Braap

Hey my name is Mike, I’m new to the forums and I gotta say that you all have already been a big help, it seems like a really great community. I just bought a 2003 Audi A3 2.7t 6-speed with 107,000 miles. It just had the timing belt and water pump replaced, has a brand new clutch, brakes, tires, wheels and has always had regular maintenance done on it (I have the service records). He also got one of the o2 sensors replaced recently. I’ve only had the car for about 4 days now, and I started to notice a lack of power and boost over 3800 rpm and what seemed like a misfire at idle, so I bought a Vag-Com cable and got these fault codes:
P1458: EGT Sensor 2 Short to Ground
P1555: Charge Pressure Upper Limit Exceeded
P0300: Random Cylinder Misfire
P0303
P0306
P1461: EGT Control Bank 1 Range/Performance

I logged some data, and there was a lot of misfires on cylinders 2,3,4 but not at the same time.

So my question is, are any of these related, and if so what is the common fix? Sounds to me like I need to replace a EGT Sensor, but I’m new to these turbo cars. Also I was under the impression that this car wasn’t chipped, but the P1555 leads me to believe otherwise, any suggestions?

Thanks,
Mike

Jim Will

While I dont have much experience pulling the codes on my own car, I've had my 2.7 for almost 12 years and 220k. I had a problem with my EGTs last fall about this time. the car showed very similar codes as yours. With bad EGT(S) your car will misfire at random under load and at varying rpms. It will do it at random and sometimes not misfire for days at a time.
My indie shop replaced my EGT last December and about 8 months later I began having similar problems, even though mine are not showing codes now, it is misfiring at random and retarding boost as well. While I can't give you a definitive reason for the Charge pressure upper limit reached code, I can say that it does often occur with the EGT codes as well.

The EGT's are a DIY fix, and can be pretty pricey. There has also been a group of failing EGT's which I would assume are due to substandard replacement parts.

Hope this helps.

Braap

Hey thanks, I'll have to look at replacing the EGT's. Also I just logged some more data and saw that my boost was peaking at 1.88 Bar or around 27psi. That is nuts... I hope that's not true. Does it spike like this if there is a leak? Is it bad to drive it like this?

Thanks,
Mike

2.7Lturbo

YES IT IS BAD TO DRIVE IT LIKE THAT


you will kill your turbos spiking that high repeatedly, after the spike what is the boost holding at? almost 2 bars is WAY over spooling the turbine, outside of its efficency island is an understatement at that point.





caveat to all the guys who might say well i sometimes spike to 27 psi blah blah blah, it is not reccommended nor is it wise. because you can do something and it doesnt automatically break doesnt mean your not causing long term damage

Braap

Hmm well that might be a problem, I have to drive 70 miles a day for work and won't have time to work on it until Saturday. When its idling, vagcom says its at 0.9 bar... something doesn't seem right. Is it really spooling that much or is the reading off cause there is a leak?

2.7Lturbo

leak would cause the reading to be lower if anything, something is deffinantly not right and im not surprised your EGT is dead, probably burned it up

Braap

EGT Temps were at 945*C and hardly ever changed, it seemed the stay there the whole log time. Any ideas why my boost would be so high?

Thanks,
Mike

Braap

Also why hasn't my CEL come on at all? Is it possible the previous owner turned it off somehow? Sorry for all the questions, I'm just new to these cars and am doing a lot of research on them.

2.7Lturbo

egt is always at 945, the sensors only read temps above 945 so if your sensors are bad you would neve rknow by looking at the temps as they are set at 945



it baffels me that you are making 13 psi of boost at idle.

Braap

Well I can hear the Turbo at idle and it definitely isn't making 13 Psi, Which makes me think the reading is off. Plus the Turbos sound normal when driving and under load too.