James Paventi

iTrader: (34)

Hello all,

I’ve finally solved my boost problem and wanted to post a quick write up … maybe it’ll save someone else a headache!

When I got this car, it had a crazy 12-4-8 boost pattern. Hmm … the pattern wasn’t a pattern for that matter. I.E. it fluctuated a lot.

Forward two months and one vacuum hose job. Actually, asked the dealer to do the job and stopped them after they broke ( and charged me for) two of the three way solenoids. First lesson: just because it’s a Mazda dealership doesn’t mean that they do quality work. They screwed up more things (enough for another thread) than I can remember. Ok, back on track. I did the hose job and ended up with a consistent 12-5-slowwww rise to 8 by redline. Oh, and I vac (no pressure), ohm, and 12V tested all of the solenoids cold.

Forward another week. While vacuum testing all of the vacuum (not pressure) activated valves I discovered that my CRV was leaking boost a bit. I also noticed that my 1” air hoses were really loose. After a set of screw down hose clamps and a new CRV valve my boost went to 12-6-9 … still the slow rise.

Two more weekends into it:
Ditched my vac only pump for a vac and pressure pump … also started Teeing (my boost gauge) into various vac hoses and discovered that my CRV was receiving strong vacuum until 4000RPM and then received 3Psi of boost until 4500 when it went to full boost. For everyone that doesn’t know it’s supposed to receive vacuum from the time the motor is off until 4500RPMs then switch to full secondary boost. At this point I broke out a color coded vac diagram (whoever did this, big BIG thanks!) and tracked the CRV control solenoid down. I connected my pressure pump to the nipple (on the solenoid) that receives secondary boost. Sure enough it leaks … I nearly wailed on it with a hammer right then and there!!!! Anyway, it was leaking pressure into the vacuum system after 4000RPMs. I disconnected the solenoid and caped the vac lines. Damn! This car moves when the second turbo comes on! 11-4-10 and the last 10 comes up fast … by 6000 RPM.

Two more days:
I’m watching the UPS tracking WWW page and drooling at the though of having the new vac solenoid in my hands … During the wait, I’ve used my PFC to set the boost to 10-4-10. I’ve decided to let whatever is causing the 11PSI in the boost pattern be. I suspect the solenoid that controls the wastegate or prespool but will wait for it to fail completely and let the PFC regulate things for now.

So what’s the moral of the story? Be very methodical and don’t give up! This car’s crazy vacuum actuated turbo system frustrated me more that any machine I’ve ever worked on. Considering that I work on computers for a living, this says something! Remember, trust no vacuum solenoid, don’t believe a word the TCA tells you and test everything in every possible way that it can be used. This last point is important. The solenoid that failed for me is one of only three or four (out of 10+) that can be reached without removing the UIM (2nd half of the intake manifold). If it had been any other I would have been removing parts for a couple of hours to get at things. I really should have done more complete testing when I did the hose job.

One last thing, when you finally do hit 10-8-10, you’re gona grin big!

jamespond24

iTrader: (13)

Congraduation, I also found out about my secondary boost go slowly down to 0. I toke the manifold out and disconnect almost all the hose and put the hose that goes out of the solenoid to a wrong connector. Thanks for the wonderful diagram this forum provided.
ONCE AGAIN THANK YOU EVERYBODY!!!

Chronos

Aren't you supposed to get full boost before 6000rpm???

half past twelve

Yea you will...I get full boost again by probably 5k..

FDjunkie

You also did something else smart, which was tapping in to the various vacuum lines so that you could really see what each circuit was doing. An excellent approach and one that more of us should keep in mind when it becomes 'our turn'.

Great job!

13brv3

Excellent approach James. Good job. Now, when you figure out why you have 10-4-10 instead of 10-8-10, let me know. I'm at 10-6-10 now, but I'm mighty happy to have that compared to the 10-6-2 that I originally had.

Cheers,

BoOsTin FD

Do you guys have 10 till redline or 10 till 6k?

I have 10 till 6k and then 8 till redline.

Look at my signature for mods.

Thanks

James Paventi

iTrader: (34)

Quote:

Originally posted by 13brv3}
Now, when you figure out why you have 10-4-10 instead of 10-8-10, let me know

See below:

Quote:

Originally posted by James Paventi
I’m watching the UPS tracking WWW page and drooling at the though of having the new vac solenoid in my hands …

I'm 99% sure that the three nipple solenoid describes above it the ticket. I'll let you know if I'm wrong.

johnchabin

iTrader: (2)

Excellent post, James. It's very useful to hear not just the problem, but the diagnosis and solution.

James Paventi

iTrader: (34)

Just a quick note to let everyone know that the new solenoid really made a difference. The secondary now recovers nicely by 5K RPM. The car is so fast, I'm going to have to get used to it before I can really watch the boost pattern.

BoOsTin FD, 13brv3,

I'll let you know what the entire pattern is once I'm used to my car.

dubulup

After I fixed my boost problem, it felt like it was the first time I ever drover her!

James Paventi

iTrader: (34)

OK ... the pattern is now 10- 5/6/7 - 10. It depends on the gear and the car's temperament.

I decided to check out the Precontrol solenoid since I hadn't tested it before. No dice, the solenoid works great. I had a look at the wastegate solenoid and purge canister while I was in the vicinity. I figured that I may as well complete my testing. These three solenoids were the only ones that I didn't test when I did the vac hose job. I figured that I could just test them down the road as the UIM didn't have to be removed to work with them …. Turns out they all work great ...

Well, the only solenoid that was left was the TCA pressure solenoid. Recall that I vacuum tested everything when doing the hose job. I.E. the only untested solenoids are the ones that have pressure applied to them. The DAMN thing leaks boost. It's no where as bad at the CRV solenoid that I replaced earlier, but this is probably why the 4500-5000 boost varies between 5 and 7. Sigh ... I'm going to have to pull the UIM to replace this one.

What was it I said earlier about testing everything in every possible way? Take my word for it, it's worth the extra time.

James Paventi

iTrader: (34)

Haven't watched the pattern close enough to know. I'll let you know after I fix the transition boost. (See my last post in this thread.)

13brv3

James,

Is your only remaining problem the low transition? As I mentioned before, that's my problem too- 10-6-10.

I tested all my solenoids when they were out, so none of them leak. Just how exactly did you test the TCA pressure solenoid to conclude it was leaking? In other words, are you absolutely sure it's leaking?

I haven't really pursued my low transition, but when I do, the first thing I would suspect is the pill in the precontrol line. My pills are there, and they looked just slightly different, but I certainly didn't confirm how many thousandths of an inch the orifice was. This just might need some adjustment do to wear and tear on the actuators, secondary turbo bearings and such, and that sounds like a job for the Home Depot controller.

If I were going to troubleshoot this, one good test would be to have someone with a normal pattern T into that nipple on the secondary side of the Y-pipe. The goal would be to see what their pressure is just before transition. I'd bet it's a couple psi lower than ours.

Good luck, and let me know when you fix our problem

James Paventi

iTrader: (34)

Thanks (for the luck)

It's the last issue ... well, with the complexities of this car, I'm fairly certain that it's the last issue. I won't know for sure until I replace the solenoid.

The pre-control and wastgate pneumatic actuators are new. I.E. wear and tear on them isn't an issue. They went in with a new set of turbos ... about 1K miles ago. Just to be safe, I tested everything out. I.E. slid under the car and pumped vacuum / pressure into the appropriate lines. The pills in my setup are a permanent part of actuators themselves, so there isn't any chance that they are screwed up.

Anyway, here is what I think needs to be done to test each solenoid.
- Determine its function with no power being applied.
- simulate this
- Determine its function with power applied
- simulate this
- use an Ohm meeter to check the resistance of the solenoid’s coil

During each simulation (test), flick the solenoid several times with your finger. See if it's inputs / output hold up. I.E. does vac / pressure leak?

Also, if you problem is only present when the car is hot, you may want to test your solenoids after baking in a 230 degree oven.

I'm shortening things a bit, but here is how I tested the CRV solenoid and TCG pressure solenoid.

CRV:
Apply 20 bars vac to the nipple under the electrical contacts
Apply 15 PSI pressure to the nipple opposite the above.
Observe a pressure / vac (your boost will work) gauge attached to the output (top) nipple. It should hold vacuum indefinitely. Note that mine didn't, the pressure leaked rapidly into the vacuum side … it took one flick of my finger and boom, pressure went into vacuum all at once. I stopped at this point as the solenoid was obviously bad. The next step would have been to apply 12V to the coil and observe that the gauge showed a constant pressure during “flicking”. I tested my new solenoid before I put it in the car, and it passed these tests with flying colors.

My TCA pressure (there is a vac too) solenoid was simpler. It vents the nipple under the electrical contact to the atmosphere. I just attached a pressure pump to the nipple opposite the one vented to atmosphere, pumped it up (15 PSI)and watched. Note that the gauge was attached to the same nipple as the pump this time. The pressure was slowly lost. It's not major, but I'm sure it's enough to slow the TCA's operation significantly. I.E. by venting the pressure out of the pressure tank.

Make sense?

Of course, I'll post the results.

13brv3

Well, it certainly sounds like you're being thorough. I didn't do the flick test, but it does sound like a good idea.

I'll be happy to be wrong, but I'd be willing to bet a cold beverage that a slightly leaking TCA pressure solenoid isn't going to be your transition problem. Of course I say this in your best interest, since I seem to be wrong about everything on this car

Cheers,

James Paventi

iTrader: (34)

Let's see, I'm right, my car works ... I'm wrong, I buy two beers and get to drink one. Sounds good either way!

Well, I just looked. The P/N for the TCA solenoid is different from the CRV solenoid. I don't see (visually) what the difference is. It might simply be the filter on the unused nipple. I'll run my test on the new one just too make sure that it's valid.


First thing tomorrow, call Mazdaformance ...

13brv3

Funny, that's become a common Monday morning task for me too

James Paventi

iTrader: (34)

Well, the new solenoid yielded a consistent 10-7-10. That's the short version.

The long version goes like ...

While I was waiting on the solenoid, I drove the car around for a few days. I noticed that if I went into the throttle late ... say after about 4Krpm ... the dip was really pronounced while the secondary came on. Also, it didn't come on as fast. This was most pronounced when going up hill.

After removing the UIM (I have this down to 15 min off, 20 on ) I installed the new solenoid and tested. Things were better, but pressure still dropped very slowly. It turns out that one of the vacuum lines I replaced had a leak ... yep, a brand new fresh hose leaked. So, having replaced a leaky solenoid and vacuum line I began to receive 10-7-10 with regularity.

Unfortunately somewhere in the middle of this I noticed a strong fuel smell during boost. I've done some searching and there are a whole host of things that can cause this. Also, my voltage has dropped off the board at idle. I think that this car was just plane abused before I bought it! I most suspect the lower intake manifold gasket due to a lack of smell when not boosting (at any RPM) and a 2 bar drop in idle vacuum. Well ... I'll leave this for the motor rebuild. I have a new alternator coming and then, given no more problems it's rebuild time.

All said, this car is in much better shape than when I bought it ... a rebuild should bring it up to status quo. 13brv, looks like I owe you a cold one ... I'll look you up the next time I'm in Florida.

13brv3

Sounds like the solenoid was at least part of the problem. Tell you what, I'll have a beer in your honor tonight, and toast to 10-7-10 :-)

Glad it's working, but sorry to hear about the other problems.

Cheers,

James Paventi

iTrader: (34)

OK ... I would've bought you a Negra Modelo (dark) or Newcastle <grin> I've been wanting to use this smiley since I first saw it ...

13brv3

Cheers

BoOsTin FD

while you guys are celebrating, how about someone answers my question. Am I sopose to have 10 psi till redline from 4500 or 10 psi till 6k and then 8 till redline.

I have changed almost everything that could cause boost problem, but i always get 8 till redline, othe than that, my boost pattern is fine. You can see in the signature the mods that i have. I guess only thing left is my Main cat.

James Paventi

iTrader: (34)

Boostin FD ... don't get all uppity on me ...

I made a few runs with you in mind and apologize, I forgot to post the results. My car seems to hold 10PSI until redline.

I just remembered that I came across a thread on this some time ago. Basically, the consensus (on the thread) was that some FD's are programmed (by Mazda) to drop to 8PSI after 6K ... some aren't. No explanation, just people's observations.

If your car is making a clean and immediate drop to 8 at 6K, I would guess that you have the Mazda computer with the special programming ... bummer. If it's more of a gradual drop, maybe your cat. I really doubt this as you've replaced it.

13brv3

Very interesting. I've never read this before, so I'll have to do some searching. Mine certainly doesn't hold 10 till redline, in fact, now that you mention it, it does seem to make a definite drop to 7 or 8 psi. I'll take the car out this morning to run it with my freshly sealed motor mount (hoping it doesn't leak), and will watch more closely to see when the boost drops. Next, I'll be installing my new PFC, so that should really test the ECU theory.

I'll post results when I get them.