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> having some bogging/bucking when warm-94 ST 7afe, please help!
post Mar 14, 2014 - 8:37 PM
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opie_7afe

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the car is a 1994 celica ST manual 1.8,not california emission,. 131,xxx miles video below as well

so this started about 2 weeks ago and have been running in circles. the car was fine when i drove it one day, later on that same day died and would barely run, managed to get it home.

currently the car is fine until it heats up once that happens when you stop and go take off in first gear as usual it will start off fine sometimes, sometimes just bucking and need to increase revs. then can continue to get up to speed sometimes, other times it will start the bucking/lurching untill about 3500 rpm. then it will drive fine once your say set at 45-60mph with cruise locked and will be fine. only happens uppon acceleration or punching the throttle from a dead stop (not like i do that anyways as i granny drive most of the time). idle sits at about 1100-1200 rpm while warm, noticed my fans dont come on even when sitting there (as you can tell by my temp) while driving the temp is pretty low (about 1/8" from the Cold mark).

parts i have replaced/tested as good:

timing belt is fine i do believe.

condenser melted, replaced with one from the original distributor that was on the car (i replaced the distributor as it decided to eat up a pickup coil with one from salvage yard)

plugs,wires,distributor cap,rotor all good

ignition coil tests on the higher end of the scale when at around 68F, primary goes out of range when heated with heat gun

pickup coils test good while about 100f or so

fuel filter(was the original one! this one made the biggest difference),fuel pump strainer/filter

idle air control valve is new, grabbed a throttle position sensor that tested good from the salvage yard, still tests good using methods in the celica BGB

cleaned throttle body and all passages inside of the throttle body

replaced most of the smaller vacuum lines/no vac leaks

tested/cleaned egr valve it dont stick at all.

map sensor should be fine

coolant temp sensor replaced with a spare i had was from another celica but tested out fine.

fuses are all fine

fan is not turning on for some reason?

o2 sensors im confused on how to check them through the diagnostic port, i did manage to get constant voltage fluxuations though more than 8, which i believe is good? but voltage is more than 0 V at 2500ish rpm. so unsure on that.

no check engine light or codes besides the abs(sensors were trashed) and airbag(will get around to replacing center module) lights

so thats what has been done, just driving me nuts as i cant figure this out! car has never given me this much trouble before. thanks guys hope i can figure this out....

heres the video:

http://youtu.be/lhpMncDY7Hc



 
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post Mar 19, 2014 - 9:10 AM
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VavAlephVav



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How about the air temp sensor?
The computer adjusts the fuel delivery based on the entering air temp, and if the temp sensor reads wrong because it is faulty, or not in the air stream it could act weird.
Couple weeks ago I forgot to put the sensor back in the intake hole when I took the airbox off to replace the fuel filter. The sensor was laying down beside the block and was reading the heat
Of the motor instead of the air temp and it acted real messed up until I realized I had forgot to put it back in hole in the airbox.
Also normal temp should be about half way, the needle covers the little water lines on the gauge. If you are below that and your fans never come on then your thermostat is stuck open.
The computer adjusts fuel rich\lean based on motor and air temp. Even when up to temp mine will kick the fans on when the thermostat opens just for half a min every 5 minutes maybe.

This post has been edited by VavAlephVav: Mar 19, 2014 - 10:28 AM


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post Mar 31, 2014 - 12:02 PM
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opie_7afe

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QUOTE (VavAlephVav @ Mar 19, 2014 - 9:10 AM) *
How about the air temp sensor?
The computer adjusts the fuel delivery based on the entering air temp, and if the temp sensor reads wrong because it is faulty, or not in the air stream it could act weird.
Couple weeks ago I forgot to put the sensor back in the intake hole when I took the airbox off to replace the fuel filter. The sensor was laying down beside the block and was reading the heat
Of the motor instead of the air temp and it acted real messed up until I realized I had forgot to put it back in hole in the airbox.
Also normal temp should be about half way, the needle covers the little water lines on the gauge. If you are below that and your fans never come on then your thermostat is stuck open.
The computer adjusts fuel rich\lean based on motor and air temp. Even when up to temp mine will kick the fans on when the thermostat opens just for half a min every 5 minutes maybe.



nope not the issue..ill figure it out myself as i always do....

would be nice if someone here let me know there was a test mode for the ECM...again got more help on a firearms forum then here....hey thats typical firearm owners are the nicest and most helpful bunch of people i have ever been around. so this is another reason WHY I DONT POST HERE! try to help others but when i need the help i dont get it....typical for people now a days dont give 2 ****s about helping others unless they are paid for it....so with that said dont expect me to be around anymore.(not like i was before)

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