legacycentral bbs

I've been having problems for a year or so with boost, never could quite figure it out, and it seemed to get worse recently. I'd replaced the alternator, knock sensor and checked a bunch of other things, but one thing kept haunting me: the intercooler.

So, in a bid to find out whether or not it really was the cause, i removed it.

The big problem i was having was that i could NEVER boost over 0.65 BAR and when under load, the car would hesitate and power was on and off.

As soon as i went back to stock, i immediately was able to boost to .85 and even overshot my AVC-R on a long 4th gear pull to a full 1.00 BAR.

I'm not going to venture too far into the possible reasons why the IC was causing problems, but i'm just pleased that the car is back to "normal". I'll inspect it sometime this week and see if it has any cracks or leaks that can be easily detected, which could explain the problems.

That's gotta be a boost leak in the intercooler or one of the hoses...

When the tank/piping is pressurized, small leaks become bigger and air blows out of them. Because of that, the pressure can't rise above a certain amount. The whole time, the ECU is still fueling for all the air since the MAF is still reading it, so the mixture becomes terribly rich, to the point of causing misfires. The result is the hesitation you experienced.

A radiator shop should be able to pressure test your intercooler and find a leak if there is one.

Could the intercooler also be obstructed in some way acting as a boost limiter? Similar to when a catylitic converter gets clogged and you cant rev over 4500rpm?

ciper's explanation is what first made me suspect the intercooler, and unless it has a hole in it of some sort, that's really the only explaination.

Come to think of it, it does seem to have become awfully noisy as of late. Granted, that could be from the air leaking out or the intake air having difficulty getting through the intercooler itself.

I'll look at it when i get home tonight.

Dave

If it's clogged, you'll still be able to build boost; it just may take longer and be less efficient. Consider that people who plumb their MBCs to the intake manifold instead of the compressor outlet are able to get full boost even with the throttle halfway closed.

Dave, extra noise is another common symptom of a boost leak.

I would check the piping to and from the IC first, it could be easy to overlook a small crack that would only leak under boost.