1ZZFE - check engine light, what to check?

[Mr Ree]

I cant believe how many people are clutching at straws in this thread.

The LOGICAL first step is to check the codes, normally done my bridging E1 and TE1 in the diagnostic port, and counting the CEL flashes to work out what code has been thrown.

For all anyone knows, it could be as simple as low brake fluid reservoir setting off the low fluid sensor when under acceleration. Taking off at lights, going up hills etc etc etc

Dont throw parts at it until you actually have diagnosed it properly.

[RS13]

If you'd read what he said, he took it for a decent blast around hills and couldn't get it to come on. Given that its' low km, freshly serviced and AA checked, I'd be hesitant to even bother with pulling codes before getting some 95 or 98 back into it.

FWIW, a lot of people tend to use lower RPM and more throttle when driving, rather than higher rpm and less throttle.. annoys the crap outta me when people at the lights take off from a slow roll in 2nd/3rd with almost WOT, can hear the poor engine detonating away to buggery yet they don't change up.. doing that up a hill, in a car with a newer, high compression motor fed crap fuel would almost certainly cause the knock sensor to throw the CEL.

All IMO!

[Mr Ree]

I would expect a modern toyota ECU to retard timing as required, far before any supposed knocking from lower octane fuel threw a CEL

How many toyotas do you know of that are designed from the factory to throw CEL's when they knock under normal driving, instead of the ECU pulling timing?

Each to their own and all that, I just see the code check as a GUARANTEE to find out the issue, rather than taking stabs in the dark and throwing things at the car in the hope it will fix the issue.

[iOnic]

The only clutching at straws going on here is from people that think running a car designed for 100 octane fuel on 91 octane isn't a problem. Yes the ECU pulls timing when knock is detected but it only does that to a point. If knock is still present, it tells you about it via CEL/MIL. My MR2 did just that and it's over 20 years old. I do agree that he should have the codes read but I don't think it's as easy as bridging TE1 and E1 on those cars. I'm guessing he will need to take it to a workshop with an OBD2 scanner to pull the DTC's and pay to be told he is running the wrong fuel.

Whether fuel is the problem or not, he is running the wrong fuel. Logic would suggest that he change fuel and hopefully fix his CEL problem therefore killing two birds with one stone. He has to change fuel regardless so why not try it before paying a mechanic to potentially tell you to? The last place I worked at, we used to charge $80 minimum just to plug the scanner in and most of the time the job was done in 5 minutes...that's almost a tank of fuel

[matt dunn]

First thing we ever do at work when a car comes in and has had the CEL on is scan it.

Never seen a CEL come on from detonaation.
sure they may run shit on 91, but it wont bring on a code unless the sensor is stuffed, and if the sensor is stuffed it will come on no matter what you put in it or drive it like.

[KiwiMR2]

Bet it does it more after driving for a while but doesn't when you first drive the car. More heat = more likely to detonate, more load (driving up a hill, accelerating) = more likely to detonate, wrong fuel = more likely to detonate.

Yep - when I took it for a blat it had been sitting for the afternoon, wife had been out during the day & did 40 or 50 km's so yeah it was up to temp.

I used it on wed & didn't notice it BUT it was cold out, southerly & rain & I only did short trips that day.

Sticker on the inside of the bB's fuel flap mentions high octane, and it runs noticably better on 98 over 95. They're the same CR as a silvertop.
Long time no see Andy

Heya mate - yeah been running Nissan's for the last few years & ended up back in trusted Toyota's again

I had a quick look at the fuel cap but nothing mentioned about what fuel should be used.

I will use 98 in the next fill & see if we can get the light up again. If it still comes up with 98 I'll go back to the dealer & get them to check out the codes I think. I've made him aware of it as soon as it happened.

Cheers
Andy

[KiwiMR2]

Well gave it back last week, they got it plugged in & no faults recorded in the Ecu - so I guess that means a faulty sensor yeah?

Been offered a 12 month warranty for $450, Autosure. I wonder if it's worth getting it?

Cheers
Andy

[andyztouring]

Re: warranty-If my Fielder 1.8S is anything to go by,the warranty will be a waste of money,my car is up to 210000kms(got it at 125000kms),and apart from normal maintenence (oil,filters,plugs brake pads,bulbs,tyres),it has not cost a cent .Nothing has played up yet.

[KiwiMR2]

Little bit more to the story now - Toyota plugged it in, history via it2 tester showed a code PO171.

Toyota guy suspected 2 possibilitys, one that the "air fuel sensor" is faulty OR two it has had "poor quality fuel" used.

He said we should run a fuel state
Cleaner through & use decent fuel if possible.

Thinking maybe get the warranty, IF it turns out to be the sensor I think it's like $1500 so the wty will cover it.....

Thoughts now?

Cheers
Andy

[1I1]

Just remember a car has to go through a pre-warrenty inspection. If they pick up on this sensor being faultly then they won't cover it as it's an existing fault

[KiwiMR2]

Might need to clean the mag sensor & see if that helps

[KiwiMR2]

Just remember a car has to go through a pre-warrenty inspection. If they pick up on this sensor being faultly then they won't cover it as it's an existing fault

Yeah had crossed my mind but it had an aa pre inspection less than a month ago & there happy going off that

Cheers
Andy

[matt dunn]

Little bit more to the story now - Toyota plugged it in, history via it2 tester showed a code PO171.

Toyota guy suspected 2 possibilitys, one that the "air fuel sensor" is faulty OR two it has had "poor quality fuel" used.

He said we should run a fuel state
Cleaner through & use decent fuel if possible.

Thinking maybe get the warranty, IF it turns out to be the sensor I think it's like $1500 so the wty will cover it.....

Thoughts now?

Cheers
Andy

Air Fuel Sensor will be the MAF sensor as said earlier,

and they are about $400 not $1500.

Post the numbers off the top of it and I will confirm a price if you want,

but with that code I would also more suspect an O2 sensor.

[KiwiMR2]

Air Fuel Sensor will be the MAF sensor as said earlier,

and they are about $400 not $1500.

Post the numbers off the top of it and I will confirm a price if you want,

but with that code I would also more suspect an O2 sensor.

Sweet, he's keeping it over the weekend to drive it some more as they havent been able to get the cel up since I gave it to him so picking it up on Monday night & I'll post the numbers then

Much appreciated.

Cheers
Andy

[KiwiMR2]

Might need to clean the MAF sensor & see if that helps

[iOnic]

PO171 is a common lean code. Misfires/detonation cause lean spikes. Has the CEL come up again since you had the codes cleared and started running 98?

Air fuel sensor is not a MAF. It's the sensor that measures air fuel ratio ie: oxygen sensor. Throwing a code doesn't mean it's faulty, more likely doing it's job and telling you when it has sensed a problem ie: too lean.

[matt dunn]

. Throwing a code doesn't mean it's faulty, more likely doing it's job and telling you when it has sensed a problem ie: too lean.

Yeah too lean because the MAF in naffed.

We do heaps of those types of MAF sensors at work, they are a real problem with drfting out of spec and you never notice till either it logs a code as it has run out of long term fuel trim,
or you bolt in a new one and feel like you just added NOS as you get the power back.

Lean codes like that are a PITA as there are so many variables,
but my bet would still be a MAF.
Need to check what the fuel trims are, reset them and see where it goes from there.