bad top speed and
10-22-2012, 02:25 PM
#1
Burning Brakes
Thread Starter
bad top speed and
Hi,
i´ve a "prolbem" with my C4.
I own the car for four years now. The car always reved to the reds in the 5th gear (without spoiler curtain and with drilled airbox).
After fitting a LWF with new clutch this year in july, i recognized a lack of topspeed and the car revs a little bit tough (is this word here correct? I mean the opposite of lively) in the higher rev-area. The resonance-flag activates, throttle cable opens the throttle valve full (double and tripple-checked this). The open-throttle-switch gets actuated (double checked).
Spoiler curtain is renewed (or, gets installed. My car had no curtain when i bought it).
The car idles fine. Starts hot and cold perfectly. Needs same fuel (round about) as the last years (now 98octane, during the last years mostly just 95octane). Same oil consumption as the previos years.
Airbox was drilled. No i´ve fitted an airbox-cover "cupstyle". Only an open frame to hold the air filter. Air-Filter is new (oem paper). Spark plugs are less then 10k kilometers old.
Spark wires are fine, distributor belt is ok, the whole assembly had an overhaul four year (~25k kilometers) ago.
But:
I fitted a cheap 200cell catalytic converter last year with a cheap noname oxygen sensor. No problems so long.
This year, during a trip to italy, the car hesitates when is was hot-restarted. Quite bad after refuel-stops.
I disconected the O2 sensor and the hesitation was gone, so i drove round about ~1,5k without oxigen sensor and replaced it with an OEM bosch part at home. Problem was solved, but my car remaind "slow".
The oxygen sensor problem was at the same time the lwf was fitted by an aircooled-shop.
Could it be, that the oxygen-sensor problem destroyed my catalytic converter? Could the converter be partly melted?
The car runs not bad, but there is the lack of top-speed of round about 20kph - 25kph....
sorry for my strange english
regards thilo
i´ve a "prolbem" with my C4.
I own the car for four years now. The car always reved to the reds in the 5th gear (without spoiler curtain and with drilled airbox).
After fitting a LWF with new clutch this year in july, i recognized a lack of topspeed and the car revs a little bit tough (is this word here correct? I mean the opposite of lively) in the higher rev-area. The resonance-flag activates, throttle cable opens the throttle valve full (double and tripple-checked this). The open-throttle-switch gets actuated (double checked).
Spoiler curtain is renewed (or, gets installed. My car had no curtain when i bought it).
The car idles fine. Starts hot and cold perfectly. Needs same fuel (round about) as the last years (now 98octane, during the last years mostly just 95octane). Same oil consumption as the previos years.
Airbox was drilled. No i´ve fitted an airbox-cover "cupstyle". Only an open frame to hold the air filter. Air-Filter is new (oem paper). Spark plugs are less then 10k kilometers old.
Spark wires are fine, distributor belt is ok, the whole assembly had an overhaul four year (~25k kilometers) ago.
But:
I fitted a cheap 200cell catalytic converter last year with a cheap noname oxygen sensor. No problems so long.
This year, during a trip to italy, the car hesitates when is was hot-restarted. Quite bad after refuel-stops.
I disconected the O2 sensor and the hesitation was gone, so i drove round about ~1,5k without oxigen sensor and replaced it with an OEM bosch part at home. Problem was solved, but my car remaind "slow".
The oxygen sensor problem was at the same time the lwf was fitted by an aircooled-shop.
Could it be, that the oxygen-sensor problem destroyed my catalytic converter? Could the converter be partly melted?
The car runs not bad, but there is the lack of top-speed of round about 20kph - 25kph....
sorry for my strange english
regards thilo
10-22-2012, 02:59 PM
#2
How long have you ran with the new o2 sensor? Had the same issue even with the new o2 sensor but disappeared after a few days. From my understanding it takes 40 cycles to clear out the fault code and go normal. Give it a few days and if problem still occurs check the cat and check what fault codes are thrown.
10-22-2012, 03:09 PM
#3
Burning Brakes
Thread Starter
I fitted the bosch OEM sensor in the middle of august and drove round about 1k kilometers in the meantime...
checking potential failure codes could be a good idea. I´ll do this tomorow!
checking potential failure codes could be a good idea. I´ll do this tomorow!
10-22-2012, 04:54 PM
#6
Nordschleife Master
Have you done anything else that we should know of?
When I had the LWF/clutch fitted, there was no loss of performance. My butt even told me that it got to the red line quicker (although I admit to have never dared to try and reach the red line in 5th!).
However, earlier this year my car started to struggle to the red line. I couldn't work out why. Then I came across this article:
Don't use 10W-60 oil
I then realized that 10W-60 had been put in the car (I previously had 15W-50 in). So, I dumped out the 10W-60 for a thinner oil again....and the car was back to normal!
When I had the LWF/clutch fitted, there was no loss of performance. My butt even told me that it got to the red line quicker (although I admit to have never dared to try and reach the red line in 5th!).
However, earlier this year my car started to struggle to the red line. I couldn't work out why. Then I came across this article:
Don't use 10W-60 oil
I then realized that 10W-60 had been put in the car (I previously had 15W-50 in). So, I dumped out the 10W-60 for a thinner oil again....and the car was back to normal!
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10-22-2012, 05:29 PM
#8
Burning Brakes
Thread Starter
@boxsey
I saw your posting some days ago and yes, i've changed from 10w40 to 10w60 this spring!
But my dads 964 had same change and there was no difference in performance...
On sunday i'll change my cat against the previous ceramic stuff and will See what if something changes... then season is over in the end of october.
Next time i use 10w40 again!!!
I saw your posting some days ago and yes, i've changed from 10w40 to 10w60 this spring!
But my dads 964 had same change and there was no difference in performance...
On sunday i'll change my cat against the previous ceramic stuff and will See what if something changes... then season is over in the end of october.
Next time i use 10w40 again!!!
10-23-2012, 12:16 AM
#9
Rennlist Member
Join Date: Jun 2010
Location: Detroit (Rock City); 1990 C4
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What? That's the beauty of a C4- the season never ends!
10-23-2012, 01:25 AM
#10
Burning Brakes
Thread Starter
It will be easy at that point to inspect the current catcon for damage- just look at the cell structure.
What? That's the beauty of a C4- the season never ends!
yes. Because of my poor little kilometers per year and the amount of salt on our roads during the winter, i think it is not worth to "destroy" the car in the winter. Usually, i need only on christmas a car during my 4 month winter-storage period.
But, this year i bought a winter (or, future all-season) car. A Golf (VW rabbit in US?) Variant with the smallest engine
Well,
i did a dme refresh over-night (ground disconnected) and it runs fine as before. I couldn´t test topspeed yet (when driving to the office across munich)....
I keep you informed guys...
10-23-2012, 02:25 AM
#11
Burning Brakes
Have you done anything else that we should know of?
When I had the LWF/clutch fitted, there was no loss of performance. My butt even told me that it got to the red line quicker (although I admit to have never dared to try and reach the red line in 5th!).
However, earlier this year my car started to struggle to the red line. I couldn't work out why. Then I came across this article:
Don't use 10W-60 oil
I then realized that 10W-60 had been put in the car (I previously had 15W-50 in). So, I dumped out the 10W-60 for a thinner oil again....and the car was back to normal!
When I had the LWF/clutch fitted, there was no loss of performance. My butt even told me that it got to the red line quicker (although I admit to have never dared to try and reach the red line in 5th!).
However, earlier this year my car started to struggle to the red line. I couldn't work out why. Then I came across this article:
Don't use 10W-60 oil
I then realized that 10W-60 had been put in the car (I previously had 15W-50 in). So, I dumped out the 10W-60 for a thinner oil again....and the car was back to normal!
10-23-2012, 03:52 AM
#12
get a bosch hammer for a proper system adaptation.
not that this is necessarily the solution, but someone suggested this above and I think your 'battery disconnect' technique was your poor response.
