the sensor lines to see any interferance,
gonna run individual negative wires back to the ecu before buying tom's ae82 loom
although it does look very nice and has better injectors than mine and all of the plugs :P

[Skylar]

dude, It's CRO (cathode-ray oscilloscope).

[kiahn]

lol woops?
i was typing really fast as im ebay-ing at same time :P
but yeh will try this and if it still dont work then bring on the ae82 loom :D

[kiahn]

found the problem!!!!!!!!!!!!!!!!!!!

unplugged one of the injectors and revved it and it runs perfect
the enjectors didnt have resistros on them so they were pulling too much from the ecu and the ecu just blanked out

[Nikkojoe]

kinda confused with that as early bigport injectors are high impediance and did not use/need any resistors to work. But if it's working for you then thats good :)

edit: looked again and found bigport injectors were 2.0Ohm low impediance, and later bigport (pink) were 2.7ohm.

[kiahn]

thats why i was confused, the AW11 injectors are high impedance 13.8 ohm
but the ae82 grey injectors are only 2 ohm, which is the lowest of all 4age injectors.
i foundmy injectors in rollaclub FAQ and put a resistor in there and BOOM it works,
learnt something new at least,

took it for a drive and first gear a lights is mental, feels like HD clutch...
clips a little then grips and revs like a mofo, turning peoples head with my 111 db exhaust. :))

[kiahn]

and AW11 bigports are 13.8 ohm, i need to get the correct resistors in there so if anyone knows what knows what size resistors i need please speak up