Steve_H

Seem to have developed a boost problem lately.....

Floor it in 2nd or 3rd and boost seems to come in waves....

Boost - Flat - Boost - Flat ....etc.....


Any ideas what might be wrong ?? What about this solenoid thing, might that need cleaning ??

Hope someone can shed some light on this.....

Steve

Steve_H

come on......someone must have an idea.....

please ???

grant620

Yes, the boost solenoid could cause this.
Try bypassing it by disconnecting the two pipes that go to it and joining them together (in a loop). Now you should have lower boost all the time.
If it's flat and ok, the solenoid is to blame. You could clean it, replace it or bypass it using a Mechanical or Electronic boost controller.
If it still does it, you could have am ignition fault, or it could be hitting boost cut?
What boost are you running?

Cheers
Grant

Steve_H

Grant

thanks for replying.....I've read quite a few of the old threads about cleaning the solenoid so I'll try that first.

Don't know what boost I'm running (MY 94 UK Turbo) I guess it's just standard boost (whatever that might be).

What's this boost cut you talk about ??

Steve

grant620

At a certain level of boost, you hit boost cut (wrong term really, should be fuel cut).
This is when the ECU sees a big stack of boost and says, "Umm, you don't wanna be doing that mate" and cuts the fuel supply, so the boost drops.

Could be this, but if you are on std boost and you don't see any boost spikes, it's more likely to be the solenoid.
As I said, temporarily bypass it - that will prove it one way or the other.

Also, try an ECU reset?

matt b.

if the solenoid idea doesnt work, check that the small pipe that connects to the underside of your airbox on the wing side hasnt become disconnected. its a pig to put back on, but rather ingeniously seems to work its way off with no troubles whatsoever. mine did the same thing resulting in your symptoms.

good luck mate,
matt.

Steve_H

OK, after cleaning the solenoid (3 port type MY94) and all connecting pipes over the weekend, the problem still exists. (boosting in waves)

Matt B. .... funny you should mention that pipe. When I came to clean it I noticed that someone had been there before. At the air box end of the pipe, there should (I presume) be a short plastic tube for the pipe to fit over ?? well, mine has obviously been broken off in the past and been replaced with a piece of brake pipe glued into the air box.

I pulled the home made connection out of the air box, cleaned it all up and glued it back in again.

Now to me the use of the brake pipe may be too restrictive.....

Is the bore on this pipe really that esential to the operation of the solenoid ??

There seems to be a restrictor at the solenoid end of the pipe, why is this there ??

Could my problem be nothing to do with the solenoid ??

I'm clutching at straws here, are there any good techie's out there who can suggest the next move ??

here's hoping....

Steve

matt b.

the pipe had broken off on mine too, the subrau original is made off the same shoddy plastic as all the other vital pipes. i driled out the hole and replaced the original attachment with a brass fitment that i got from a hydraulics firm, for a couple of quid. the outside diameter of this was slightly larger,but the internal diameter was slightly smaller, but it didnt seem to make much of a difference. so you could do that. HOWEVER, whilst jigging around this weekend with my blitz induction kit and its position i had to remove this pipe (noticing the restriction that you mention, that id never seen before) and replace it with some longer hose so that it could reach the new position. this new pipe without in line restrictor seems to have had a slight affect on the idle, which was very even before, and now is a bit uneven, but other than that all is well with all systems. therefore im not convinced this would cause you turbo problems, BUT if this pipe were hardly connected at all, ie by some bodgy fix using brake pipe, then it would cause you boost probs for sure. at least, it would be one possible reason for it.

hope this helps. good luck, get back to me if i can help further.

also, if somebody could tell me what this in-pipe restrictor is for and what im wrecking by running wiithout it id be grateful.

matt.

grant620

Steve,
Did you try and bypass the solenoid in the end or not?
Cause it could still be faulty, albeit now clean
I would loop it out and take it for a spin mate.

Grant

Steve_H

Grant.....no I didn't by-pass the solenoid.

You mentioned joining two pipes together.....mine has three pipes, so I didn't know which two to join together.

I beleive the early models had a "three port solenoid ??" and later models had a "two port" ??

Do you know which two I should join ??

Anyone else ??

Steve

redwrx

Ive got MY93 wrx...and had similar probs.

I cleaned and replaced boost solenoid, wasnt that.

Coil packs is another favorite for boost problems, but before you go down that route, i'd have a look at your plugs ...i left them till last and found them to be the fault. Check the gaps, i was running 1.1 on Platinum's.. told to try 0.7 and guess what? problem cured.

I tried replacing the MAF sensor aswell, i even threw a new dump valve in...good excuse to get it..

but it was the plug gaps..

apparently they are quite sensitive to the gapping.....


HAve a look at the Coil packs, see if they not damaged, or cracked..as this can cause cut out so im told, you can measure the resistance across them looking for about 0.8 - 1 ohm again, its just stuff i tried from reading other threads.

Hope this helps


Frank

Steve_H

Nice one Frank......I had been thinking down the route of plugs / coil packs next....

Think I'll check these on the weekend.

Anyone come up with an answer as to which 2 of the 3 pipes to connect together to by-pass the solenoid ??

Steve

TonyBurns

iTrader: (3)

I had a problem on my MY00 where i was getting overboost (on off on off etc) now the problem turned out to be a clogged wastegate pipe, a quick drop off and 26 quid later the car was flying again
Anyway i take it your car has no modifications? (this can cause overboosting which i have also suffered ) but your best bet would be to get it on a rolling road (or add a boost gauge) to see where your boost drops off (if its a clogged pipe it wont reach its optimum position and boost will just die )

Tony

scrappy_doo

Same problem with MY94 WRX I am changing the plugs this weekend as I already changed boost solenoid and it wasn't that bugger !