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Toyota Levin 4a-ge 20v Silvertop


Lexus2192
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I am having some idle and fuel management issues. When the car gets to running temperature, idle speed fluctuates between 500-900 rpm. It stays at nine, then it would fall. Reving will bring it back to nine, but after a few seconds there it will fall again. Also whil cruising in any gear with a small throttle opening tends to generate bucking and surging as if the fuel was being abruptly open and cut and fast inetrvals. Particulary hazardus whil lifting off in a turn...

All of the usualy stuff has been checked already, ecu, vacuum hoses, plugs, leads timing etc. The last suggestion I have had was to have the oxgen sensor replaced.

Is there more than one??? And if so where are they located??? And futher more, can anyone help me out with a part number???

I have been strggling with this for a while, and I really dont know what to do next... any info would be welcome. Thanks.

LaterZ

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from

http://www.users.bigpond.com/vidore/toyota_4age_engine.htm

i get:

L-Type Air Flow Meter (AFM) Sensing. Sequential Injector Triggering. Side Fuel inlet injectors. Note top fuel inlet injectors will fit but require fuel rail from 3rd generation 16 valve due different injector spacing to 1st & 2nd  generation engines.

duno if that helps though

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injectors is part of the efi-s system (wel maybe not s, proabbly is though).

anyway, thats electrnicaly controlled, as said, what controls that? the ecu!, i susgest you do a fault code check on her, if that comes up null, go check with a tuner shop. your ecu may be buggered.

dont pay any cash until you know what is wrong however (no point getting a new ecu when you injector itself may be bung), however the ecu would pick this up.

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Okie... here is the deal with the ECU. The original ECU for the car was faulty, and the car had the same problems, along with others(VVT was dead). But I picked up another ECU and that fixed almost all the problems. And it was checked out fine.

The thing with diagnostic checks (by the way, I already did that and everything checks out fine) is that it never always points to the problem.

How can you tell if an injector is faulty? Driven hard, this car moves. It can d0 160kph in 3rd no problem. But at idle, just as throttle is applied, for that split second rpms fall 300-500 before accelerating through the range.

This car is driving me nuts, but I know its and eletrical sensor dohickie somewhere... it has to be...

Kepp your thoughts comin Cozmo... believe me.... I need ideas :(

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hmm.. my car seems to do this i think... you press the throttle a TAD and the revs just drop.. but if you are driving and you apply the same pressure, the car can slowly accel?

i think its just resistance from the wheels to the tranny... you sure its a problem, or you just are being to gentle with the car?

hmm.... i still stand with the tune up shop... um, im not completely sure how to check an injector... usually you plug into your ecu, check for lean / rich mixture settings, and rev the engine.... it will usually adjust it self (so, lean... rev.. rich.. lean... lean... rev rich.. lean....) etc.. but if she stays lean.. or stays dead during the entire test, the injector is just putting in a safe dosage, to keep the car going. But in such a case the check engine light should come on.

you might as wel check your sparkies... duno if it could even make a difference, but it might help.

check your leads while your at it too.. unplug one, (not the lot please no!), put a multi meter on each end, on ohm's, it should NOT be any higher than 15,000 over 30cm of wire.

if it is they are shot completely, but new wires i think have a resistance of around 1,500-3,000.

i duno what else X_X... u changed ur exhaust? like is it much bigger?

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Okie guys, have already changed the spark plugs... three times in one year. Also the leads are brand new. The idle/throttle problem with the dip in revs happens whne it is in neutral as well. So no resistance there Cozmo.

I am still not too worried about the Airflow meter, but that is the next thing on the list in the O2 sensorisnt the culprit... Thanks Kid. But ummm is there any negative effect in using a different airflow meter like the one u suggested? Do you have one installed in your 20 valve???

Believe me Cozmo this car gets anything but gentle treatment... the headers are factory stock but the original muffler(s) were replaced with a free flow type... but the standard tail pipes...

Should be pulling out the O2 sensor in the next few days... i.e. if I get the time ;)

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i still cant stress the ecu check... it has all the answers locked away.

um, yeh, how much for a new o2? check out prices...

man, other than that, you got me stumped X_X

yay for map sensors!

02 sensor isnt that dear.....bout £130 in the uk from toyota....

AFM is mmy next upgrade....will be essental anyway for when I plan on turboing her :)

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  • 2 weeks later...

I'm having the same exact problem. Already had everything checked, vacuum lines, ecu, even had the throttle bodies cleaned. I'm almost 100% sure AFM is the culprit. Need to replace the O2 sensor too. Anyone know the part number? I need a 4-wire sensor.

Lexus2192, this may help you: http://www.my-acoustic.com/Car/Sudden_Bad_..._Successful.htm

A little hard to understand, but you'll get the idea.

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Okie.. should get some info on the O2 sensor in a couple of days.

"Noobs" The AFM seems to be working fine. I checked the link... but that guy had major problems. My car seems to be running rich at all times leading me to believe it has to be O2 sensor. So will check that first.

"Surf" What is a Mines's ECU??? Never heard of it. Where can I locate one. Is it a direct plug in setup???

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KID, have you gotten your O2 sensor as yet?

You mentioned b4 that the AFM can be upgraded using one from a 2.0L Celica. Can I do the same withe the O2 sensor???

My research is being done in the States and the Mk1 MR2 had a single wire O2 sensor here, but the Celica withe the 3S-GTE 2.0L has the 4 wire, but it looks different from the one on my car (it is bigger) Does the size matter???

Why is this O2 sensor such a pain to get???

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KID, have you gotten your O2 sensor as yet?

You mentioned b4 that the AFM can be upgraded using one from a 2.0L Celica. Can I do the same withe the O2 sensor???

My research is being done in the States and the Mk1 MR2 had a single wire O2 sensor here, but the Celica withe the 3S-GTE 2.0L has the 4 wire, but it looks different from the one on my car (it is bigger) Does the size matter???

Why is this O2 sensor such a pain to get???

got the o2 and the flange fitting as wrong so back to square one..but have part number now....so hopefully :)

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