Hi all, still fighting ongoing boost issues.......
Gradually eliminating possible causes one by one!
Story so far ....
Excellent boost on primary and dropping boost on secondary by about 2/3 psi.
Vac hose replacement done (couple of solenoids and acv changed at the same time)
New aluminium pcv valve fitted as the old one was busted.
2 Check valves replaced
Tonight on closer inspection I discovered one of my new hoses was too short and was kinked - it was the one to the charge control actuator - it was supplying no vacuum to one side of the actuator so the door to allow the secondary turbo wasn\'t opening. Have sorted it now and the actuator is working fine.
My boost is now a little short on the primary turbo - I think that the reason for this is - When I replaced the Pills in the wastegate actuator line and prespool actuator line I noticed that they weren\'t quite as snug in the hoses as they were in my old hoses. From reading up this could cause a drop in primary boost by the amount I\'m getting. Anyone else agree ? If so how can I make the pills tighter in the hoses? Is there anything I can replace these pills with?
The transition point between the 2 turbos is very nice now but the boost is way short when the secondary turbo is online. Got a few theories as to the problem that I\'m going to check on Saturday. Any suggestions are welcome though.
Other things I\'ve noticed now after doing this
Vacuum at idle sits around 16inHg (just about right I think)
My idle speed seems to be around 1200 when the engines warm - any suggestions on the cause and what idle speed should be
There is now a rattle coming from somewhere at low revs - dunno how to explain but around 2000 revs it starts - seems to be coming from directly in front of the driver and it stops around 2500-3000 revs.
When I took the car for a test tonight, I got wheelspin in second gear even when accelarating gradually - got quite a fright actually cos its never done it before! Happened once in third gear too. Might have been slippery roads but I don\'t really believe that as it wasn\'t really all that cold!
Has anyone tried changing to the simplified sequential setup? as seen here
http://www.turborx7.com/images/turbos/turbo_system_simplified.jpg
if so how did it go?
was it easy to do and how reliable has it been?
Come on folks rack those brains and lets see if we can get another rx7 back to full health
On a different note I have a parcel shelf for sale if anyone needs one - Complete with 6x9 speakers (pioneer) £70 if so.
When troubleshooting mine (similar problem) i used the smaller vac hose for the "pill" lines, to give a tighter fit. Eventually i put Dawes Devices in both lines, instead of the pills, to fine tune the boost, got a 10 - 8 - 10 now (instead of 8 - 2 - 2).
Just a suggestion.
Jon
My symptoms are about the same!
Have
replaced all vacuum / pressure lines
tested every solenoid, check valve, and actuator.
replaced inlet manifold gasket
replaced turbos!!
Yes, I guess you could could replace the pills with something you can adjust, and then get the boost up to the correct pressure.
However, I worry - thats repairing the symptom, and not the cause.
Areny you overevving the Turbo by using this method?
I actually had to make my own pills as they were missing when i got the car from Japan (hence the 8 - 2 - 2 boost pattern)... Took ages to try to drill the right size holes.
Eventually i thought "sod it" and got the dawes devices. Problem solved.
To tune the transition after fitting the dawes\', i also adjusted the turbo-pre-control actuator rod (adjusts pre-spool of 2nd turbo) to get it just right...
Jon
I thought about the "non sequential" but was told that altering the boost pattern without altering the fueling (Standard ECU) could cause lean and rich conditions at the wrong time.
Jon
QuoteOriginally posted by hmltnangel
Hi all, still fighting ongoing boost issues.......
Could have had that as my epitaph when I had a Z :D
Just stumbled across this Googling to find out if "pills" are what I thought they were... might help you?
http://robrobinette.com/boost_controller.htm
Diagrams and everything...
Anyway, yea, if the pills aren\'t quite snug, more of full turbo pressure will reach the wastegate actuator, leaking around the edges of the pill, so you won\'t reach as much boost. (The idea of the pill is that it "hides" some of the boost from the wastegate. Without the pill in place, as soon as the turbo is delivering 7psi the wastegate will open and the turbo starts to spool down. The wastegate opens when it sees what it thinks is full boost - so if you are hiding some of the boost, the amount of boost you have is actually over "full".)
In other words in a system working properly with pill in place, the pressure at turbo is (say) 10psi, the pressure on the turbo side of the pill is 10psi, the pressure on the wastegate side of the pill is 7psi, and the pressure at the wg actuator is 7psi. Therefore, you HAVE 10psi of boost, and the wastegate THINKS it is maintaining 7psi.
QuoteVacuum at idle sits around 16inHg (just about right I think)
I presume the second turbo circuit is shut at idle so a vac leak in that wouldn\'t show up...
QuoteWhen I took the car for a test tonight, I got wheelspin in second gear even when accelarating gradually - got quite a fright actually cos its never done it before! Happened once in third gear too. Might have been slippery roads but I don\'t really believe that as it wasn\'t really all that cold!
Boost could be spiking? When you say "accelerating gradually" I guess you mean you were on part throttle and keeping foot still - sadly in an FI car (esp one that\'s misbehaving) that doesn\'t necessarily mean linear power delivery...
I had a very similar problem. Loosing boost on the second turbo. After much searching by WGT it turned out to be the JDM speed limiter was screwing things up. After replacing it and putting in a larger dia pill the underboosting was sorted. Unfortunatly its now overboosting!
Boost controler here I come!!!
how was the speed limiter screwing things up?
also what are dawes devices? where do i find them and how much?
I am going to pop on the narrower hose and squuueeezzzeee the pills in there anyway.
The main concern is the rattling?
Gradual accelaration was a smooth slow push down on the accelarator and still got wheel spin but the boost guage continually read 0.65 kg.
I originally got my Dawes Devices through J W Racing (UK), but i dont think they stop them now.
Try http://www.apexperformance.co.uk/catalog/product_info.php?cPath=120_130_135&products_id=519&PHPSESSID=c91f64102bd58ab13648be5c835ff8e7
This is the one that the 200SX boys use, and is basically the same thing.
Information about the devices is at http://www.dawesdevices.com/
Cheers
Jon
hehehehe,
if you\'d said a manual boost controller i\'d have known exactly what you meant ....had one on my mr2.
Still curious about the solenoid under the manifold .... does turning the wheel on it make any difference ?
also has anyone tried changing to the simplified setup that keeps the sequential system as per this diagram?
http://www.turborx7.com/images/turb..._simplified.jpg
Hiya, still working on the car and noticed something new tonight.....
The rattle that was coming from the car (see - who nicked the boost) does seem a little worse. It appears that it\'s coming from under the intake plenum somewhere and from under the bonnet it sounds more like a ticking noise that starts around 2000 revs. If you put your ear to the intake plenum then it sounds louder and if youmove your ear to just in front of the plenum (near the pressure chamber) it gets louder...
any suggestions folks .... cant start the engine with the extension manifold off so suggestions would be nice before I go tearing bits off!
Air Pump?
Right folks, still busily workin away. Think I might (thats a big MIGHT) have found the cause of the problems. As above I noticed the ticking coming from under the plenum, upon investigation (by investigation read - sticking my hands in little places) I discovered that there\'s air leaking under the plenum, now I\'m no expert but it seems to start around 2000 revs so that would suggest a leaky acv, eh?
So therefore I have the following question(s)
1. what does the acv do? (air control valve assembly)
2. does it affect secondary turbo boost?
3. does evryones air pump sound like it farts when it\'s sucking air in with no hose on it?
It appears from the diagrams to go to the Relief solenoid and the switching solenoid. Does this mean my car doesn\'t know when to swap over to the other turbo or maybe even doesn\'t know when to start prespooling the second turbo?
1. ACV contols air for emissions, and directs air to either cat, manifold or air filter.
2. It has nothing to do with boost control. However, if there is a leak down there, then one of the other solenoids that do control boost could be missing its boost source.
3. Mine\'s more of a moo than a fart:p
Jon
suppose a moo is a good way to describe it!
Yeah the acv seems to be connected to the switching solenoid and the air bypass solenoid - i\'m assuming that these have something to do with the turbochangeover and maintaining vacuum.
New problem now!!!!!!
changed the hoses with the restrictor pills ..... now i\'m getting scary boost of 0.9kg (12/13 psi) so bad that i\'ve not yet discovered if the second turbo comes in! Will ind out today.
Good thing is I can hear the first dump valve start to slowly release air around 3200 revs - this would appear to suggest that the second turbo is actually spooling up. Then venting as normal before the changeover?
The switching solenoid switches the ACV air IIRC, and has nothing to do with the turbo control IIRC.
Jon