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No power after 3500rpm

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Old 12-28-16, 06:01 PM
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No power after 3500rpm

After replacing my motor in my second gen 13b rx7, it falls on its face (or has no *****) around and after 3500rpm, any reason why?
Old 12-28-16, 06:37 PM
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There's a chance the secondaries are not turning on. Could be poor grounding, problem w/the injector plugs. If you unplug the TPS and remove the vacuum hose to the pressure/boost sensor that will create load on the engine while in idle mode so you can test things while the car stays put in the driveway.
Old 12-28-16, 08:36 PM
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The secondary injectors Are not firing that's why it sounds like it's at a rev limiter?

Last edited by Oneils garage; 12-28-16 at 08:48 PM.
Old 12-28-16, 10:14 PM
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Originally Posted by Oneils garage
The secondary injectors Are not firing that's why it sounds like it's at a rev limiter?
Not sure what a rev limiter would sound like but can you tell us if the engine is JDM, and if so, did you use the JDM ECU?
Old 12-29-16, 12:46 AM
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Junk yard motor

I bought the motor to from a junkyard in San Bernardino out of a 89 fd convertible, no I do not believe it is a JDM motor, and no I did not get the ECU with it.
Old 12-29-16, 01:20 PM
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And what year is your car?
Old 12-29-16, 02:41 PM
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Originally Posted by lduley
And what year is your car?

The car is a 1986 mazda rx7 fc 13b non turbo.
Old 12-29-16, 02:54 PM
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How about a missing vacuum line from the fuel rail regulator? It's on the front end of the top fuel rail.
Old 12-29-16, 05:45 PM
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Ok so you took a s5 engine, and put ALL your s4 hardware and electronics on it?

And yes, that will cause issues, long as it is hooked up to a vacuum source on the intake you should be ok, IDR where it goes from the factory
Old 12-29-16, 06:48 PM
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Originally Posted by lduley
Ok so you took a s5 engine, and put ALL your s4 hardware and electronics on it?

And yes, that will cause issues, long as it is hooked up to a vacuum source on the intake you should be ok, IDR where it goes from the factory
I didn't see any type of grounding wire that would be a problem and I did fix that vacuum line. And as far as the injectors I remove the secondary injectors and tested them confirming that one of them was bad so I replaced both of them with injectors off of my other motor, was on a test drive, just left the driveway and ran out of gas so it will have to wait until I get some. I'm not sure what you mean by S5 and S4 but yes I did just use the bear motor and none of the components. I'm hoping the cause of the problem was the bad injector that being said one of the primary injectors might be bad also correct?
Old 12-31-16, 08:26 AM
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86-88 are s4
89-91 are s5

You have a 86 (s4) and you took the engine out've a 89 (s5)

As long as you used ALL your external parts and wiring, you'll be fine

It IS possible your primary's are bad too, may as well send all 4 out and have them rebuilt/reflowed
Old 12-31-16, 04:59 PM
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Originally Posted by lduley
86-88 are s4
89-91 are s5

You have a 86 (s4) and you took the engine out've a 89 (s5)

As long as you used ALL your external parts and wiring, you'll be fine

It IS possible your primary's are bad too, may as well send all 4 out and have them rebuilt/reflowed
I just looked up the inventory list on the junkyard. I've got my motor from and I was mistaken and that RX7 was in 88 not in 89 so I should have no computer or electronic problems and as far as my primary is being bad I will have to test them

Old 01-01-17, 07:15 AM
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find the vacuum diagram for the s4.(search..it's in here..or Foxed.ca)
That hose would hinder your fuel,so you need to address that hose.
Old 01-04-17, 10:22 PM
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Timing?

If it could be vacuum, can it also be timing?
Old 01-05-17, 11:15 AM
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In post #10 you stated you were driving the car and ran out of gas. We do not know if you put more gas in the car and how the car ran. Are you keeping us in the dark to serve a purpose?




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