ok so let me explain what i have going on. i have two fc turbos. one is a 88 10th ae and the other is a 87 turbo2. i decided to swap the powertrain/drivetrain from one to the other. i installed the motor and transmission along with the power fc/engine harness out of my 88 into the 87. starts up no problem at all and revs fine. problem comes in when you are trying to accelerate past aprx 3500-3800 rpm which is where the secondaries come in at. any clue what could be causing this as it came out of my 88 rx7 running fine. is there anything that is being a 87 could be throwing off?

 

You could use an LED light connected to the ECU to see if the ECU is triggering the injectors to begin with. You could have a ground issue. The plugs might have a faulty connection (the secondary trigger wire at the ECU, which is Green striped, should have 12 volts w/key to on and this should indicate if the plug is connected properly) The engine senses load for the injectors (secondary) to be activated and this comes from the TPS and boost sensor (W/the TPS unplugged and the vacuum hose to the boost sensor removed you could rev the engine and it should try to activate the secondaries as if you were cruising down the road and got on it).

 

great info i will look into it when im home and post up what i find. to be sure i understand you correctly unplug the tps sensor and the boost sensor ( assume cap the vacuum hose off so its not a big vac leak and leave the nipple of the boost sensor open ) then when free revving it will try to activate the secondaries

 

Just the hose is removed and not the electrical plug unlike the TPS where the plug is disconnected. The FSM advise capping the hose of the boost sensor but it's not really necessary.

 

ok so last night i verified the injectors are getting 12v. i also did what you recommended with the tps and map but no change. im wondering if im chasing the correct problem. might be a ignition related breakup. i hope to check spark tonight on all coils. would it show any symptoms if it was only firing on the leading or trailing?

 

Not sure. But which wire did you check for 12 volts (was it the wire from the ECU or was is the Black/Yellow wire)?

 

i pulled the upper intake off and checked at the actual injector pigtails. dont know the colors at the pigtail because the pigtails were replaced.

 

Each injector has two wires. One is powered by the main relay while the other wire comes from the ECU. The ECU wire should have 12 volts w/key to on but pulses a ground when they are being used. So, w/just the key to on then both wires on each injector would have 12 volts (not just one).

 

Makes sense.. ill check tonight and see what i fine. Is it possible that the dwell setting on the coils were reset with it being un plugged for so long? Ive just never had a problem with the injectors

 

If the CAS was set previously and done so properly then it would not go out of wack on its own accord. If you have access to the main engine ground you should temporarily remove it so as to clean it. And just for the heck of it check the ohm reading on the secondary injectors to verify what they are. And did you go from 88 into the 87 or vice versa?

 

yes that is what i plan on doing hopefully tonight is going through the grounds

 

and yes this motor/trans/injector resistor pack/engine harness w power fc came from my running 88 1othae. the cas was set long ago so

 

The 88's shouldn't have the resistor pack for the spark plugs (I don't believe) if that's what you are referring to (was done away with in mid year 87).

 

no i am referring to the injector resistor pack

 

88's didn't have the injector resistor pack. 86-mid 87 did, everything after mid 87 was high impedance.

 

I believe he's referring to the fuel relay under the air box as the injector resistor pack when it's actually a relay.

 

Maybe so. I was told it was the resistor pack...anyways i fixed it tonight! Found where the 10ohm resistor i had in line with one of the secondary injectors had broken. So its running and boosting properly now. Thanks for the help guys