88 n/a rx7 not getting power to injectors.
 

I have seen and read a few posts about this, but can't make sense of them I'm not very good with a volt meter but checked the injector plugs with a test light and some injector tester kit I got from oreilys. None of them show any power while turning the car over. I have tried 3 different ecus and nothing. I have fuel through the fuel system, the fuel pump is good and I have replaced all of the soft fuel lines and blown out the hard lines. The motor starts if I use starting fluid or if I spray gas in the intake. I don't know what else to check, PLEASE HELP! Thanks for the help in advance.

With the key in run, you should be seeing +12V on the black wire w/ blue stripe at the injectors. The ECU provides the ground signal to switch the injectors on. Probe these leads with the other lead on metal of the engine block.

The part I find strange about you saying you're not getting power to the injectors, but it starts with starting fluid is that the same +12V wire that feeds the injectors also provides +12V to the ignition coils, so you shouldn"t be getting spark, either.

try using a Noid light just to make sure that it's working. Check & clean your ground under your UIM.
Worked for me. Hope it helps.

it's probably the fuel pump or the AFM. jumper the fuel pump test connector and turn the key to on and you should feel pressure going through the fuel lines.

Is this by chance an engine swap?

I checked with a noid light and got nothing, also do you by any chance know the color of the ground I'm looking for?

The fuel pump works and fuel is circulating, i checked every way possible.

Yes, it's a swap from the same year and model 13b n/a. My first motor caught for so i bought a running replacement. Everything fits nicely and is plugged in, I'm just not getting any injector pulse.

Which injectors are you testing? The primary injectors, hardest to access, are used for starting and idling, while the secondaries, easiest to access, are not used. Again, make sure the injectors, specifically the primaries, are receiving voltage w/key to on ( as well as start) on the Black/Yellow wire.

I'm assuming you swapped the harness as well because of the fire, are you sure it wasn't out of a car older than 87.5? If it is and you used the older harness you are probably missing the injector resistor pack on the passenger side fender underneath the stock air filter box.

check the engine fuse inside the cabin, this would prevent the fuel pump from running though unless you have it jumpered.

Are you getting +12V to the injectors? Test like I said. We can't help you if you don't do this test.

Make sure the meter is set to DC volts. For this test, it doesn't matter if you check the primaries or the secondaries.

Would that cause no 12v at all at the injectors? Should i go get another harness from lucky 7? Also, if I posted a picture of the passenger side inner fender would you be able to tell me if it is missing? Could I just replace that part? Or do I have to change the entire harness?

I jumped the fuel pump and have disconnected the return line to make sure the fuel is circulating.

Again, I am terrible with a volt meter. However, I have tested it with a 12v light tester and none of the four plush show any constant 12v or pulse with ignition on or rolling it over.

The Red meter lead measures the voltage and the Black meter lead is placed to a ground such as the negative battery terminal or the alternator housing. The injector receives voltage on the Black/Yellow wire w/key to on ( not constant power).

The lead coil has a white plug w/two wires. One is Black/Yellow. Same wire at the injectors. If this wire does not have voltage w/key to on then check the EGI INJ fuse in the engine fuse box.

And use a battery to practice on w/respect to using a multimeter if need be.

The engine fuse box only has 4 or 5 slots in it right? the cover melted and i can't read it which one do i need to check?

If the B/Y wire at the lead coil has voltage w/key to on then you know the EGI INJ fuse is good. Secondly, in the FAQ section you will find a pic of the fusebox cover. And it would be the 40 amp fuse.

I checked this when I got home, and it had power. Molotovman told me to also check for the resistor pack and I found it on the old harness so I plugged it in. Just as I went to try and start the car, the starter took a dump! :scratch: I ordered a new starter and will pick it up tomorrow, hopefully then the car will fire. I will update as soon as I get it put together. Thanks for all the help guys, much appreciated!

Did you try tapping your starter with a hammer, or did it burn up?
That resistor pack is probably the issue since it was missing.

try bumping the key numerous times, the starter wiring is usually bad on these cars.

Yeah I tried tapping the starter with a small hammer, it turned over half a turn really slow and died. I even tried hooking up a remote starter and that didn't work after cleaning all the contacts. I'm hoping the resistor pack was the problem. I'm going to pick up the starter now, hopefully it runs!

Why would an 88 have a resistor pack? Change to high impedance injectors happened in mid 87.

86-88 have the resistor pack
S5 doesn't.
Trust me I learned the hard way.

...

It definitely does... I finally put in my new starter and the resistor pack. I now have 12v at the injectors with the key on. However the car barely rolls over. So i replaced my terminals with new ones, added another wire from the battery to the starter for more amperage but it's still rolling slow. Even with a 200 amp charger on it.. This car hates me! Lol

I disagree. So does the Mazda parts fiche, claiming that the resistor pack for the injectors stops at VIN ending at 550168, june 1987. Part number HE21-18-831.

The 88 FSM doesn't show the resistor pack in the engine wiring diagram.

I've worked on S4's that didn"t have them.

It wouldn't make sense, either. A car either has low impedance injectors and resistors, or high impedance injectors. All 88's are high impedance, so what would the resistors be doing?

Yea they stop making them in 87 for the cars that were sold brand new as an 88 but made in 87? Just sayin every s4 I've seen HAS the resistor pack. My s4 didn't have the RP so I had to wire in resistors in the harness. And no. 88's have low imp injectors. I'm going based off of my experience with USA model fc's not sure where in space your gettin your info.

...