Problem i cant get to the bottom off.. collective thinking needed lol

[weeJohn]

Kon you said your idle is set at 1500 rpm, does that mean when the cars warm or cold? How have you done that, by adjusting the throttle cam stop screw so the butterfly is opened slightly or another way?

What happens when you linkout E1 and TE1 in the diagnostics plug, does the idle drop down to below 1000 rpm then or does it stall lean?

 

[Texx]

Could possibly be an injector sticking shut intermittently at low duty cycles, then freeing off as the injector duty spikes with boost.

 

[GTti]

Could possibly be an injector sticking shut intermittently at low duty cycles, then freeing off as the injector duty spikes with boost.

This is what I was thinking and was wondering if it was a specific cylinder (Injector) causing the issue. It would be enoughto cause the poor running prior to the point where it clears, just seems odd that it would always clear at the same point.

 

[HYBRID]

And the car can still drive at --- ? I would of thought that was next to impossible on petrol?

I've seen mine go to 18, 19 then lean then --- and the car was long dead even on idle

I wouldn't of said the injectors were leaking, rather sticking and not opening and perhaps related to the fuel pressure behind them.

thats what everybody iv met has been saying lol... it jerks alot at --- but for some odd reason it still keeps going lol... damn fucking insane car

 

[HYBRID]

Kon you said your idle is set at 1500 rpm, does that mean when the cars warm or cold? How have you done that, by adjusting the throttle cam stop screw so the butterfly is opened slightly or another way?

What happens when you linkout E1 and TE1 in the diagnostics plug, does the idle drop down to below 1000 rpm then or does it stall lean?

Hi John,

well idle plays alot really.. but i try to keep 1500rpms all the time, both hot & cold..

iv adjusted the idle that by adjusting the idle screw.. on forged engines we prefare them to have a high idle..

when we did the diagnosis it dropped the revs to a perfect 1000rpms (for once idle was not playing up) & was idleing between 15~17af.. but wasnt dying out.. its like the ecu was looping so to speak.. when it saw the car lean out to much it pulled it back up to 15af & a few seconds later it was back at 17af .. this of course applies to when she was under diagnosis bud

rest of the time its how iv described above..

kon

 

[HYBRID]

Could possibly be an injector sticking shut intermittently at low duty cycles, then freeing off as the injector duty spikes with boost.

i was thinking about that bud.. however the problem to that is that on WOT (yes i know its normal lol as im running bigger injectors & next to no boost) my af goes close to 10.4~10.6af .. so im not to sure about the injectors playing up.. it is a possibility.. but then again, why would it always go at the same point?

kon

 

[HYBRID]

the grounds for all the sensors (TPS, CLT, AIR and MAP) are at the ecu

they are grounded directly in the ecu and nowhere else (E2 and E21) on the 26 pin plug of the ep82 ecu

i remember one of mine going bad and i was getting some bad readins from the sonsors for a while until i found out the wire at the ecu end had broken

hi mate, thanks for your help, so i should check for a broken or bad earth next to the ecu? will have a look with a multimeter & see what i can get.. if i just add an earthing point & join it to e2 & e21 would that be a bad idea?

kon

 

[weeJohn]

I would have my reservations about directly earthing E2 and E21 directly to earth, they are earths specifically for sensors wired into the ecu, tobe kept "clean"

It does sound like your IAC valve is still in the control circuit Kon. As you know of the 3 wires to it, one is a 12 volt feed, and the other 2 are switched to earth through the ecu to either open (RSO) or close (RSC) the valve. I would have a quick check of the wiring to check the closed switch wire is not earthing somewhere and closing the valve on you.

This does not offer any explanation as to why it only does this sometimes, but its another thing to rule out.

The fact it does this more when the engine is cold is odd, and would point me towards the O2 sensor signal dropping off because of low EGT`s, but you have ruled that one out I think.

 

[Sharagath]

hey kon,
u say your engine dies at the moment your AF shows underfueling.

what sensor(i think is still is) could make the ECU think it was heavaly overfueling without showin that in the wideband

- air temp
is only capeble of adjusting that much even when shorting out or missing earth connection


what is you have a vacum problem?
when i accedentaly pulled of my vacum hose connected to my boost bauge(what was also connected to my MAP sensor) the engine died instantly.
if your map sensor is reading more and more vacum that on normal idleing it will die.

have you measured the voltage that sits between the block and you batteries negetive pole?
a difference in the negativeness(can't find the right word in english) on the earth of a car can give a very different sensor working.
the difference between 12 and 0 is 12, if the 0 is a bit higer because of a bad earthing point your difference gets smaller so your readings calculate that you have an other value that there is. if negative is 5V your sensors could only measure a difference of 7V.
lest say they read normaly 9V the now do read 9-5 = 2V, that is 77% lower than normal.

i wrote this while is was thing, just to share my thoughts.

 

[HYBRID]

I would have my reservations about directly earthing E2 and E21 directly to earth, they are earths specifically for sensors wired into the ecu, tobe kept "clean"

It does sound like your IAC valve is still in the control circuit Kon. As you know of the 3 wires to it, one is a 12 volt feed, and the other 2 are switched to earth through the ecu to either open (RSO) or close (RSC) the valve. I would have a quick check of the wiring to check the closed switch wire is not earthing somewhere and closing the valve on you.

This does not offer any explanation as to why it only does this sometimes, but its another thing to rule out.

The fact it does this more when the engine is cold is odd, and would point me towards the O2 sensor signal dropping off because of low EGT`s, but you have ruled that one out I think.

hmm good point john.. ill see if i can trace the wires from the ecu's side & from the sensor side to see what the iat is doing.. would it make sense to see what happens if i just unplug the sensor clip? ie if something happens car dies or goes rich, it will be an indication that its working.. but if nothing happens it would show i have a problem with either the wireing or the sensor itself..

as for the o2 sensor i really feel its doing my head in.. i just bought a new one & installed it coz i said maybe the other one was playing up.. it did fuck all was a start, however what uv said is correct, though i find it very strange that the o2 sensors would need all that heat, in the past i had monitored the lambda readings & it had always started giving a signal at around 500egt.. now if i fall under 650egt it will start to screw itself over & loose the idle & loose all af..

somthing i noticed today is that if i leave it idle for a while, as soon as the engine comes close to operating temperature, the car does not idle to the rich side.. but instead it starts to lean itself out?!?!?! iv never heard of this one before, coz as far as i know to keep running the engine the ecu riches out & goes back to "choke mode" so to speak, ie riching it out to say around 11.5~12.1af .. what this crazy car is doing is leaning to 17s ?!?! :shoot:

any ideas lol?

thanks
kon

 

[HYBRID]

hey kon,
u say your engine dies at the moment your AF shows underfueling.

what sensor(i think is still is) could make the ECU think it was heavaly overfueling without showin that in the wideband

- air temp
is only capeble of adjusting that much even when shorting out or missing earth connection


what is you have a vacum problem?
when i accedentaly pulled of my vacum hose connected to my boost bauge(what was also connected to my MAP sensor) the engine died instantly.
if your map sensor is reading more and more vacum that on normal idleing it will die.

have you measured the voltage that sits between the block and you batteries negetive pole?
a difference in the negativeness(can't find the right word in english) on the earth of a car can give a very different sensor working.
the difference between 12 and 0 is 12, if the 0 is a bit higer because of a bad earthing point your difference gets smaller so your readings calculate that you have an other value that there is. if negative is 5V your sensors could only measure a difference of 7V.
lest say they read normaly 9V the now do read 9-5 = 2V, that is 77% lower than normal.

i wrote this while is was thing, just to share my thoughts.

oh.. didnt know that about the earths.. ill have to check that out & probably ill add a few extra earths.. they should be able to help (i hope!!)

as for vacum, i dont have any vacum leaks bud.. its not doing anything vacum related.. more something electrical..

the ecu gets its readings which could alter fuelling off the o2 , the water temp & off the iat... they are the ones which contribute to the ecu's fuel maps when of course the car is off boost.. now i have changed the o2 & water temp sensors..

btw if it makes sense this problem was one that happened gradually.. ie it did not get very bad from the 1st time.. it started happening slowly.. ie 1st it just used to lean out for a split second.. & very rarely.. this started happening more frequently & for a longer time ...now adays it does it all the time..

hope this helps its not easy to explain..

kon

 

[weeJohn]

I am not sure how often the IAC valve operates to regulate the idle, I imagine it would not be that often that it might completely close, so removing the plug from the valve after the car is started from cold for a few seconds would be an easy test for a short in that wiring.

As your local friend said, earths are very important, including the for the O2 sensor. The only earth the 1 wire sensor relies on is the earth it gets through the exhaust. You could try linking an earth wire onto a bolt on the turbo outlet to keep a good earth on the exhaust. 650 degrees of EGT could possibll be the operating temp minimum range, but 550 does seem more the norm for Toyota sensors.

 

[HYBRID]

hi john, thats a good idea, ill add an earth to the turbo..

i have a little update, yesterday chris sat i nthe car looking at the aem whilst i pulled sensor plugs out.. here are the results:

1.) map sensor.. --> car dies.. good it means this one works lol
2.) water temp.. --> engine check light comes one.. so it means its giving a reading.. ie good
3.) single wire water temp sensor.. --> works well
4.) iat.. --> removed.. i dont get any engine warning light, doesnt affect idle in any way when warm or cold so it could be the culprit.. my only worry is why the hell doesnt the ecu light start flickering.. if the ecu is still getting a ground signal from this wire if say its earthing out.. would it mean that its getting any random reading from where-ever is touching? (not sure if that makes sense to read but its the best way i could explain it...)

im gonna add a few earthing points this week maybe it will change something, ost of my old earthing kit seems to have served its time & needs retireing lol

kon

 

[Sharagath]

iat?
inlet air temp?

 

[HYBRID]

iat?
inlet air temp?

yep

 

[Sharagath]

as far as i know my previus NA setup, disconnecting the iat didn't effect the engine.
i don't know if it is a ntc or ptc, that could differ the results/effect.
is it on the inlet tube or on the manifold?

it is more the less a non inportant sensor by my knowlegde. 2 wired directly from the ecu.

 

[HYBRID]

yes it is 2 wires to the ecu.. but surely it would give some sort of signal? its on the far left of the plenum.. has a dark grey clip connected to it.. i dunno what it does. .but i know its choke related.. does anybody know where it comes into effect?

i unpluged it when it was cold & when it was hot & the damn thing still didnt change anything lol..

kon

 

[weeJohn]

.. if the ecu is still getting a ground signal from this wire if say its earthing out.. would it mean that its getting any random reading from where-ever is touching? (not sure if that makes sense to read but its the best way i could explain it...)

kon

Problem with DC is its always looking for a path back to earth. The ecu gives out a 5 volt positive signal to the sensor, but the 5 volts would not be read by the ecu interior components, until the components are connected to earth, creating a path.

So if the wire that is carrying the 5 volts back to the ecu gets shorted to earth, the 5 volts never gets to the ecu, it has got to earth at the short.

The IAT sensor is a big resistor, like the water temp sensor, its resistance decreases as temperature increases, if you disconnect it , it just thinks the air temp is high, so it does not adjust fuelling as much as it would if it thought the temp was low.


You can replace it with a fixed resistance for test purposes, I think its max resistance is 2k ohms.

 

[Texx]

i was thinking about that bud.. however the problem to that is that on WOT (yes i know its normal lol as im running bigger injectors & next to no boost) my af goes close to 10.4~10.6af .. so im not to sure about the injectors playing up.. it is a possibility.. but then again, why would it always go at the same point?

kon

A sticky injector could operate OK at higher duties due to spending less time in the closed position.

For example, if say at idle (900rpm) an injector opens and closes 450 times a minute and at 4000rpm the same injector opens and closes 2000 times a minute, it will spend more time closed when the engine is at idle, so is more likely to stick under those conditions.

If an injector skips a cycle, the O2 sensor will then see the AFR drop and try to compensate by raising the duty on all 4 injectors possibly resulting in a steep rise in AFR which then confuses the ECU into leaning the AFR back off again.

It might be worth running some injector cleaner through the fuel system and see if you get any improvement. Could be an easy fix...

 

[HYBRID]

will do texx! thanks for the idea mate!! i havent cleaned them out in a loong time, so its a good idea i didnt think of that always another good thing to rule out

one tiny question, would a bad earth situation (hypothethically nothing is confirmed) cause a fault in the injectors to lean out (periodically) the fuelling table, due to the longer lag times at idle?

kon