Have spark, no fuel... won`t start
 

Ok, as usual I did too many things at once and now i`m trying to track down this issue. Here`s whats going on. When I go to start the car, it`ll turn over, but won`t fire. I checked the lead and trail coils, have spark. Jumped the fuel pump, it works. Now for what I`ve done

I installed a fmic with piping, relocated battery to rear pass. bin, taraus 130amp alt, fuel pump rewire, apexi pfcw banzai s4 harness.
Im getting fuel to my fuel rail, cuz one of my injector o-rings was tore and it sprayed out. I replaced it and no leak, but seeems like my injectors aren`t working. Will the fuel pump rewire screw with the injector relay? It acts like the 40amp fuse is pulled, like the deflooding procedure. I checked the fuses, everything seems to be in check.

I figured it was the pfc so I removed it and installed my rtek and maf again....no fire. So im lost atm. Could the injector resister box be shot? Engine ran before all the mods. Or, could the injectors be bad? They came out of a running motor (750`s) and my secondaries are brand new modified bosch 1680`s. Guess i`ll try and switch back to my 550`s and maybe find a injector resister..

Oh, forgot the car is a early 87 TII, it was stock before i added all this stuff, also added a full RB exhaust, aem wideband.

Any suggetions would be helpfull!

if you jump the connector and the pump runs its working properly. You most likely need to check your wiring and fuses. the alternator if done wrong can blow a fuse. also check your ground under the rats nest.

something with the wiring for the rtek/computer is not letting the injectors open/

Could be a number of things but if you have the Resistor Box then it is for use with only low impedance injectors. Are these what you are using? And when you say you "jumpered the fuel pump" does that mean you jumpered the "fuel check connector" and w/key to on the pump ran or did you provide a voltage source directly to the pump and it ran?

yep, I have low imp injectors. I jumped the fuel pump on the pass. side strut tower with key on. Pump runs, i hear pump in back and can hear fuel running thru the fpr.... Something isnt letting the injectors fire. I checked all my grounds, and fuses. everything is good to go. I wanted to blame the pfc, but switched back to the rtek with maf and still nothing. I shoulda known better to do a ton of mods at once... makes it a pita to track down specific problems.

How long were those 750's out of use before u installed them? Injectors can "seize" up pretty easily when I'm disuse. Verify the spray pattern on the injectors as sometimes injectors will click and still be clogged/stuck.

oh, and the rats nest went bye bye last year.... like I said all was good until I added a bunch of stuff.... I`m letting my brain relax... I`ll probably go work on it this weekend and it`ll be something stupid that I overlooked. Thanks for the replies so far guys!!

not sure... bought them from Viperkiller last week on here. Ill prolly switch my 550s back in to see if thats the problem. Now that the tmic is gone its not that hard. I was gonna replace my injector clips but they were still looked really good, not crumbly like most.

If you're planning on switching out the primary injectors w/the originals then you'll be able to test them at that point to see if they emit fuel or not. Also, if you're willing to pull the CAS out of its perch and disconnect the electrical plugs to the coils and w/key to on you can spin the CAS and you should hear the primary injectors clicking to help verify if they are firing or not.

Pin 3E and 3C of the ECU should have battery voltage w/key to on as well.

I got a spare cas laying in my parts bin.... can i just hook that up first and spin it to see if they are firing? Or do I have ot remove them first?

You can just disconnect the plug to the installed one and plug it into the standby one. You might want to disconnect the electrical plugs to the coils to silence them so you can focus your ears on any noise coming from the primary injectors. And also perhaps check the ECU pins I mentioned in the last statement of my previous post.

^ I used that method and listened w/a stethoscope, the injectors clicked, but still weren't supplying fuel.

I ended up applying 12v /ground leads to the injector plug(s) directly and pulsing them for 2-3 seconds w/the fuel rail primed to 40psi, which cleared out the blockage/sticking. Spinning the cas will only open the injectors for a couple ms which is not enough to fix the problem, only verify what you already know.

Check that there is 12V power at the injectors with the key in the on posistion.

With the PFC your fuel pump should be priming as soon as you turn the key to the on posisiotn.

ok, tried the spare cas, the fuel pump primes when i spin it, but i dont hear the inj. clicking. i remember doin this back in 06 on my n/a-tii swap. geen out of the mod game for awhile. the pump doesnt prime when you turn the key on with the pfc hooked up, itll prime if i jump the check connedtor or spin cas. wont fire with rtek in either. anyone got a pic of the s4 tii ecu they could put on here? my phone is ancient and takes forever to search.

oh, and the readout on the pfc for fuel pump voltage is 4.98v if that matters

It is not the FP voltage, it is the fuel temp sensor voltage, which does not exist on the S4/S5 so it defaults to 5v.

If the fuel pump does not prime when you turn the key forward, then there is a problem with the circuit opening relay wire or the relay itself.

Pin 3C and 3E are in the smallest ECU plug and 3C is Light Green/Black while 3E is Light Green. If these wires have battery voltage w/key to on that means the Main relay is feeding the Solenoid Resistor Box and that the injectors are receiving this voltage and the plugs/clips to the injectors are secured properly for if they were disconnected the voltage supplied to the injectors via the box (Brown wires) would not pass the voltage onto the Light Green wires that lead to the ECU.

Well, looks like there are at least 2 problems: fuel pump cuircut, and injector signal. Even w/ no fuel the injectors should operate when the CAS is spun.

As advised, check the voltage at the connectors. If they all show 12v then you might also want to try swapping the primary and secondary injector pins at the ecu and doing the CAS test again.

How exactly did you rewire the fuel pump?

Post #3 in the link provided.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/88-rx7-wiring-diagram-968998/

ok, i think i might have it figured out. i took my cas out to verify it itself is working. got the injs to click with spare after disconnecting and reconnecting everything i messed with. took cas out of car spun it and nothing happens. im gonna restab it and ill let everyone know. oh by the way after spinning spare a bunch of times car now fires but dies right away which leaves me to believe cas

doubtful, sounds like a weak ground.

ok that didnt work... ive regrounded the engine ground with 10 gauge, sanded down paint to metal and soldered all my connections... again if i spin the cas by hand, itll get enough fuel to start for a split second then no fuel again

Did you check the 15 amp eng fuse behind the kick panel? Sometimes the most obvious gets overlooked.

could the ground wire at the ecu be crap? ive just got the pfc ecu sitting on my floor... not bolted down like the stock one...isnt there a ground down there somewhere too for the ecu?

The stock ECU is grounded internally and not by being bolted down. Not sure about your version though. When you say you can get fuel briefly if you turn the key to off and back to on and then respin the CAS does it again provide fuel for just a brief time? Are you doing this test w/the fuel check connector jumpered?