my car is an 86 na, and my problem is when the secondary injectors are supposed to come on i loose all my power, at about 4000 rpm. In the factory manual it says the resistance on the injectors is supposed to be 12-16 ohms, but i am only getting about 2-4. i'm not sure what that means. Does anyone have any ideas?

thanks

 

Sounds like shorts in the injector . Replace them.

 

No. The 86 gets low impedence injectors of approx 2ohms. I usually see 2.3 ohms. The book your reading is wrong.

See if one of your secondary injector plugs has not fallen off or is not getting batt voltage on one of its pins. And or reseat the solenoid resistor package and try again.

 

did you swap injectors to some high imps ? if you did you need to bypass your resistor box for it to spray.

 

If your reading the page I attached below......................that is NOT for a 86 car. Buy a 86-87 FSM.

 

ok, on the injectors pins i get 12v on one pin in both plugs, i don't know where the solenoid resistor package is, or how to reset it. all my injectors are stock

 

It's a silver box bolted to the fender under the AFM/air filter. I was talking about just pulling its plug off and then putting it back on. Nothing more. Sounds silly, but try it anyway.

Do yourself a favor. Idle the engine. Then pull the vacuum hose off the pressure sensor. Make sure you have vacuum on that line.

Solenoid resistor looks like the jpg attached. Ignore the part with the red lines around it. The picture is on the package from the bottom side of it.

The online 88FSM will work for about 87% of the items on a 86 car.

Since you have voltage on the injector plugs.........that's good, so it can't be a lack of volage. The plugs must have been on the injectors or you would have said so.

Will your engine go above 4000rpm if your light on the gas pedal?

 

it will go over even heavy on it i just don't have any horsepower after 4000rpm, i took the injectors out, i am changing the omp lines today anyway, i checked them with wires to my battery and it sounds like they both open. i will try unplugging that resistor here in a sec. As a side note if you have aftermaket air flilters mount them far enough back that they don't touch that resistor. i burnt a hole in a bonez air filter cus of that thing

 

ok i tried all that, even swapped primary and secondary injectors, still nothing. my car is soooo slow it is depressing. i checked the hose to the pressure sensor and it has vac, the car actually stalled when i took it off, but it started right back up with it off. I have no idea what else to look for, any more ideas?

 

Just a thought...

Do you have any cats in the exhaust system? A plugged cat will choke the engine at high rpms and cause similar symptoms.

 

yea i have a catback system. but the cat should be good it doesn't have alot of miles on it. i'm starting to wonder if my fuel tank has crap in it. i just can't think of anything else.

 

Remove the seconday injectors and read the number embossed on the side of it near the jack. A number like 199550-1350 or -1370??????? OR?

 

what does the number mean?

or what are the differences between them? resistance?

 

195500-1350......i have also checked the sock, i am lost i hope that helps

 

From the FAQ:


What size injectors does my RX-7 use? What colour are they?
Year Engine Plug Size Colour Part #
84-85 13B NA, low square center, 680cc, orange, 195500-0900
86-87 13B NA, low square center, 460cc, red, 195500-1350
86-87 13B Turbo, low square center, 550cc, tan, 195500-1370
88 13B NA, high square offset, 460cc, purple, 195500-1350
88 13B Turbo, high square offset, 550cc, purple, 195500-1370
89-91 13B NA, high oval center, 460cc, red, 195500-2010
89-91 13B Turbo, high oval center, 550cc, purple, 195500-2020

1350s are 460cc NA injectors. 1370s are 550cc turbo injectors. It doesn't tell you anything about resistance since both highs and lows share the same PN. Tab offset will tell you however.

The colors listed are not 100%. I have 3 sets of injectors that do not match what the FAQ says they should be.

 

I just thought maybe someone had put the wrong size injectors in, but you have the right ones.

 

what else could cause me to loose so much horspower? i could be paranoid but i think it has gotten worse. it does seem like it drives better when i push lightly on the gas, or right as i come off the clutch i get a second of power but thats it.

 

its not that ur losing hp, its that the secondaries are not coming online at all, i have the same problem as u.
im 99% sure that my solenoid resistor is the problem because iv done everything else to fix it and nothing worked. if u can get ur hands on another one try it and see if it works, if not than it could be either u need to clean up all your grounds or reground everything. regrounding the ecu could fix it also. i think its pin 2C.

read through the fsm and try all of the things it lists in there
you can get all of them on pdf here
http://mazdarx7.iougs.com/fsm.shtml

 

but the secondaries have voltage. it's still an electrical problem?

 

Check your fuel pressure at the pump. Remove the access cover to the pump. Then remove the hose from the hardline to the right (as you look fwd on the car). Install a fuel pressure gauge on that output hardline.

Key to ON. Yellow fuel pump check connector jumpered. The gauge should read what the FSM says. Something like 65-80 psi.

The 86-87 FSM shows how to check the secondary injectors to see it they come on. Remove and plug the vacuum line that goes to the boost/pressure sensor Then with a warm/hot engine, rev the engine to over 3800 rpms. The engine should stumble a bit when you hit the 3800rpm mark. The meaning of that is, that the secondarys came on line and the primarys duty cycle was cut in half.

Good that you have voltage to the injector plugs. Now it's up to the ECU to pulse a gnd to the injectors when the conditions are met.

 

ok thank you all for the help

 

ok now it's acting even worse then before. it is slow reving and when i finally get it up to 4000 rpm it won't go any higher, it just bounces around 4000 rpm. At first i thought it was just because i had the vac line off for the boost sensor but it is doing it with it hooked up to. i had just put the fuel pump back in after cleaning the sock a few days earlier. i'm worried. i don't know wtf i did

 

limp mode???

 

Not on an 86... I don't think us S4 guys get that.. Only the S5s where they switched to electric MOP....

Check the fuel pressure, get back to us As I noted in another thread (S4 NA Running Lean) right around this one, for the range you need to check, pick up a gauge from a local hardware store.. Unless you plan on leaving in the car, don't bother to spend the cash on a "Car specific" autometer gauge or something.. But do be sure to remove it when you're done!

 

did you check your gas tank?was there any crud inside?