RACE_MX

I own a 2005 E55 with 20k miles and I am experiencing an odd issue. In 1st or 2nd gear from low rpms when I accelerate to approx 1/2 throttle the blow off valve goes off causing a hickup in the power delivery. Any input appreciated.

Cylinder Head

iTrader: (1)

Blow off valve?

dchl21

its normal. and sounds sexy as hell.

Toadster

you're probably experiencing what happens when the supercharger engages - does the car lurch forward (or buck) a bit?

RACE_MX

When I step on the gas I can hear the blow off valve release pressure and the car loses power for a split second. It's very annoying.

_AMG_

Twin screw superchargers dont use blow off valves.

RACE_MX

Not sure - guess I don't know what I own. Thanks for contributing.

btw, your car is a terd.

MBH motorsports

The 55k engine has a bypass valve sitting under the throttle body housing. It could be opening up for some reason. However if it is there would be a fault code (not CEL). I would check the fault code. It really could be a range of things From voltage issues, to spikes in intercooler temps. The list could go on without knowing if there is a fault code. You will have to seek someone out to read the fault codes.

The simplest thing to do might be to reset the adaptations in the car. Search for "sneaky ECU reset" there is a step by step walk through on how to do it. Or you can disconnect your battery for a while. None of these may help you, but at least its a place to start.

RACE_MX

I took the car in and fault code said the intercooler thermostat was bad? This was replaced and the issue remains.

MBH motorsports

You could have an intermittent intercooler pump. Not sure if that totally adds up though. I've seen these stock pumps cause some strange things in my day. Most of the time the car is down on power and intercooler temps are high. However I've seen a few other strange things manifest from a bad IC pump. Its very common for them to go out. In fact there should have been a worldwide recall on these Bosch pumps. They pretty much suck. Remember I'm not saying that's the issue you are having, but its a place to at least look at.

When the bypass valve opens up i'm pretty sure the supercharger disengages. So the could be something going on with the clutch.

GT-ER

If this problem occurs after more than one wide open throttle run then it's your intercooler pump.

RACE_MX

No it's not after running the car hard. It happens all the time.

justinwrock

Is the sound your hearing a chirp?

dchl21

.....

Yacht Master

No blow off valve on E55K.
What you hear and feel is the supercharger engaging. As you press the throttle and demand more power the supercharger comes on line and causes a 30-40 hp loss then in a split second the boost makes the engine produce much more power.
All E55K have this characteristic, it is normal.

Over 500 posts on the topic, don't worry every newbe asks same.

CharlyE500

You should go test drive other E55 to compare if the same.

RACE_MX

Yes sounds like a chirp

dchl21

thank you... try to enjoy it... i really like that sound... it sounds like the beast is really powerful..