S4 hot power loss, glowing cats.
#1
Rennlist Member
Thread Starter
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.
#2
Archive Gatekeeper
Rennlist Member
Rennlist Member
Shall I toss my spanner in the mail tomorrow? Had you posted 4 hours ago I could have had the wife deliver it. She's in SD giving a talk tonight.
#3
Rennlist Member
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
Inventor
Rennlist Member
Rennlist Member
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
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
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
Rennlist Member
Thread Starter
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.
#7
Inventor
Rennlist Member
Rennlist Member
Sounds way rich.
O2 sensor?
You know you're supposed to get a car running right BEFORE you put some fancy chips in the mix, right?
Did you adjust the CO screw at all?
O2 sensor?
You know you're supposed to get a car running right BEFORE you put some fancy chips in the mix, right?
Did you adjust the CO screw at all?
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#8
Rennlist Member
Thread Starter
O2 sensor has a receipt. I didn't do it.
Didn't touch the MAF. Got it from Roger and stuck it in.
Rich is rich. Glowing cats and nearly unable to run is not chips or MAF. It's something else.
Didn't touch the MAF. Got it from Roger and stuck it in.
Rich is rich. Glowing cats and nearly unable to run is not chips or MAF. It's something else.
#9
Rennlist Member
Thread Starter
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.
#10
Inventor
Rennlist Member
Rennlist Member
Temp II?
I meant the chips' CO adjuster screw - the MAF CO screw is not wired S4-up.
I meant the chips' CO adjuster screw - the MAF CO screw is not wired S4-up.
#11
Rennlist Member
Thread Starter
I'm gonna Check plug wires tomorrow.
The change over 10 minutes from Cold working fine to hot barely accelerating is strange.
#12
Rennlist Member
Thread Starter
Thanks!
#13
Archive Gatekeeper
Rennlist Member
Rennlist Member
Boxed up and OTD in the AM.