Weird shifting and throttle issues.
05-23-10, 09:57 PM
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Weird shifting and throttle issues.
This just started happening a couple of days ago. The transmission has been shifting into fourth gear and O/D far too early, by the time I reach 25mph.
If I put the accelerator pedal to the floor it will not downshift and will accelerate very slowly since it's already in a high gear.
The kick-down switch and Power ECT do nothing.
It down-shifts perfectly fine when I brake or slow down and up-shifts smoothly, but way too fast. This doesn't seem to be something to do with the transmission at all. I changed the fluid and filter out a couple of months ago and it has worked flawlessly until now. Disconnecting the battery overnight did absolutely nothing.
What would cause this?
If I put the accelerator pedal to the floor it will not downshift and will accelerate very slowly since it's already in a high gear.
The kick-down switch and Power ECT do nothing.
It down-shifts perfectly fine when I brake or slow down and up-shifts smoothly, but way too fast. This doesn't seem to be something to do with the transmission at all. I changed the fluid and filter out a couple of months ago and it has worked flawlessly until now. Disconnecting the battery overnight did absolutely nothing.
What would cause this?
05-24-10, 06:33 PM
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Duh! Why didn't I think of that. Thanks! But would this cause the car to shift up too fast? I barely depress the accelerator and the car just upshifts immediately usually going through all gears up to 4th within a few seconds.
Oh, and my idle speed is at 1700RPM, ridiculously high. I already replaced the TPS and that did nothing.
Oh, and my idle speed is at 1700RPM, ridiculously high. I already replaced the TPS and that did nothing.
Last edited by Sixdown; 05-24-10 at 06:40 PM.
05-24-10, 08:12 PM
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Duh! Why didn't I think of that. Thanks! But would this cause the car to shift up too fast? I barely depress the accelerator and the car just upshifts immediately usually going through all gears up to 4th within a few seconds.
Oh, and my idle speed is at 1700RPM, ridiculously high. I already replaced the TPS and that did nothing.
Oh, and my idle speed is at 1700RPM, ridiculously high. I already replaced the TPS and that did nothing.
I noticed that once the car warms up there's exhaust smoke coming up from the back of the engine bay. It seems my EGR could be at fault for the high idle then...
Any ideas? The car shifts too fast, drives like crap, and has a ridiculous idle.
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05-27-10, 05:10 PM
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So it didn't end up being the AFM. The issue went away for a day and then reappeared again. I'm starting to suspect an ECU issue. Does the LS400 have a Transmission control unit?
05-29-10, 02:01 PM
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The weird shifting issue occurred after a mechanic of a friend of mine messed with my throttle housing. Maybe he messed something up there, although I know that the throttle cables are all adjusted. The high idle issue seems to be a separate problem.
05-31-10, 12:24 PM
#11
You say the throttle cable has been adjusted but was the kick down cable to the transmission also adjusted as I had exactly the same problem on mine after replacing the starter motor and it was due to this cable not being correctly re-adjusted.
You pull off and the gear change is very fast into OD and you get a thump as the gears change?
You pull off and the gear change is very fast into OD and you get a thump as the gears change?
05-31-10, 05:47 PM
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You say the throttle cable has been adjusted but was the kick down cable to the transmission also adjusted as I had exactly the same problem on mine after replacing the starter motor and it was due to this cable not being correctly re-adjusted.
You pull off and the gear change is very fast into OD and you get a thump as the gears change?
You pull off and the gear change is very fast into OD and you get a thump as the gears change?
UPDATE. Just went out to check the cable and it was certainly way too loose. I adjusted it and took it for a test-drive and it shifts completely normally...for now. Now I really need to figure out why my idle is incredibly high. I'm burning ridiculous amounts of gas sitting in traffic.
Last edited by Sixdown; 05-31-10 at 06:32 PM.
06-01-10, 08:30 AM
#13
Glad you sorted the gear shift problem. As for the fast idle have you removed the air ducting to see if the throttle butterfly is completely closed in the throttle body at idle?(If the throttle cable from the pedal has been over adjusted it may be preventing the butterfly closing completely hence the high idle speed) Also when you replaced the TPS did you set it back up correctly?
At least you are 50% there now!
At least you are 50% there now!
