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Acceleration Faltering - 6G Celicas Forums

Topic #76224 28 posts Started by Tigawoods
Tigawoods
#1
lets cut to the chase.

-car ran fine after cam install

-small valve tap

-after 2 weeks small knocking noise that seems to be coming from below the cam gear and only sounds when its around 1000rpm

-had an exhaust problem - detached the midpipe to run open downpipe until i got it fixed

-car ran super lean at low rpms under a fair load and sputtered as if its grasping to find power. sputters from stop to go at low rpms and drops super lean

-new mid pipe welded on

-car still sputters from stop to go at low rpms but now it gets a bit rich or just sputters with an even 14.X A/F r

- AND at 4900rpm under 100% throttle the car falls on its face and looses power. if anything under 100% throttle there is no problem.



i have a race this sat. and sun. i really need to figure out if this is a tune problem or an internal problem.
any insight at all will be helpful! thanks!

This post has been edited by Tigawoods: Jan 23, 2011 - 11:58 AM
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
bmj67
#2
have you checked you timing belt is correct and hasnt jumped tooth.
Tigawoods
#3
would it be possible for it to jump a tooth after 3 weeks of clean driving?

the car altogether wouldnt run right through all the rpm ranges if the belt was off right?
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
lagos
#4
Did you clear out the negative SAFC settings I put in for you?

Since installing those cams, you are going to need to add fuel in the upper rpm range.
15PSI - 30MPG - Megasquirt Tuned
blu94gt
#5
Sounds like some of the symptoms of a bad throttle position sensor, but could also have to do with the tune.

I've seen cars with a bad TPS that have the same full-throttle type issues; sensor goes bad and doesn't read the right value when XX% open and car mis-adjusts fuel. Can cause the car to run like crap all kinds of different ways.
1999 Celica GT
Tigawoods
#6
>
QUOTE (lagos @ Oct 8, 2010 - 12:56 PM) *
>Did you clear out the negative SAFC settings I put in for you?

Since installing those cams, you are going to need to add fuel in the upper rpm range.

it gets super rich in the higher rpms so we had to add more air. still needed neg correction kindasad.gif

>
QUOTE (blu94gt @ Oct 8, 2010 - 2:55 PM) *
>Sounds like some of the symptoms of a bad throttle position sensor, but could also have to do with the tune.

I've seen cars with a bad TPS that have the same full-throttle type issues; sensor goes bad and doesn't read the right value when XX% open and car mis-adjusts fuel. Can cause the car to run like crap all kinds of different ways.

that does sound like it could be the problem. ill give it a look see. thanks for posting! keep it coming!
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
Tigawoods
#7
did a bit of searching and found somewhat similar stories. others suggested that it could be fuel filter problem. IAC valve problem, or an o2 sensor problem.
mainly from this thread
http://www.6gc.net/forums/index.php?showto...4187&hl=TPS

now his car was running lean more so than mine is.
mine isnt running lean TOO much at all but it is still running lean. only from stop to start and at low rpm under load
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
Tigawoods
#9
bump.
cars finally home now
and i can start to check things out
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
Tigawoods
#10
so here is what i found after i opened everything up

the tension on the timing belt was loose.

i re-timed everything and the car ran. but it ran super super rich which is abnormal

i also noticed that the knocking noise at 1000rpm was actually the belt rattling due to lack of tension on the long stretch of belt btwn the tensioner and the oil pump gear.

after i started the car ran it, turned it off. checked the belt, it was loose again just like when i had opened it up in the beginning.

what do i do?
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
4-eyed-freek
#11
loose again? is it a new belt? are the teeth on the belt worn?
It takes 8,460 bolts to assemble an automobile, and one nut to scatter it all over the road.Celica: The name is derived from the Spanish word for "heavenly" or "celestial".Back-2-Back July COTM 15&16
Tigawoods
#12
the belts about 3yrs old. the teeth arent worn. im kind of thinking that it may be the tensioner spring. MAYBE
it seems fine but it might be off the tiniest bit
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
Smaay
#13
im going with the tensioner slipping.
2001 Celica GT-S Turbo1997 Supra TT 6speed1997 Celica 3MZ/1MZ swap1990 Celica All-Trac
presure2
#14
are you not tightening the tensioner bolt?
i would replace it, as well as the belt, if its been slipping.
Former Team 5SFTE pro member ;)13.6@108MPH, 5SFTE Powered
Tigawoods
#15
maybe im not tightening it enough?
replace the bolt or tensioner pulley?
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
presure2
#16
>
QUOTE (Tigawoods @ Jan 6, 2011 - 9:16 AM) *
>maybe im not tightening it enough?
replace the bolt or tensioner pulley?

is the tensioner slipping out of adjustment after you tighten it?
if it is, your prolly not tightening it enough, or the hole could be stripped?
make sure the threads are good, then use some blue loctite on the bolt when you install it.
if the pully on the tensioner is good, then there is no need to replace the tensioner.
Former Team 5SFTE pro member ;)13.6@108MPH, 5SFTE Powered
lagos
#17
Mike if you need a new timing belt and tensioner, we have them in stock at work. Pretty inexpensive and a great time to replace them for OEM. I doubt the ones that are on there now are OEM and could be part of the problem.

13568-09041 BELT, TIMING 26.10
90507-17003 SPRING, TENSIO 2.27
15PSI - 30MPG - Megasquirt Tuned
Tigawoods
#18
took out the bolt and about 1/8th of the hole is stripped.

the belt is only 3yrs old and its denso

This post has been edited by Tigawoods: Jan 6, 2011 - 11:39 AM
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
presure2
#19
>
QUOTE (Tigawoods @ Jan 6, 2011 - 11:38 AM) *
>took out the bolt and about 1/8th of the hole is stripped.

the belt is only 3yrs old and its denso

if the bolt hole still has enough threads for the bolt to bite down well, get a new belt, and use loctite on the bolt.
if not, i dont know if you will have the room to retap it for larger bolt, you'd prolly want to use a "timesert" or helicoil to fix it instead.
from what i've read, the timeserts work better than the helicoils.

and you, the KING of pics, with no pics???? WTF dude?! laugh.gif
seriously tho, pics would be sweet.
Former Team 5SFTE pro member ;)13.6@108MPH, 5SFTE Powered
Bitter
#20
I like time-sert better, install it with some 'liquid steel' epoxy so it's in permanently.
2000 Celica GTS 'slowest gts evar'1998 Mazda 626 FS-DE/CD4-E
Tigawoods
#21
well here is what i did.
i got a similar thread and size bolt from toyota from there bolt bucket (lol)
the stock bolt on the tensioner pulley only uses 50% of the the hole given
the bottom half of the hole had good threads on it so that holds great

the belt btwn the idler and oil pump has tension now

timed it and started it.
rich with the AFR at 10.
corrected the SAFC to -20 at idle which brought the AFR to 12.5 at start and when somewhat warm 13.5

checked the timing and the notch is showing up 1/8th of an inch past the 0 mark.
would that be cause for concern?
the car idles a tiny bit rough

what should i do now
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
presure2
#22
are you talking mechanical timing?
or checking timing with a timing light?
if its mechanical, you need to reset the timing again.
if your checking timing with a light, you need to let it fully come up to temp, bridge e1 and te1 in the diagnostics box, then adjust the distributor till it is at 10*BTDC.
Former Team 5SFTE pro member ;)13.6@108MPH, 5SFTE Powered
Tigawoods
#23
with the light yeah.
cool ill do that now then
thank ya thank ya
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
Tigawoods
#24
all together timed and running again and guess what....no change.
the belt flapping noise is gone now that there is even tension, but just like in post 1 the car is still faltering under load in everygear except 1st.

when i first drove the car after i had fixed it, drove down to the highway and got on and did a little pull and didnt have a single problem. stopped by pep boys came out and got back in and then drove it again and the old problems arose.

tps senor?

my exhaust has gone to crap, could that be an adding factor?

iac valve?

clogged fuel injector?

FPR?

fuel filter?

the car runs fine when driving regular. AFR is perfect, just when under load

This post has been edited by Tigawoods: Jan 15, 2011 - 10:40 AM
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
lagos
#25
Have you checked the safc setup to make sure its on the right car/cyl/sensor setup and that the electrical connections to the ECU are in good shape?

What are you using to monitor AFR?

Did you use a timing light to correctly set the ignition (not mechanical) timing to 10TDC with the ecu in diagnostic mode by having TE and E1 bridged in the diagnostic box with the check engine light blinking?

What type of corrections did you put into the safc in the low and high throttle maps?

This post has been edited by lagos: Jan 15, 2011 - 11:32 AM
15PSI - 30MPG - Megasquirt Tuned
Tigawoods
#26
all the car/cyl/sensor adj. are the same as they where when we first plugged it in back in KOP

havent checked the ecu

i have a prosport wideband AFR Gauge

set the timing to 10 BTDC with the distributor and the timing light. it was in diagnostic mode.

the corrections that i am running now are ALOT different than what i was running when i first had the cams running right.

at idle im at -20% to get it from running rich. at a cold start its at 12.5 then gradually goes to 14 after. still at -20%
i have a curve from that to 0% from idle to about 2800rpm

the mid range is perfect without correction

at the top end from 3600+ i have a 17% correction.
the afr hold at 14 with that correction under maybe 50% throttle. under full load it goes to 12.5 then eventually 11 when it gets closer to redline
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
Tigawoods
#27
to add to the previous post.
the car is timed right and is running fine at idle (with -17% correction on the SAFC)

the original problem is still occurring
at about 45 percent throttle at any RPM in 2nd gear to 5th
engine stutters, as if its not getting spark or enough fuel, i dont know.


cant really fix anything right now since i brought the car to school and it is under a foot of snow lol
1995 GT::::Diffusing the Situationエキサイティングカーレーシングチーム!march2010 COTM:6GCfeature2014:january2015-2016-2018 COTM
lagos
#28
>
QUOTE
>engine stutters, as if its not getting spark or enough fuel, i dont know.


The wideband you have will tell you if its fuel or spark related. Just watch the wideband when the issue occours. If it pegs lean, its fuel.
15PSI - 30MPG - Megasquirt Tuned
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