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HELP: Unsolved Boost Problem

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Old 09-26-04, 11:24 PM
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Originally Posted by Mahjik
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.
wow man, you know so much about this car, i wish you were in my area so i could just have you check the car out. So do you think i should just take the car to PF, because i dont think i want to take it to a mazda dealership.
Old 09-26-04, 11:27 PM
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Originally Posted by 7THSIGN
wow man, you know so much about this car, i wish you were in my area so i could just have you check the car out. So do you think i should just take the car to PF, because i dont think i want to take it to a mazda dealership.
I don't think Peter is messing with RX-7's anymore (or that his shop is open, I think it might be closed which was said in a recent thread).

I do think, as I said earlier, that you need to take it to a different shop.
Old 09-26-04, 11:34 PM
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Originally Posted by Mahjik
I don't think Peter is messing with RX-7's anymore (or that his shop is open, I think it might be closed which was said in a recent thread).

I do think, as I said earlier, that you need to take it to a different shop.
see the problem in my area is that there are no shops i know of that work on rx7's. that is the probelm im facing. i think what im going to do is print the website you gave me and take it to the shop and show him it.

so how did you find out you had a solonid problem when your gave up last year?
Old 09-27-04, 12:55 AM
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Originally Posted by 7THSIGN
see the problem in my area is that there are no shops i know of that work on rx7's. that is the probelm im facing. i think what im going to do is print the website you gave me and take it to the shop and show him it.

so how did you find out you had a solonid problem when your gave up last year?
He probably tested the solenoid and found that it was faulty. Troubleshooting is actually testing each component to eliminate possiblities and narrow down the search to find the cause.

I know there's got to be some decent shops in that part of the country (maybe not in your "area", but not that far away). What about Malloy Mazda? Or is it just that Ray Crowe is able to get the best parts prices?
Old 09-27-04, 07:35 AM
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you don't need another boost controller. it will not solve your problem.

if your boost is going to zero at 4500 it can only be your wastegate and the associated control mechanisms.

i agree, as usual, w Kento. you either need to find another shop or figure it out yourself. there are plenty of resources on the web. diagnosing a wastegate control sytem problem is relatively easy.

good luck,

howard coleman
Old 09-27-04, 09:05 AM
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Originally Posted by broken93
1) You need a different shop
I reiterate.
Old 09-27-04, 11:02 AM
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Yeah the car has been taking out of the shop last week, so its not there anymore. I have read that you can change the bov to the cvr and then the cvr to the bov and test the cvr like that. I might do this myself and see the outcome.
Old 09-27-04, 12:02 PM
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Originally Posted by 7THSIGN
Yeah the car has been taking out of the shop last week, so its not there anymore. I have read that you can change the bov to the cvr and then the cvr to the bov and test the cvr like that. I might do this myself and see the outcome.
Why go through all the trouble of switching them? Just unplug the "airbox end" of the CRV and see if you hear it venting boost after 4500 rpm...

I then suggest reading up on the car as much as possible before you do any more work on it (or otherwise find a reputable shop to do the work).
Old 09-27-04, 01:03 PM
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Originally Posted by Kento
Why go through all the trouble of switching them? Just unplug the "airbox end" of the CRV and see if you hear it venting boost after 4500 rpm...

I then suggest reading up on the car as much as possible before you do any more work on it (or otherwise find a reputable shop to do the work).
Sorry about that I meant "cvr". yeah I have been reading up on the car and its motor. Its just getting to the point where we wish we never purchased an rx7. We heard rumors about the car and the problems it has but never thought we would bump in to so many. Mind you this is not the only problem we have encountered on the car since the last 3 months we have had it. I was able to fix the others but this is the last problem that needs fixing and there is no point in having a rx7 that performs like a pinto. But I know how this car SHOULD perform and thats whats keeping me going on fixing it.
Old 09-27-04, 02:47 PM
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Originally Posted by Kento
I then suggest reading up on the car as much as possible before you do any more work on it (or otherwise find a reputable shop to do the work).
I reiterate.
Old 09-27-04, 08:10 PM
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Possible vacuum problem. You can verify this by accelerating WOT, and after you pass the 4500 rpm, get out of the gas until you build 20 inches of Hg (check your boost gauge, or wait a second or two), then get right back on WOT. If you regain 10 psi boost after 4500 rpm by building engine vacuum through decleration, you'll know it's a vacuum problem.

Common causes for vacuum leaks are:
-cracked/broken vacuum hoses
-bad vacuum chamber check valve
-bad vacuum chamber (cracked/split)
-vacuum chamber full of oil (this was my problem)

Other common causes for secondary turbo problems (past 4500 rpm) are:
-bad turbo control actuator solenoid
-bad turbo control actuator
-bad charge control valve
-bad charge control valve actuator

Read that link thoroughly. It gives a good rundown on how to diagnose turbo control problems.

Do the simple stuff first, and work outward to the more complicated and expensive (turbo control and charge control actuators).

The solenoids and actuators are pretty stout on these cars, and your cousin's is fairly low mileage, but based on the symptoms, check the turbo control actuator solenoid, and the turbo control actuator itself (if the vacuum is fine).

Yes, the sequential turbos are a dream when they're working, but life really sucks when the turbo control system is screwed up!

Good luck!

Last edited by SleepR1; 09-27-04 at 08:20 PM.
Old 09-29-04, 06:06 PM
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OK, well I unplugged the cvr pipe that goes tot he intake box and we revved the motor to 6,000rpms and no air was coming out from the pipe. I then did the same for the abv pipe and air came out from it. is the cvr pipe not supposed to make air flow like it did?
Old 09-29-04, 06:11 PM
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Originally Posted by 7THSIGN
OK, well I unplugged the cvr pipe that goes tot he intake box and we revved the motor to 6,000rpms and no air was coming out from the pipe. I then did the same for the abv pipe and air came out from it. is the cvr pipe not supposed to make air flow like it did?
Did you "drive it" or just "rev it in neutral"? You have to actually drive it to put load onto the engine to engage the turbo transition and secondary boost.
Old 09-29-04, 07:25 PM
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I didnt drive it, damn!!!! ok well Ill do it while Im driving. Will I be able to hear it while driving though?
Old 09-29-04, 07:28 PM
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Originally Posted by 7THSIGN
I didnt drive it, damn!!!! ok well Ill do it while Im driving. Will I be able to hear it while driving though?
Yep, it's damn annoying if you leave the CRV vented. It should close around 4000 rpms. If you keep hearing it blow after 4500 rpms, then you know it's either the CRV, the Charge Relief Solenoid, or one of the vacuum lines connecting those together.
Old 09-29-04, 07:53 PM
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Thanks a lot Mahjik! I will try it again.
Old 09-30-04, 12:18 AM
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Mahjik, I did run the test again but i did not hear any noise at all. Good news is I found a reputable shop in my area that works on strictly rx7's! I will be taking the car in tomorrow and let them have a look at it. I will keep you updated on what happens. Thank you.
Old 10-17-04, 11:03 PM
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So...it's been a couple of weeks...has anything happened? Is it fixed?
Was it the Charge Control System or the Turbo Control System?

I'm curious because I have a similar problem....Full boost on Primary dwindling to Zero boost just past transition.
I have a feeling that it's my Charge Relief Solenoid because the CR Valve closed nicely when I removed the vacuum line, although I do need to test it properly.
Old 02-02-05, 09:06 PM
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Man still no boost...
Old 02-03-05, 10:28 AM
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quick question,

when you hit the accelerator do you hear a noise like rushing air on the passenger side of the car??
Old 02-03-05, 01:35 PM
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lennie, what would that mean? PM me....
Old 02-03-05, 01:44 PM
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It would mean there is a leak or blow off valve opening too early. (But the stock blow off valves open into the airbox and usually can't be heard)
Old 02-03-05, 01:58 PM
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he is asking about the crv possibly staying open when it should close at the transiition point. i and many others have asked him about the crv and he says it is fine.
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