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Need help with rev limiter & sensors?

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Old Feb 24, 2006 | 06:33 PM
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From: Ada, Ok
Need help with rev limiter & sensors?

I just bought a 93 RX-7 montego blue very nice car. The car has a new engine in it with 2500 miles and i have fuel cut-off's/ rev limiter at 6500 in 3rd and 4th gear. Are those rev limiters factory or did the place that put the engine in set the limiter that low? What can i use to remove the rev limiter so i can actually rap out the rpm instead of short shifting?

I also found some disconnected wires and was wondering what they connect to? I will post some pics if someone can tell me what they go to? Also exhaust smells like the car is running very rich & very rough at idle is that normal with a car with 3"downpipe midpipe &catback.

Here are the pics of the disconnected wires.

Pictures

Last edited by OkBlue_FD; Feb 24, 2006 at 06:49 PM.
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Old Feb 24, 2006 | 07:51 PM
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You are overboosting because the previous idiot owner installed a full exhaust with no form of ecu or boost control, apparently. The "limiter" you are hitting is the ecu cutting fuel to try to protect the motor because the car is boosting far above the limits of the stock ecu (10 psi).

Running very rough, in conjunction with the mods and overboosting the car is doing, more than likely means a blown motor.
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Old Feb 24, 2006 | 08:02 PM
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You're not hitting a rev limiter. You're likely hitting fuel cut caused by overboosting.
Do you have a boost gauge? Boost controller? ECU to deal with the open exhaust?

If the answer is no to any of the above, stop running the car hard preferrably stop driving it alltogether for now. You need to get control over the boost issue.

I would start with 1) put the cat back on, if you have it, or get a 2.5" diameter exhaust gasket to put between the mid-pipe and downpipe/exhaust. 2) get a boost gauge asap. 3) a boost controller, or remove the restrictor pill from the line to the wastegate actuator (should be able to just replace the line).

Read all the stickies at the top of this forum and learn about the car. You're quite possibly moments from a blown engine, if it's not too late already (dunno about that rough idle...)

These cars are kinda picky when modding them and you need to understand what the effects of the changes are and how to manage them.

This is the place to be if you really want to learn about the FD. There is probably more collected info here about them than anywhere else.

Good luck.
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Old Feb 24, 2006 | 08:07 PM
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Good to see another Oklahoma FD. Your best bet is to follow these guys advice and hope your motor isn't already gone.
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Old Feb 27, 2006 | 02:59 PM
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I dot think the motor is gone, it just idles rougher than what im used too, besides that the car runs great smooth through the entire rpm range. The car does have a boost gauge and boost controller but he said it was turned all the way down when i bought the car. He also told me that the boost gauge was reading 5psi off and it does read about 15psi at full throttle. It is a defi boost gauge & it reads 5 psi when the car is turned off. Should i turn the boost controller down more and if so which direction do i turn the **** because ive been scared to touch the boost controller from hearing all of the horror stories of people blowing their engines. It is a turbo xs boost controller.

Last edited by OkBlue_FD; Feb 27, 2006 at 03:03 PM.
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Old Feb 27, 2006 | 03:09 PM
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Originally Posted by OkBlue_FD
I dot think the motor is gone, it just idles rougher than what im used too, besides that the car runs great smooth through the entire rpm range. The car does have a boost gauge and boost controller but he said it was turned all the way down when i bought the car. He also told me that the boost gauge was reading 5psi off and it does read about 15psi at full throttle. It is a defi boost gauge & it reads 5 psi when the car is turned off. Should i turn the boost controller down more and if so which direction do i turn the **** because ive been scared to touch the boost controller from hearing all of the horror stories of people blowing their engines. It is a turbo xs boost controller.
You need to have someone look at it, someone that knows what the hell they're doing.
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Old Feb 27, 2006 | 07:38 PM
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Originally Posted by LUPE
You need to have someone look at it, someone that knows what the hell they're doing.
Well said.
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Old Feb 27, 2006 | 09:05 PM
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I dont see how the car could be overboosting with a manual boost controller because arent the manual boost controller supposed to keep the boost at the same level through the entire rpm range. So for the computer to be cutting off my fuel i have to be hitting 12psi i my higher rpm ranges since that is the cutoff for the computer. I dont see how i could had a blown engine and still be able to run just fine. It just smells a like it is running rich to me which i guess is better than running lean. If no one else has any other input i will just go ahead and call rotary performance tomorrow since they are the closest rotary specialist.
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Old Feb 27, 2006 | 11:12 PM
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You're not going to get all the answers in this thread....you are lacking a large amount of basic knowledge that is going to require you to spend some time learning more about the car. Going to a rotary specialist (or at least talking to them) is your best bet, and Rotary Performance is one of the best.
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Old Feb 28, 2006 | 08:21 AM
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If the wastegate gets overwhelmed, which is common with a full exhaust, no boost controller in the world is going to be able to maintain stable boost. This is called boost creep.
There is a billion threads on this, do a search for "boost creep" to get more info.
And you only need to hit 11 PSI in the high rpm ranges for fuel cut to occur (think it's 10.7 to be excat).
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Old Feb 28, 2006 | 11:22 AM
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From: Ada, Ok
Thanks for the info guys and understand now. I have an extra set of turbos and would like to port the wastegate on them and that should stop my boost creep problem, Correct? I searched and couldnt find a how to on that could some one help me with a link.
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Old Feb 28, 2006 | 06:01 PM
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Originally Posted by OkBlue_FD
Thanks for the info guys and understand now. I have an extra set of turbos and would like to port the wastegate on them and that should stop my boost creep problem, Correct? I searched and couldnt find a how to on that could some one help me with a link.
Correct, porting the wastegate is the proper way to clear up boost creep.
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