trying to track down noise; driving me crazy!
03-27-2005, 06:55 PM
#1
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trying to track down noise; driving me crazy!
I realise this is going to be hard to diagnose, but I thought: run it by you guys; you never know!
The noise happens only at full throttle acceleration.
Sounds like heavy detonation; like heavy pinging, rattling.
It can't be detonation, because the head gasket would've blown by now, and the KLR should've cut timing/boost long before this rattling is allowed to continue for the length of time it does (sometimes the rattle goes on for the entire time I put my right foot into it in, let's say, 4th gear); also, the noise seems to come from some place other than the engine compartment. (Am I to assume correctly, that if it was detonation, I would hear it from the engine compartment only?)
My wrench and I have looked to see if a heat shield is being hit somewhere.
When under load the engine tilts/torques slightly toward passenger side and we looked to see if this causes any kind of contact somewhere. Any possible locations of contact we addressed by removing/ bending, etc. but we haven't gone through the entire car.
Anybody know where to look? What could we be missing?
Anybody experienced something similar?
It seems to be happening more when there's good traction, like in the upper gears (lots of load on the car). Sometimes, the rattle is only for a second, sometimes for a stretch of 3 to 5 seconds!
Could it be something in the transmission of power; let's say, from the driveshaft all the way until the power hits the ground? The CV joints feel fine and we can't seem to see anything loose by the brakes, etc.
It does absolutely does sound like heavy detonation. It can't be, could it?
I do have an O-ringed head. But, that doesn't mean it could withstand that kind of detonation without blowing the head gasket, could it?
Sorry for the long post; it's just driving me crazy!
I would appreciate any kind of hints; any at all.
The noise happens only at full throttle acceleration.
Sounds like heavy detonation; like heavy pinging, rattling.
It can't be detonation, because the head gasket would've blown by now, and the KLR should've cut timing/boost long before this rattling is allowed to continue for the length of time it does (sometimes the rattle goes on for the entire time I put my right foot into it in, let's say, 4th gear); also, the noise seems to come from some place other than the engine compartment. (Am I to assume correctly, that if it was detonation, I would hear it from the engine compartment only?)
My wrench and I have looked to see if a heat shield is being hit somewhere.
When under load the engine tilts/torques slightly toward passenger side and we looked to see if this causes any kind of contact somewhere. Any possible locations of contact we addressed by removing/ bending, etc. but we haven't gone through the entire car.
Anybody know where to look? What could we be missing?
Anybody experienced something similar?
It seems to be happening more when there's good traction, like in the upper gears (lots of load on the car). Sometimes, the rattle is only for a second, sometimes for a stretch of 3 to 5 seconds!
Could it be something in the transmission of power; let's say, from the driveshaft all the way until the power hits the ground? The CV joints feel fine and we can't seem to see anything loose by the brakes, etc.
It does absolutely does sound like heavy detonation. It can't be, could it?
I do have an O-ringed head. But, that doesn't mean it could withstand that kind of detonation without blowing the head gasket, could it?
Sorry for the long post; it's just driving me crazy!
I would appreciate any kind of hints; any at all.
03-27-2005, 11:42 PM
#3
Nordschleife Master
Excellent, a new noise quest!!!
The dme should cut back if heavy detonation is taking place, so i doubt it's that.
Does your mechanic really know these cars?
I have to wonder about the cvs.
Take it to another mechanic to let them drive it, it won't cost you anything.
The dme should cut back if heavy detonation is taking place, so i doubt it's that.
Does your mechanic really know these cars?
I have to wonder about the cvs.
Take it to another mechanic to let them drive it, it won't cost you anything.
03-28-2005, 12:24 AM
#4
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I will give you a shot on the dark! Check your windsheild rubber gasket along the upper windsheild edge. It was a noise that was hard to pin down. It sounded like it was coming from the engine/firewall or a heat shield. If you find that some of the rubber is loose put some black electricial tape on it to hold it down and go for a ride. This noise was dependent on speed and cross winds until more of it loosened up and then it would start to come in at specific speeds.
03-28-2005, 02:22 AM
#5
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Thread Starter
Yes, Peckster, a new noise quest that's definitely a PITA!
I'll have to get someone else to drive it.
Special,
what chips I have doesn't mean much.
However, I must admit, that in the interest of maximum power, this is a detonation friendly setup; which is why I'm a little scared:
3 liter, 9 to 1 compression, aggressive timing, 16 psi boost, and a not too rich air/fuel of 12.4 to 12.7
However, I'm using water/methanol injection, and like I said before, wouldn't the KLR have thrown in its' safety measures.
I have retained the stock DME/KLR, knock sensor, and CV.
Is there any way that, even though I have kept these stock knock control components, that my knock control might not be working? I understand that if the knock sensor and/or the KLR are not connected properly, I wouldn't even be able to make boost.
I have wondered about those of you that have stand alone, how knock control is integrated?
I'll have to get someone else to drive it.
Special,
what chips I have doesn't mean much.
However, I must admit, that in the interest of maximum power, this is a detonation friendly setup; which is why I'm a little scared:
3 liter, 9 to 1 compression, aggressive timing, 16 psi boost, and a not too rich air/fuel of 12.4 to 12.7
However, I'm using water/methanol injection, and like I said before, wouldn't the KLR have thrown in its' safety measures.
I have retained the stock DME/KLR, knock sensor, and CV.
Is there any way that, even though I have kept these stock knock control components, that my knock control might not be working? I understand that if the knock sensor and/or the KLR are not connected properly, I wouldn't even be able to make boost.
I have wondered about those of you that have stand alone, how knock control is integrated?
03-28-2005, 02:46 AM
#6
Burning Brakes
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How about turning the boost down to ~14 psi and taking the car for a run. It should still run strong and torque on the engine, so if it is some mechanical contact that should still occur. However, if it is detonation simply turning down the boost 2 psi should solve it since you will be leaving the chips alone the mixture will be more rich and there will be (duh) less boost.
HTH,
John
HTH,
John
03-28-2005, 10:49 AM
#7
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It's hard to say sitting at the computer what that noise is, but my guess would be detonation, like Johne sad turn down the boost and see if you still get the noise.
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03-28-2005, 01:51 PM
#8
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TT,
Since we have a transaxle, the engine twisting should be limited to how much the engine torque can twist the steel torque tube, which I suspect to be very little. However, I think the motion upward would be somewhat more, but more so in lower gears.
If you hear detonation and the timing compensation is working then the pinging/rattling should start out loud and immediately be reduced to a lower level or disappear. Supposedly (I have not tried it yet) you can test the knock detection system by tapping on the sensor during idle and hear an idle stumble.
If it is a heat shield rattling, then I see no other way than to go through each and every shield manually either with a rubber hammer or deflect it with a finger at the edge and let it go to initiate a vibration.
Apparently you got your engine repaired and much more so. Do you have a reference to more details (process, parts used, performance, etc.)??
Laust
Since we have a transaxle, the engine twisting should be limited to how much the engine torque can twist the steel torque tube, which I suspect to be very little. However, I think the motion upward would be somewhat more, but more so in lower gears.
If you hear detonation and the timing compensation is working then the pinging/rattling should start out loud and immediately be reduced to a lower level or disappear. Supposedly (I have not tried it yet) you can test the knock detection system by tapping on the sensor during idle and hear an idle stumble.
If it is a heat shield rattling, then I see no other way than to go through each and every shield manually either with a rubber hammer or deflect it with a finger at the edge and let it go to initiate a vibration.
Apparently you got your engine repaired and much more so. Do you have a reference to more details (process, parts used, performance, etc.)??
Laust
03-28-2005, 07:56 PM
#9
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Thread Starter
Johne,
that's a very good suggestion; this way I would rule out the detonation.
Although, the more I think about it, it can't be detonation. Also, I pulled the sparkplugs today and they all looked good. If it was detonation (that severe), you'd see something on the plugs.
Laust,
thanks for responding; don't know for sure what you mean by your last question (I just sold my old engine and bought another one and have to iron out some bugs)
Yeah, I think I'm going to pull every freakin' heat shield, then drive the car, and do process of elimination. This is insane!
Upon a fairly thorough visual inspection we can't find any probable contact points that would cause this rattle.
I'm wondering if the torque from the engine is overwhelming something; something in the drivetrain is twisting too much causing it to hit something; maybe in the transaxle? But then, it wouldn't have this rattling noise because oil and grease on the transmission components would really dull the sound, wouldn't it? Wasn't there a consensus at one point that the stock transmission can only handle so much power?
Anybody, any thoughts?
By the way, motor mounts are good
that's a very good suggestion; this way I would rule out the detonation.
Although, the more I think about it, it can't be detonation. Also, I pulled the sparkplugs today and they all looked good. If it was detonation (that severe), you'd see something on the plugs.
Laust,
thanks for responding; don't know for sure what you mean by your last question (I just sold my old engine and bought another one and have to iron out some bugs)
Yeah, I think I'm going to pull every freakin' heat shield, then drive the car, and do process of elimination. This is insane!
Upon a fairly thorough visual inspection we can't find any probable contact points that would cause this rattle.
I'm wondering if the torque from the engine is overwhelming something; something in the drivetrain is twisting too much causing it to hit something; maybe in the transaxle? But then, it wouldn't have this rattling noise because oil and grease on the transmission components would really dull the sound, wouldn't it? Wasn't there a consensus at one point that the stock transmission can only handle so much power?
Anybody, any thoughts?
By the way, motor mounts are good
03-28-2005, 08:41 PM
#10
The torque from you engine is not overwhelming your transmission - especially with open diff.
Also - why is it that you think it can't be detonation? You have ruled it out?
You have 9:1 compression, aggressive timing , pump gas and 16 psi boost?
What is your water/fuel mass ratio at 16 psi boost?
Also - why is it that you think it can't be detonation? You have ruled it out?
You have 9:1 compression, aggressive timing , pump gas and 16 psi boost?
What is your water/fuel mass ratio at 16 psi boost?
03-29-2005, 05:49 PM
#11
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Thread Starter
Yeah, I've ruled out detonation.
If a driver was to hear that intense of an engine rattle (as described in previous post) from the cockpit at speed, you can imagine what would've happened to the engine by now! This has been going on for awhile.
If a driver was to hear that intense of an engine rattle (as described in previous post) from the cockpit at speed, you can imagine what would've happened to the engine by now! This has been going on for awhile.
