s4 jolts massively!

[ade-5]

Hi guys have a 93 s4 and today on the way home I went to accelerate and the car jolted massively! I mean it scared the sh*t out of me. Seems according to the boost display it happens between 1.4 and 1.5 bar and before hand it wouls sit at 2.0 comfortably. Its almost like hitting a rev limiter. Any ideas guys? Cheers

[Greg_S]

Most likely a boost leak

[UrS4boy]

AAN boost leak testing

Most likely a boost leak

Agree. Most likely a split in the Michelin Man hose that opens up under full boost (but remains closed under lower boost levels)

AAN Boost Leak Testing Hints:

http://www.s2forum.com/forum/showthread.php?t=63987&highlight=boost+leak+testing

[ade-5]

Can't seem to find anything obvious as of yet :-( and tight as you get down to the intercooler.

[Vorsprung durch Technik]

I had exactly the same symptoms your describing on my URS6 when i took a leap of faith and actually bought the car thinking i bet it's something simple.

Lift up the coil cover and look at the wires where they exit the back. Have they been chopped about in the past and is the original brown plastic sheathing on the wire heavily cracked causing arcing like mine was. There was absolutely nothing wrong with either my P.O.S. or my coils.I changed that part of the the loom for a good one and it has purred super smooth ever since achieving max 2.2 boost in 6th going up hill to give it as much aggravation/chance to play up as possible but perfect.

Give your wiring a try....a very probable cause along with what the other guys have said.

[ade-5]

This is the first time its happened and iv had the car a couple of months now. Will be another thing on my list to check. Need to try and get to the bottom intercooler hose anyone have any advice on how mainly without stripping unnecessary parts.

[prj]

Pressure test it instead of taking half the car apart

[UrS4boy]

This is the first time its happened and iv had the car a couple of months now. Will be another thing on my list to check. Need to try and get to the bottom intercooler hose anyone have any advice on how mainly without stripping unnecessary parts.

Remove the belly pan and the Michelin Man hose will be staring you in the face.

[ade-5]

Pressure test it instead of taking half car apart

lol just my daily driver and working all weekend so if can find it sooner rather then later

[ade-5]

Remove the belly pan and the Michelin Man hose will be staring you in the face.

Il try and get belly pan off tomorrow. Kind of hoping it is the bottom hose. Will be asking where's the best place to get replacements next lmao

[Vorsprung durch Technik]

My idea with the wiring is only 3 allen bolts and it's of.Dead easy

[ade-5]

My idea with the wiring is only 3 allen bolts and it's of.Dead easy

may even try your idea first lol

[driftin jo]

I have had this 3 times and every time it was the MAF connector, pissed me off the first time as I was advised it was a boost leak and after spending hours pissing about looking for leaks and other stuff it was a simple 2 min fix. I would try the connector first as if it is that you will save hours of your time. If it isn't that you have lost nothing!

For ref

http://www.s2forum.com/forum/showthread.php?t=24544&highlight=maf+connector

[Vorsprung durch Technik]

if not coil loom this could be problem as it sounds electrical to me.could even be the thermo switch

[UrS4boy]

I have had this 3 times and every time it was the MAF connector, ....]

This is why the MAF connector is No.1 in the checks in my "One Missing and Hesitation Diagnostic" post:

http://forums.quattroworld.com/s4s6/msgs/22611.phtml

This seems to be more of boost leak but time will tell.