1uz-fe airflow metre probs

[mick08]

I've done a search but i can't find anything, I think i may have air flow metre probs, it seems to run fairly well without it plugged in but i used to think that must be the problem if the car runs fine, but i have since learned that the ECU is in 'limp home mode' with a pre-determined air\fuel ratio curve or whateva you call it, this may sound fine but it is way RICH way way RICH, and it pings too. I did take a gamble on a 2nd hand AFM but i think it was a dud aswell cause i still have the engine stumble and miss. My question is what else could it be masking when i unplug the AFM, like yes it makes the miss go away but to my way of thinking if the problem lied in another sensor why doesn't it still fuck up?? What other sensors are bypassed and not used when its in limp home mode? I have been living with this problem for 6mnths now and the reason for this is a new AFM assy from toyota is $1200-$1400 and i'm a bit sceptical to waste more money on a 2nd hand unit that may shit itself in 5min even if it does work, has anyone else had AFM issues with their 1UZs?

[wilbo666]

Have you tried pulling the check engine codes from the engine ECU?



Cheers
Wilbo

[mick08]

there in lies another problem, the eng has been swapped into a 93 hilux 2wd and i dont have the internal diag plug, i do have the eng mounted one but it doesn't have the W terminal in it, i need to find which wire on the ECU plugs in the W wire, it all got too hard 6mnths ago so i just left it but its now chewing to much juice-hahahaha do you know the pin-outs for a 91 soarer? or what colour the W wire is?

[mick08]

OK found W wire, and it flashed out 2 4 3 1 7 8, does anybody have the fault codes and there numbers for a 91 soarer?

[wilbo666]

http://soarercentral.com/sc-forum/me...tml?1100787369

24 - THA (Air Temp Sensor), open or short

31 - Air Flow Meter

78 - Fuel Pump ECU


It does sound like you have an issue with the AFM (or more likely AFM wiring)...

Have you checked the AFM wiring from the AFM plug back to the engine ECU for continuity?
Check for +5V and GND at the AFM plug?

Cheers
Wilbo

[mick08]

OK thank you for your prompt replies, i did the fault code extraction as ive been driving it with the AFM unplugged, it came up with those codes which is fine but when i wiped them by disconnecting the batt and reconnecting the AFM the test light just flashes constantly, i took the car for a quick drive and as usual the problem didn't occur for a few mins then it did so i stopped and checked the codes thinkin it may have changed now but the light still just flashes, so i unplugged the AFM and finally got a code 24 (intake air temp) does this mean its a short in the Air intake Temp sensor? 78 code i'm not worried about as i use an external pump on this conversion and don't have the fuel pump ECU, it runs off a tachometric relay instead, is it strange that the 31(AFM circuit) fault went away?? Thanx again for that fault code site, ive put it in my favourites...

[mick08]

OK just read the rest of your message, my AFM has 5wires do you know which wire should have pos5v? and which one is GND? I do have some wiring diagrams so should be able to trace the wires back to the ecu, thanx again for your help its much appreciated.

[mick08]

OK just did that test seems the AFM plug is getting 5v to the blue/red wire and 5v to the yellow/black wire and also earth on the brown wire that my wiring diag says should be earth-(theres 2 brn wires) so i must have a problem with the air temp sensor, its intergrated with the AFM soooooo, fuck i'm back to square one, You don't happen to know where to get one cheap do you? HaHaHa

[mick08]

OK just throwin an idea out there, what if i get an air temp sensor either universal or a toyota item, anything that works with that 5v ECU output and screw it straight into my soarer air box using the 2 wires from the plug? I know you can get threaded ones, Would that work? i can't see why not but i'm a diesel fitter and not a sparky-HAHAHAHA what do you reckon?

[wilbo666]

so i must have a problem with the air temp sensor, its intergrated with the AFM soooooo, fuck i'm back to square one

Not sure if I follow your logic there mate.

I would expect a code 24 (Air Temp Sensor Error) when you unplug the AFM, because as you say the air temp sensor is internal to the AFM, and if you unplug the plug it's disconnected (an error).

Maybe you can find someone to test your AFMs?

Cheers
Wilbo

[auto351]

Looks like the pin outs are the same as the 7MGTE the Temp sensor is across pins 1 (E2) & 2 (THA)



Mesure these pins ( 1 & 2 )on the AFM and see if you get the same reading at the ECU plug ?

Not sure if they are a direct replacemnt but 7MGTE #22204-42010 & 1UZ-FE 22204-42011

but you can buy just the sensor for $80.00
http://www.ebay.com.au/itm/TOYOTA-SU...item35ba13e809

[dumbass]

don't waste yr time testing
find a second hand air flow,
they won't bring up a code unless they r totally fkt
or wiring is faulty and yours isnt bringing up a code
when normal running and it's impossible to test airflow
with multimeter unless u know exactly what to look for
as they are frequency signal not a rising voltage.
it could also be your ecu as I've seen similar issues
and guy got ecu repaired and fixed his problem
they are just an old motor these days and they r starting
to fail

[mick08]

Wilbo, what i mean is whether its the AFM or the Air Temp Sensor they are one in the same and I'm still lookin at $1400 to replace it, and auto351 thanx for that info, i did see that on Ebay but its in the states and ive already wasted $90 on a 2nd hand one that looked good but didnt work, what did you guys think of retrofitting a universal air temp sensor in the airbox somewhere? My soarer info says that at 20deg it should be 2000-3000 so id say the 7M info will be the same, i'll check my resistance, hopefully its uptheshit and i'll try to find a universal one with the same OHMS resistance table, thanx again for replying so quick...

[mick08]

Hey dumbass, i agree they are old motors but since i got one in my daily drive i kinda wanna fix the prob caus its costin me a fortune in fuel, 2nd hand units are thin on the ground and most ppl don't wanna seperate them for the engine, if they do they want hundreds for em, its prolly cheaper to go aftermarket ECU......

[manny]

Ignore the Air Temp Sensor error as that will sort itself out once you have a known good AFM in there.

Don't spend $1400 on a new AFM - find a know good one from someone and swap to test first and then if yours is proven stuffed, find another used one for ~ $100 to swap in.

Like has been suggested, open the lid to the ECU and rule out leaky capacitors if you haven't already.