S4 hot power loss, glowing cats.
#1
S4 hot power loss and rough running (update 12/13/14)
White 88.
Started driving it as I am whittling down my stable, and need it for work until I sell it.
What I did:
Cam Covers
Belt
Seals
Wires
Plugs
Caps
Rotors
Coils
MAF
14 pin plug
Alternator rebuild
Powersteering
Oil Lines
24lb injectors
Porken Chip
Cam Sensor
As a Clue to the subject question, what I did not do yet is
Intake off for
TPS (tested okay when I was able to get to it)
Knock sensors
Vacuum lines I can't see now (did check when I was able)
Replace Flappy valve bulb (did test, working)
Idle stabilizer (idles well, but low)
Symptoms - Car ran really well at first drive, but now that I am driving it daily it seems very down on power and "loose"
Slow to rev, and it doesn't scream like a well tuned S4 should, even an automatic.
Like something is pulling on it.
If I lose the knock sensors, how does the ECU know to pull timing? Does it? Can I fake a good sensor to check? I don't have a sharktuner and don't have any interest in them as my own cars will all have aftermarket ECUs.
Idles well, but low.
I could take video if that would help.
Mileage - 78k.
I've been with these cars for 14 years now, and every time its something freaking different. The only thing holding me to these cars now that I have an E55 and know what a fast car is, is this great community (and couple unnamed key players), Greg Brown, and Todd.
Unless you like tragedies, go to the last post. I have updates
Started driving it as I am whittling down my stable, and need it for work until I sell it.
What I did:
Cam Covers
Belt
Seals
Wires
Plugs
Caps
Rotors
Coils
MAF
14 pin plug
Alternator rebuild
Powersteering
Oil Lines
24lb injectors
Porken Chip
Cam Sensor
As a Clue to the subject question, what I did not do yet is
Intake off for
TPS (tested okay when I was able to get to it)
Knock sensors
Vacuum lines I can't see now (did check when I was able)
Replace Flappy valve bulb (did test, working)
Idle stabilizer (idles well, but low)
Symptoms - Car ran really well at first drive, but now that I am driving it daily it seems very down on power and "loose"
Slow to rev, and it doesn't scream like a well tuned S4 should, even an automatic.
Like something is pulling on it.
If I lose the knock sensors, how does the ECU know to pull timing? Does it? Can I fake a good sensor to check? I don't have a sharktuner and don't have any interest in them as my own cars will all have aftermarket ECUs.
Idles well, but low.
I could take video if that would help.
Mileage - 78k.
I've been with these cars for 14 years now, and every time its something freaking different. The only thing holding me to these cars now that I have an E55 and know what a fast car is, is this great community (and couple unnamed key players), Greg Brown, and Todd.
Unless you like tragedies, go to the last post. I have updates
Last edited by BC; 12-13-2014 at 08:55 PM.
#3
Six degrees of retard feels like two too many beers, and you should call them mentally challenged.
Knock sensors send a frequency that spikes when there is a knock. The easiest way to see if they are good is carefully replace with a known good one. If the ECU does not see the frequency of the knock sensors it backs off to a default timing.
Feeling down on power can be so many things. Friend of mine has a base 944. He tells people that their car feels down on power, he will trade with them for a few days and when you get yours back it will feel like it accelerates right up there with a top fuel dragster.
Knock sensors send a frequency that spikes when there is a knock. The easiest way to see if they are good is carefully replace with a known good one. If the ECU does not see the frequency of the knock sensors it backs off to a default timing.
Feeling down on power can be so many things. Friend of mine has a base 944. He tells people that their car feels down on power, he will trade with them for a few days and when you get yours back it will feel like it accelerates right up there with a top fuel dragster.
#4
If you've got a LED lying around you can wire it to the '88 diagnostic plug and see knocks and/or if the EZK has detected an error (With S4.S300s chips.)
The LED will stay on if there is a knock or hall sensor error.
More info - https://rennlist.com/forums/928-foru...ock-light.html
The LED will stay on if there is a knock or hall sensor error.
More info - https://rennlist.com/forums/928-foru...ock-light.html
#5
It's like a hard drive that's 98% full that's never been defragged in a computer that hasn't been rebooted in over a year.
#6
Okay. Started up cold. Ran okay. Revved pretty good.
Then, got warm, got worse.
Barely made it home. I do not think think this is a retard issue.
It barely was able to accelerate at all. Not able to Rev.
Finally got home. Idles fine. A bit cyclic.
Looked under the car. Glowing cat (slightly)
Going to do some searching. I have heard of this but never experienced it.
Then, got warm, got worse.
Barely made it home. I do not think think this is a retard issue.
It barely was able to accelerate at all. Not able to Rev.
Finally got home. Idles fine. A bit cyclic.
Looked under the car. Glowing cat (slightly)
Going to do some searching. I have heard of this but never experienced it.
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#9
Car was fine before and after chips. Even if it was running like crap, chips aren't going to make that big of a deal to have the cats go nuclear.
#11
I'm gonna Check plug wires tomorrow.
The change over 10 minutes from Cold working fine to hot barely accelerating is strange.
#12
Thanks!