An Engine Noise Mystery Quiz
August 14th, 2012, 11:06 AM
#41
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I was told the H2O hydraulic screwtinator had been replaced when they replaced the piston return springs.
August 14th, 2012, 11:21 AM
#42
"Car"mudgeon
Join Date: Feb 2011
Location: Perry, GA
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Seriously if it's not electrical, not vapor lock and not on the engine then I am clueless here I think
August 14th, 2012, 11:40 AM
#47
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Okay, I've had time to think about it a bit.
Any "cutting out" problem makes me think immediately of an electrical problem, like a misplaced wire from the recent points / condenser change touching ground randomly, but you said it isn't ignition, so that eliminates that thought.
The next thing is fuel starvation. It doesn't exactly translate to "cutting out," but customers / wives will describe a problem in lots of inaccurate ways.
How about bad / disintegrated fuel intake sock in the fuel tank, combined with some foreign gunk in the tank? When there's a decent amount of fuel pump suction, it pulls in the gunk and blocks the intake, causing the car to stall. After a few minutes, the gunk is released back into the tank and the intake is cleared.
On rainy days, the customer drives more slowly and cautiously, so less fuel flow is developed, and gunk doesn't get drawn in.
A '71 Nova should not have a fuel return line, so flow will vary, as I described.
- Eric
Any "cutting out" problem makes me think immediately of an electrical problem, like a misplaced wire from the recent points / condenser change touching ground randomly, but you said it isn't ignition, so that eliminates that thought.
The next thing is fuel starvation. It doesn't exactly translate to "cutting out," but customers / wives will describe a problem in lots of inaccurate ways.
How about bad / disintegrated fuel intake sock in the fuel tank, combined with some foreign gunk in the tank? When there's a decent amount of fuel pump suction, it pulls in the gunk and blocks the intake, causing the car to stall. After a few minutes, the gunk is released back into the tank and the intake is cleared.
On rainy days, the customer drives more slowly and cautiously, so less fuel flow is developed, and gunk doesn't get drawn in.
A '71 Nova should not have a fuel return line, so flow will vary, as I described.
- Eric
August 14th, 2012, 11:42 AM
#48
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Okay, I've had time to think about it a bit.
Any "cutting out" problem makes me think immediately of an electrical problem, like a misplaced wire from the recent points / condenser change touching ground randomly, but you said it isn't ignition, so that eliminates that thought.
The next thing is fuel starvation. It doesn't exactly translate to "cutting out," but customers / wives will describe a problem in lots of inaccurate ways.
How about bad / disintegrated fuel intake sock in the fuel tank, combined with some foreign gunk in the tank? When there's a decent amount of fuel pump suction, it pulls in the gunk and blocks the intake. After a few minutes, the gunk is released back into the tank and the intake is cleared.
On rainy days, the customer drives more slowly and cautiously, so less fuel flow is developed, and gunk doesn't get drawn in.
A '71 Nova should not have a fuel return line, so flow will vary, as I described.
- Eric
Any "cutting out" problem makes me think immediately of an electrical problem, like a misplaced wire from the recent points / condenser change touching ground randomly, but you said it isn't ignition, so that eliminates that thought.
The next thing is fuel starvation. It doesn't exactly translate to "cutting out," but customers / wives will describe a problem in lots of inaccurate ways.
How about bad / disintegrated fuel intake sock in the fuel tank, combined with some foreign gunk in the tank? When there's a decent amount of fuel pump suction, it pulls in the gunk and blocks the intake. After a few minutes, the gunk is released back into the tank and the intake is cleared.
On rainy days, the customer drives more slowly and cautiously, so less fuel flow is developed, and gunk doesn't get drawn in.
A '71 Nova should not have a fuel return line, so flow will vary, as I described.
- Eric
August 14th, 2012, 12:02 PM
#49
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Okay, fine.
Fuel filter or fuel line clog / obstruction reducing fuel flow to the bare minimum required to drive conservatively in the rain, but when more than that is demanded, the float bowl empties and the car dies. It can be refilled slowly by cranking, and then you're off again.
- Eric
Fuel filter or fuel line clog / obstruction reducing fuel flow to the bare minimum required to drive conservatively in the rain, but when more than that is demanded, the float bowl empties and the car dies. It can be refilled slowly by cranking, and then you're off again.
- Eric
There's a more in-depth reply in the 
August 14th, 2012, 12:34 PM
#53
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OK, here is what was going on. A few good thoughts were given and some were close in nature.
This car was driven on a driveway that must not have been paved. It was a little dirty underneath and there was a 2" section of metal fuel line back near the front of the leaf spring that was encapsulated in mud. In trying to figure this out, I was looking over the fuel line and found a very faint stain on the frame rail where the mud was covering the line. As it tuned out, the line had started to rust and it had a small hole in it which became visible when the mud was removed. The hole would cause a loss of suction so the pump wasn't always able to pick up fuel from the tank. When it rained and the dirt was wet it did a good job of sealing off the hole. I suspect when the car sat for a few minutes the fuel would start to run into the line and the hole would leak a little fuel and hence the stain that was somewhat visible. When the line became filled the car would start again. Not sure of exactly why everything worked as it did when the dirt was dry. The bad section was removed and a piece of hose was clamped in place and the problem never came back.
This car was driven on a driveway that must not have been paved. It was a little dirty underneath and there was a 2" section of metal fuel line back near the front of the leaf spring that was encapsulated in mud. In trying to figure this out, I was looking over the fuel line and found a very faint stain on the frame rail where the mud was covering the line. As it tuned out, the line had started to rust and it had a small hole in it which became visible when the mud was removed. The hole would cause a loss of suction so the pump wasn't always able to pick up fuel from the tank. When it rained and the dirt was wet it did a good job of sealing off the hole. I suspect when the car sat for a few minutes the fuel would start to run into the line and the hole would leak a little fuel and hence the stain that was somewhat visible. When the line became filled the car would start again. Not sure of exactly why everything worked as it did when the dirt was dry. The bad section was removed and a piece of hose was clamped in place and the problem never came back.
August 14th, 2012, 12:38 PM
#54
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The other one I can throw out there will need to wait until tomorrow. But before I do so, it involves a 1992 Olds Cutlass Ciera. Is that too new or do you guys want to mull this one over? Not sure how much everyone wants to talk computers and sensors etc. Let me know and if there is interest I will do it tomorrow.
August 14th, 2012, 12:43 PM
#55
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August 14th, 2012, 12:55 PM
#56
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August 14th, 2012, 12:57 PM
#57
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I think anything computer controlled is going to give too many variables for diagnosing over the web. Then again, it'd be a cool challenge...As long as it's not something like mud caked fuel line with rust holes that seal on Wednesdays and Fridays when it rains and is sunny at the same time but only when person X is driving and they're eating a Big Mac and a ICEE while texting on the phone to a foreign dignitary about nuclear powered easy bake ovens 
August 14th, 2012, 02:10 PM
#58
Big Daddy No Bucks
Join Date: Jul 2010
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I think anything computer controlled is going to give too many variables for diagnosing over the web. Then again, it'd be a cool challenge...As long as it's not something like mud caked fuel line with rust holes that seal on Wednesdays and Fridays when it rains and is sunny at the same time but only when person X is driving and they're eating a Big Mac and a ICEE while texting on the phone to a foreign dignitary about nuclear powered easy bake ovens
But I found & bought a single TSB at a yard sale years ago & it deals with those exact issues to a "T"".
Are you telling me now that I finally found an opportunity to use it ... I won't be able to ?.
August 14th, 2012, 06:28 PM
#59
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I think anything computer controlled is going to give too many variables for diagnosing over the web. Then again, it'd be a cool challenge...As long as it's not something like mud caked fuel line with rust holes that seal on Wednesdays and Fridays when it rains and is sunny at the same time but only when person X is driving and they're eating a Big Mac and a ICEE while texting on the phone to a foreign dignitary about nuclear powered easy bake ovens
No, it won't get into any crazy computer stuff. Actually, I will spell out most of what was going on and how the various systems worked and what wasn't working and see if anyone has any thoughts. It will be an interesting read.
August 15th, 2012, 04:41 AM
#60
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Here goes with the 1992 Cutlass Ciera. This car was my company car and I picked it up new. 3.3 V6, auto trans and most power options. The car was problem free up to 13,000 miles when I began to experience intermittent (yep..here we go again) torque converter locking and unlocking while driving. I could be driving along at 60 mph and the converter would just start to unlock and then lock. This may go on for several minutes and then not return for a few weeks. One night after a sales meeting/dinner, I was on the way home and I had the cruise set at 50. I was just sitting back, feet away from the pedals (won’t do that anymore) and one car about 6 cars lengths ahead of me. Suddenly, the car just goes full throttle, kicking down into passing gear and I got pretty close to the car in front of me before I was able to jump on the brakes. Since it was dark and the headlights were on, the guy in front of me must have wondered what I was doing. And Toyota thinks they have the market cornered on sudden acceleration. Heck, Olds was 20 years ahead of them…. LOL! Being that it had 13K miles, I was just out of warranty. I took it to the dealer who said they would cover it under warranty given the odd nature of the problem. Since it was intermittent, they had a hell of a time duplicating this. No codes were in the computer either. I did experience the sudden acceleration several more times after that but always had my foot near the brake when I set the cruise. And hitting the brakes always made it stop. One day I was on 95 and no one was around so I thought I would let it go to see how long it would continue. At 80mph I hit the brakes as it was still full throttle. I know this is a tough one to throw out there and I won’t let this hang out there too long. I’ll be busy for a few hours this morning but will check back later this morning to see what thoughts are offered.
Brian
Brian
August 15th, 2012, 05:42 AM
#62
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I think this will lead to more ideas by explaining it in this manner and that will be to give the answer now. So I’ll do this backwards. The answer to this was…there was no solution. Oldsmobile ended up buying the car back as neither the dealer nor the techs in MI who were talking with the dealer techs could figure it out. The car was taken to the dealer about a dozen times over a year’s time and they threw everything at this that they could think of. But they didn’t replace one part that I think may have been the problem. So I’m taking suggestions on what this part was. Maybe it was the problem, maybe not….Olds sure didn’t seem to know. When they bought the car back from my employer, it had 57K miles. They refunded all money less $0.10/mile for the first 13K miles, which was the point when the problem showed up.
The converter and sudden acceleration are related. The way everything works is there is a speed transducer on the back of the speedo. That generates a signal between 0 and 5 volts DC depending on vehicle speed that is sent to the computer. Depending on voltage (and other inputs) certain functions happen. It will know when to lock the converter and the voltage value also represents vehicle speed. One day when it was acting up I went straight to the dealer and the tech jumped in, connected the scan tool and we took a ride. We watched the voltage reading jump all over the place. When it went to 0, the converter unlocked. When voltage came back, it locked. But then we also saw voltage drop to a low number rather than 0. When that happened and the cruise was set, the computer though the car had slowed dramatically which caused the sudden acceleration. Over the year’s time, the dealer installed 3 computers, 2 dash harnesses, 3 speed transducers, 2 printed circuit boards and a completely new speedo with transducer. I was told they were shipping the car back to MI so the engineers and techs at Olds could look it over and I never heard any more about it. The company bought a new 94 Ciera from that dealer and that car was flawless for 90K miles when it was sold for my next car.
As mentioned above, in my mind, there was one more part in that system which controls the torque converter and cruise control functions that wasn’t replaced. Pure speculation at this point. Thoughts?
The converter and sudden acceleration are related. The way everything works is there is a speed transducer on the back of the speedo. That generates a signal between 0 and 5 volts DC depending on vehicle speed that is sent to the computer. Depending on voltage (and other inputs) certain functions happen. It will know when to lock the converter and the voltage value also represents vehicle speed. One day when it was acting up I went straight to the dealer and the tech jumped in, connected the scan tool and we took a ride. We watched the voltage reading jump all over the place. When it went to 0, the converter unlocked. When voltage came back, it locked. But then we also saw voltage drop to a low number rather than 0. When that happened and the cruise was set, the computer though the car had slowed dramatically which caused the sudden acceleration. Over the year’s time, the dealer installed 3 computers, 2 dash harnesses, 3 speed transducers, 2 printed circuit boards and a completely new speedo with transducer. I was told they were shipping the car back to MI so the engineers and techs at Olds could look it over and I never heard any more about it. The company bought a new 94 Ciera from that dealer and that car was flawless for 90K miles when it was sold for my next car.
As mentioned above, in my mind, there was one more part in that system which controls the torque converter and cruise control functions that wasn’t replaced. Pure speculation at this point. Thoughts?
August 15th, 2012, 01:07 PM
#63
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My thoughts are that this was exactly something like mud caked fuel line with rust holes that seal on Wednesdays and Fridays when it rains and is sunny at the same time but only when person X is driving and they're eating a Big Mac and a ICEE while texting on the phone to a foreign dignitary about nuclear powered easy bake ovens. Only, there is no answer to the problem except to perform a gas cap overhaul.
August 15th, 2012, 01:29 PM
#64
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My thoughts are that this was exactly something like mud caked fuel line with rust holes that seal on Wednesdays and Fridays when it rains and is sunny at the same time but only when person X is driving and they're eating a Big Mac and a ICEE while texting on the phone to a foreign dignitary about nuclear powered easy bake ovens. Only, there is no answer to the problem except to perform a gas cap overhaul.
My thought was there was only one other device that would disconnect the cruise and also unlock the converter. We're all done this too. If you're cruising down the road and you want to knock the cruise off you can do by turning off the cruise switch or you can do one other thing. That thing has a switch. If the switch were defective, it could have caused the signal to be lost or be restricted. Brake light switch! There was basically nothing else in that electrical system that wasn't changed. We'll never know but that was what I thought it could be.
August 15th, 2012, 10:27 PM
#65
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Here's a tough one
'68 442
non-std engine- '67 425 HC 4-bbl
TH400
4.33 gears, posi
OAI not hooked up
If I depress the accelerator pedal more than just a little, a loud squeal emanates from the rear of the car. It will continue as long as the gas pedal is held down, usually. Sometimes the entire rear end of the car goes kind of sideways also when this noise is happening. Oftentimes a medium to large quantity of smoke will also be observed at the aft end of the car. Subsequent investigations usually reveal some sort of carbon leakage strips on the pavement, as if black paint or lamp soot has dripped from the car onto the asphalt. Also, this usually correlates to finding black zits or particles adhered to the lower section of the rear quarters, just aft of the wheels.
Letting up on the gas pedal seems to greatly diminish or even stop the squealing. It's so bad that sometimes it even attracts the attention of Law Enforcement Officers.
The tires look ok, if a bit worn. The brakes and bearings seem ok. It doesn't make this noise on the inspection rack, OF COURSE.
Like the 1-legged man said,
"I'm stumped!"
I think the Trunk Monkey is spilling his drink and smoking.
'68 442
non-std engine- '67 425 HC 4-bbl
TH400
4.33 gears, posi
OAI not hooked up
If I depress the accelerator pedal more than just a little, a loud squeal emanates from the rear of the car. It will continue as long as the gas pedal is held down, usually. Sometimes the entire rear end of the car goes kind of sideways also when this noise is happening. Oftentimes a medium to large quantity of smoke will also be observed at the aft end of the car. Subsequent investigations usually reveal some sort of carbon leakage strips on the pavement, as if black paint or lamp soot has dripped from the car onto the asphalt. Also, this usually correlates to finding black zits or particles adhered to the lower section of the rear quarters, just aft of the wheels.
Letting up on the gas pedal seems to greatly diminish or even stop the squealing. It's so bad that sometimes it even attracts the attention of Law Enforcement Officers.
The tires look ok, if a bit worn. The brakes and bearings seem ok. It doesn't make this noise on the inspection rack, OF COURSE.
Like the 1-legged man said,
"I'm stumped!"
I think the Trunk Monkey is spilling his drink and smoking.
Last edited by Octania; August 15th, 2012 at 10:31 PM.
August 16th, 2012, 05:21 AM
#66
I might be a case of plumbuminous pede in the steering wheel to pedals connectinator.
Adam
Last edited by arodenhiser; August 16th, 2012 at 05:32 AM.
August 16th, 2012, 07:31 AM
#67
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Here's a tough one
'68 442
non-std engine- '67 425 HC 4-bbl
TH400
4.33 gears, posi
OAI not hooked up
If I depress the accelerator pedal more than just a little, a loud squeal emanates from the rear of the car. It will continue as long as the gas pedal is held down, usually. Sometimes the entire rear end of the car goes kind of sideways also when this noise is happening. Oftentimes a medium to large quantity of smoke will also be observed at the aft end of the car. Subsequent investigations usually reveal some sort of carbon leakage strips on the pavement, as if black paint or lamp soot has dripped from the car onto the asphalt. Also, this usually correlates to finding black zits or particles adhered to the lower section of the rear quarters, just aft of the wheels.
Letting up on the gas pedal seems to greatly diminish or even stop the squealing. It's so bad that sometimes it even attracts the attention of Law Enforcement Officers.
The tires look ok, if a bit worn. The brakes and bearings seem ok. It doesn't make this noise on the inspection rack, OF COURSE.
Like the 1-legged man said,
"I'm stumped!"
I think the Trunk Monkey is spilling his drink and smoking.
'68 442
non-std engine- '67 425 HC 4-bbl
TH400
4.33 gears, posi
OAI not hooked up
If I depress the accelerator pedal more than just a little, a loud squeal emanates from the rear of the car. It will continue as long as the gas pedal is held down, usually. Sometimes the entire rear end of the car goes kind of sideways also when this noise is happening. Oftentimes a medium to large quantity of smoke will also be observed at the aft end of the car. Subsequent investigations usually reveal some sort of carbon leakage strips on the pavement, as if black paint or lamp soot has dripped from the car onto the asphalt. Also, this usually correlates to finding black zits or particles adhered to the lower section of the rear quarters, just aft of the wheels.
Letting up on the gas pedal seems to greatly diminish or even stop the squealing. It's so bad that sometimes it even attracts the attention of Law Enforcement Officers.
The tires look ok, if a bit worn. The brakes and bearings seem ok. It doesn't make this noise on the inspection rack, OF COURSE.
Like the 1-legged man said,
"I'm stumped!"
I think the Trunk Monkey is spilling his drink and smoking.
or install rear tires that have an adhesion value more closely matched with that of the road surface.
August 16th, 2012, 07:38 AM
#68
Adam
But wait..... I am still 4 wheel drums.... Hhmmmmmmm.....
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