I may be driving the car normally (say, a commute home). After getting into some empty backroads, i decide to drive a bit more enthusiastically for a few minutes. I come to a stop sign, stop, and then let it rip. 6k rpms in 1st, then 6krpms into 3rd aaaaaaaand a gateway to hell opens up in the engine bay. Power drops, engine note deepens, throttle response wanes, and the SES light comes on. I dont get an "engine failsafe" message on the display, by the way. The car drives, but it feels like it's limping along. I pull over, turn the car off and start it back up. All is well again and the car takes a beating through the gears and RPMs. Like nothing happened.
Of course, I check the codes (with the peake) and I get:
"Catalyst system efficiency, Cyl #1-4" and seemingly random misfire codes. The first time it happened, it was cylinder 4. Now i checked again and it was in 1 as well as in 4 (however, I did not clear the codes last time this happened. It has now happened 3 times).
What puzzles me is that this only happens on the first attempt to let it rip. As if the car isnt ready to play and I catch it by surprise. Mind you, this doesnt happen every time I start to play. It's only happened about 3 times out of 20 or more times. Anyways, a simple restart makes it all go away and she's as healthy as she can be. No sputtering, pulling strong, everything. And yea, it always happens when going from 2nd into 3rd. Never from 1st into 2nd or 3rd into 4th.
I may be driving the car normally (say, a commute home). After getting into some empty backroads, i decide to drive a bit more enthusiastically for a few minutes. I come to a stop sign, stop, and then let it rip. 6k rpms in 1st, then 6krpms into 3rd aaaaaaaand a gateway to hell opens up in the engine bay. Power drops, engine note deepens, throttle response wanes, and the SES light comes on. I dont get an "engine failsafe" message on the display, by the way. The car drives, but it feels like it's limping along. I pull over, turn the car off and start it back up. All is well again and the car takes a beating through the gears and RPMs. Like nothing happened.
Of course, I check the codes (with the peake) and I get:
"Catalyst system efficiency, Cyl #1-4" and seemingly random misfire codes. The first time it happened, it was cylinder 4. Now i checked again and it was in 1 as well as in 4 (however, I did not clear the codes last time this happened. It has now happened 3 times).
What puzzles me is that this only happens on the first attempt to let it rip. As if the car isnt ready to play and I catch it by surprise. Mind you, this doesnt happen every time I start to play. It's only happened about 3 times out of 20 or more times. Anyways, a simple restart makes it all go away and she's as healthy as she can be. No sputtering, pulling strong, everything. And yea, it always happens when going from 2nd into 3rd. Never from 1st into 2nd or 3rd into 4th.
Any clues?
Pretty random. Cat efficiency code could be a bunch of things. Don't remember, do you have headers?
If so, check the connections at the flange and where the collectors go into the exhaust pipe for leaks.
I would think maybe air leak past the MAF's is upsetting the ECU. Check the intake tubes, especially where they go into the plenum. There is a rubber O ring on each side, they tend to wear or get crushed if not put back carefully.
Other possibility is exhaust CPS. I know there is no code, but change in engine note and loss of power is symptomatic. And the fact it immediately clears up after runing the car on and off indicates it is not mechanical, but electronic.
Perhaps access to a GT1 would be more helpful?
Regards,
Jerry
__________________
'01 Black/caramel
Dinan Stage 3 suspension, SS jet coated headers, ESS SC kit, open brake ducts, Hamann front splitters, TEC cupholder, U.S.(Euro style) tilt/slide armrest, 6k HID fogs, 6k super white low beams, V1/Stealth1, dual head LI, 2.65 diff w/40% lockup/2x dynamic, compact spare, Euro trailer hitch, Mocal oil cooler, ACS type rear spoiler, Rogue custom SSK and tranny mounts, ST 355 BBK (fronts), BP sway bar brackets, Bluetooth retrofit
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Pretty random. Cat efficiency code could be a bunch of things. Don't remember, do you have headers?
If so, check the connections at the flange and where the collectors go into the exhaust pipe for leaks.
I would think maybe air leak past the MAF's is upsetting the ECU. Check the intake tubes, especially where they go into the plenum. There is a rubber O ring on each side, they tend to wear or get crushed if not put back carefully.
Other possibility is exhaust CPS. I know there is no code, but change in engine note and loss of power is symptomatic. And the fact it immediately clears up after runing the car on and off indicates it is not mechanical, but electronic.
Perhaps access to a GT1 would be more helpful?
Regards,
Jerry
Thanks a lot, Jerry. I do not have headers. I'll try to check the other stuff. I would be surprised if this is what the exhaust CPS does. I know that it changes the exhaust note, but this change that I'm experiencing is with engine response and it's just insanely down in power. Kind of like taking off the line in 5th.
Thanks a lot, Jerry. I do not have headers. I'll try to check the other stuff. I would be surprised if this is what the exhaust CPS does. I know that it changes the exhaust note, but this change that I'm experiencing is with engine response and it's just insanely down in power. Kind of like taking off the line in 5th.
From experience, exhaust CPS feels like you lost 100 hp. Cars sounds king of "boomy", almost like you have an exhaust leak.
The fact it goes away on restart indicates it is not a hard mechanical problem. I would expect MAF's to be consistent for example. Same with an air leak, although it could change as the car warms up.
But focus on things that are connected to the car's computer, only thing that comes to mind when a "reboot/restart" clears it up.
G/L, keep us posted.
Regards,
Jerry
__________________
'01 Black/caramel
Dinan Stage 3 suspension, SS jet coated headers, ESS SC kit, open brake ducts, Hamann front splitters, TEC cupholder, U.S.(Euro style) tilt/slide armrest, 6k HID fogs, 6k super white low beams, V1/Stealth1, dual head LI, 2.65 diff w/40% lockup/2x dynamic, compact spare, Euro trailer hitch, Mocal oil cooler, ACS type rear spoiler, Rogue custom SSK and tranny mounts, ST 355 BBK (fronts), BP sway bar brackets, Bluetooth retrofit
"I come to a stop sign, stop, and then let it rip. 6k rpms in 1st, then 6krpms into 3rd aaaaaaaand a gateway to hell opens up in the engine bay. Power drops, engine note deepens, throttle response wanes, and the SES light comes on"
Sounds like it only wants to play when you use the gearbox in sequence.
"I come to a stop sign, stop, and then let it rip. 6k rpms in 1st, then 6krpms into 3rd aaaaaaaand a gateway to hell opens up in the engine bay. Power drops, engine note deepens, throttle response wanes, and the SES light comes on"
Sounds like it only wants to play when you use the gearbox in sequence.
Hehe, I can kind of see how it might seem like that. But no, I always shift in sequence (although I sometimes downshift from 6th into 4th, skippin g5th).
But I do follow the 1,2,3 sequence when taking off. When I said "6k rpms into 3rd," I was describing 2nd. The issue is triggered somewhere between the shift from 2nd into 3rd. And only when revving past 6k rpms and not all the time.
When I first got my beast, I had almost exactly the same experience, though mine would occur when downshifting from 5th to 4th, then hammering it on the freeway. Blatty sound in exhaust limp mode, then after a couple of minutes or a stop and restart, all is well. Replaced all four CPS, problem has never reappeared. Did not occur consistently, but intermittently. Jerry also has his finger on a good explanation--some sort of exhaust or vacuum leak that is making a sensor (such as a pre-cat 02) unhappy, causing it to send funky signals to the ECU. There are good threads on the board from someone who had these symptoms and discovered a crack in the pre-cat 02 bungs that was causing leaks and triggering the ECU to become protective by either causing the engine to run rich or go into limp mode. To be safe and based on mileage, I replaced my pre-cat 02 sensors as well. Have never had another experience such as you describe.
--Peter
PS: I forgot to send your spoiler before I got out of town! I will send it as soon as I am back in the City!
__________________ The Beast
2001 E39 M5 LeMans Blue with Black/Blue Sport Interior and Titanium Trim, ESS Supercharger, RMS In-Plenum Intercooler, RMS Plenum Plates and "Shorty" Velocity Stacks, Dinan TBs and Headers, CNS Catback Exhaust, Evosport High-Flow Cats, Dinan 3.45 Differential, GC Coilovers (550 Front/325 Rear), Dinan Front and Rear Swaybars, Dinan Monoballs, Dinan Wheels (18 x 9 Front/18 x 9.5 Rear), Bridgestone RE050 RFTs (275 Front/285 Rear), UUC EVO3 SSK with DSSR, Voltphreaks VPR-S40P Endurance Battery (14 lbs.), Setrab 16-Row Oil Cooler, Dinan Under-Plenum Heat Exchanger Removal Kit, Vorsteiner Double-Sided CF Hood with Open Vents, CA CSL-Style CF Trunk Lid, Zionsville Super Duty Cooling System, OKD Plasma Ignition Coils and Plug Boots, Smoked Hella Tailights, Clear-Corner Hella Euro Headlights, CA ACS-Style CF Front Splitters, Custom Stereo Using Stock HU, PLX Digital Gauge, V1/S1 Mounted in UGDO Location, Recaro Sportster CS Seats, Schroth 4-Pt Street Harnesses, and Various Other Bits and Pieces
Coming Soon!
Stoptech "Trophy" Brakes, TC Designs Roll Bar, TC Designs Rear Sway Bar Brackets, Aquamist HFS-6 Meth Injection with Custom CF/Aluminum Trunk-Mounted Fuel Cell Designed by Howerton Engineering, XRP HS-79 Hosing, Rogue Stage 3 280mm Clutch with JB Racing LTW Flywheel, Dinan Differential Subframe Reinforcement and Dinan Foglight Deletion Kit.
a) it's been rainy for weeks
b) thanks to a botched powdercoating job, I'm rolling on winter tires in the middle of June.
Also, about the fact that I get a "catalyst deficiency" in cylinders 1-4 and misfires on those cylinders as well... could I take that as a cue of which sensor (bank) might be giving me trouble?
Linear Mode
