997TT Won't Idle / Loss of Power
 

Ladies/gents,

Today I did my flash and everything went great. I took the car out a few times over the day and everything was fine.

Later in the day my mate stopped by with his Gallardo so we went for a spirited drive. I noticed mid power band loss of power then all of sudden a kick in the ass at the top end. First thought was clutch.

Few more pulls and it's getting worse, bucking through the rev range. I stop on a back road and now she won't even idle. Just dies out. So anyways I managed to get about 10km home through traffic without stopping (ask me how stressful that was.. and kind of entertaining) and started looking into it.

Throwing a code B1510 "Air mass (HFM) ahead of throttle valve - Implausable Signal". I should have thought of it before I limped home, but I went and disconnected the MAFs and she idles fine. So I'm guessing one or both of my MAFs are cooked.

It's likely coincidental that this arose right after my flash but I'm wondering if those with more knowledge than me could possibly link the two? I drive my car pretty hard and never had a problem till today. Additional boost pressure finally did them in? I don't know.

I haven't had a chance to talk to the tuner yet and I in no way want to point the blame on their tune. I'm just wondering if the increased power/boost could have accelerated the MAF death?

Cheers gents.

A hose has popped out loosing you boost...
I beleive its just after throttle body at T rubber hose leading forced aair left and right to the engine...

def sounds like a hose popped which occurs more likely once you up the boost.

Would a popped off hose still make sense now it idles perfectly fine with the MAFs disconnected? I'm thinking yes as the MAF isn't trying to make corrections with a boost leak.

Unfortunately unless I can reach it through the deck lid I won't be taking a look for a few days. I pulled my back yesterday and I'm in cripple mode right now.

Appreciate your guys input.

Yea I agree, you popped a boost hose either at the intercooler or at the plenum right on top of the motor. Same thing happened to me when I installed my exhaust, the intercooler coupler didn't seat completely and the first time it boosted hard I got the same thing.

Naturally I went straight into thinking the worst. I was thinking VTG actuator rod stuck or something since it's so common. Popped coupler or hose is a much easier fix (depending on accessibility) and makes sense based on your guys input.

Does anyone have any tips for where to look for the vac leak and how to access it? Bit of a rats nest in there. I can't seem to find the T near the throttle body that you blokes mentioned.

There are many places where a boost leak can reside - basically anywhere along the intake or exhaust system where one part connects with another one. Perhaps you will be lucky and find the obvious culprit that you can fix by tightening a hose clamp or replacing a gasket or something similar. If it's not so straightforward, then you need to do a pressure smoke test at least 3-5 psi higher than what your tuned motor is boosting at. So if your boost has been upped to 22 psi for example, you need to put a 25 psi load on the system to reveal whatever leaks might be lurking at the top of your power band. It does no good to put a lighter load into the system as it won't reveal whatever is going on up top. Markski@911tuning on the 996 forum has an excellent thread describing this process which, btw, can take hours to do properly, may involve lowering the motor, etc. etc. You may want to do a search and digest what he has to say. If you get to this stage, you may also want to enlist the assistance of a qualified shop unless you are mechanically adept and have the necessary equipment.

With regard to your MAF's, they can fail and cause the problems you describe. A voltage test would be the first step to determine if they remain in spec but even if they are one or both could be in the process of failing which can make this an intermittent problem that's very hard to track down. I chased a similar problem around for months before finally deciding to replace the MAF's after exhausting all other likely culprits and, voila, it worked. However, it was a $1500 gamble and not one that should be undertaken until all other avenues have been tried. You do not want to use aftermarket parts, rebuilt MAF's etc. as they can cause as many problems as they solve. I'm not religious about using oem replacement parts but in the case of MAF's, that's the only way to go as they are specifically calibrated for model year and Porsche variant.

There are probably quite a few other possibilities that a good diagnostician in a good shop would also consider and test for. Hopefully your situation is not anymore complicated than a loose host clamp but if it is, well, just be prepared. Good luck!

Appreciate your blokes input. Steamboat, I came across one of your old threads while searching. Looks like you speak from first hand experience.

Fortunately for me it was a simple fix. I took my gibbled ass to the garage as I couldn't sit around not knowing. I blew the drivers side intercooler piping off. Removed the wheel, fender liner and bolted her backup. Cleared codes. All good.

I am wondering if this is going to happen again though. The clamp on that hose looks a little weird. Is there an aftermarket solution most people switch to avoid issues with higher boost?

Cheers

Well, despite all that experience I'm still pretty dumb but less dumb than I used to be! It has proven to be a costly, albeit interesting, education in any case. :D

When I was chasing the leak monster we replaced the standard hose clamps and installed T-clamps wherever they would fit and wherever we could reach without dropping the motor. Not sure if that's necessary but by then we were running out of more conventional ideas. Also, Evoms makes a (very expensive, imo) "leak proof" throttle body conversion kit that connects the Y-pipe with an 82 mm throttle body which is often the source of boost leaks but I don't have any personal experience with it. Have a great and leak-free summer!

PS Glad your story had a happy ending!

t clamps the way to go, but only replace those that fail....luckily (knock on wood) ive only blown the throttle body hose as that's weak as hell and replaced with IPD plenum and their hose / clamp which is much nicer than stock!

That is exactly the same one as popped off for me! I am not a big fan of the push lock style connectors they use.

Bump for the answer to this question.
How to reinforce the existing clamps without going the whole piping replacement ( and getting the 997.2 inter-coolers, which I want to do too)

I experienced similar symptoms last year. Turned out the intake duct to the MAF popped loose under boost.