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No power and rough until 4700 rpm

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Old 06-07-04, 09:07 PM
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No power and rough until 4700 rpm

I'm having a problem with car under 4700 rpms. It starts, but has a rough idle (shaking motor and vibrating car). On acceleration, the car barely gets moving and acts like it's bogging down. As soon as I get to 4700 rpms, it sounds like the plugs are missing for just a split second, and then it's like someone just flipped the switch to the "on" position. The car sounds perfect and rockets up to redline. I recently put 1300cc injectors in the car, as well as doing the "poor man's" non-sequential. I just changed out the plugs and that didn't fix the problem. Don't think it's the injectors cuz the secondaries don't come on at low rpms, right? I would guess that it's the non-sequential, however, with the plugs missing, it almost sounds like a computer/electrical problem. Any ideas???
Old 06-07-04, 09:36 PM
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compression check, shaky at idle means broken apex seals or a disconnected map sensor, so check map also. im not fully sure what "poor mans non seq" is so i couldn't help ya on that...
Old 06-07-04, 09:41 PM
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um is your car tuned because you may be injecting way too much gas into the engine.
Old 06-08-04, 12:38 AM
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Not the compression. The car only runs bad below 4700 rpms in every gear (and always right at 4700). Also, the compression was great prior to doing these mods, and these probs began the very first time I started the car. Map sensor is connected. As for the tuning, I changed the setting on the PFC for secondary injectors to 1300cc. ...but they shouldn't even be a factor at low rpms...
Old 06-08-04, 12:50 AM
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Make sure the 1300cc injector is installed replacing the secondary not primary injectors. It will probably be the cause of that sympton.
Old 06-08-04, 09:37 AM
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The primaries and secondaries are not interchangeable (without modification), due to their difference in size.
Old 06-08-04, 11:15 AM
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perhaps one of the injectors is stuck open? RC says that it happens on occasion but they dont like to warn people about it since it happens so infrequently. Basically you arent supposed to store injectors for a long time after they are cleaned. mine were stored for 6 months now and still are fine go figure.
you can check them by getting a 9v battery and touching the injector connectors
you should hear a click with power and feel it click back when you remove the wires from the connectors.
Old 06-08-04, 01:48 PM
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both primary and 2ndary are denso side feed, can be interchanged. If with modifing the oring, it could leak too much fuel into engine, and cause flooding or stumble.
Old 06-08-04, 05:55 PM
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Maybe I don't remember this correctly, but I thought that with modification (either to the fuel rail, or adding an o-ring to the injector) you can put the secondary injectors in the primary position. However, the primaries would be much too long to fit in the secondary rail (not that you would ever want to do that anyway). But, how about if I had the connectors to the injectors reversed? Would I show the symptoms I'm having now? ...and, is it possible for RC to accidentally enlarge the primaries instead of the secondaries (I also sent in my primaries for cleaning)?
Old 06-08-04, 08:25 PM
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IF UR non-seq , you may want to re-check ALL your vacuum lines again , and make sure the flapper door hasn't shut itself. I would also check the vacuum diagram for non-seq . conversion and double check the lines to be sure you've got it right ... happened to me.
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