NorthernWoodsman

So, i finally got around to buying a new Supra AFM that was not tampered with. i installed it back in december. things have been running great ever since. reduced lag at take off and a little better pull in 4th and 5th gear on hills.

but, yesterday, the check engine light comes on. just read the code (25) which is Lean air/fuel ratio.

is there any reason that this would be happening other than having the Supra AFM installed?

if it is the AFM, why no check engine light for almost two months?

what, if any, damage might i be doing to the motor by driving like this?

more importantly, how do i fix this issue? remove the AFM? anything else?

thanks,
matthew

blake.nemitz

probably wont help, i was getting same code and i was a little low on antifreeze and the coolant temp sensor on the back top of the block wasnt getting an accurate reading, topped off with 1/4 gallon and it went away. how's your 02? and with the lean condition are you getting a ping?

NorthernWoodsman

hmmm, really? the coolant level gave you a Lean air/fuel code? i'll check my level, but i think it is okay.

i'm not getting any ping. the truck runs damn good right now.

mightymouse

iTrader: (6)

x2 check the o2 sensor.

NorthernWoodsman

i was just about to reply about the 02 sensor.

i had one replaced a while back. assuming it's still okay.

how do i check them to see if they are functioning properly? there are two on this model truck IIRC?

blake.nemitz

with a volt meter for the o2, there are several write ups on here somewhere. and with the coolant sensor thing it was wierd you would think it would go into a rich condition, its probably manifesting it from something else wrong who know. i would test your o2 and if that doesnt work you might have to pop the cover off the afm and give it a couple clicks rich. when mine was running lean it was a champ and felt more powerful, when i fixed or hid the problem the light went off but its not as peppy as it was in the lean condition. some of those gremlins arent so bad huh

NorthernWoodsman

thanks. i'll look for the write ups.

i have no interest in messing around with the AFM. at least not right now.

do you know of any damage that could be done to the motor by running it Lean?

blake.nemitz

ya you can burn valves burn holes in pistons, ect... but if you run the factory timing 8* you should be ok as long as you dont have any pre detonation, if you are advanced to say 15* like i am it can definitely cause damage pre detonation can be catastrophic to engines. i would fix it you might be able to run for a while or even years like that but what if its only a couple weeks and all of the sudden your smokin and ruined your motor? also have you reset the ecu and seen if it comes on again? with the supra afm you have a larger openiong for air to come through if it is tuned like your old one it will run lean, sucing in more air than it thinks, thats why i said give it a couple clicks. most of these swaps on vz motors as far as i have read requires the afm to be re tuned by clicking it rich or lean to get a stoic af ratio. if the afm is causing it nothing will fix it other than clicking it rich or putting the old one back on. only other thing i can think of it the ait intake air temp sensor but i believe those are part of the afm

blake.nemitz

if you get too lean you will get a knock if you dont then run it, the egr should take care of pinging unless you removed it then you need to figure this out to be safe. check your o2 if it was fine for 2 years its probably your culprit

NorthernWoodsman

good news and bad there i suppose. definitely don't want to ruin my motor. haven't cleared the code yet. i'll check timing tonight hopefully. it should be set stock ad i haven't ever messed with it.

i have a 22RE motor, not the VZ. i really, really, really, don't want to mess with the AFM. if i have to, do you have a link to any instructions on how to adjust it?

from the sounds of it by your situation, adjusting the AFM will just eliminate any advantage of having it in the first place.

damn, this is getting to be a real PITA. i don't want the stock POS back on as the lag on take off is horrendous IMO. damn, damn, damn.

i'm so busy with school too. maybe i''l just remove it for now. i need to drive the truck and have little time to work on it. don't want to F up the motor.

blake.nemitz

well tahn disregard everything i said ha ha re's are tough little suckers and is your afm from an 82? 3vze engines suck and dont take the abuse a 22re does. im not sure of the timing specs. and the advantage of the supra afm is a larger opening for the air to get in, adjusting it to a stoich ratio will not make it same as stock. it allows alot more air in and quickens throttle responce.
afm adjustment

http://www.4x4wire.com/toyota/minutemods/afm/

its easier than it looks

blake.nemitz

also heard only 82 supra afm's are plug and play others require adjustment. if your barely lean and arent getting a knock code dont be afraid to drive it.

NorthernWoodsman

yep, the AFM is the correct one. i made sure of the numbers before i bought it. when i considered doing the swap, everyone on here that had done the swap reported zero problems. the first time i tried the swap i had a faulty AFM. The truck ran good for a few days and then not so good and it threw the same code as now IIRC. However, with the new AFM now the truck runs great and continues to run great, but its throwing a code again.

didn't get to check the 02 sensor tonight. maybe tomorrow.

myyota

When was the last time you replaced the fuel filter ?. I would try that first. If you decide to replace the 02 sensor, use a Denso, thats an oem replacement. Do not use a Bosch 02 sensor, they don`t work well in toyotas.

Reedr125

I would unplug the + terminal on the battery. For 2 minutes. Reset the computer. See if the codes come back.. Then track down the problem. It could be a fluke, and the problem may never return.. Have you jumped it or anyone lately?

NorthernWoodsman

haven't jumped anyone or been jumped either.

fuel filter was replaced in august of 2009. napa brand filter. i think i might replace it with a toyota filter. i also just bought a denso 02 sensor yesterday. plan to check my old sensor tomorrow, hopefully, and replace if needed.

NorthernWoodsman

....I drove to work this morning and the check engine light was still on. this is because the weather here has been shi**y and i don't have a garage to work in and so i haven't had a chance to swap the 02 sensor and reset the ECM. but, this afternoon, on the way home from work, the check engine light was now off.???

any ideas on how the light shut itself off and/or why it would do that?

Duffdog

The light shuts itself off if the problem is not emissions related. But...the ECU still saves the code. You can still read it by jumping the e1 te1 connectors. As far as your lean condition-- there are two things you can do about it: 1: reset the computer and wait to see if the ECU corrects the fuel map on its own 2: change out some fuel components for more fuel flow (fuel injectors)

But this can get complicated and might require outboard fuel management devices.

NorthernWoodsman

but, does this also mean that it is NOT my 02 sensor that is the problem then?

it is sounding more like it is the AFM swap that is the problem. although it is still really weird that it took two months before the check engine lit up.

has anyone else experienced this situation after the supra AFM swap? if so, what did you do to correct it?