anothercarguy

First let me begin by saying I consulted this forum extensively as a guest before I bought my 996TT. Thank you for allowing me to benefit from your knowledge. I hope to repay the favor some day.

It is my first post here and my first Porsche (switched over from M3) so please excuse any faux pas...and any help is much appreciated.

I bought a modified 996 Turbo in 2012, with 40k miles on it (larger throttle bodies, larger KKK turbos, modified Y pipe blow through MAF, EVO airbox) Over the last year and half have put on 4k miles.

Few hundred miles ago, the CEL came on intermittently. Reset CL, put Techtron...changed the oil. Felt a hesitation around 3k RPM. No performance issues other than that. Reset lights, seemed to be ok.

Drove the car 70 miles, misfires above 3k RPM. I had my garage change the spark plugs, clutch, coil packs.

I drove the car about 50 miles, no issues. Then CEL came back, this time with bigger and more frequent misfires. Car went into limp home mode. Occasionally could see unburnt fuel.

Took her back, shop had my car for 4 months, finally said all misfires were specific to one bank. Changed the solenoid bracket and sensor/actuator (which is what I told them to do in first place).... and now they say that the ABS/PSM light is on...Ordered a new MAF (not the OEM, I have a custom blow through...think it is a For MAF)....light is still on.

The shop has now given up....say they can't "fix" the issue because it is too heavily modified to know what exactly is wrong.

the shop has been great in terms of trying their best/good intentions...but I cannot believe that this is such an unfixable issue!

They say the car drives fine now, other than the lights....but I have a feeling that this is just temporary.

I have asked if they performed a vacuum leak test, they said yes. The owner's son who seems unfamiliar and wary of mods (did not know what my MAF set up was) says it "could be a twisted camshaft"?? Am less confident he knows what he is talking about.

Any suggestions? Please Help!! I'm already out significant $$$ and no solution.

enzowho

To recap, it sounds like you have done plugs, coils, maf, variousness solenoid brackets, and vacuum leak. My next guess from that list is maybe a bad injector, given the modifications I could see aftermarket injectors being added. Seems a few aftermarket injectors have given people problems.

anothercarguy

Thank you!

I am not sure how thorough their vacuum leak test was. I have asked them to spell out what exactly they did.

Would a faulty injector throw off an error code? Is there a way to "test" for a faulty injector?

neanicu

Most important,what are the codes?

wross996tt

Yes, report the actual codes....also if they changed the coil packs and plugs, what did they use? And are the plugs gapped correctly? Make sure all of the connections are tight. I had a bunch of problems with the EVO air box...any chance you can swap that out?

TheKane

ABS/PSM issue comment only, I have no experience with the misfire issue. My ABS/PSM has issues when in a turn and I'm trail-braking (or light braking). It is un-fixable. I've had wheel sensors cleaned and tested. The issue is caused by my aftermarket rims. The computer can't quite figure out wheel speed/rotation, etc. and thinks I'm sliding around. The problem is worse with severely worn tires or a bent rim, or unbalanced tire, or if you hit a reflector in the road in the turn, basically any thing that unsettles the tire contact with the surface of the road. Using stock sizes fixes it. I run with my PSM off if I'm driving hard or on very curvy roads. Actually, I always run with PSM off. Friends of mine who have 996 Turbos don't have this problem, but it is a known issue.

anothercarguy

I have asked for the error codes, but the shop is a little cagey in responding to anything via email. I will go there in person on Monday.

They only install OEM parts, both for coilpack and plugs. I think they gapped it correctly...but you never know.

I have 19 inch HREs on right now (which I personally do not care for as the ride quality sucks when you are driving down Queens, NY).

The issue does not happen under braking, it popped on right after they finally listened to me and change the actuator solenoid + bracket on the side with misfire.

I believe I have the original EVO airbox which has some notoriety for blown MAFs. The shop switched the MAFs and called me and said, "You have some off the wall intake system that has a Bosch unit meant for a GM car and sits on top of the Y pipe...we replaced the MAF but the ABS/PSM is still on".

I thought he meant that I have a blowthrough MAF...but I can't have a blowthrough system AND a EVOMS airbox...so not sure what he is talking about. It is not a Hitachi unit...so not sure what else it could be other than OEM.

I am open to changing the intake system...but not sure what the hell MAF system I have that is "custom" but still uses Bosch. Not sure how much it would be to switch it all back to stock....the shop said "It would be over 5k in parts and labor and you still aren't guaranteed it would be fixed...".

I just cannot believe the shop, which is a Porsche exclusive garage, has the car for 6 months and cannot tell me what the issue is...I know they have good intentions. Just hoping it isn't some big variocam issue or twisted camshaft issue they keep saying it might be.

Will get back to the group with 1) error codes 2) MAF part they installed 3) pictures of my car's set up

"02996ttx50

sorry to say, but i think you're shop is clowning you. six months and "if you go back to stock airbox for $5k there's no guarantee etc". i would cut my losses with them honestly. also, there is no way they gapped the plugs at all ( not that this is causitive ). they took em out of the little boxes and screwed em in is all. guaranteed.

the criteria you should use when deciding on repairs for a modded pcar should include this: if they cannot identify any and ALL aftermarket "bolt on" parts with a visual inspection of them? drive ( or limp ) away to another shop. seriously. gl w it! six months, really!? sounds like a fugazi to me.

GermanCarSpecialists

Check and see what tune you have. On some EVO cars they ran a Hitachi specific MAF file on the tune. That is a piece of information for you.

anothercarguy

I hear you X50. This is my first modified/turbo car...I have always had M3s before this...so am learning not all shops are mod-savvy.

New piece of info...

The MAF that was in, and which they replaced with a new one of the same is a Bosh Unit # 0261230042. The link below shows that it is compatible with my car....

They tried fitting a regular MAF but said it did not fit because of the custom MAF/Y pipe set up...so they reordered a new unit of what was already in there.


http://www.oreillyauto.com/site/c/de...2203&ppt=C0033

anothercarguy

and yes 6 months, really. I went back to them 3x in 6 months...the same problem popped up within a 100 miles.

They get great reviews and the owner has been doing this a long time. I think they're strictly older/stock car shop though...

Kevin

The part number that you have written is NOT a MAF sensor.. It is the MAP sensor. Two different sensors.

anothercarguy

You are 100% right. It is what my car had and they just replaced the part. Apparently I do not have a traditional MAF set up...they tried and traditional MAF does not fit.

I will post pic of set up.

IF the setup was done correctly (MAPless tune)...not sure that is a MAP problem...since they just put in a new one...and are not usually prone to failure...


Will take pics and post video link (if possible) when I get in.

"02996ttx50

i have feeling you may still be mixing up the MAP sensor and the Mass Air Flow meter as kevin the pro in here has pointed out. because unless i'm mistaken the "mafless" tune ( as in protomotive's etc ) you called a "MAPLess" tune wouldn't have a maf at all ( hence the name! ), and you've already said that you had a MAF of unknown mfg or design.

you've also mentioned that you had issues and that at 3k rpm that does tend to indicate ( to me at last from my experience ) that you may have indeed fried your MAF, whatever kind it is !? lol. stutters at 3k along with abs/psm cels indicate to me that you had/have a failing maf. ( notwithstanding the variocam whatzit that also occurs at around 3k rpm )

by way of anecdotal comparison i knew that i pegged the limiter on my car recently and fried the maf as soon as random abs/psm cels ocurred along with idle "hunting" and, well, i've been down this road before with my modded car, and i am well aware of the voltage spikes that hit the maf ( eg if the rev limiter has been raised as in many tunes to 7200 ). the fact that i had a cel stored that read maf value "low" also helped me self determine that i had indeed fried another one.

i just replaced it 30 minutes ago with my usual 996/986 generic MAF that i buy on ebay or amazon for $47.00 and installed it in all of the 2 minutes that even i am capable of doing and my car is again, blazing fast, with no cels or idle hunting issues. i'm not sure what my point is, beyond that you need to find out what maf your using and replace it with a new one. given you didn;t have these issues before for over 4k miles you said so that leads me to suspect that you've fried your mystery maf is all lol.

but if i were you, i would still endeavor to find a different shop for diagnosis and repairs in the future.

anothercarguy

Ok, time to do away with some misinformation and some actual data. Turns out the guy I am talking to and the guy doing the repairs are two different people. one knows his stuff, the other is a "finance" guy.

Here is what they found:
1) broken solenoid bracket
2) cracked coil packs.

Replaced these, with new spark plugs misfire went away.

Here are the error codes that still remain:
P0023 Camshaft Adjustment, Bank 2
P0103 Hot Film MAF Sensor
5525 Torque transmission from the DME intermittent

To clear up the misinformation the Finance guy told me, and the actual car guy was able to clear up:
1) I have a MAF, it is right there near the intake. They did NOT replace. Reason? $700 bucks, and when they drove it around WITHOUT plugged in, the problem did not go away...and seemed to be performing within range.
2) They replaced the MAP which sits on top of the Y pipe. Reason, couple hundred bucks and possibly related.

How does the car drive?
ABS does not work, but otherwise seems to drive fine...even under boost.
ABS PSM and CEL all on.

The car guy's diagnosis:
1) Lots of mods including larger throttle body, hard to diagnose
2) Did spray test for vacuum leak, ruled it out
3) Something may be wrong with camshaft, something about "carbon rings may be damaged...or the camshaft may be twisted".
4) May be an issue with the intake or throttle body mod
5) May be issue with the ECU tune