Trouble starting one dry plug
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this engine was from another car- i don't know exactly what year the engine was. These injectors look like they have been in the car for the last 30 years. Can i assume the resistor packs are attached to the engine? this engine did come complete with everything on it. Pat
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From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
this engine was from another car- i don't know exactly what year the engine was. These injectors look like they have been in the car for the last 30 years. Can i assume the resistor packs are attached to the engine? this engine did come complete with everything on it. Pat
https://www.rx7club.com/2nd-generati...mp-car-470664/
1986 and 1987 model cars used low impedance(2-3 ohm) injectors. Low impedance injectors have a center notch on the plug. The wiring harness used with LI injectors integrates an injector resistor pack, wired inline between the ECU and injectors(under stock air box) to bump overall load seen at the ECU to 12-13 ohms.
1988 and later models used high impedance injectors. 1988 HI injectors have an offset notch on the plug, and all post 1988 injectors are HI with an oval plug(until 3rd generation side feed injectors which are totally different). The wiring harness on these models deleted the injector resistor pacl, carrying the 12-13 ohm load from the injectors directly to the computer.
When performing engine/wiring/injector swaps, the type of setup must be noted and kept together. This is easy as LI injectors will only plug into a harness meant for them(due to the position of the plug notch) and vice versa for HI injectors and harnesses. 88 and post 89 HI injectors and harnesses are not interchangeable.
A car that previously ran one type of setup can be changed to the other…keep the injectors and wiring harness together. The ECU will not know the difference.
It is also possible, but not necessarily recommended, to use HI injectors on a LI harness and vice versa:
••
TO do so you must modify the injectors to fit the opposing wiring harness by taking off the notch on the plug.
••IF using LI injectors on a HI harness, you must splice into the harness, at each injector lead (for a total of 4) 10 ohm/10watt resistors available at radio shack for a couple of bucks. Doesn't matter which wire of the 2 per injector you splice to, polarity isn't an issue here. This bumps the LI resistance up to acceptable load for the ECU to see.
••IF using HI injectors on a LI harness, you must unplug the resistor pack. Next, locate the supply wire in the center of 5 terminals. Bridge jumper wires from this terminal to each of the 4 outlying terminals, which basically completes the circuit without resistors, carrying the HI injectors' 12-13 ohm load directly to the ECU just as a HI harness would.
https://www.rotaryresurrection.com/2...ctor_info.html
1988 and later models used high impedance injectors. 1988 HI injectors have an offset notch on the plug, and all post 1988 injectors are HI with an oval plug(until 3rd generation side feed injectors which are totally different). The wiring harness on these models deleted the injector resistor pacl, carrying the 12-13 ohm load from the injectors directly to the computer.
When performing engine/wiring/injector swaps, the type of setup must be noted and kept together. This is easy as LI injectors will only plug into a harness meant for them(due to the position of the plug notch) and vice versa for HI injectors and harnesses. 88 and post 89 HI injectors and harnesses are not interchangeable.
A car that previously ran one type of setup can be changed to the other…keep the injectors and wiring harness together. The ECU will not know the difference.
It is also possible, but not necessarily recommended, to use HI injectors on a LI harness and vice versa:
••
TO do so you must modify the injectors to fit the opposing wiring harness by taking off the notch on the plug.••
IF using LI injectors on a HI harness, you must splice into the harness, at each injector lead (for a total of 4) 10 ohm/10watt resistors available at radio shack for a couple of bucks. Doesn't matter which wire of the 2 per injector you splice to, polarity isn't an issue here. This bumps the LI resistance up to acceptable load for the ECU to see.••
IF using HI injectors on a LI harness, you must unplug the resistor pack. Next, locate the supply wire in the center of 5 terminals. Bridge jumper wires from this terminal to each of the 4 outlying terminals, which basically completes the circuit without resistors, carrying the HI injectors' 12-13 ohm load directly to the ECU just as a HI harness would.https://www.rotaryresurrection.com/2...ctor_info.html
Last edited by FührerTüner; Jan 31, 2019 at 07:59 AM.
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From: NY
OK I will compare the wire harness tht came with the engine to the one in the car. I checked once and all connectors looked the same. The injector connector plugged right onto the injectors...so i think that part is ok. I'm pretty sure all my trouble stems from the lower injectors being fried...but i'll find out soon enough. thanks for the advice. Pat
Joined: Jul 2013
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From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
OK I will compare the wire harness tht came with the engine to the one in the car. I checked once and all connectors looked the same. The injector connector plugged right onto the injectors...so i think that part is ok. I'm pretty sure all my trouble stems from the lower injectors being fried...but i'll find out soon enough. thanks for the advice. Pat
Last edited by FührerTüner; Jan 31, 2019 at 09:22 AM.
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From: NY
Just look under the air box and see if you have a resistor box there. All FC ECUs need to see high impedance injectors one way or another. 86-87 used low impedance injectors and integrated a resistor pack into the harness to up the resistance to ~15ohms. If youre using the 86-87 engine harness that came with your car, you most likely have resistor packs. The engine you have is probably from an 88 that used a harness with the resistor pack deleted.
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Update: so with the correct fuel injectors the car starts right up and runs nice! It turns out it's a 1988 engine , but was shipped to us with an 86 upper intake ( loose).....the only issue so far is that if you warm it up, then turn it off, then try to restart it, it won't start......just turns over and over....OK new to rotaries...am i missing something in my starting procedure? or do i have another problem? thanks again Pat
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From: NY
Yeah sometimes you can get away with that but the fuel cut off switch goes a long way. If you want to test it before wiring a switch just yank the egi fuse
Last edited by CryoSignal; Feb 8, 2019 at 12:00 PM.
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From: NY
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I'd start with a compression check.
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From: NY
We got it figured out.....the engine is an 88, the upper intake ( which was shipped loose) was an 86. so the upper injectors were low impedance, the lowers ones were high impedance. the injector rebuilding shop let me know. so when i got the right injectors it started right up. Now i jst need to prefect my restarting procedure. i've never owned a car that can flood out as quick as this one!
Joined: Jul 2013
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From: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
We got it figured out.....the engine is an 88, the upper intake ( which was shipped loose) was an 86. so the upper injectors were low impedance, the lowers ones were high impedance. the injector rebuilding shop let me know. so when i got the right injectors it started right up. Now i jst need to prefect my restarting procedure. i've never owned a car that can flood out as quick as this one!
Rotary engines lose compression after the engine heats up.
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From: NY
well when my son restarts it after it was just shut off- he does something with the gas pedal- like pumps its twice while it's turning over and it starts everytime for him,. a guy in japan told him to do that - he has a right hand drive turbo car that he bought over there and had it shipped home. anyways. it works for him. maybe i'll try it the next time i have it out.
My mom lets me redline
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From: Cornwall, ON
Not sure if anyone answered the sensor question: that is your IAT(intake air thermosensor). This is important if you're running stock ECU. 20C is the failsafe if disconnected.
Last edited by Rotary Alkymist; Feb 19, 2019 at 09:51 PM.
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