tzbfwt

iTrader: (1)

I know the Forum doesn't need another Boost issue thread - but I've searched alot and not seen my EXACT problem.

5 speed, engine replaced with a reman, turbos replaced with "allegedly good" used ones, full silicone hose job, removed the following to simplify control system:

Double Throttle
AWS
EGR
All Air pump control solenoids/valves (Air pump still installed - runs direct to Cat)

I used a "simplified sequential" vac hose diagram I found on the web.

Downpipe, with stock cat. Stock ECU. Could swap on a PFC if that would help with troubleshooting. M2 Medium IC - all intake hoses appear to seal OK.

Boost Pattern 8-5-2 (2 could be 0 , I don't hold it at high RPM for long). 2nd and 3rd gears are the same. Warm or hot - same boost pattern.

I've got two pressure/vacuum gages tee'd into the lines to the Turbo Control actuator - at 4500, the pressure side is good: 8-10 PSI, the vauum side is about 4 inches Hg.

No check engine lights. Engine has good vacuum at idle (17-18). Charge control valve pulls in at idle - but have not watched it actuate yet - need another pair of eyes. Secondary Charge relief valve checks good with a vacuum tester. Both vacuum and pressure tanks appear to hold vac & pressure after car is off for 5 minutes. Primary charge relief makes the right noises when I let off after boost - seems to be working.

Made sure I put the boost pills in the right hoses - and they are oriented properly.

In short, it seems like I'm getting decent primary boost - but it drops to almost nothing when I hit the secondary transition.

My next ideas were to pull the vac line off the charge control valve (force it open)and see if that gets me some secondary boost. If nothing there, then wire the turbo control actuator to "full open". I want to see if the secondary turbo is alive and will make boost. I've heard no funny noises or seen any smoke that would tell me that there is a problem with it.

Question: Is 4 inches of vacuum enough at the TCA or should I see more? If so - where should I look on the vacuum side for leaks? Car just passed emissions - but I wonder if the cat is starting to clog?

Any other help from the Gurus ???!

tzbfwt

iTrader: (1)

No one wants to take a shot at this one?

How about just a simple answer - does anyone know if 4 inches Hg is the normal vacuum level at the turbo control actuator?

Thanks

Jim

moconnor

iTrader: (14)

I did similar testing last year and I suspect you should see more than -4" Hg but can't recall for sure. A failure at the vacuum side of the TCA is typically caused by faulty check valve. I would replace them all with Viton valves.

tzbfwt

iTrader: (1)

OK - I will "check" the check valve on the vacuum side - I ordered some Viton valves from Dale Clark - but I can't remember if I installed them during the hose job or just re-used the old ones...

The real lesson here is don't let your FD project stretch out over 3 years and 3 houses - you forget what you did - and you lose stuff...

Jim

tzbfwt

iTrader: (1)

Some progress - but still not solved. Checked the vacuum side check valve - in the line to the Upper manifold - it was good, I disconnected this line and applied 10 inches Hg to the "vacuum side" of the system - it held 10 for 2-3 minutes, slowly leaking down to 8/9 - so I think the vacuum side is relatively leak free. The charge control valve also pulled in when I applied vacuum - as it does when I start the engine.

I did find an unplugged vacuum port in the UIM that I hadn't noticed before - I plugged it with a hose/bolt and now I have a nicer & lower idle, so at least I've made some progress.

I disconnected the vacuum line to the charge control valve and drove the car - same boost pattern - the boost is dropping off after 5-6000 RPM to 5 or less.

I think I'm going to remove the stock cat and replace it with a straight pipe to see if I've got a clogged cat - other than that I can only guess that I've got a DEAD secondary turbo - which would SUCK.

Jim

twomucboost4u

iTrader: (9)

If the cat was clogged you would notice it on the fist turbo as well... Have you gone over your simplified seq.? Sometimes we miss things the first tiem around... I would go back through and make sure you have all the right solenoids connected to the right electrical. If it was a leak in the secondary system you would have boost in the secondary and it would drain out with RPM. Being that it is pretty much non-existant I would have to think something is not working correctly. Waistgate, Turbo, Solenoid, prespool. You should be able to pull any vacuum line off and hear a whooshing sound from the system being pressurized. Have a freind come over and turn car on while you watch the actuator on the Y-Pipe to make sure it is actuating. If its not moving at start up you might have a bad solenoid.

Chris

mad_7tist

sounds like you are loosing boost thru the crv. when the ccv opens the crv should close. was the boost pattern good before the hose job?

tzbfwt

iTrader: (1)

Boost pattern was 10-8-10 before reman engine, hose job, and new "used" stock twins.

I'm only seeing about 8 PSI primary boost on the boost gage - but ambients are around 100F here... Charge control is moving - pulling in at start up. I checked the charge relief valve with a mitivac - it works as the manual says it should.

I also suspect the cat because the last set of stock twin launched the primary turbine down the downpipe and into the cat - you can imagine how much oil that pumped into this old stock cat...

I've checked the hoses as best I can without taking the UIM off... Since swapping in the mid pipe is easier that re-doing the rats nest, I'm gonna try that first.

Jim

supraturbo1987

iTrader: (4)

Well, I have the same set up as you...left the airpump on as an idler too. I have MBC though and no pills. I have a 9-5-3 or something like that....clearly not right, so I am going to mess with these controllers and see if I can get it worked out. I currently DO run a midpipe, but am going to put a cat back on for smell reasons (not me, but my wife)

Trev

the-k-man

I had a clogged cat problem. My primary would boost 10 lbs then when the secondary was suposed to kick in, boost would just drop dead. I checked everything and could not find the problem. I ended up just losening the bolts from the DP to the cat, wedging it open a little and I got my secondary boost back.

Ive replaced the cat now, but it is a easy way to test if that is the problem.

tzbfwt

iTrader: (1)

Unbolted the front of the cat and inserted a 1" spacer to hold it open while I drove (loudly) thru the hood.

Primary boost was a nice strong 10 PSI, but it still falls to 5 psi or less at transition and higher RPM - so it's back to the turbo control actuator and the diving into the rat's nest I guess.

twomucboost4u

iTrader: (9)

So I just helped a freind with a similiar boost problem had good boost untill transisiton then would lose it all. Ended up being his Turbo control Solenoid vavle.

Chris

dgeesaman

iTrader: (7)

Based on having bought several low mileage rats nests and thoroughly testing each solenoid, it's very possible that one or more is not functioning correctly. I test for release under pressure load and vacuum load and slow leaks. I pitch a good number of them based on these results.

4" in not enough. You should see most or all of the vacuum your engine generates under braking, which in my car is 20-22". Even after using some vacuum to operate the solenoids in primary mode, there should be 15" or more left during secondary operation.

Losing 1" per minute is probably not bad, but it's not what I'd consider normal. On my car I don't see any vacuum or pressure drop for much longer than that. Consider too that the leak will be worse when you have 10psi adding to the 10" of vacuum. It could be a check valve or a solenoid.

I would get a Mityvac with the vacuum+pressure gauge before diving into the rats nest.

Dave

tzbfwt

iTrader: (1)

As usual, it took me forever to get back to the car and troubleshoot the problem.

Having an 07 MazdaSpeed 6 as my new daily driver might also have something to do with it... and it's about eleventy billion degrees in my garage these days...

Enough chatter - pulled the upper intake and went over my simplified vacuum diagram again... Doh !!!!

Back in 2005? when I did the vac hose job, I must have been a bit confused - I had a couple of hoses leading to the Charge control solenoid and the Charge Relief solenoid screwed up! The secondary boost line that comes from the secondary turbo side of the Y-pipe should "Y" and go to both charge relief and charge control solenoids- it was wrong - it never went to the charge control solenoid, so even though that solenoid was working as advertized, it never had secondary boost "available" at the valve so it could be supplied to the charge control actuator which needs equal pressure (secondary boost on both sides) to open - so it was never opening. It still pulled in at idle because my charge control soln was getting vacuum, but it could never supply sec. boost and equalize the pressure at the CCA. I also had vacuum applied to the wrong side of the Charge relief solenoid - who knows what problems that was causing - I don't think my CRV would have opened the way that it was plumbed - so maybe that was keeping my secondary from being able to build boost before transition?

Also - before diving into the rat's nest, I found a vacuum port open under the UIM - I had left a nipple unplugged near the "cluster" of ports near the throttle body - where the PCV valve and the main vacuum supply port is. Fixing that leak gave me a nice low 800 RPM idle - the stock ECM is happy now. I've got a 10-8-9 boost pattern and I'm reminded how hard these cars pull up to 80 MPH - even on wimpy stock turbos...

So - in summary, things I screwed up during my engine swap:

Rebuilt my own turbos (and launched a wheel into the cat)
Swapped the water temp and fuel temp connectors - car runs really rich...
screwed up CCA and CRV vacuum hoses
Missed one vacuum port in the UIM
oh yeah - put the clutch disk in backwards and had to drop the tranny again...

I will NOT be opening a 3rd gen RX7 repair shop anytime soon. Thanks...

Any suggestions on getting up to the true 10 psi on the secordary turbo? Home deport boost controller? Electronic boost controller? Swap in a Power FC and see what happens?

sbnrx7

iTrader: (4)

I like happy endings.

tzbfwt

iTrader: (1)

Me Too!!!

And I forgot to add to my "uck-up" list:

Used the wrong type of fuel injection rubber hose when I installed the walbro pump - the hose disentigrated after being submerged in fuel and I lost fuel pressure - that was fun to troubleshoot.

Now - just need to fix my dome light door switch... Does it ever end?

Monkman33

iTrader: (28)

It never ends........ I promise......

tangoshark

iTrader: (18)

does anyone know if there is anything wrong if my car holds 15inHg vacuum at idle at operating temperature when the double throttle control hose is pulled off?

According to Autosportracetech.com, there should be no vacuum when that hose is pulled off.

gracer7-rx7

iTrader: (16)

That doesn't sound right. Which page on that site specifically says that?

tangoshark

iTrader: (18)

I figured it out. You are not supposed to watch the boost gauge when doing this test. Rather, put your figure on the hose to make sure there is air being sucked in on the hose when under operation temp and no air being sucked in at op. Temp.