Mazda Rotary Club

Ok chaps heres the deal,

 TII with a rebuilt block (not run in yet) its running etc, and although I dont want to build up any boost on a standard engine, I noticed yesterday when I held the throttle down to 6000 rpm that the boost only just crept onto the positive side of the guage and quickly snapped back down to vacuum before I took my hand off the throttle.
 Bearing in mind the car had sat still (and in many, many pieces) for 5 years, I\'m thinking wastegate actuator?

 Any thoughts?

 Thanks in advance!  :wiggle

were you in nuetral?,   if so, you wont build any boostat 8000rpm let alone 6, you need the engine to be under load.  If you were driving and you accelerate slowly, you will still not create boost...  You need the car under load, the more load, the earlier the boost will come in.  Revs dont neccessarily match up to boost.

Ah, right! :)  Must engage brain then 1st! lol!

 Thanks Ant.  Although I\'ll still be surprised if it runs problem free though after all those years stationary :)

:wave

You may be pleasantly surprised, but good luck anyway.

Bye the way, dont trust the dash mounted boost gauge, they are crap, new or old....   Get an aftermarket one to get a good reading, even if you dont leave it in place although its always good to know what boost you are running if you are going to modify the car.

If you have a non standard exhaust or the cat removed from the stock one then you may find that you boost cut in 3rd or 4th when you are giving it some wellie,   I know some people dont like boost cut defenders but others say boost cutting is not good as it starves the rear rotor of fuel. Which cant be good either when you are under full load.    The stock set up can cope with 10 or 11 psi of boost without problem so if you only run this level boost then you will need the boost cut defender but will not be doing the car any harm at all.  With a good exhaust/air filter and 10psi of boost it will be a different car.  If you need i have a boost cut defender, i have one (plug and play 30 second instal) which i have just taken off my TII which you can have for the price of a drink.

If you do find that you are running less than 7psi of boost there a few things it could be,  blocked cat  (if you have)  knackered duty solanoid, which means that you will run actuator boost level which is on 5 psi,  this allows the ecu to back off the boost if it feels temps are too high or even knackered baffles in the back boxes can cause it.

Hope im not teaching you to suck eggs as i know you have had a quick EGI, but the Turbo makes all the difference
regards
tony

"If you need i have a boost cut defender, i have one (plug and play 30 second instal) "

errrr brett has one already ... but stu hasnt

Thanks Tony,

 I was at Rx-Heaven today (and discoered that chris who works there is in fact an old school buddy, small world eh?) and they are putting a Greddy boost guage aside for me.  As Grinder says, I have an FCD (not fitted yet, as not intending to boost for a good 1000miles or so) ready to go.

:wave

Oh yeah, and I\'m sure your spare FCD would be given a good home by Grinder :D

thanks brett :)

Thanks for the info guys, it boosts fine on the road.

so how is the car brett - what you expected ?

The car is great, runs smoothly, all the electrics work and upon inspection it must have had a full brake overhaul just b4 it was laid up, although the discs were corroded there was no actual wear it also has green stuff pads :)

Quote from: antnicukIf you do find that you are running less than 7psi of boost there a few things it could be,  blocked cat  (if you have)  knackered duty solanoid, which means that you will run actuator boost level which is on 5 psi,  this allows the ecu to back off the boost if it feels temps are too high or even knackered baffles in the back boxes can cause it.

regards
tony

 Right, so much for my \'its boosting ok\' speech.  Sounds like the duty solenoid is not playing as the car is boosting to around 4-5psi (halfway up the positive side of the boost guage) although the exhaust is pretty knackered atm I know its still flowing well.  I\'ll be testing the solenoid some point this week to see if its actually getting a signal from the ECU.
 Your post has been really helpfull Tony, many thanks :)

dont trust the stock dash mounted boost guage,  check the reading from your after market gauge.

If your air temp is reading high, the ecu will make it run less boost so make sure thats connected.

I\'ve checked the internal guage against my test guage and its reading within 5% of the other one.  Temps have been low too, I wont be at all surprised if its the solenoid or the wiring to the solenoid as it all sat outside for far too long.  Still, all the whiule I\'m running it in I dont really care, give it another 700 miles and I\'ll get around to sorting it out :)

Can any one confirm my suspicion that the duty solenoid is not capable of creating an ECU error code?

no idea matey - but i have a boost controller here that you can connect to the duty selenoid thingy - that you can up the boost with

your not having it - just though i would mention it !!!!

4-5 PSI - sounds pretty low though - i could get mine neatly to the top of the stock gauge - but you had to really batter the car ... usually it would go half way

is the actuator rod connected on the bottom of the turbo OK ??

I\'ve found the problem, (Well ok I gave the car to my Dad out of exasperation and asked him to have a play) Theres a pipe split on its inside edge on the left hand side of the UIM, runs from the turbo to Intercooler pipe into the control valve.
 All I have to do is replace it and I should start seeing some proper boost.

blimey - how did he spot that if you didnt ??

He\'s got about 30 years more experience than me! :)

yeah that must help !

you will have to keep us all posted and tell us what it runs like once you have bedded it all in !!

Its got 700miles on the block now, so I\'m going to start giving it some throttle now :)
I\'m going to start making my exhaust this weekend. (Assuming nothing else needs doing)

Right, I\'ve changed the split pipe and still have the same boost problem.  
Are there any common faults on the Vacuum lines running to the duty solenoid?