RPM rises 400 when doing 3 to 4 shift [MERGE]
Jan 24, 2004, 12:05 PM
#1
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throttle issue, anyone else experience anything like this?
I'm gonna try to explain this the best that I can, so bare with me.
What's happening is that whenever I shift at a decently high rpm (let's just say > 4500 or so) and whenever I let off the gas at such an rpm, the engine seems to 'hang' at that rpm for a second or so. This is causing me much distress because everytime I shift for example, I can't properly rev match the upshift because the rpms are higher than I'm expecting!
At first I though it was my foot action, a simple matter of coordination gone wrong. Then I started to notice that this was occuring even when I wasn't shifting! Hell I can reproduce it even when I'm sitting still, if I rev it up. It also seems to be much more prevalent in lower gears (1/2/3/4) rather than 5th.
I tightened my throttle cable up a bit, thinking the extra slack might be fooling around w/ the tensioner, plus it was a little loose being that she's got a good 10k miles on her now. I also took out my d/v and relubed it (it needed it anyhow). None of these things helped matters though.
I am wondering if somehow the throttle body b/f valve is hanging up on something, or if this is an ECU-related issue.
Anyone else experience anything like this? I'll try to get a video of it on Monday. I'm not crazy, my friend noticed it too!
What's happening is that whenever I shift at a decently high rpm (let's just say > 4500 or so) and whenever I let off the gas at such an rpm, the engine seems to 'hang' at that rpm for a second or so. This is causing me much distress because everytime I shift for example, I can't properly rev match the upshift because the rpms are higher than I'm expecting!
At first I though it was my foot action, a simple matter of coordination gone wrong. Then I started to notice that this was occuring even when I wasn't shifting! Hell I can reproduce it even when I'm sitting still, if I rev it up. It also seems to be much more prevalent in lower gears (1/2/3/4) rather than 5th.
I tightened my throttle cable up a bit, thinking the extra slack might be fooling around w/ the tensioner, plus it was a little loose being that she's got a good 10k miles on her now. I also took out my d/v and relubed it (it needed it anyhow). None of these things helped matters though.
I am wondering if somehow the throttle body b/f valve is hanging up on something, or if this is an ECU-related issue.
Anyone else experience anything like this? I'll try to get a video of it on Monday. I'm not crazy, my friend noticed it too!
Jan 24, 2004, 09:53 PM
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I'll move it over to the tech forum in a sec. But you should contact Coolguy... I seem to remember him mentioning having this issue recently.
SC~
SC~
Jan 24, 2004, 10:08 PM
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what you have is called "throttle hang" it is common for Ford vehicles (thats how i know) what it is is an unusally high amount of carbon left over after ignition that the car detects and has to burn off. means yuor running very rich.
Jan 24, 2004, 11:54 PM
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SC, I will do that thanks.
Are you guys saying this is almost a normal thing? I know these cars run sickly rich from the factory, maybe mine's an anomoly running richer than most.
Are you guys saying this is almost a normal thing? I know these cars run sickly rich from the factory, maybe mine's an anomoly running richer than most.
Jan 25, 2004, 10:33 AM
#7
Ha!
I did notice this, but it seems intermittent, I can't always duplicate it, but it seemed to happen if I'm shifting quick at a high rpm. I kept thinking I was crazy... I thought I was focking up the shifting, like getting into the gas while the clutch was still depressed.
Oh well, once I'll go for a drive once my car is running again (waiting for a replacement camshaft angle sensor that I broke) and see if I can duplicate it...
FB
I did notice this, but it seems intermittent, I can't always duplicate it, but it seemed to happen if I'm shifting quick at a high rpm. I kept thinking I was crazy... I thought I was focking up the shifting, like getting into the gas while the clutch was still depressed.
Oh well, once I'll go for a drive once my car is running again (waiting for a replacement camshaft angle sensor that I broke) and see if I can duplicate it...
FB
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Jan 25, 2004, 09:26 PM
#8
webguy,
It sounds like the trottle plate is sticking a little. Biggest cause would be carbon build up on the back side of the throttle plate. This can eventually start to creep into the shaft area and cause it to stick or hang up a little. Easy to check.
To clean it, use carb cleaner and hold the throttle open and clean the backside of the throttle plate. It is usually easier to get a majority of it with a rag after spraying it and then give it a good hosing down with the carb cleaner. Usually it is possible to pop the spring free of the cable cam, which makes it a lot easier to hold it open like that. Of course the car is not running when you do all this.
If you run it immediately after, you will need to blow out the carb cleaner that is lingering in the intake. OTherwise it will pretty much dissapate after 20 minutes or so.
This buildup is pretty common on higher mileage cars. With the boost of a turbo you get more of this blow by in the intake. A catch can will significantly cut down on this.
It sounds like the trottle plate is sticking a little. Biggest cause would be carbon build up on the back side of the throttle plate. This can eventually start to creep into the shaft area and cause it to stick or hang up a little. Easy to check.
To clean it, use carb cleaner and hold the throttle open and clean the backside of the throttle plate. It is usually easier to get a majority of it with a rag after spraying it and then give it a good hosing down with the carb cleaner. Usually it is possible to pop the spring free of the cable cam, which makes it a lot easier to hold it open like that. Of course the car is not running when you do all this.
If you run it immediately after, you will need to blow out the carb cleaner that is lingering in the intake. OTherwise it will pretty much dissapate after 20 minutes or so.
This buildup is pretty common on higher mileage cars. With the boost of a turbo you get more of this blow by in the intake. A catch can will significantly cut down on this.
Jan 29, 2004, 10:39 AM
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timzcat, I plan on investigating just as soon as temps rise above 40 degrees. 
But for real, since today has been warmer (it's ~30d F) I've noticed this isn't occuring as often. Very sparsely in fact. Interesting... cold weather sure ****s with a lot of things on a high strung vehicle like this!
But for real, since today has been warmer (it's ~30d F) I've noticed this isn't occuring as often. Very sparsely in fact. Interesting... cold weather sure ****s with a lot of things on a high strung vehicle like this!
Feb 9, 2004, 05:30 AM
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Mine started doing something similar last night. After a hard back road run I noticed the idle was around 2500. The throttle was sticking in that position. I could either pull the pedal out or move the throttle cable and it would go back to normal idle. But as soon as gas was given it would stick back at 2500.
If it's due to carbon build up that's pretty crappy after only 4400 miles.
If it's due to carbon build up that's pretty crappy after only 4400 miles.
Apr 4, 2004, 08:15 AM
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RPM rises 400 when doing 3 to 4 shift
When I am in third gear at 100% throttle and I shift at 5000rpms the tach goes up in RPMS to 5400 instead of dropping withot my foot on the gas. I talked to a few people and they believe that I have a bad throttle sensor. Does anyone have clue as to what the problem may be. 
Has anyone had this problem?
Has anyone had this problem?
Apr 4, 2004, 11:21 AM
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Sounds like my problem, NOT clutch related IMO. My clutch is perfect, just like brand new, after 15k miles.
Check out this thread:
https://www.evolutionm.net/forums/sh...light=throttle
Check out this thread:
https://www.evolutionm.net/forums/sh...light=throttle