having some bogging/bucking when warm-94 ST 7afe, please help! Options

[opie_7afe]

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

[cjpost]

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

Are you saying the filter hasn't been replaced in 131,000 miles?

[englishdas]

I have the same issue, but my fans are stuck on. Replaced Rotor Arm, Distro Cap recently, seemed to smooth out the acceleration for a few days, but the kangaroo-ing seems to have returned. Hmmn....

I'll be watching this thread with interest. Hope you get sorted, Opie.

[opie_7afe]

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

Are you saying the filter hasn't been replaced in 131,000 miles?

yes it was not replaced for that long, it has been replaced as i stated, other wise why would i state that made the biggest difference....i did state every thing i have replaced or tested.

also guys i dont ask questions unless i have run out of options which i have, i dont have the cash to just throw parts at this thing. i have searched and searched for hours on end and still no information that would help figure this issue out...

This post has been edited by opie_7afe: Mar 15, 2014 - 11:05 AM

[englishdas]

Sorry buddy, just watched the video, I have a different (currently unsolved) issue.

That must be frustrating the hell out of you. I know I'm a relative noob, but does it have the stock air system, it's not got an aftermarket with like a 3" intake or anything does it?

I just read recently about keeping the diameter of the piping down even on aftermarket systems, as oversizing creates bog-down/sluggish acceleration issues. If you've checked it, I apologise, it must be driving you mad.

[opie_7afe]

Sorry buddy, just watched the video, I have a different (currently unsolved) issue.

That must be frustrating the hell out of you. I know I'm a relative noob, but does it have the stock air system, it's not got an aftermarket with like a 3" intake or anything does it?

I just read recently about keeping the diameter of the piping down even on aftermarket systems, as oversizing creates bog-down/sluggish acceleration issues. If you've checked it, I apologise, it must be driving you mad.

yes it has a intake, but ID of pipe is about the same ID as stock air hose. and its been on for a year or two with no issues....this only happens when engine is warm...but obviously nobody has a clue here, im getting more help on one of my gun forums.....

[VavAlephVav]

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

[opie_7afe]

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)

[ILoveMySilly97]

^well that escalated quickly. Sorry that everyone here isn't as mechincal inclined as the firearms people. The majority of us members are new since most of the older ones has upgraded their cars ot a different car or just dont have time to come on actively anymore. With that said hope your problem gets fixed.

[richee3]

would be nice if someone here let me know there was a test mode for the ECM...

Jump the TE1 and E1 pins in the diagnostics box under the good and count the CEL flashes. For the issue to be only after the engine has warmed up, you have an issue with one of your sensors. Pull the code from the ECU and that will get you started. Since it sounds like you've already tried that, I'd look into the CTS again. If I'm not mistaken, the 7A has two sensors- one that goes to the gauge and one that goes to the ECU. Have both tested good? Your temp gauge is reading way too low so you either have a CTS or thermostat issue. Your O2 sensor will affect fueling as well so it's also something to look into after you figure out how to test it.

[VavAlephVav]

U MAD BRO?

I know cars piss me off, I try to ask other people for advise across the interwebs sometimes, but ultimately I have to remember that I am The Only One who is actually there with the car.
and others can only be of so much help. although it's nice when I come across somebody who has had the Same problem I do, or better still if I learn about the problems others have had
before it happens to mine. So I was feeling rather lonely when you didn't reply back for 10 days. I guessed you had just figured it out and didn't want to share anymore about it. :'(

I have a Toyota manual for my motor and it gives nice troubleshooting for these kind of electronic things, but the pdf only has the 5sfe, 3sgte, 3sge motors.
I still haven't got a factor manual for the car itself.

couple of things I do notice:
"map sensor should be fine" - 'should be' , as in you tested it and are sure?
"idle air control valve is new, grabbed a throttle position sensor that tested good from the salvage yard,"
is the IAC new or was that from the salvage yard too? for that matter, it is a Toyota sensor or aftermarket?

I had a problem with the IAC on my Jeep and the sensor I bought at Oreily would not work right, so I went and got one from Chrysler and it worked just fine. I think electronic sensors are the kind of thing
I will always go to the dealer for from now on.

and because I was messing with my IAC just the other day, mine also doesn't want to idle down at 700 like it should, it wants to hang out up around 1300 but if you bump the throttle just a bit it will come down.
so when I took the IAC off it was a bitch to get too because I needed my little stubby screwdriver and had to squeeze my hand up against the firewall to press it up tight while using some channel locks to turn the screwdriver.
and once I got it out I realized it didn't work at all like the one on the jeep so much. and as it popped out I heard a little click. I could see that the rod of the throttle plate went through the intake, with throttle cable and a spring on one side
and the IAC with some little pins on the other side. the IAC had its own little springloaded mechanism inside it, and seemed to operate freely.
I was expecting there to be something else to clean inside of it and there wasn't, except maybe the throttle plate itself.
but when I put the IAC back on it wasn't so easy to get it to Pop right into place, it was on there but didn't quite seem to fit just right. yet I could screw it down and start it like that.
But when I started it I found the throttle stuck and would not return on the spring automatically and I had to push it back with my hand (at the motor).and It took me a while to figure out I didn't have it on quite right.
the throttle would not spring back on its own, when I loosened the screws on the IAC a bit it would let go of it enough so that the throttle would work like normal. so I tried to drive it like that and it seemed ok until I put my foot in it and
then it did this spooky hesitate and choke like it didn't want to run at all. so I nursed it back around the corner to our driveway and shut it off again.
What I finally realized was the IAC has to go back on exactly the right way or it won't work correctly, the little pins on the end of the throttle plate had to go into the hooks on the IAC just right.
but even after that my idle is still too high, the throttle cable just won't go all the way back in automatically but usually will if you goose it a bit. (but I'm tired of doing that at every stop light)

I believe it just may be a faulty IAC in my case, some of my symptoms were similar to yours, but may not be the only problem.
also, the fans are on a temp sensor and they come on at the same temp as the thermostat opens, so the only time the thermostat is open is when the fan is on.
and mine gets hot within about 2 miles of driving and stays there. if yours doesn't get close to normal until its sat at idle a while, like you did in the vid, you have the thermostat probably not working right. may not be the only problem.
as Richee pointed out Coolant sensors, all seem temp related. with a 1994(as mine is too) OBDI has more that you will have to get a scanner for, and less you get from reading the flashing light on the dash.
likewise the idle speed could be caused by the computer reading a low temp and keeping the idle up.


and searching keywords for your problem to find old threads of people with similar problems is another good way to do things.

[opie_7afe]

mad aint even the word, im to the point of about to leave it in a parking lot with the keys in it and hope it gets stolen....

IAC is new aftermarket(easier to remove TB to install the part with tb on). i cannot afford most dealer parts. TPS is from the salvage yard(from a wrecked corolla),new coolant temp sensor, yes i know what one is what...., used(from a parts place that tests their parts) map sensor(helped a tiny bit). i get no codes during normal operation(yes CEL works) i use test mode and still get code 31... only when warm it will set the code.

the ignition primary tests 1.5 ohm secondary is 12.51 kohm secondary. ive replaced nearly all vacuum hoses. injectors are all fine in terms of resistance, all click the same rhythm with a stethoscope..of course would help if toyota made an easy test port for fuel pressure....dont have access to a tester.

im to the point now where im not going to buy a part unless i am 100% sure thats part of the problem...im tired of the "it might be" "it could be" "have you done this"

i have searched and searched and searched, im not searching anymore #1 most search features suck ass and dont give the results you want #2 most threads dont get an answer or the OP never replies if the problem was fixed or not...

[VavAlephVav]

true, dealer parts are pricy, but for the sake of electronic parts I have seen a big difference in the aftermarket stuff not always working right.
Yet I think one of the nice things about places like the Pick-n-Pull is that for little things like the IAC you can just put the damn thing in your pocket and leave as if you didn't find what you needed. which could be a cheap way to maybe double check and see if it's just the IAC control not working quite right.
also that thing is real touchy and if its not on just right or adjusted it can act real funny. you can find 7afe 's in Corolla's too.

[Box]

For the record had I seen this when it was first posted I'd have helped. Had you not thrown a hissy fit I'd have helped now, but all of a sudden I can't help but feel apathetic.

[cwong]

mad aint even the word, im to the point of about to leave it in a parking lot with the keys in it and hope it gets stolen....

I take it off your hands. Leave it in a parking with keys and pink slip ill pick it up for you buddy. Your not far from me. Then you wont have no worries

[opie_7afe]

sorry for the attitude, im just to the point where i hate working on cars now...especially when something should be so simple to diagnose and its not as simple as it seems. i figured out the issue, was the coil gone out and needed a thermostat.

part of the attitude was issues in my personal life so sorry for projecting it on you guys....i am no longer in SC i was forced not by my choice to move back to RI.....this car may be up for sale but i am not sure yet...i need to get a new windshield, abs sensors and airbag ECU before i even attempt to pass inspection which is something i totally forgot about....just a crappy time in my life where i basically need to start over as if i am 18 years old again....