Bogging/loss of power at 4k stage 2 car

[616_S4]

Hey guys, just recently bought my first s4 a 2001 black s4 six speed 146k with stage 2 giac, xs power turboback exhaust, and spec stage 2 clutch. Let me state I have searched high and low but cannot find any solutions for my problem. when I got the car it ran good but bogged once and a while at around 4k usually in higher gears, normally would run perfect! It idled a little rough and still bogged/misfired at 4k so I changed out the plugs to new ngk bkr7e and it seemed to make it idle better and give smoother power delivery but today when driving i went WOT and it bogged way down every time id hit 4k no matter what gear, this time the difference is no flashing cel and just sounds like its getting no boost. I tried gapping them smaller and pulling the green springs out of the 007 forge and putting in the yellow ones but to no success. I got the car scanned a day ago and got 3 codes. P0300 Random/Multiple cylinder misfire,P1113 H02S 1 Bank 1 heater resistance too high, same thing for bank 2. I constantly have a cel on, though i was under the idea that that was from the stage 2 and new exhaust, all mods are less than 2000 miles old. Any help would be greatly appreciated as this has been my dream car since I was twelve and am so eager to get it working great!

[slowSfaux]

Do a boost leak test before you go any further. The misfires could be a result of a boost leak, though the o2 heater codes probably aren't. Considering its the primary o2s and not the secondarys, your tune is probably not the cause of those codes. O2s are likely bad, but boost test first. Search boost tester on here and there's a writeup on how to make your own for under $20 at home depot.

[616_S4]

Do a boost leak test before you go any further. The misfires could be a result of a boost leak, though the o2 heater codes probably aren't. Considering its the primary o2s and not the secondarys, your tune is probably not the cause of those codes. O2s are likely bad, but boost test first. Search boost tester on here and there's a writeup on how to make your own for under $20 at home depot.

gotcha, I was afraid of that, I wonder if the leak opened up bigger today thats why it started bogging at 4k in all gears. I was under the assumption that with a stage 2 tune the o2 sensors had to be coded out or something like that? luckly i only drive about a mile a day right now with school. literally less than a half mile to school haha. Should I be running the yellow or green springs in the diverter valves?

[f4m0u5]

What did u tighten the plug gap to?


Id start with a boost leak test. Make sure to take off oil cap and remove the pcv valve from y pipe and then block the port on y pipe. If you dont do this you will end up blowing seals and leaking oil from your motor.

But with the 02s whats the eaxact codes? If its bank 1 s1 and bank2 s1 then those are your primary o2s and should be replaced.

If its bank1/2 s2 then its from havong no cats or highflow cats. And you could either add o2 sensor spacers to get rid of cel or just live with the cel

As for 007 springs i personally run the yellows on a stage 2 tune with 0 issues.



Good luck!

[616_S4]

What did u tighten the plug gap to?


Id start with a boost leak test. Make sure to take off oil cap and remove the pcv valve from y pipe and then block the port on y pipe. If you dont do this you will end up blowing seals and leaking oil from your motor.

But with the 02s whats the eaxact codes? If its bank 1 s1 and bank2 s1 then those are your primary o2s and should be replaced.

If its bank1/2 s2 then its from havong no cats or highflow cats. And you could either add o2 sensor spacers to get rid of cel or just live with the cel

As for 007 springs i personally run the yellows on a stage 2 tune with 0 issues.



Good luck!

Plugs were at .025 when i got the car, but just for peace of mind i put in new ones gapped at ngk specs, then i moved them down to .030 i doubt its the spark plugs tho. Exact codes are P1113 H02S 1 bank 1 heater resistance too high and P1131 H02S 1 bank 2 heater resistance too high. those are the codes i got from getting scanned quick at autozone.

[verstappen]

Definitely check for boost leaks, I doubt is your spark plugs though I don't think it is necessary to gap at .030, next could be coils, my original coils ran fine all the way up to 160k miles, died shortly after and was getting a serious bog down on high rpms on 3rd and 4rd gear and a P0300. 2.0T coil swap made it all better.

Report back!

[616_S4]

again got it scanned today and got the same codes. looks like its the bank 1 and 2 o2 sensors. Just curious i have an exhaust leak i cant find could this be part of the problem? and could having both of these be bad cause the problems im running into?

[verstappen]

again got it scanned today and got the same codes. looks like its the bank 1 and 2 o2 sensors. Just curious i have an exhaust leak i cant find could this be part of the problem? and could having both of these be bad cause the problems im running into?

Bad O2's could lead to a miss, and poor performance. Since they are not expensive replace them if you want, they are 50 bucks each (bosch) at autozone (either up or downstream) but, if you have a boost leak or bad coils or ECM's the bog down will remain.

[616_S4]

Bad O2's could lead to a miss, and poor performance. Since they are not expensive replace them if you want, they are 50 bucks each (bosch) at autozone (either up or downstream) but, if you have a boost leak or bad coils or ECM's the bog down will remain.

What about the exhaust leak, it sounds like its right around the flex pipes or downpipes, I don't know much about the exhaust system, just that it is an XS power system turbo back, single muffler right at the back, stainless steel, twins the whole way, i think they are 3 inch downpipes, o and its just clamped the whole way right now :(

[verstappen]

Yeah, sorry I missed that. You should definitely fix the exhaust leak since it can be messing up what the O2's read, are your downstream O2's coded out? Because if there is a leak by the flex section your downstreams would be reading lean most-likely. I hate exhaust clamps, I only have one union in my exhaust, downpipes to cat back, I welded everything else.

[616_S4]

Yeah, sorry I missed that. You should definitely fix the exhaust leak since it can be messing up what the O2's read, are your downstream O2's coded out? Because if there is a leak by the flex section your downstreams would be reading lean most-likely. I hate exhaust clamps, I only have one union in my exhaust, downpipes to cat back, I welded everything else.

Since I just bought the car I don't really know if the rear ones are coded out or not, I was under the assumptions they were not due to it having full exhaust and giac stage 2 tune. But it's not throwing any codes for that just three codes total. I plan on getting the exhaust all welded up soon just so I don't have to worry about that anymore!

[slowSfaux]

The primary o2 sensors are in the downpipes, a couple of inches from the turbos. An exhaust leak at the flex pipe (2 feet after the sensor) should not affect them. As I said, they are likely bad, and not a result of your tune. Boost leak test first, replace o2s and gap plugs to .026 and if it still misfires it's probably weak/dying coils and Ignition control modules.

[slowSfaux]

And since you aren't showing any catalyst efficiency codes, the rear o2 were either coded out entirely, the catalyst check was coded out or the range of "normal value" was modified, or its possible you already have non-foulers on the sensors.

[616_S4]

did a boost leak test and found one hose that had lost its clamp and came off, the little one that attaches to the intake tube, like on the little nipple of it, still ran poorly but just bogs doenst backfire anymore, the exhaust leak sounds even worse now than it was when I bought the car! going in tomorrow to get the exhaust welded up and fix the leak.

[616_S4]

so I got the exhaust all welded up and seemed to help a decent amount still not wanting to boost all the way and will still bog but for sure helped, looks like its o2 sensors next?

[AudiSportB5S4]

Power loss @ 4k is usually one of two things..

1) MAF (try unplugging it and doing a pull, see if it's okay.. If it is, then your MAF is bad)
2) EGTs are bad and they are dumping fuel which happens right around 4k and then you lose a bunch of power as the engine will cut boost levels to limp mode.

Easiest thing to try is number one.

[616_S4]

Power loss @ 4k is usually one of two things..

1) MAF (try unplugging it and doing a pull, see if it's okay.. If it is, then your MAF is bad)
2) EGTs are bad and they are dumping fuel which happens right around 4k and then you lose a bunch of power as the engine will cut boost levels to limp mode.

Easiest thing to try is number one.

somebody over on audiworld told me to disconnect the battery to clear the codes, im just worried from other stuff ive read that it could reset my giac tune, and he also suggested that it could be overboosting? which would be the N75 valve.

[Spoorguy]

somebody over on audiworld told me to disconnect the battery to clear the codes, im just worried from other stuff ive read that it could reset my giac tune, and he also suggested that it could be overboosting? which would be the N75 valve.

Same exact issue I had when I bought my 02 with 155k and a giac tune. Initially because i needed it ASAP because i had no car, I just went and had it scanned then there first course of action was to replace plugs and coils...good to do but I didn't know about the coil conversion and it didn't fix the job. Come to find out it was a bad ICM so luckily there was a guy on the forums who sold me a set for real cheap since he converted over to the 2.0 pack, and it fixed it. I checked for boost and exhaust leaks, cleaned out the DVs, check many if not all hoses for vacuum, i mean i was all over the place trying to figure it out because I didn't wanted to make sure whatever I purchased next would actually fix the problem. I also cleaned out the MAF because it was pretty filthy. Safe to say I learned a lot those couple weeks from looking all over the place and reading through a bunch of threads. I'd say if you have a buddy around with a 2.7t then swap out ICMs and see if that'll help because that's an easy way to determine if one of them is bad. Another thing I noticed was that it wouldn't really misfire till a good amount of boost, so if I drove it and didn't really get to about 4k or anything above 10psi, I "usually" was good. Just a suggestion for what worked for me, but don't buy coils and new ICMs, if you've got that much money, just covert it over to 2.0. Good luck!

[616_S4]

What o2 sensors would you guys buy? Im not sure exactly what to buy, some people say go oem bosch and others splice in universal ones? how much do these cost? I've looked around and don't know exactly what I should buy.

[f4m0u5]

The cheapest bosch o2s are on rock auto for around 90$ a pop. U could go with the universal one but i always just use a plug in one.

[616_S4]

The cheapest bosch o2s are on rock auto for around 90$ a pop. U could go with the universal one but i always just use a plug in one.

gotcha, just ordered the bosch ones off of amazon for 92 bucks a piece, free two day shipping tho!

[AudiSportB5S4]

somebody over on audiworld told me to disconnect the battery to clear the codes, im just worried from other stuff ive read that it could reset my giac tune, and he also suggested that it could be overboosting? which would be the N75 valve.

It won't reset the tune, that's not possible from disconnecting the battery. I would recommend unplugging the MAF like I suggested and reporting back if that was it or not. If not, I would continue down the O2 route.

[616_S4]

Same exact issue I had when I bought my 02 with 155k and a giac tune. Initially because i needed it ASAP because i had no car, I just went and had it scanned then there first course of action was to replace plugs and coils...good to do but I didn't know about the coil conversion and it didn't fix the job. Come to find out it was a bad ICM so luckily there was a guy on the forums who sold me a set for real cheap since he converted over to the 2.0 pack, and it fixed it. I checked for boost and exhaust leaks, cleaned out the DVs, check many if not all hoses for vacuum, i mean i was all over the place trying to figure it out because I didn't wanted to make sure whatever I purchased next would actually fix the problem. I also cleaned out the MAF because it was pretty filthy. Safe to say I learned a lot those couple weeks from looking all over the place and reading through a bunch of threads. I'd say if you have a buddy around with a 2.7t then swap out ICMs and see if that'll help because that's an easy way to determine if one of them is bad. Another thing I noticed was that it wouldn't really misfire till a good amount of boost, so if I drove it and didn't really get to about 4k or anything above 10psi, I "usually" was good. Just a suggestion for what worked for me, but don't buy coils and new ICMs, if you've got that much money, just covert it over to 2.0. Good luck!

Now it doesnt really misfire, just bogs, when it misfired before id get a flashing cel and now it just cuts power and bogs.

[Spoorguy]

Mine bogged too and seem to go limp, didn't really mention that. Some people said that was a possible sign to a faulty icm, worth a try. If you want I could send you a bad one I have just laying around. Could swap out and see, still would work with figuring out whether you got a bad one or not unless both are going out. Just pay for shipping and its yours

[616_S4]

since getting the exhaust welded it doesnt sound like a honda under my car anymore, but it still smells! wonder if this could be a result of the bad o2 sensors causing it to run lean/rich? At least it still sounds sexy! What rpms should i start hearing the turbos spool up? and my forge 007 that i put the yellow springs in now kind of chirp if i boost with the little boost i have at the moment, is that bad?

[phila_dot]

Get the O2 codes sorted.

And since you aren't showing any catalyst efficiency codes, the rear o2 were either coded out entirely, the catalyst check was coded out or the range of "normal value" was modified, or its possible you already have non-foulers on the sensors.

No further O2 diagnosis will run with fatal codes on both sensors.

EGTs are bad and they are dumping fuel which happens right around 4k and then you lose a bunch of power as the engine will cut boost levels to limp mode.

My money's on EGT's

[slowSfaux]

No further O2 diagnosis will run with fatal codes on both sensors.

I was unaware that our ecus wouldn't run the check if the upstream o2s had errors. Makes sense though. And to the OP, phila knows more about how our ecus work than probably anyone on this forum. His guess is better than most.

[616_S4]

Get the O2 codes sorted.



No further O2 diagnosis will run with fatal codes on both sensors.



My money's on EGT's

God i hope its not the EGT's $$$$$

is it weird that they'd stop working all of a sudden?

[616_S4]

I forgot to mention that my car had been sitting for 5 months before i bought it, don't know if that makes a difference?

[616_S4]

found a boost leak, driver side by the coolant and stuff cant figure out for life of me where its coming from, its pretty big because you can hear it with little boost.

[616_S4]

FOUND IT!!! Turns out we were all wrong, super leaky injector!

[616_S4]

Also found that the TBB had not been put on fully when replaced!

[f4m0u5]

Awsome great to see you fixed it! And actually posted the problem unlike most people who leave ilthe thread with a dead end

[Timtheguru]

Also found that the TBB had not been put on fully when replaced!

Weren't all wrong if there was a boost leak at the TBB.. :P

[slowSfaux]

Seriously, the first suggestions you got were to boost leak test. But yeah, I'm glad you sorted your problem.

[616_S4]

Well what I thought was leaking out of the injector turns out to be leaking out to the intake manifold gasket, of course working on putting everything back together my buddy broke the vacuum check valve, so now the car will sit until the part comes....

[616_S4]

Ok guys need your help again! just threw a bunch of money in at the mechanic, and was gonna have them do the primary o2 sensors since im getting a code for it, they tell me that it wouldnt matter if they are new o2 sensors since i have no cats at all. Second they tell me that when they scanned my car, it showed the stock ecu, but when i bought the car it was supposed to be stage 2 giac, Ive driven a stage 1 apr tune and mine is by far faster, so im pretty sure its tuned. hope i didnt buy a lemon!

[vavJETTAw36]

The primary O2 sensors have nothing to do with catalytic converters. Your secondaries are the ones that will check for cat health.

Not sure how they were able to just scan the car to tell you that you don't have a stock Ecu. What the hell were they scanning with?


Sent from my iPhone using Tapatalk

[616_S4]

The primary O2 sensors have nothing to do with catalytic converters. Your secondaries are the ones that will check for cat health.

Not sure how they were able to just scan the car to tell you that you don't have a stock Ecu. What the hell were they scanning with?


Sent from my iPhone using Tapatalk

I have no idea! they said that without the back pressure of the cats it would throw the primary o2s off!

[vavJETTAw36]

I have no idea! they said that without the back pressure of the cats it would throw the primary o2s off!

Sounds like bs to me. Turbocharged engines do not need back pressure