I'm doing a stock engine swap right now to my 86' N/A. The new engine is from an 87' and is also n/a. What CC injectors do I need to use? I know that the CC changed a lot between the years and I want to get it right the first time when ordering the new injectors. Thanks for the help!

 

All NAs are 460CC.

What might be different is that the '87 may be high impedance, while your '86 is low impedance.

 

Thanks for the help Aaron cake, being that the new engine is from an 87' I'm assuming that I have to get high impedance injectors then. Right?

 

Or would it be possible to send my injectors from the 86' N/A engine out to get cleaned and flow tested and put them in the 87' N/A engine? I know you (Aaron cake) said that the 87' N/A engine has high impedance and the 86' N/A has low impedance so I'd rather ask then to waste my money and run into problems. If I can't do that does anyone know where I can get all 4 NEW or REMANUFACTURED high impedance 460 CC injectors for my 87' N/A engine?

 

no he said that MIGHT be the difference. u really should get out of the "new member" section now that ur post count is high enough and visit the 2nd gen section. they will know what if any differences there is. yes u could just send urs off to be cleaned and tested.

 

I know that he said might but since he (to me) is like a guru at Rx-7's I figured I'd ask him to know for sure. I also know that I can send them out and get them cleaned but I want to know if they're definitely going to work in the 87' N/A engine like if low impedance injectors won't work in an engine that needs high impedance injectors. There might not be enough resistance to open the injectors giving me the 4,000 rpm hesitation or other problems. Had it happen in my last FC so Im trying to get everything right this time. I'll check out the 2nd gen. section then though, thanks.

 

Most '87s are high impedance. So, if you are keeping the 86 wiring harness, then just use the injectors from the earlier engine. Have them cleaned by a professional injection shop. If you want to use the injectors from the '87 engine, you will most likely have to bypass the resistor block on the harness.

 

Mid-year 87, Mazda switched from low to high impedance injectors. If the 87 has low imp. inj., they will be identical to the 86. If they're high, the clips will be different, along with the part # on the injector and, iirc, the injector color. The engine harness and ecu is different between the low/high impedance injectors.

I had an 88 GTU that had a small engine bay fire that fried the engine harness. Since I didn't have a high impedance harness, I swapped in a low one and changed the ecu. Plug and play and ran fine after the swap.

 

God,,so many Run around answers!
If the Car has LO impedance injectors:..put a Digital OHM Meter across an Injector and take a Reading..if it reads about 3-4 ohms they are LO impedance,
IF the injector reads 10-14 they are HI impedance injectors
NOW,the cars that have LO impedance injectors will have an Resistor pack below the Stock Air Box.(passenger side,in front of the strut tower).It is a Small silver looking thing with a Thumb size connector.It contains 4 Resistors,one for each injector.
IF the harness does not Have a Connector and a Resistor pack in that location then it is Most likely a HI impedance injector Harness.
..There is a TRiCK to it all too,.
IF you want to Run LO impedance injectors WITH a HI impedance harness,you can spliec into the Harness and add 10 OHM 10 watt Resistors(radio Shack).that will make the ECU "see" HI impedance injectors.
AND...if you want to Run HI impedance injectors on a LO impedance Harness,,The Trick here is to Bypass the Resistor pack,by Splicing the wires off the Resistor pack and making them Connect back though the Connector..(twist and solder the wires together,it will Cut the resistors out of the Circuit and you just now have the wires going straight through to the HI impedance injectors).
By the way,the ECU's see a HI impedance circuit anyways..that is why you either have LO with resistors OR HI without a pack.
..see?.wasn't that more helpful??

 

Well I went to check the 7 for the resistor pack that misterstyx69 mentioned and it's there but I figured it would be because it's an '86. I unfortunately can't check to see if the '87 N/A engine has high or low impedance injectors because I bought it as just the block with no other parts. Since I don't have the injectors from the '87 N/A engine and I'm using the '86 wiring harness I'm just going to send out the '86 N/A injectors to have them cleaned and flow tested. If I run into any problems I now know the basis of what I have to do. They were all very helpful answers, thanks!

 

So I was thinking, if I use the injectors from the '86 N/A engine and it turns out that the '87 N/A engine uses high impedance injectors, wouldn't the injectors not open because there isn't enough resistance? This is how my engine will be set up : '86 wiring harness, '86 ECU, cleaned '86 low impedance injectors, and '87 block. If the '87 N/A is high impedance I just have to bypass the resistor, right? or is there something I'm not getting here? Sorry for all the questions, lol.

 

"'86 wiring harness, '86 ECU, cleaned '86 low impedance injectors, and '87 block"

That works, no need to bypass the resistor if you are keeping the 86' injectors with the 86' wiring and ecu.

 

Yeah I'm keeping it like that, thanks for clearing that up for me!