[Mk2] [Turbo] Another boosting problem !

[Michael-MR2]

got a rev 2 turbo , had it now for about a year an a half an its always had boosting problems . Some days it would run great an then others wouldn't pull you out of bed ! Anyway fitted a boost gauge and got the boost put up to 14.5 , and the problem is still there. What seems to happen is , as a said can be running fine boosting well then just loses power an only boosts to 10 ! an when doing this the engine sounds different , an dump valve sounds quieter , sounds restricted in some way anyway 3rd dump valve later , pressure tested , smoke tested , new afm , amongst other things . anyone any ideas ???

[jimGTS]

do you have a fuel cut defendor??
have you check your igntion timing??
have you checked for error codes??
are you using high octane fuel??

[STU13 B]

What sort of boost controller have you got?

If its a MBC sometimes the ball bearing sticks inside the spring. My 200sx S14a had this problem, took it apart and sprayed WD40 inside and it sorted it.

It u have no FCD u are hitting fuel cut @ 1bar, safe is 13psi on Rev2 Tubbys. I had this problem with mine so reduded the boost down. I need 2 get my FCD fitted then i can run 14.5 again. I think the car goes onto safe mode, so will only run stock boost if theres a fault.

As said check for fault codes.

[Michael-MR2]

eh fuel cut defender ? yeah using the right fuel , ignition timing ? and error codes would they not show up on a diagnostic machine cause its been on a couple different ones an didnt show up anything , and the problem was there even before i had anything done with the boost . And dont no what kind of boost controller was fitted , just looks like a brass valve that you can open or shut (if am even at the right thing)

[jimGTS]

well i suggest you learn how things work then dude regarding boost controllers....

without running a fuel cut defendor, fcd, soon as you hit around 13psi, fuel will be cut to the engine, and itll hit a brick wall (least thats how it feels)...
you need to raise this fuel cut limit if you plan on running anything over 13psi...(0.9bar), you use a fcd to do this.

error codes, please do this yourself, and dont pay anyone, all you need is a paper clip! and you can check it yourself! there is info on this on the knowledge base section..

igntion timing, if its to far advanced, youll be knocking and possibly detting, which is VERY bad for the engine, you need to check this is normal/correct with as timing gun....

[triggermad4it]

i had that problem with mine boosting then not so i changed dizzy cap and rotor arm leads and plugs this solved the problem after market dump valves and intakes affect boosting just give it a bit of stick and it sorts the problem also

[Michael-MR2]

cheers ill check the error codes , an ill try to find out about the other things

[AdDaMan]

i have the same sort of problem, most days its fine and boost 10-11psi but sometimes it only goes to about 7psi and feels very restricted and doesnt go anywhere really. Its a near standard car so im hoping its prob just dizzy cap or leads so will change those next to see.