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^Good point. You can't just say "boost problems = replace everything" that that will fix it. It's quite possible you will spend the money and do the work and STILL have the same problem. Figure out the root cause FIRST then start replacing parts.
Dale
Henry definitely gets it. I’m all for preventive maintenance. After everything is working perfectly you want to put in new solenoids, have at it. But until you solve the problem that just creates more chaos.
Hey everyone, I know it's been over a year since I updated this post, but I lost motivation to solve the issue and drove the car as is for a while. I recently regained motivation to solve it, and have since pulled the entire solenoid rack from the car and have been troubleshooting each solenoid.
*disclaimer: I will only go through my findings on the rack solenoids relevant to the operation of the sequentials. Turbo Control Solenoid (Solenoid E), Charge Control Solenoid (Solenoid F), Charge Relief Solenoid (Solenoid H). Also, as a recap, I replaced the TCS (vacuum) mounted near the ACV already, so I won't be going over that solenoid here.*
1. Missing o-ring on the oil filler neck. At some point, someone put black rtv on it and sent it with no o-ring and it was DEFINITELY leaking. There's oil all over the area and I could hear it hissing when I got into boost (not sure if this would cause a boost leak or if it was just venting "crank case" pressure)
2. TC Solenoid (E):
Cold Behavior:
Resistance: 40ohms
Solenoid engages when energized
Basic vacuum test: pass
Basic pressure test: pass
Energized vacuum test: pass
Energized pressure test: pass
Hot behavior (oven at 250F for 10 minutes)
Solenoid does not engage when energized
Basic vacuum test: pass
Basic pressure test: pass
Energized vacuum test: fail - unable to hold vacuum (allowed to cool enough for solenoid to engage when energized, but still warm to the touch)
Energized pressure test: fail - unable to hold pressure (same condition as above)
3. Charge Control Solenoid (F)
Passed all tests hot and cold
4. Charge Relief Solenoid(H) Cold Behavior:
Resistance: 40ohms
Solenoid engages when energized
Basic vacuum test: pass
Basic pressure test: fail - slow leak
Energized vacuum test: pass
Energized pressure test: fail - sticks at 10psi
Hot Behavior:
Same symptoms/results as cold behavior
Besides those solenoids, I also had numerous other solenoids in the rack not engage when energized after being heated in the oven. After being allowed to cool, they began to engage again. A friend of mine who is single converted is going to give me all of his old solenoids from his rack to test, and I will attempt to replace me bad ones with his good ones. I will probably end up buying a couple of new ones though, because who knows what condition they're in. I will update again once the car is all back together and (hopefully) put together correctly. I'm really hoping the hot behavior of solenoid E is the cause of my low boost after transition. Let me know what you think.
Honestly I would just bite the bullet and buy all of them just for peace of mind and get it over with. Murphy's law says you will replace the couple that are not working/kinda working, then a month later, the others will join in and give up the ghost. Its Cheaper if you buy them in Japan like I did, saved a couple hundred dollars over even the Ray Crowe prices when you include all the fuel parts I bought as well (FPR, FPD, Hose) These things are 30 years old and should just be replaced at this point. I made a video of my restoration, not a complete "how to" but gets the point across on the need to replace these parts. These cars are now considered "classics" for a reason. I've got all the part numbers for the solenoids and fuel system parts I used in the video.
I know people mentioned its not a guarantee to fix, and its really not, but you have it open already, things are really old and have been exposed to high heat for 30 years, I just consider it maintenance at this point, especially the fuel parts under the UIM. Its really not that big of investment to replace them all and you would have that part of your car you don't have to worry about any longer.
Dude, I saw your post on Reddit and that’s what prompted me to take it all apart. I commented on your post and mentioned that I didn’t know you could take the whole rack out in one piece like that.
Thanks for commenting, I agree with you that it’s all 30 years old and needs to be replaced. I’m just determined to isolate the issue before I do that.
Can you direct me to how you purchased the parts in Japan and saved yourself all that coin?
Dude, I saw your post on Reddit and that’s what prompted me to take it all apart. I commented on your post and mentioned that I didn’t know you could take the whole rack out in one piece like that.
Thanks for commenting, I agree with you that it’s all 30 years old and needs to be replaced. I’m just determined to isolate the issue before I do that.
Can you direct me to how you purchased the parts in Japan and saved yourself all that coin?
I used RHDJapan.com and go through their "OEM" store. You can put in factory part numbers and they will check stock and let you know if they can get them. Took them about a week to get to me, so not bad. I feel safer ordering the solenoids from Japan as well. I figure with so many more on the road there and still being maintained, their dealer stock has to be more fresh than ours right? Less of a chance of one of these solenoids sitting on the shelf for 15 years and finally getting sold. You can try other sites like Nengun.com that have the same type of service and sometimes beats RHDJapan's pricing. I have ordered from both without issue. I tend to go with RHDJapan more because I have more points racked up with them from ordering things over the years. For price comparison, some of the solenoids were about half the price I got quoted from Ray or what you find from Atkins or one of the other reliable Rotary suppliers. I originally ordered one of my solenoids from Ray when I first got the car to get it running properly, then after research and poking around I found the OEM store option from Japan. I still order parts from Ray that the OEM store can't get because he is still likely to be the best price we have here in the states for most things but RHDJapan is worth a try sometimes, it helped me with this project. That's where I got the NGK Power Cable plug wires as well, a fraction of the price of the higher end ones in the states here and these fit like factory.
Make sure you test any new solenoids before install. Even BNIB solenoids are not guaranteed to be working 100%. Read back through old threads, plenty of members report sticky / leaking solenoids right out of the box. Most likely NOS that have been sitting on a shelf. I can confirm through experience as well, I bought new ones and 1 of 3 weren't working properly when tested. I was able to exchange mine but I purchased through a US vendor, not sure how much luck you would have trying to exchange from RHD Japan.
Good luck with your sequential issues. I went through this whole process including losing motivation for a while and picking back up later so I know how frustrating it is. Just keep at it, testing everything, and you will eventually find / fix the issue.
Make sure you test any new solenoids before install. Even BNIB solenoids are not guaranteed to be working 100%. Read back through old threads, plenty of members report sticky / leaking solenoids right out of the box. Most likely NOS that have been sitting on a shelf. I can confirm through experience as well, I bought new ones and 1 of 3 weren't working properly when tested. I was able to exchange mine but I purchased through a US vendor, not sure how much luck you would have trying to exchange from RHD Japan.
Good luck with your sequential issues. I went through this whole process including losing motivation for a while and picking back up later so I know how frustrating it is. Just keep at it, testing everything, and you will eventually find / fix the issue.
This is one of the reasons why I opted to buy from Japan. I figured less of a chance of getting one that had been sitting on a shelf for a very long time. I don't know how they would handle the return process if you did have a bad one honestly, but for the price, I could buy two of some solenoids for the price of one here so it was worth the shot.
So I finally got the solenoids in from japan. Opened the box, and tested them. I ordered 3 new ones, and NONE of them are working correctly. They each have different problems (some of them may be usable in the correct location on the rack). They all seemed a little sticky as well. A couple taps seemed to free them up, but sometimes they would stick again. I’m currently waiting for them to heat up in the oven to perform the hot tests, and again once they cool. I will have to see if RHDJapan would be willing to send new ones again.
Any chance that heat cycling them may coax them into working correctly?
Admittedly, I have been using a 9v battery as per the testing guide that I linked above. Although, aside from not energizing while hot, they all have some sort of problem holding pressure or vacuum. 2/3 of them leak when I apply pressure when they are not energized. 1 of them leaks vacuum while energized. This morning, on the solenoid that failed the energized vacuum test with 9v, I retested with 12v with the same results.
Even if 12v power were enough to get the solenoids to engage while they are at temperature, they still all leak vacuum or pressure.
Admittedly, I have been using a 9v battery as per the testing guide that I linked above. Although, aside from not energizing while hot, they all have some sort of problem holding pressure or vacuum. 2/3 of them leak when I apply pressure when they are not energized. 1 of them leaks vacuum while energized. This morning, on the solenoid that failed the energized vacuum test with 9v, I retested with 12v with the same results.
Even if 12v power were enough to get the solenoids to engage while they are at temperature, they still all leak vacuum or pressure.
That's a bummer. I honestly didn't even bother checking mine and everything seems to be operating properly, for all I know mine may not have passed the initial tests but still work fine when in normal operating conditions. I do wonder if they do need to be cycled a bit if they sat for a long time? Might be worth it to add a drop of oil or something then cycle a bunch with full power then check. In reality these things are typically operating under 13+ volts. I don't know the design of the plunger inside the solenoid and to why a brand new one wouldn't seal but it may be worth taking and old one apart to investigate.
That’s a great idea. I have a couple that I know are junk, I’ll cut one up and inspect the inside and post some pictures. A drop of oil in there may help them seal, that’s a good idea too, but I’ll cut one up first
I just have a hard time believing such a high rate of failure of brand new solenoids even if they sat for long periods of time unless they were stored improperly like open and high humidity. How much of this is normal to see from a new solenoid that just needs to be cycled under normal operating conditions?
Since I had mentioned this route in the group text, I figured I'd seach around for the best thread. I think this one has the best How-To guide for the custom/DIY route: https://www.rx7club.com/3rd-generati...-rack-1124206/
Thanks for linking that here, Ryan. Unfortunately, those solenoids are discontinued, but it is definitely still something I may look into if I continue to have problems with new parts. I also have a hard time believing that the failure rate of brand new components could be so bad. It makes me feel a little insane, but when I go perform the exact same tests under the exact same conditions with a used, known good solenoid, I get results that indicate it's working properly.
Here's what the inside of one of the factory rack solenoids looks like:
To be honest, my initial impressions, surprisingly, are that the solenoid seems to be pretty robust. This solenoid in particular had a slow pressure leak while de-energized and had a vacuum leak while energized, and it was one I removed form my car. Upon inspection, there don't seem to be any obvious mechanisms of failure. Any damage to the conical seal on the piston and the coil was done by me with the dremel. The seals seem to be otherwise in tact, and the material doesn't seem to be baked, cracked or hardened like we so often see with factory vacuum lines. Furthermore, the interior of the solenoid and the piston seem to be pretty clean and free of dirt and debris.
I will see if putting a drop of oil into the solenoid will help the sealing characteristics, but, unfortunately, I see no other way to repair them without destroying them.
So it looks like that tip may degrade causing leaks on older solenoids but brand new maybe they just need to be seated in a bit after some cycles? What type of material is the tip made out of, looks like rubber from the pictures. Really does make me wonder what fails the most with these higher mileage solenoids. Is it the coil portion or the sliding mechanism? It may be possible that moisture or other "crud" could ultimately end up in some of these causing them to react slowly or stick a bit. That spring may weaken over time as well not being able to hold the seal.
Yes, definitely interesting. The conical tip as well as the thin seal on the back of the piston seem to be made from some oil resistant rubber.
The seals in this one don't seem to be damaged or degraded. The spring is also VERY light. I assume it's a return spring. There's no way this spring would seal against 10-15psi. The condition of the spring, however, could contribute to the solenoid sticking when it's de-energized.
After seeing this, I have no clue how the failure rate of brand new solenoids could be so bad. Almost makes me want to send it and install them in the car, but it would really suck to tear it all back out again. Still waiting to hear back from RHDJapan on the status of getting replacements. Really hoping they just send me some new ones no questions asked, and I get to keep these ones lol
I haven't looked at the older post, but after you have the new solenoids sorted out, IMHO, you have to make sure to have a mini-pressure regulator on your pressure tank limiting pressure to around 9.5-10 psi. If you don't, the new solenoids will go bad rather quickly, since they don't stand up for long to high pressure, if you run or plan on running above stock boost pressure.
Mike
Thanks for the tip. Is there a regulator that you recommend? In the meantime, I will see what McMaster has available.
I will find the one I use. I am currently out of town. Not many of the solenoids use pressure (most the vacuum tank) but the ones that do will last much longer. Also use your best functional standard solenoid and reroute the vacuum/pressure lines and rewire it to become the turbo control solenoid, which is unreliable and fails all the time.
Chris at RotaryPerformance did this modification years ago to my car and it worked for more than 10 years and didn’t fail.
Mike
I haven't looked at the older post, but after you have the new solenoids sorted out, IMHO, you have to make sure to have a mini-pressure regulator on your pressure tank limiting pressure to around 9.5-10 psi. If you don't, the new solenoids will go bad rather quickly, since they don't stand up for long to high pressure, if you run or plan on running above stock boost pressure.
Mike
Interesting, do you know how long it'll take to cause problem? I've been running the same setup on 14psi since 2014.
Interesting, do you know how long it'll take to cause problem? I've been running the same setup on 14psi since 2014.
I don’t believe there is any set time frame for potential failure but like any other component in the stock system, the basic design was likely designed to run at or below stock pressure levels. Anytime you stress a component towards is limits its failure rate increases. I have run my pressure regulator since approximately 2008 with no solenoid failures on new solenoids installed at the same time.
Mike
03-22-24, 05:29 PM
