Tried to have a good read up and have had a quick look for any hard pipes or anything dislodged without much success.
The car boosts fine at 1bar in any gear then if i change up the boost only hits 0.2bar. Step off the throttle and give it a small time and then it boosts back to full pressure.
Does this mean i have a dodgy solenoid, sticky wastegate ???
Any advice would be greatly appreciated..
Shaun
Yeah mate, dodgy solenoid. I had the same issue with mine, tested them all with a mityvac and found a couple to be dodgy !
Could also be a hose collapsing in the rats nest.
All the hose is pretty new, it was swapped about 11k ago and all looks in very good condition. Only iffy one was the one leading to the boost sensor :eek
Cheers, how do i test them ?? is the mityvac the hand held jobby for vac testing ??
Shaun
does it drive correctly again after seeing vacum?. also if you keep accelerating up the revs does it spool eventially? and at what revs does it all happen.
matt
Yeah mate thats right, bloody good piece of kit and worth the money !!
Quote from: gmogleYeah mate thats right, bloody good piece of kit and worth the money !!
ill second that, was the 1st thing i perchased when i decided to do the rats nest.
Been a godsend ever since, used it on bleeding brakes, clutch, testing valves and just about anything else i can think of :)
the pressure chamber under the the strut brace (black box) holds a small amount of pressure so that it can activate solenoids and actuators quicker when you arent on boost so that you can boost more instantaneously this is probably your problem.
under it is a check valve (green and whitr plastic thing with an arrow on it) air should only go one way through so take it out and blow through it to check. this may be leaking or in two bits. there are also 3 more next to it on the right and one under the rear of the plenum check these also.
there is also a vaccum chamber (another black box) which relates.
hth
Cheers, I had a look at the pressure chamber and couldn\'t see any leaks, might take it off and test if its holding a vacuum.
I\'ve re cable tied the check valve, but was struggling to get it off the pipe that disappears into the engine.
Will have another good look when it drys up.
Cheers Guys :D :D
Shaun
oops sorry the boost does slowly build back up and then kicks in.
Are the one-way valves easy to get hold of ?? Are they a mazda only part ?
Shaun
i might have some valves about, they are £34 i think from mazda each, you can get some from the states but will take a little while. they can be checked by blowing through them onto salt etc. i advise checking them definately.
i do think under the plenum is not your problem as boost does kick in.
try looking above the turbo area. the y pipe in particular. The holse from the pressure chamber goes to the y pipe and the other hose goes next to the chamber below it.
i think your problem is either with the hoses that attach to your y pipe, Lower inlet manifold or the area at the front of the turbos ie below the airbox/filters - the hoses here go from the actuators on the turbos - from under the car you will see two rods attached they have a joint which has a circlip these also fall off as they are very fine and usually rusty.
i have fixed all my boost issues and (i had alot of them) and now done a few for friends. - my advice is start with the easiest of things, check everything thoroughly ie take hoses off if need be and check for cracks etc - i bought ebay rubber hose with a huge wall thickness but the heat made them close up inside but they still looked fine outside.
hope this helps,
give me a call if you need to.
Tested 2 of the valves with the blow test and they seem ok, need to dig a bit more to get to the others.
I\'ve ordered a mityvac off ebay and will try and do a proper check :D
Read an interesting post on rx7club about the higher boost setups screw up the contol solinoids and some people are now putting a pressure regulator into the system to reduce the pressure back to 9-10psi at the control bits.
Shaun
You can get viton check valves either from a guy on rx7club or on ebay...about $15 for 4 and far better quality than the OEM ones.
Yep, I did some digging online, when i had a connection ! and found this last night
http://www.coleparmer.co.uk/catalog/product_view.asp?sku=9855322
will probably order 4 and see if they are the cause.
Shaun
hi shaun
what was the name off the place you got the mityvac from and how much was it thanks
the ones from rx7 club work fine, and it sounds like the check valve to one of the chambers is fduked or the chamber leaks, ie not holding preasure/vacume.
sorry i cannot remember which would cause this. whats happening is after the change over the turbos arnt going none seq again.
matt
correction, i think its vac as after reaplying vac from engine (letting revs drop) the tubs return to normal.
matt
ps i have both chambers if you need them.
Cool, may be giving you a shout for them once I\'ve tested them with th new gizmo :D
Just as I need the car while i swap engine in the 1st gen !
Shaun
Quote from: shaunwilCool, may be giving you a shout for them once I\'ve tested them with th new gizmo :D
Just as I need the car while i swap engine in the 1st gen !
Shaun
i have chambers, hoses, valves, solenoids and just about everything you need mate so let me know if you are in need.
Cheers guys :D
Want it running right by rotorstock, so not much time :eek
Shaun
Quote from: adibhi shaun
what was the name off the place you got the mityvac from and how much was it thanks
oops, only just spotted this question. Bought it off ebay for £41 all in, called
chrometrader0 on ebay !
Just a quick update, I used a foot pump and a bucket of water to test all my one way valves and the easy to get to vac chamber. Found 2 of the valves where leaking. Got some 2nd hand ones off pip while picking some other bits up. Tested them and one was leaking (only paid a couple of quid for them) so had a dig and found a good one off the bits I don\'t need on the 13b EGI engine for the 1st gen !
Just taken car out for a run and the pickup is quicker, slight hesitation (0.35) then full boost, change up again and its 0.35 boost for a few seconds before it builds up again.
I\'ll try and check the other vac chamber in the week but its buried under the alternator !
Shaun
I still reckon it is one of the solenoids mate and not one of the check valves.
Check this link out:
http://rx7.voodoobox.net/howto/solenoid_check/solenoid_check.html (http://rx7.voodoobox.net/howto/solenoid_check/solenoid_check.html)
Tells you how to test the solenoids properly. I reckon when you test yours you will be suprised and I would expect one of these to be wrong.
Check also the vac piping, see if any are kinked or almost kinked as these can collapse when they are warm.
I hope its something as simple as that !
I\'ll wire up some thing to do the test and see if its one of them ! Reading through this it definitely needs a pressure regulator in the loop before the control solenoids to stop them from sticking !
Cheers
Shaun
Reading that page makes me definitely think its that what is causing the problem.
I just hope it is !
Cheers
Shaun
Mine had the same problem as yours, it would accelerate through 1st turbo, 2nd would then sometimes work and then other times not. The main issue also would be if I accelerated hard into the 2nd turbo, then let off and put my foot back on. The car would make a loud noise as if it was struggling to accelerate. If I let the revs drop to about 4000 rpm and then accelerated it would be fine.
But when I did my rats nest after that I found 1 way check valves going both ways, loads of loose hosing with one major kink in one and 2 solenoids faulty. I honestly cant remember which solenoid it was to be honest but that seemed the most likely candidate giving me the problem. Did the test as shown above and it would hold the boost before releasing rather than letting off straight away. When I put it all back together and tested it the car felt like new !!
You could plumb in a gauge to show vac pressure going into the chamber to test it isnt overboosting.
Good luck mate !!!
sounds like i\'ll need it :Giggle
I\'m going to plumb a pressure regulator in too so i don\'t kill the replacement ones too with 1 bar of pressure :D
Shaun
Pressure regulator thread on rx7club :
http://www.rx7club.com/showthread.php?t=480079
Shaun
I had thıs problem last year aswell...but it was only random...would happen only from standıng start rather than rollıng...weırd...3 or 4 need replacıng now though so wıll check them next week...ıs there a specıfıc solenoıd that causes ıt?
ive still got a top notch rats nest if anyone needs any bits,
hth,
t
I\'ve taken the plenum off and had a go at checking all the check valves. The upper one and the middle 3 (no egr valve and couldn\'t reach back one) Plus I struggled to get to the front two. I got a coulple of replacement valves when i left my exhaust at pips so ended up unplugging the boost control one and plugging in a known good valve and putting it in the egr position. Boost seems to be good. It running lower that it was before, more like 0.85 bar so will need to change my boost controller settings to compensate.
I put it all back together, don\'t think i have any vac leaks. Nice stable Idle once warmed up and the boost is coming in quite quickly too.
Have to say its a bugger of a job, I was trying to do it in situ without removing alot of stuff and some are just completely impossible to get to !
Should be able to do a few gears on full boost in the morning with quieter roads so hopefully that will show the outcome !
Shaun