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Secondary injectors not reciving power???

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Old Jan 31, 2013 | 09:46 AM
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Secondary injectors not reciving power???

My car doesnt want to to go more than 3000 rpm so i decided to take a look at the secondary injectors and one of them was bad, so i found another one that was working properly and cleaned everything and put it back but the problem persisted so i did a power test to the injectors conections and there was no power to the connector when i accelerated more than 3000rpm so were should i start loking for anything wrong??
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Old Jan 31, 2013 | 10:01 AM
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The ECU pulses ground to the injectors. They should have 12v on one wire with the key on, and you'll have to use a multimeter set on % duty to see the pulsed ground coming from the ECU.

Other reasons the engine may not rev over 3000 rpm:
Clogged fuel filter
Bad AFM
Clogged catalytic converter
Bad TPS (yes, narrow range... i know, but it's true)
and the list goes on...
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Old Jan 31, 2013 | 10:20 AM
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Ok i narrow it down to bad AFM or TPS i checked everything else and it ok but could any of does could lead to the secondary injectors not activating because i checked for the 12v source to the injectores and they were good and i put a injecter tester on there and i saw no pulsation for both
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Old Jan 31, 2013 | 10:28 AM
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The secondaries won't fire until 3800 rpm anyways.
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Old Jan 31, 2013 | 10:56 AM
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What do you mean by narrow range on the bad TPS?
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Old Jan 31, 2013 | 11:41 AM
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If you unplug the TPS and remove the vacuum hose to the Boost Sensor then that will place the car under load when the engine is idling so you can rev the engine thus while idling and it will allow the secondaries to be triggered (unlike other normal situations) to come on line.
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Old Jan 31, 2013 | 12:42 PM
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since no one has asked yet, is this a series 4 or 5 car?
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Old Jan 31, 2013 | 12:50 PM
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Series 4 N/A with a port job every internals are 8 month old
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Old Jan 31, 2013 | 03:01 PM
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OK, series 4, but what year? If it's (I believe) 88.5 or earlier, you have a fuel solenoid resistor mounted near the bottom front of the shock tower near the airbox.

Are you getting 12V to one of the pins on ALL injectors, with ignition on? If not, that's an easy part to check. On the fuel resistor, you have a 5 pin plug. One of pins is common, goes to the resistor and four come out of it. So you should have the same resistance on four current paths.

lol here, this is why I made a thread way back: https://www.rx7club.com/2nd-generati...erence-671004/

post #2, pic. 5. I mean to add more pics of stuff...oh well it's only been 6 years, lol! Anyone else, add to it if you like.
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Old Jan 31, 2013 | 03:23 PM
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Originally Posted by pfsantos
OK, series 4, but what year? If it's (I believe) 88.5 or earlier, you have a fuel solenoid resistor mounted near the bottom front of the shock tower near the airbox.

Are you getting 12V to one of the pins on ALL injectors, with ignition on? If not, that's an easy part to check. On the fuel resistor, you have a 5 pin plug. One of pins is common, goes to the resistor and four come out of it. So you should have the same resistance on four current paths.

lol here, this is why I made a thread way back: https://www.rx7club.com/2nd-generati...erence-671004/

post #2, pic. 5. I mean to add more pics of stuff...oh well it's only been 6 years, lol! Anyone else, add to it if you like.
yes its a 88, and yes i'm getting 12v to all injectors with ignition on. and no i dont have the rectangular box on pic #5 i have a relay there.
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Old Feb 1, 2013 | 05:39 PM
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do a TPS sweep with the engine warmed up off the green TPS wire(connector still connected, key on engine off). there should be no jumps or dips in voltage while doing a steady sweep of the throttle.

the reading should start at 1 volt and steadily rise to about 4.6v at 35% throttle.
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Old Feb 2, 2013 | 08:26 AM
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I put in a new AFM and a new computer and now it doesn't throw any gas or spark. I verified all the fuses and the main relay but everything was in order. im kinda pissed right now because the car was starting fine and everything any help for this poor bastard.
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Old Feb 2, 2013 | 04:33 PM
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swap your old AFM back in and see if it at least runs again.
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