RPM rises 400 when doing 3 to 4 shift [MERGE]
Apr 8, 2004 | 03:45 PM
#46
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From: San Jose, CA
tsi, it is a big deal because when you're trying to pull a non-grandma (aka quick) shift, your revs aren't falling fast enough and you end up using your synchros to pull the engine speed down to proper rpms! It's total mahem as far as I'm concerned. And I initially thought it was the clutch too, but it works fine otherwise and has nothing to do with engine speed, so I had to cancel that assumption. It seems more likely that the engine is just gobbling too much fuel, or being fed too much. 
Do you have the p0300 error code problem at all btw?
More info to come from me Monday!
Do you have the p0300 error code problem at all btw?
More info to come from me Monday!
Apr 8, 2004 | 04:11 PM
#47
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From: Northern Michigan
webguy - I meant to say that it isn't that big a deal for my uses at a road track. I agree that it is very annoying though! Especially now that I know it's the car's fault, not mine. I definitely want to fix it. It reduces my enjoyment of the car. I can see that drag racing with this glitch would be a real pain.
I've never got any error codes.
It's definitely not the clutch. It's hard to believe it's the TPS since you only get the symptom under very specific conditions. I would have thought that a TPS fault would show up under with other problems, but what do I know. A CBV problem seems more likely to me. Maybe the throttle plate return spring is too light?
I appreciate you updating if you learn anything new.
I've never got any error codes.
It's definitely not the clutch. It's hard to believe it's the TPS since you only get the symptom under very specific conditions. I would have thought that a TPS fault would show up under with other problems, but what do I know. A CBV problem seems more likely to me. Maybe the throttle plate return spring is too light?
I appreciate you updating if you learn anything new.
Apr 8, 2004 | 04:15 PM
#48
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Damn I was hoping there might be a link between this and the misfire problem. Oh well.
What is a CBV? For me this problem exists under no specific conditions, it just comes and goes depending on (insert problem here). I can duplicate it but not reliably. <sigh>
What is a CBV? For me this problem exists under no specific conditions, it just comes and goes depending on (insert problem here). I can duplicate it but not reliably. <sigh>
Apr 8, 2004 | 05:36 PM
#49
Originally posted by webguy330i
mad_VIII, it's kinda like if you were to leave you foot on the gas after getting right past the clutch disengagement point right?
I cleaned and re-lubed my Forge d/v and that didn't help. I suppose if the pressure wasn't be properly 'diverted' by the d/v, it could cause the throttle plate to hang up for 1/2 a second, which would in fact cause this problem, but then again there are stock cars doing this as well. I have had the intake and d/v on for too long to remember if it started before or after for me. I'm fairly certain it was after but that doesn't mean those mods have anything to do with it.
mad_VIII, it's kinda like if you were to leave you foot on the gas after getting right past the clutch disengagement point right?
I cleaned and re-lubed my Forge d/v and that didn't help. I suppose if the pressure wasn't be properly 'diverted' by the d/v, it could cause the throttle plate to hang up for 1/2 a second, which would in fact cause this problem, but then again there are stock cars doing this as well. I have had the intake and d/v on for too long to remember if it started before or after for me. I'm fairly certain it was after but that doesn't mean those mods have anything to do with it.
Well my UTEC should be here monday so I'll see if that cures it like the guy that said the aem cured his...
Apr 8, 2004 | 07:25 PM
#51
Originally posted by timzcat
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.
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.
thanks for the write up.
Ben
Apr 8, 2004 | 07:28 PM
#52
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From: Northern Michigan
CBV = compressor bypass valve. Same thing as a diverter valve?
My problem is pretty consistent. The closest Mits dealer is 200 miles away, otherwise I'd take it in.
Exactly as Mad said, for me it is just like you kept your foot on the throttle past the clutch disengagement point.
My problem is pretty consistent. The closest Mits dealer is 200 miles away, otherwise I'd take it in.
Exactly as Mad said, for me it is just like you kept your foot on the throttle past the clutch disengagement point.
Apr 8, 2004 | 08:57 PM
#53
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Ah yes same as d/v. I just don't think that's it, mine worked fine for thousands of miles, and it hasn't changed a bit in terms of the internals of it (and it's ridiculously simple anyhow). I am thinking it's a fuel issue. Besides what's the d/v going to do besides send a shockwave of pressure back up to your throttle plate, which is already closed when you let off the throttle? Then again the TP isn't closed 100%... for idle purposes, but even if it were the pressure would be equal on both sides of the throttle plate so it wouldn't pop it open, really... hmm... ok you got me thinking. 
If the plate were biased open a bit, the pressure would tend to push through on that side where the gap is, but it's SO slight I don't know if that could be it. What do you think?
If the plate were biased open a bit, the pressure would tend to push through on that side where the gap is, but it's SO slight I don't know if that could be it. What do you think?
Apr 8, 2004 | 09:24 PM
#54
I posted on this a looong time ago and hardly anyone responded. I thought it was my DV as well so I put the stock back on and it made no difference. I have no idea what it is, just that it happens when under a load before redline under hard part throttle, and then it over-revs. I have just been ignoring it for 5-6 months so I hope someone finds a solution.
This problem really sucks. Hopefully somone will figuire out this problem.
Apr 9, 2004 | 01:14 PM
#58
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From: U.S.M.C.
i just hit 15k and mine starting doing it......i also noticed that my vaccum on my boost gauge is not dropping as quickly any more......so obviously there is a problem........i think its the tps.........any one got any feed back or a cure????
Apr 10, 2004 | 10:59 AM
#60
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From: San Jose, CA
SSKILLA, I definitely HEAR this happening. Since I have the intake it's a pretty loud setup up front, and whenever this happens the d/v makes a slower, "fluffier" sound rather than the snappy "PSHHHH!" that I've grown to love and many around here have grown to fear. 