intermittent thumping(?) from motor
11-26-13, 11:34 AM
#1
intermittent thumping(?) from motor
not exactly sure how to describe this...
you can hear it every time it makes the sound. it stops for a second then starts up again. anyone have any idea what i should be looking at?
full non-seq
stock twins
intake
blitz smic
power fc
stock fuel
stock cat
omp delete running pre-mix (not sure if thats relevant)
you can hear it every time it makes the sound. it stops for a second then starts up again. anyone have any idea what i should be looking at?
full non-seq
stock twins
intake
blitz smic
power fc
stock fuel
stock cat
omp delete running pre-mix (not sure if thats relevant)
11-26-13, 02:02 PM
#2
i watched your vid a few times...sounds like a timing issue by the way it idles or even too rich of at idle. what's your tune look like? fuel and timing maps? do you have a wideband to confirm its running rich?
Last edited by ondabirdhouse; 11-26-13 at 02:06 PM.
11-26-13, 02:07 PM
#3
BRAP BRAP BRAP...
Join Date: Mar 2008
Location: Plano, Texas
Posts: 424
Likes: 0
Received 0 Likes
on
0 Posts
Mine acts somewhat similar but there isn't a thud. It is more of a misfire at idle which for my port, is to be expected. I'm not very good at diagnosing these types of things but could it be a late burn? It sounds like it's trying to backfire at idle.
11-26-13, 02:34 PM
#4
Full Member
iTrader: (1)
Join Date: Sep 2012
Location: Lavagna (GE) Italy
Posts: 195
Likes: 0
Received 0 Likes
on
0 Posts
At first I think about a subwoofer XD
Idles seems not to be affected from this thumping.
Check injectors (especially primary) for leaking or bad spray pattern/wrong fuel quantity
remove Cat and see if something inside is moving (it's stupid but it's really fast to check)
Btw knock sensor say something? What about detonation?
Mine with a primary injectors dead can't idle well...but when idling make a similar noise becouse it' to lean....
Obviously my idle is really rough becouse only 1 of the primary have issues
Idles seems not to be affected from this thumping.
Check injectors (especially primary) for leaking or bad spray pattern/wrong fuel quantity
remove Cat and see if something inside is moving (it's stupid but it's really fast to check)
Btw knock sensor say something? What about detonation?
Mine with a primary injectors dead can't idle well...but when idling make a similar noise becouse it' to lean....
Obviously my idle is really rough becouse only 1 of the primary have issues
Trending Topics
11-26-13, 11:31 PM
#8
Rotary Enthusiast
My car sounds like that when i first start it again, after its been driven for awhile/fully up to temp,
then has been shut off; left to heat soak and started again.
It clears up when it gets fresh cool air into the intakes etc..that's what mine does anyway and i don't worry about it.
then has been shut off; left to heat soak and started again.
It clears up when it gets fresh cool air into the intakes etc..that's what mine does anyway and i don't worry about it.
11-26-13, 11:55 PM
#11
Mine does this to a lesser (quieter) degree when its started up from dead cold.
I am pretty sure that it is slightly rich and there is some fuel that makes it into the hot exhaust manifold and ignites in there, periodically, giving that noise.
It hasnt bothered the car and it does go away once it fully warms up. My injectors were all cleaned and tested a while back, and I dont think they are a cause. I think its just startup richness.
I am pretty sure that it is slightly rich and there is some fuel that makes it into the hot exhaust manifold and ignites in there, periodically, giving that noise.
It hasnt bothered the car and it does go away once it fully warms up. My injectors were all cleaned and tested a while back, and I dont think they are a cause. I think its just startup richness.
Thread
Thread Starter
Forum
Replies
Last Post