funny idle / no throttle responce no tacho.

[Faceplant456]

Car - AE86

motor - Small port 4A-GE

use - supposed to be my daily

problem - has funny idle, no throttle responce & no tacho reading.

occurs/started when - starting the car.

personal situation - need to fix these before i can drive/register the car

No tacho: ok so i need to know where the tacho wires are in the engine bay so i can join them into the engine loom.

Funny idle: it revs up and then down over and over again. see this video.

http://www.youtube.com/watch?v=WVFVTDzapxc

No throttle response: it just dose nothing ... i open the butterfly and it just gets louder.

[Nikkojoe]

Tps needs setting, and you have an air leak

Have you wound the idle screw down? Have you done a proper cold start setup, or did you not worry about it and leave the cold start valve under the throttle body still attatched?

[ke70dave]

do a diagnostic test on ecu. some sort of sensor error.

mine did that when i first fired mine up, turned out to to be TPS.

unplug the TPS and see if it helps, it will run pretty good without it (if it is the problem)

damnit i was beaten by nicjoe!

[slide86]

i can hear that it has a massive vacum leak from somewhere. that would cause teh hunting at idle

it is revving way to high for idle and by what is happening when you crack the throttle, id say your timing is way to advanced.

the tacho wire is a black wire that should be on the drivers side, near the strut tower. SHOULD be.......

[timbo]

check your tps, sound similar to mine when the tps came lose and the wings off the throttle weren't moving the sensor. as for the tacho i assume by your comment that it is not related to the engine trouble, as in didn't previously work?

damn i got to think and type at the same time, you guys are too quick!

[Faceplant456]

ive checked for vac leaks.. the tps sounds more like the problem ... as i moved it a little bit and it and it slowed down the idle a lil... but if thats the problem then that could also explain the no throttle response ... ill try this tomorrow morning.

[Faceplant456]

the tacho hasn't worked when ive owned the car ... but in saying that this is the 2nd time Ive started since Ive owned it.

so the no tacho part is more a question of wheres the wire ... if someone could provide a pic that would be nice... otherwise im going to go hunting for the wire mentioned above by slide86

i will also check my timing.

the cold start system under the throttle body is still there but i have blocked all the pipes off as i couldnt work out where they go ... if someone can explain that it would be nice to ...

also thanks very much for the quick response to this... i would have to say this is the best response ive had to a tech question so far.

[timbo]

take it off completely and make sure it goes in properly and tighten the fkn screws up! i have failed with this previously...

the two pipes that come from under the throttle body are for aircon?

[Faceplant456]

so re-set the position of the TPS? with it unplugged the car will still run yes?

[Faceplant456]

i have 3 pipes under the thottle body ... well 5 actually ... 2 are water contolled and the other 3 are air ... the water ones are connected and the air ones are covered over with duck tape.

[timbo]

so re-set the position of the TPS? with it unplugged the car will still run yes?

yes, i would. and make sure the wings are in the right place on the sensor (NOT in the grooves on rotating piece). car will run with it unplugged.

[timbo]

ok the water ones are for wax set/cold start and the top air ones are for power steering bottom one for ac.

[Faceplant456]

the throttle body is connected to the power steer that i dont have?

ok sh heres the list to try out tomorrow ...

test TPS
check timing
check vac leaks
locate tacho wire.
ecu diagnostic

anything else to add to it?

[timbo]

let me rephrase:

two pipes facing down is for cold start
three pipes facing forward, two top are for power steering, bottom for a/c

check list looks good to me

[ke70dave]

dont forget the ecu diagnostic

[Faceplant456]

so what should i do about the 3 facing forward pipes ... just block them off ... or join them into each other?

[Faceplant456]

the ecu diagnostic is annoying on these because you need to count the flashes of the check engine light to find out whats wrong ... its not just like throw the scan tool on and see what comes up .. they made this system really weird.

[ke70dave]

nah its not annoying, its great. best way to to find out if a sensor is playing up.

just print off the codes and count! and yeah i have done it many times, and its easy and works well.

saves randomly changing sensors hoping it is it (which i have also done, before i discovered ecu diagnostic)

btw has the check engine light been flashing at all? if the ecu logs an error the check engine light will come on/off at random intervals.

[Faceplant456]

i am yet to fix my check engine light ... lol i have to send the signal from the ECU to the dash globe.

[timbo]

so what should i do about the 3 facing forward pipes ... just block them off ... or join them into each other?

bloke them all off individually. mine just has the hose cut off with a bolt in the end, dodgy but effective.

[Faceplant456]

ok ive fixed the throttle response problem ... i took the TPS off and cleaned the contacts then re-positioned it.

but now its idling really high.

i have also tried a different computer but nothing changed ...
and i had a look for the tacho wire but no luck.

check out these new videos to see what i mean.

http://www.youtube.com/watch?v=FOE2SUzTyq0

http://www.youtube.com/watch?v=RaF8A8PAKJ4

any one got any ideas?

[timbo]

firstly i assume you have wound down you idle screw on the throttle body.

try taking the hose off from the intake cam cover to the manifold. place you finger over the hole on the manifold and see if the revs drop.

[Faceplant456]

ok. sounds like a plan ...

other than the problems how do you guys think the engine sounds ... best vid to hear it is the one with the map sensor connected ...

[timbo]

seems smooth, but what is that knock?

[Faceplant456]

i cant hear any knock ...

there shouldn't be any as the motor was just rebuilt. maybe you can hear some random noise. i recorded these on my ipod so they arnt the best in sound quality or picture.

[ke70dave]

that doesnt sound all that great, you checked the cam timing and ignition timing? could just be the video/sound quality but yer doesnt sound normal.

high idle = air going in somewhere. just have to find the leak.

[Faceplant456]

cam timing is spot on ... and i checked and reset the dizzy timing today as it was leaking oil from there...

so ive got the timing right but its idling high ...
ive replaced alot of the vac lines and made new ones for were i didnt have them i cant see or hear that i have a leak anywhere... what else could it be ... ive also tryed a different ECU.

[ke70dave]

when you have the engine running, stick your hand over the inlet.

if the engine still runs then you have a air leak.

if your hand gets eaten and engine dies, then you dont have air leak.

if your scared of getting your hand eaten use something else (peice of flat metal perhaps) but DO NOT let it get sucked into engine. (ie dont use rubber sheet etc)

[timbo]

well it revs smooth but i can def hear something lumpy etc?

[Faceplant456]

when you have the engine running, stick your hand over the inlet.

if the engine still runs then you have a air leak.

if your hand gets eaten and engine dies, then you dont have air leak.

if your scared of getting your hand eaten use something else (peice of flat metal perhaps) but DO NOT let it get sucked into engine. (ie dont use rubber sheet etc)

sounds like a damn good plan.

[Faceplant456]

well it revs smooth but i can def hear something lumpy etc?

u sure ? at what point in the vid?

also it sounds like shit in the one with the map sensor disconnected. but i can tell you its all good ... no knocks in this motor.

[Nikkojoe]

You need to set your tps still. If you d/c your map and it idles like shit, tps is not set properly. The tps should report to the ecu that its now in idle mode and will stop taking map sensor readings (when you d/c the map sensor, throws engine into limp mode causing lumpyness and limitted throttle).

Having a tps set correctly will also bring down your idle about 100rpm, but will cause it to bounce revs if you have an air leak (you may have adjusted it so it doesn't bounce, but you have moved it too far). You need to fix the source of your air leak first!

[Javal]

You need to set your tps still. If you d/c your map and it idles like shit, tps is not set properly. The tps should report to the ecu that its now in idle mode and will stop taking map sensor readings (when you d/c the map sensor, throws engine into limp mode causing lumpyness and limitted throttle).

Having a tps set correctly will also bring down your idle about 100rpm, but will cause it to bounce revs if you have an air leak (you may have adjusted it so it doesn't bounce, but you have moved it too far). You need to fix the source of your air leak first!

This man speaks the truth.

[Faceplant456]

when you have the engine running, stick your hand over the inlet.

if the engine still runs then you have a air leak.

if your hand gets eaten and engine dies, then you dont have air leak.

if your scared of getting your hand eaten use something else (peice of flat metal perhaps) but DO NOT let it get sucked into engine. (ie dont use rubber sheet etc)

i did this ... it died ... no vac leaks.

i tryed to adjust the tps but it did nothing ...

[blinded]

Being that your throttle response is normal, yet it is idling high now, is the problem something as simple as an idle speed screw or the likes? (assuming the 4age has a manual idle speed screw) Might just be wound in too far causing the butterfly to not snap shut at idle. :S

[ke70dave]

done cpu diagnostic yet?

i like blinded's idea to.

[timbo]

did you take the hose from the oil breather off the manifold?

[Faceplant456]

ok i did some more looking into it and i followed the diagnostic chart from my 4A-GE manual that i scored from my old work ... (toyota dealership)

and i have found that my auxiliary air valve is stuck open ...

after i covered the hole over with my finger it slowed the idle down to what i think is about normal ... its hard to tell because my tacho isnt connected.


my idle speed screw is fully down closing it off completely.
i have yet to connect the check engine light up to my dash cluster.
taking the valve cover breather off just increases idle speed as it acts as a vac leak .

[timbo]

oh fuck why didn't i think of that! i made up my own gasket to bi-passed it. by taking off the oil breather hose i ment plug it up with your finger...

[Faceplant456]

yea i did that to ...

im gonna try and find a working auxiliary air valve but if that fails then i guess ill have to block it off.

[timbo]

they will be pretty hard to get unless you buy a complete throttle body second hand... but then you need the TPS to match if it doesn't come with it. i just use foot power for cold starts!

[Faceplant456]

yea that is an option but i prefer the cold start system to be there ... if i find one of these brand new i will post the price and where from up here.

[cbjaust]

I have a Throttle body from a 16V bigport if you need...

[Faceplant456]

i got a mate near by who is going to lend me one to test.

also i got my tacho working today after trying many different wires i finally found it.

now the bad part ... with the auxiliary air valve open it idles at 3k rpm ... with it closed its at 2k .... so still got issues.

[Faceplant456]

All FIXED!

[hachi_dk]

how did u drop the rpm below 2k?

[Faceplant456]

today i took off the wax idle speed controller along with the rest of my throttle body and i just went nuts and took everything apart and cleaned it all then i put it all back together to the toyota 4A-GE book spec's and BAM! idle is now at 1000RPM. and when i fix the TPS up correctly it should drop to 800RPM.

[cbjaust]

what do you mean by "wax idle speed controller"?

[timbo]

the cold start works on letting in more air, thus revving the motor at 2000rpm until warm. coolant goes through a wax set diaphragm and only when the coolant reaches a certain temperature the wax melts and closes off the valve letting in the excess air.

[Nikkojoe]

Actually it just works off a spring, there is no mythical wax. The spring expands causing the valve to shut. Usually the valve can get sticky due to a lot of build up of crap in the idle air ports. Throttle body cleaner followed by wd40 seems to help them out.

Gze use a bi-metalic strip to rotate the IAC valve.

[timbo]

well there you go, ive been told! in this case i might actually try and fix mine, i thought i would have to melt down candle sticks or something haha

[Skylar]

Please post a youtube video explaining how this unit works as proof of this absurd suggestion. I am too lazy to go outside and have a look for myself.

[Faceplant456]

this is what we are talking about ...

for more info on this go to page FI-87 in the 4A-GE manual

http://mitchee.com/ae82/4A-GEManual.pdf

[Skylar]

Haha. So where did anyone get the idea that this thing has wax in it?!?

[Faceplant456]

some other cars use one that has a wax plate that moves with heat ... an early version of the bi metal strip.

[timbo]

yeah as above, this is what i was told about the 4age setup and took it to be true, clearly incorrect as per the picture... i do feel somewhat stupid for taking someone's word rather than actually having a look myself.

[Bullet27]

Hi hope someone can help me urgently with my problem. One morning a few days ago i started the car in the morning and let it warm up. it started fine and idled as normal. After a few minutes i did not hear the engine. when is went out the engine died. I started it again and it started but had a miss ( like the engine is running on three pistons). I left the car and used my other car for about 3 days. On the weekend I tried to check out the problem but the engine would not even swing. I push started it and the engine started but the miss is still there. I checked the plug wires and all in order. i never had problems with the starter before. Are this two problems related. What can be the problem with my baby?