Mike W

I wonder if any of you guys have experienced this- 95% 0f the time my car appears to run fine although it has felt a little underpowered even under boost. Every once and a while the car feels like it has gained 50-100hp. It becomes an absolute rocket. It has happened so rarely (happened a couple of days ago) I can't equate anything that is going on with the car. It seems like the turbo whine is much louder, although I could be imagining that. My wrench who has not examined the car thinks it could be a problem with the boost controller, although I am not so sure about that. Any one experience anything like this? Mike W

viperbob

When you say your car is under powered, what does your boost gauge in the dash say? If you have a problem somewhere, then it will limit boost to .5 BAR. It will run totally fine otherwise. If it clears up, you may be going then .8 (or normal boost) and you feel like the car is much faster. But this is the proper performance for the car. Have you mechanic pull the codes from the ECU?

If there is a problem, it could be anything from the boost controller to the MAF to an O2 sensor. All of these would put the car in limp home mode. And you have no CEL?

Mike W

Viperbob, I was hoping you would respond thanks. Fact is I really havn't looked at the gauge much. It seems that it does go beyond .5 bar (my blitz gauge has not been installed yet). Should I be able to reach .8 bar in first gear without hitting the rev limiter? The cel light has been on since the 30,000 mile service. The problem(?) preexisted the service so I don't believe the cel is related to this issue. The car still has power - how much will limp mode effect performance.?

KRA993tt

Hi Mike,

I am not trying to answer for Bob but the manual talks about doing a boost pressure test drive in 2nd or 3rd gear and the boost pressure "must be at 0.6 - 0.7 bar between 4000 and 5000 RPM during acceleration." I think it is common to see 0.8 bar under full load in 3rd gear. Try a search about boost pressure levels if you are unable to get these levels. I can not remember how low the limp mode takes you but it is quite low and I think would be very noticeable when trying the above test. I would only do this test though if you are certain that the CEL is definitely not a real problem. I hope this helps.

Mike W

thanks Keith. The car does spin to .8 bar. I will try 4000-5000 rpm in 2nd and third. The car does appear to run ok. Once again the "wierdness" happens only once and a while and feels like the car picks up 100hp. Mabe it is the boost controller.

vrus

Mike,

One thing you should check.. Unbolt the intercooler from the car, and check the black plastic upper manifold where it connects to the lower manifold. There are individual black plastic tubes that have band clamps securing them to the lower intake manifold.

If your car uses a bit of oil and the oil seeps down there, sometimes it causes the upper manifold to lift off under boost. (This happened to me once or twice).

With the intercooler off, try and lift up with your hands on the upper manifold. If it moves, you'll have to remove it, use some brake cleaner to get the oil off, and then retighten it.

If you have this problem, the manifold will lift under boost, the engine will get more air than the MAF read in, and the car will run sluggish. Usually the manifold moves when you are doing rapid Off-boost/On-Boost transitions.

Hope this helps.

Mike W

Victor, You might be right. I do notice an oil smell after hard accelaration. Certainly worth looking into. My car has a muffler bypass so mabe this is the reason, but I don't hear much whine from the turbos even under high boost.

frisbee54

Hi Mike did your shifter arrive ok? How do you like it? Doug

Mike W

Doug, Sorry I meant to email you. The shifter arrived and I really like it. I have not installed it yet but will get to it this weekend. Mike