Still stumped on acceleration lag..
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Instructor
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Still stumped on acceleration lag..
So I've tried to do my timing, but I can't find the marks for the life of me. Still haven't tried that white out trick though...but I just finished doing a tune up yesterday and was hoping that it would somehow help the problem I've been having. Ever since I baught my 85 months ago it's always had an acceleration lag to it. When I'm driving (even at a low speed like 20 mph) and I give it a decent amount of gas, the rpm will raise but it will take a second to put the power to the wheels...still stumped on what it could be...thanks for any help again guys appreciate all of it!
Team Owner
Joined: Aug 2004
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From: Park City Utah
Sounds like a typical automatic transmission down shifting...then going, to me. If the RPM's go up right away, doesn't sound like the motor is the problem.
What happens if you put the shifter in "low"/1 (1st gear) run it up to, say, 2000 RPM, then punch it?
What happens if you put the shifter in "low"/1 (1st gear) run it up to, say, 2000 RPM, then punch it?
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Instructor
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I'm not able to do that because the leather on the shifter clumps up when I try to put it into 1st low so it goesnt go all the way back...would putting it in low drive be the same thing?
Last edited by Mike1985; Nov 12, 2014 at 06:59 PM.
Le Mans Master
Joined: Jan 2006
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From: Orlando FL
A new boot might fix that problem if you wanted like new operation.
Sounds like on an 85 the clutches might be slipping.
Does it have lock up on the torque converter? Then try the test at 50 mph and see if there is slippage.
Last edited by pcolt94; Nov 13, 2014 at 01:19 PM.
Race Director
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From: Anaheim CA
Did you attach the timing light to #1 spark plug wire? It's fairly easy to get it on #3 if you're not paying attention.
If the above fails to resolve your issue then it's possible that the outer ring of the harmonic balancer has shifted.
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Did you open the EST connector (tan wire with black stripe) next to the windshield wiper motor? If you don't then the ECM will put in 20° of advance and you will not be able to see the timing mark.
Did you attach the timing light to #1 spark plug wire? It's fairly easy to get it on #3 if you're not paying attention.
If the above fails to resolve your issue then it's possible that the outer ring of the harmonic balancer has shifted.
Did you attach the timing light to #1 spark plug wire? It's fairly easy to get it on #3 if you're not paying attention.
If the above fails to resolve your issue then it's possible that the outer ring of the harmonic balancer has shifted.
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Instructor
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Goodness, I have the same effect with my 94 going into the Low gear. Found out when the leather boot is off all works great locking into proper positions. I believe the leather is just getting stiff as our cars age and due to sun or heat. It's not a problem for me as I do have the [D] and the next two lower notches. I don’t race and it just fine for my use.
A new boot might fix that problem if you wanted like new operation.
Sounds like on an 85 the clutches might be slipping.
Does it have lock up on the torque converter? Then try the test at 50 mph and see if there is slippage.
A new boot might fix that problem if you wanted like new operation.
Sounds like on an 85 the clutches might be slipping.
Does it have lock up on the torque converter? Then try the test at 50 mph and see if there is slippage.
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Drifting
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Alberto-Italy
Safety Car
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From: SANTA CRUZ CA
Happened to me, so just a humble suggestion.........
Check the accelerator cable from the pedal to the cable end in the
engine bay for out-of-adjustment. Any slop will cause lag.
http://www.corvetteamerica.com/cf/di...ategoryid=X805
Check the accelerator cable from the pedal to the cable end in the
engine bay for out-of-adjustment. Any slop will cause lag.
http://www.corvetteamerica.com/cf/di...ategoryid=X805
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Instructor
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Tested this about 10 times today in D, it happened twice but then didn't do it the other times..
Team Owner
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From: Park City Utah
I suggested putting it in 1st gear, since there is no down shifting from first. If there was a delay in first, it would have to be your engine. In any gear higher than first, there will likely be a delay as the trans figures out which gear to shift to, executes the shift and then engages the clutches.
Chaos' car takes a second b/c he has that slow soggy e-throttle.
Oil Producer
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hey wanted to chime in here. if your boot is hard like mine, take the bezel off, u can either leave the boot on bezel like i did or remove, grab some "neets foot" oil from a leather tack shop, and use a brush or sponge or your hands and drench the inside of the boot. not the side you see when installed....the sueade side that is the backside of the leather. let it sit for a few days. it'll take a bit, but my leather soaked mine up like a sponge and i re applied a few times.
nice and supple now. and it was stiff as a board. there are a couple places that have cracks but u cant see them.
hope this helps somebody.....and yah.....of course a person could just buy a new boot but for some of us we need to put limited funds into other things.
ive been thinking this would work great on leather seats bug id have to get the leather off and apply from the inside out and seems like alot of work.
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Right....but the problem there is that the trans can and will likely down shift from "D" (3rd gear), down to second, or even first, depending on your road speed.
I suggested putting it in 1st gear, since there is no down shifting from first. If there was a delay in first, it would have to be your engine. In any gear higher than first, there will likely be a delay as the trans figures out which gear to shift to, executes the shift and then engages the clutches.
Chaos' car takes a second b/c he has that slow soggy e-throttle.
I suggested putting it in 1st gear, since there is no down shifting from first. If there was a delay in first, it would have to be your engine. In any gear higher than first, there will likely be a delay as the trans figures out which gear to shift to, executes the shift and then engages the clutches.
Chaos' car takes a second b/c he has that slow soggy e-throttle.
Team Owner
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From: Park City Utah
It's NOT normal for the engine to have a delay. '80's and '90's Corvette engines have incredibly good throttle response, so if the delay is your engine "doing nothing" for a few seconds after you punch it, that is not right. If the delay is the time it takes for your trans to shift, and the RPM to increase correspondingly, then that is normal.
My "test" that I've suggested it a way for you to isolate which it is; the engine, or the trans. W/the trans in first gear, it can't shift. There is no shifting and it would/should behave just like s stick shift car, in first gear. Get the car rolling in first gear, maybe 15 mph....hit the gas. Car should go as fast as you can get your foot to the floor.
Le Mans Master
Joined: Oct 2008
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From: Houston Texas
It's normal for the automatic transmission to have a delay, while it goes through an operation of shifting gears.
It's NOT normal for the engine to have a delay. '80's and '90's Corvette engines have incredibly good throttle response, so if the delay is your engine "doing nothing" for a few seconds after you punch it, that is not right. If the delay is the time it takes for your trans to shift, and the RPM to increase correspondingly, then that is normal.
My "test" that I've suggested it a way for you to isolate which it is; the engine, or the trans. W/the trans in first gear, it can't shift. There is no shifting and it would/should behave just like s stick shift car, in first gear. Get the car rolling in first gear, maybe 15 mph....hit the gas. Car should go as fast as you can get your foot to the floor.
It's NOT normal for the engine to have a delay. '80's and '90's Corvette engines have incredibly good throttle response, so if the delay is your engine "doing nothing" for a few seconds after you punch it, that is not right. If the delay is the time it takes for your trans to shift, and the RPM to increase correspondingly, then that is normal.
My "test" that I've suggested it a way for you to isolate which it is; the engine, or the trans. W/the trans in first gear, it can't shift. There is no shifting and it would/should behave just like s stick shift car, in first gear. Get the car rolling in first gear, maybe 15 mph....hit the gas. Car should go as fast as you can get your foot to the floor.
Bingo ..OP is this your first Automatic? The converter also has a stall built in, stock is somewhere from 1500-2000 IRC.Mine has a 3500RPM stall
Last edited by ch@0s; Nov 14, 2014 at 11:21 AM.
Thread Starter
Instructor
Joined: Aug 2014
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It's normal for the automatic transmission to have a delay, while it goes through an operation of shifting gears.
It's NOT normal for the engine to have a delay. '80's and '90's Corvette engines have incredibly good throttle response, so if the delay is your engine "doing nothing" for a few seconds after you punch it, that is not right. If the delay is the time it takes for your trans to shift, and the RPM to increase correspondingly, then that is normal.
My "test" that I've suggested it a way for you to isolate which it is; the engine, or the trans. W/the trans in first gear, it can't shift. There is no shifting and it would/should behave just like s stick shift car, in first gear. Get the car rolling in first gear, maybe 15 mph....hit the gas. Car should go as fast as you can get your foot to the floor.
It's NOT normal for the engine to have a delay. '80's and '90's Corvette engines have incredibly good throttle response, so if the delay is your engine "doing nothing" for a few seconds after you punch it, that is not right. If the delay is the time it takes for your trans to shift, and the RPM to increase correspondingly, then that is normal.
My "test" that I've suggested it a way for you to isolate which it is; the engine, or the trans. W/the trans in first gear, it can't shift. There is no shifting and it would/should behave just like s stick shift car, in first gear. Get the car rolling in first gear, maybe 15 mph....hit the gas. Car should go as fast as you can get your foot to the floor.