HELP: Unsolved Boost Problem
 

Ok, after checking all the vacuum lines, the silonoids, and the wastgate, my cousins boost leak is still unsolved, but my shop does have an idea on what the problem might be. The car only has an hks exhaust and dp, other then that its stock with about 65,000miles on it. My shop said that if we used an electronic boost controller and set boost using that, it would fix the boost leak problem. what do you guys think of this solution? Anybody run in to this same problem and solved with this action?

we did plug in a boost gauge and saw that the boost would hold at 10psi but then drop to 0psi right after 4,000rpms.

Thank you.

You have checked all the intercooler coupler connections, right? Especially the one for the Y-pipe/crossover pipe?

Yeah we did check that as well.

So your boost pattern is 10-8-0?

If so, I don't see how a boost controller is going to fix that.

Sounds like the secondary BOV (the one for the secondary turbo) is letting all the air out.

yeah me to, thats why I wanted to ask you guys because I cant see how installing a ebc will fix the problem. the max boost the car gets is 10psi which is the right boost setting but it only get it for a second then drops to 0psi at about 4,000rpms. Its been 2 months since we bought the car and I just cant find the problem. I hope its not the motor!

This sounds very interesting, has this problem accord with you?

Uh, you mean the charge relief valve...

Try venting the CRV to the atmosphere instead of the airbox, and see if you can hear it venting when your secondary boost drops. You should be able to hear it, since you're apparently losing all boost.

Thanks. Ill check it out.

ok I checked charge relief valve/bov pipe. It was fine. Do you guys think the spring in the wastgate is just worn out and cant hold boost anymore? I think we are going to try to get a ebc cheap and see what happens when we control boost with that.

If the wastegate is having problems, you either get limited to 7PSI or you have uncontrollable boost upwards of 14-15PSI (wastegate spring lowest limit is 7 PSI).

If you have anything less than 7PSI, there is a problem with the turbo system outside the wastegate.


How did you check/test the Charge Relief Valve?

Well I had the shop check it and they said it was fine, they keep telling me that the wastegates are missed up and that i need a ebc. Im about to just take the damn thing to PF.

If they really think that's the problem; tell them if it actually fixes the problem, you'll pay for it. If not, you aren't paying for the EBC or the labor.

Did you actually watch them "check it"? If so, what did they do? If the shop is telling you to buy a boost controller to solve your "problem with a wastegate", then I'd question their actual tuning and diagnosis skills.

Thanks for all your feedback and help man, its just that we have had the car for about months now and still no boost. Its frustrating knowing the power is there but we cant find it. The shop will not sell me the ebc, I need to find one my self, I dont even know which one to get. What do you recommend? Thanks

No I didnt see them do it, but I trust them, I have known them for 4 years now. They checked everything out on the car. Thats the only thing left to try.

If the shop won't purchase the EBC for you to test their theory (since they say that will fix the problem), find another shop.

They are just guessing and are just going to run down your bank account. EBC's are nice to have, however, that is AFTER the turbo system is functioning correctly.

When you have time, take a read through this page:

http://www.autosportracetech.com/RX-...leshooting.htm

wow, thanks for that link, thats is a lot of great information! So since the boost hold to 10psi then drops right after, what do you see the problem is?

The best thing to do is follow that link and skip to the secondary turbo section and perform those tests. I believe they are in order of what is most likely to fail first.

Basically, it seems like your CRV is not closing, thus venting all your boost at/after transition.

There could be various causes:

1. Bad/damaged CRV
2. Bad/damaged Charge Relief Solenoid
3. Bad/damaged vacuum line

It sounds like the shop where the car is at, does not know what they are doing. I would recommend removing it from that shop before you waste any more money and either ask for local help or find a better shop.

1) You need a different shop
2) You probably have a failed secondary CRV, like Mahjik said. After the gate in the y-pipe opens during the secondary transition, the boost will drop to zero as it now has a path to escape through the open CRV
3) You need a different shop

Thank you everyone, from what you guys are telling me, it sounds like the CVR! Do you know where I could go on the net or this site to see a photo of this unit.

My friend introduced me to a guy in my area that owns a white 94 rx7 with a T-78 on it. I went to the guy and asked him what he thought, he showed me what he thought the problem was, he pulled out of his junk area a plastic looking unit that could fit in my hands. He said he thinks that the problem. I think he was showing me the CVR. Is this a common problem on rx7's? I cant wait to fix my cousins car. have a rx7 boosting at 0psi is no fun. thanks for all the help everyone.

George

https://www.rx7club.com/forum/attach...postid=1261370

The CRV looks just like the stock BOV. Each one has a label on it (the BOV is labeled ABV and the CRV is labeled CRV).

Simply replacing the CRV might not fix the problem. The CRV is controlled by air which is regulated by it's corresponding solenoid (Charge Relief Solenoid). I rarely hear of the actually CRV failing, but do hear of the solenoid failing often. My solenoid finally gave out last year.

...

How many solenoids are on the rx7? the shop said they checked all the solenoids. Thank you for the photo!

Take a look here:

http://www.scuderiaciriani.com/rx7/v...e_diagram2.jpg

You can see all the solenoids. If that shop thinks that no secondary boost is a wastegate problem, then they have no idea how to test the solenoids.