Replacement Solenoids
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Joined: Nov 2002
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From: HuntsVEGAS, AL
Replacement Solenoids
After learning the cause of the failure of my sequential system ...
It was the pressure side Turbo Control solenoid. The one I replaced it with was also bad.
Both the original solenoid and the replacment still pass Mazda's check procedure (in the shop manual) with flying colors.
But here is what's happening. There is a spring in the solenoid that returns the valve back to its initial position when the power source is removed from the solenoid. Over time, the heat weakens that spring and the pressure in the line between the solenoid and the turbo control valve holds the solenoid open (the spring cannot overcome the pressure). So, the pressure can't escape and the turbo control actuator is held open when it should not be.
The solenoid I had in the car couldn't take more than about 9 psi without sticking. The original solenoid in the car couldn't take more than about 11 (I'm running 12.5). I tested several spares I had and finally found one that was happy even at 15 psi. I put it in the car and went for a test drive..... car now performs perfectly and life is good
I can post a detailed test procedure for the solenoid valve if anyone is interested. You basically need to put 12v and a ground to the solenoid, then put pressure (about 12 psi to start) on the nipple that would go to the actuator and then remove the 12v and see if the solenoid lets the pressure in the line vent. If it doesn't (or is very slow doing it), then you have a problem. Let me know if anyone wants a nice how-to with pics. You have to test it as it is used in the car, the blow through test the shop manual outlines will not work with this solenoid. A very bad solenoid can still pass that test.
Thanks for all the troubleshooting help guys. My advice, if you're having the problems described above would be to buy a NEW pressure side Turbo Control solenoid.
- Dave Disney
... I started searching for aftermarket solenoides that would replace all the stock ones and be able to function properly under loads greater than 17 psi. I haven't had much luck although I have found a few companies that make custom one, but I'm sure the cost would be even greater than the stock ones. Does anyone have any ideas on where I can look? BTW, the first person that says "Just go N.S." is a bone-head. 
Originally Posted by autoxer
It was the pressure side Turbo Control solenoid. The one I replaced it with was also bad.
Both the original solenoid and the replacment still pass Mazda's check procedure (in the shop manual) with flying colors.
But here is what's happening. There is a spring in the solenoid that returns the valve back to its initial position when the power source is removed from the solenoid. Over time, the heat weakens that spring and the pressure in the line between the solenoid and the turbo control valve holds the solenoid open (the spring cannot overcome the pressure). So, the pressure can't escape and the turbo control actuator is held open when it should not be.
The solenoid I had in the car couldn't take more than about 9 psi without sticking. The original solenoid in the car couldn't take more than about 11 (I'm running 12.5). I tested several spares I had and finally found one that was happy even at 15 psi. I put it in the car and went for a test drive..... car now performs perfectly and life is good
I can post a detailed test procedure for the solenoid valve if anyone is interested. You basically need to put 12v and a ground to the solenoid, then put pressure (about 12 psi to start) on the nipple that would go to the actuator and then remove the 12v and see if the solenoid lets the pressure in the line vent. If it doesn't (or is very slow doing it), then you have a problem. Let me know if anyone wants a nice how-to with pics. You have to test it as it is used in the car, the blow through test the shop manual outlines will not work with this solenoid. A very bad solenoid can still pass that test.
Thanks for all the troubleshooting help guys. My advice, if you're having the problems described above would be to buy a NEW pressure side Turbo Control solenoid.
- Dave Disney
I doubt aftermarket solenoids exist in the kind you're thinking. The cost, if properly spec'd, could be more than stock prices.
I'd like to buy new ones and then test them very carefully to really compare against my stock ones. That way I can establish stricter criteria for testing.
I've also toyed with wrapping each one in silicone tape to insulate them a little bit from engine heat. Maybe building a fan (computer fan) and a simple duct will help draw cooler air through the rats nest area to prolong life. Hmmm.
Dave
I'd like to buy new ones and then test them very carefully to really compare against my stock ones. That way I can establish stricter criteria for testing.
I've also toyed with wrapping each one in silicone tape to insulate them a little bit from engine heat. Maybe building a fan (computer fan) and a simple duct will help draw cooler air through the rats nest area to prolong life. Hmmm.
Dave
Yeah, that's what I'm thinking. If you're running the stock twins, you're beating the crap out of them at 17psi.
I've looked for giggles and grins, and haven't been able to find anything that would do the job. Really, the stock solenoids do the job for a LONG time before they fail - I doubt there's something else out there that can do the same job for 10 years and still be working perfectly. They're under a LOT of stress.
Dale
I've looked for giggles and grins, and haven't been able to find anything that would do the job. Really, the stock solenoids do the job for a LONG time before they fail - I doubt there's something else out there that can do the same job for 10 years and still be working perfectly. They're under a LOT of stress.
Dale
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VVThat's meVV
Joined: Oct 2003
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From: Austin, TX
Thats what I was thinking. The best thing to do in any case with a car you just got and don't want any little issues ariseing is replace all the little things that wear out. I know it'll be costly, but its less things you have to worry about in the long run. I broke a few of my silonodes when doing the vac lines, so I went simplified so I could move them around to were the good ones were where I needed them. I still need to finish the rest of my engine mods for the twins though. Running a cat without the airpump working isn't good for it.
BNR built motor and twins
Joined: May 2003
Posts: 1,235
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From: 2 hours drive from sanity
Originally Posted by Klar
BNR3's can run 17psi with out a problem, but you'll have to ask GoodFella what he does to make it all work at that level.
PV = nRT
Joined: Jan 2003
Posts: 2,250
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From: New Zealand (was California)
non-seq still uses a solenoid for the WG actuator unless one directly ran the compressor nipple to the WG w/ inline restrictor (pill) or manually adjustable ball valves.
Last edited by clayne; Nov 30, 2004 at 04:19 PM.
I think that the stock solenoids are fine for all locations EXCEPT for the pressure-side TCA solenoid. I have had consistent problems with this one over the years--its operation being inconsistent and unreliable. I am looking for a suitable non-stock replacement, possibly substituting another solenoid (such as the Precontrol/wastegate solenoids) and/or Mod'ing or making something.
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Joined: Nov 2002
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From: HuntsVEGAS, AL
Originally Posted by Mahjik
If the stock solenoids are lasting 10 years or more, why not just use the stock part? It will be good for another 10 years.
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Joined: Nov 2002
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From: HuntsVEGAS, AL
Originally Posted by Klar
Why would you need ones that can handle more than 17psi?
Thread Starter
Joined: Nov 2002
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From: HuntsVEGAS, AL
Originally Posted by Speed of light
I think that the stock solenoids are fine for all locations EXCEPT for the pressure-side TCA solenoid. I have had consistent problems with this one over the years--its operation being inconsistent and unreliable.
BNR built motor and twins
Joined: May 2003
Posts: 1,235
Likes: 1
From: 2 hours drive from sanity
I'd give you my old solenoids to test out but some guy in Canada bought them about 6 months ago. Good luck on the search for better made ones... I'm sure they're out there, it's just finding them.
Originally Posted by HDP
They worked 10 years at stock boost levels... the ones I have now work fine, but not very well above stock levels.
If you are trying to run the stock sequential system at 17 or above, you'll have a tough time getting full primary boost (like everyone else who as tried). Usually, before they can build full primary, they hit the transition point. Search for posts from "artguy" and "kwikrx7" and read their issues on the topic. Those are about the only two guys in the last few years to try and run high boost levels with the stock sequential system (here on the forum).
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