5A-FE AC RPM Idle and Acceleration Problem

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amjad111 (amjad111) 2012-08-28 05:48:14 +0500 #41

click here and get your answer
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kawafan (kawafan) 2012-08-29 19:46:30 +0500 #42

WTH ^^^ Mods Spammer here.

kawafan (kawafan) 2012-08-29 19:50:17 +0500 #43

So the after 2 days , i took the time to call the Elect Guy , he came checked and fixed it in 30 Seconds , i dont know how coz he just touched the wires and said , Start the car , and it did . he did something behind Glove box .
i plugged unplugged every wire so maybe some grip loosen issue but that didn't work for me . so here is the error 51 and i will check the TPS censor from mechanic and will post the result here.
The Issues are still the same , same accelration issue on IDLE , but will post the final result after mechanic work.

kawafan (kawafan) 2012-09-14 07:14:35 +0500 #44

Hi
Today i get cleaned my ISCV , and throttle Body
ISCV is now working fine.

Also tried to reset the TPS . but its still the same , same acceleration problem , Fans are also automatic.

the BATT connection now all time live so CPU can store reading or error codes .

Now after a 5 km TRIP the ECU is throwing.

Error 24 , 42 and 51

After TPS adjustment there is still 51 and two new errors 24 and 42 , so what are these about .

Also the drive of car is too much painful , ON AC the rpm is on 1100 and Still on Signals i need rev to 3000rpm then use the clutch otherwise the its turned off.

Without AC the rpm is on 2000 ,

if i drop down the rpm , ( mechanics were trying to do so) the car off more frequently .

SO guys i am alone in the world now and having terrible drive experiences ,

What Now ?

Xulfiqar (Xulfiqar) 2012-09-14 11:12:33 +0500 #45

Error code 21 = O2 sensor signal (Is the O2 sensor connected? make sure the sensor is in good condition)
Error code 42 = Vehicle speed sensor signal (it should get 4 pulses per wheel revolution)
Error code 51 = Missing IDL signal or engine started with A/C signal (badly adjusted TPS - usually caused by mechanics fiddling with the throttle stop screw)

The A/C idle control function is a separate vacuum solenoid that connects to the manifold with two thick vacuum pipes, it also has an adjustable allen head plastic screw on it. It would have two wires one 12V and the other wire comes from the ISC pin on the ECU - when the A/C signal is routed to the ECU at pin AC1. When it works with A/C you then adjust the idle rpm from it. Make sure the throttle body is in original position - btw there is no idle speed adjustment on these TB - the throttle stop screw is not meant for idle adjustment.

This solenoid connector would be near the MAP sensor connector on the engine wiring. To idenfy the solenoid look inside an engine bay of a 1.6 GLi corolla of AE100 series - which is also called indus corolla.

Jeep_junkie (Jeep_junkie) 2012-09-14 15:47:11 +0500 #46

I thought I had already replied to this thread but I guess it never got posted.

Kawafan, Xulfiqar has got you going in the right direction. First and foremost, you need to resolve the code 51. Make sure the throttle blade is fully closed at idle, then set the TPS so that the IDL switch inside it is on. For this, you'll need to get a diagram for your vehicle that shows which terminals to connect with a multimeter.

Once you've down that, you need to verify that your ISCV is working properly. For that, listen for a clicking sound from your engine when you turn it off. That's the sound of the ISCV resetting to the fully open position for the next engine start cycle. If there's no sound, either the ISCV is bad or it's not getting any power. The ISCV should receive power for two seconds from the main EFI relay after the engine is turned off. For this to happen, the EFI relay needs to be wired up properly, meaning that your key switch should provide switched power to the IGSW pin of the ECU, allowing the MREL pin to output voltage to the main EFI relay, which in turn switches power to the +B and +B1 pins of the ECU. If this basic wiring scheme is followed, the ISCV should operate normally.

Xulfiqar (Xulfiqar) 2012-09-14 16:03:08 +0500 #47

If the engine can idle perfectly smooth without A/C load then then the A/C idle boost up solenoid is missing or not working - Its usually missing in swaps.

kawafan (kawafan) 2012-12-03 13:56:38 +0500 #48

countless tries of months and tried out at least 5 'expert' computer electrician , the problem is same , the last one told me is , the Wiring is the basic issue and now we need to change the wiring , so what Xulfiqar bhai you say about this . now in current weather we are not using the AC , but without ac CAR rpms are sometime 800 and sometimes 500 , that is ok , but when closing to signal , or applying brake while holding even clutch , the rpms suddenly drop to 100-200 and brakes and steering got Hard and nearly useless , and that is the most dangerous situation i feel 2-3 times in last few weeks .

Xulfiqar (Xulfiqar) 2012-12-03 14:20:27 +0500 #49

there is no voodoo or black magic in wiring of these simple engines - if your engine is correctly wired up it should be very easy to repair. The A/C idle up is the job of a separate solenoid that is bolted to the body of the car and has two thick vacuum pipes on it, it makes a vacuum leak in the manifold to adjust rpm on A/C load.

The idle hunting without reason is usually caused by "cleaning the IACV rotary valve" and then not lubricating it. It is also caused by electricians trying to direct short it to ground to raise rpm on A/C. Find yourself someone who is willing to work - The wiring needs to be checked and connected properly. The faults will usually rectify once all logic sequences as fulfilled. Uptil now it sounds like you are experiencing "quick fix electricians" only.

kawafan (kawafan) 2012-12-03 14:38:32 +0500 #50

Thanks Xulfiqar Bhai for really detailed info , but i found the best electrician i can and when i tell them about the check light or sta signal they definitely think i am some kind of idiot and talking chines to them , i can see it on their faces , even they are some popular electrician like Iqbal from chubarji ,also the people when hear its the Altered , its engine swapped , the first thing they say is ,
'aisa hota hey' , yeh rehna hee hey '
if anyone can point me to right electrician in Lahore , i will be very thankful , the budget is not a problem in problems like these

Xulfiqar (Xulfiqar) 2012-12-03 15:35:08 +0500 #51

seems like you found an incompetent person, you need to find someone - who maybe a car electrcian or not to trace out the whole wiring and make sure its connected like Toyota meant. Till then you can keep shooting money at it with no result.

SER_GTR (SER_GTR) 2012-12-03 16:04:49 +0500 #52

TOYOTA wirings Are Easiest And Most Friendly .........!

Its A 1 Hour JOB to check the whole pin out and trace fault if done correctly...!!

mostly swaps fail here due to wiring failure...they can't make it work perfectly....!!

Good Luck finding one....or being one yourself......i can't find one at my time so i become one...!!

Xulfiqar (Xulfiqar) 2012-12-03 16:15:53 +0500 #53

True on that. old toyotas are the easiest, You can do them while half asleep - or as a freind of mine would say - that they are so simple that one can help out a person with an old toyota engine wiring problem while one is watching p0rn.

The weirdest wirings in jap cars are Subarus and Mitsubishis. but once you get around their basic concepts - it becomes pretty ok.

SER_GTR (SER_GTR) 2012-12-03 16:28:39 +0500 #54

^^ LOL

Nissan's Are Tricky Too.....!! But They Are Interesting To Work On...!!

koolminded (koolminded) 2013-05-17 06:06:10 +0500 #55

Hi guys I faced this strange issue for one year in altered vehicle. The main problem is feed line not sensors or computers!!!
when AC or other things are turned on the electric fuel pump starts missing (low voltage = low RPM= low pressure feeding)
i changed fuel pump which throws fuel upto 30 feet away corrected all the issues I again changed the old pump fault again realized. so make power cable of pump strong (like woofer becoz it take 8.5 ampere for full function) first then buy mitsumi or denso new pump without compromise and get rid of this intermitent fault

xsxd (xsxd) 2013-05-17 06:40:24 +0500 #56

So what you're saying is that changing the cable and pump resolved the issue for you?

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Xulfiqar (Xulfiqar) 2013-05-17 10:24:22 +0500 #57

how thin of a wire were you using?? and how was your system wired up, the circuit opening (fuel pump) relay takes off from the main relay (or key) and is fused.

koolminded (koolminded) 2013-05-17 15:47:59 +0500 #58

Thanks Xulfiqar
I am electronics engineer and have 20 years experience in SAT networks, Tv channels and R&D i am very logical guy with precise
measuremnts tools i didnt wire the car it was wired using copper 2mm flexible multistrand wires made in japan using UPVC wire can bear
18 Ampere at 2 meter length but those wires had no issue I changed them because they had joints at each 3 feet for my satisfaction.
main culprit was fuel pump all enginners, EFI technicians all sensors including vacuum sensors which controls RPM
was tested using external 5V DC and -100 to -700 PSI B-vaccum pump reading chart was perfect at room temp and at 85C
ECU was also cheated by applying fake voltage and digital signals I2C but it didnt leave its sttubronness.
It was challenge for me so it was solved at last by changing fuel pump which everyone ignores!!!

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Xulfiqar (Xulfiqar) 2013-05-17 16:03:19 +0500 #59

This is usually my point too, if the fuel pump cannot sustain enough pressure to the fuel rail, the engine will run bad, to correctly test it one needs a simple pressure gauge to measure about 100 psi (giving a gauge is best measured half way)

Most wiring jobs for such "swaps as the term goes now" were ham fisted. The safety necessity of a circuit opening relay and a fuse is also overlooked.

But good, always good to see someone gather empirical data before cutting a cheque rather than shooting parts at the car.

SER_GTR (SER_GTR) 2013-05-17 17:04:46 +0500 #60

We LOL Always At The Way They Check Fuel PUMPS.....!!