Acceleration Faltering, Details 2nd page Options

[Tigawoods]

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

[bmj67]

have you checked you timing belt is correct and hasnt jumped tooth.

[Tigawoods]

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?

[lagos]

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.

[blu94gt]

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.

[Tigawoods]

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

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!

[Tigawoods]

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

[Tigawoods]

and this thread. which the result came to be the alternator
http://www.6gc.net/forums/index.php?showto...hl=TPS&st=0

[Tigawoods]

bump.
cars finally home now
and i can start to check things out

[Tigawoods]

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?

[4-eyed-freek]

loose again? is it a new belt? are the teeth on the belt worn?

[Tigawoods]

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

[Smaay]

im going with the tensioner slipping.

[presure2]

are you not tightening the tensioner bolt?
i would replace it, as well as the belt, if its been slipping.

[Tigawoods]

maybe im not tightening it enough?
replace the bolt or tensioner pulley?

[presure2]

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.

[lagos]

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

[Tigawoods]

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

[presure2]

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?!
seriously tho, pics would be sweet.

[Bitter]

I like time-sert better, install it with some 'liquid steel' epoxy so it's in permanently.