89 NA Vert

Been having fuel issues recently and have gone through and refreshed most of the system. I just put a brand new fuel pump in hoping it would solve my issues but now it seems worse. The pump refuses to turn on, even with using the jumper in the engine bay and now I’m sorta lost on what to do next or how to test the electrical. Any help would be very much appreciated

 

There’s no click from the relay when the key is switched to on, I have a feeling that might be my issue

 

There are many threads on here about testing this. It is different between the S4 and S5, I think.
Also, check all fuses and the factory service manual. There are many possibilities here, I don't have time to dig into this myself.

Factory Service Manuals:
https://foxed.ca/indexmobile.php?page=rx7manual

 

The fuel pump circuit opening relay, which cuts the fuel if the engine stalls, is located under the dash to right of the steering column. The circuit opening relay has a yellow connector.

The fuel pump also has resistor/relay located in front of the air filter box. Here is a photo: https://www.google.com/search?q=rx7+...BNIAl5sNahK1M: The fuel pump receives full voltage at start-up and then drops to lower voltage shortly thereafter. If the resistor had failed, than when the relay opens to drop the voltage the fuel pump will lose power and the engine will die. Check the relay and resistor as per the FSM.

 

if anyone needs a resistor shoot me a PM, i've got a box of them for some reason

 

Okay so I’m getting power to the pump now, but the car won’t start. It’ll sputter and act like it wants to and instantly die. Here’s a video of what that looks like


(Edit) Didn’t know that would send as a download. If you don’t want to open it I understand. It pretty much just starts and revs to 1k rpm for half a second then dies. In the video it actually got to 2.5k before dying. It just doesn’t want to stay on it seems like. Any ideas?

 

The car has sat for about a month and a half now, only been started once a couple weeks ago for about a minute. Is that long enough to need fresh fuel maybe? I’ve tried the deflooding process a couple times now. I pulled my plugs and they did have some fuel on them, wiped them down and tried again, still nothing

 

Update, I pulled the plugs again and cleaned them off but this time decided to check for spark. (Probably should’ve done this to begin with, I know) And now my leading coils have no spark to them. Down the next electrical rabbit hole I guess

 

Okay so Here’s where I’m at.

The pump and filter are both brand new. Injectors were cleaned and tested.

I’m getting power at the pump but no fuel is making it out the secondary fuel rail.

The Circuit opening relay tested good for resistance, the resistance relay in the engine bay tested slightly out of range for resistance but I’m planning on deleting it anyways. My multi meter isn’t measuring voltage probably so I couldn’t test the relays with that, only ohms.

I tried the car both with the resistance relay and with jumper wires in the plug to simulate it being deleted, both having no effect.

On the tank, I only have 4 bolts holding the pump hanger bracket so it doesn’t make a good seal, waiting to be able to drive it to a shop that can redrill and tap the holes. I’m not sure if this could cause my fuel pressure to drop.

The pump turns on with the yellow jumper jumped.

I changed out the primary rail for an s4 Primary with the pulsation damper deleted. I swapped the ignition coils for a working one from a parts car so I have spark again.

The only thing I can think of is a vacuum leak or fuel lines are clogged somehow within the last 2 weeks of not running. I may have a kink in the fuel line but I can find one from the top of the car. I’m unable to get under it until it runs or absolute worst case scenario I try and find a trailer I can borrow.

I had the intake manifold together and it ran with the old pump, just poorly. The manifold has not been messed with since it ran 2 weeks ago either. Anytime I would give more than 10% throttle the fuel would cut and it would pop and bang like crazy, almost like a 2 step affect.

I’m sure this looks like the ramblings of a crazy man and it’s started to feel like I’m becoming one, I don’t know where else to go with this. Please offer me some ideas, I won’t be able to work on the car tomorrow but I will get back on it the next day.

 

According to Google, the fuel should be good for 3 to 6 months. In a sealed gas tank, probably even longer. A couple years ago, my '90 RX7 was out of service for about 9 months and it started right up on the old gas. I just kept diluting with fresh gas once it was running again.

Here are some things that I would check and/or recheck:
Are the wires hooked up correctly at the pump? Are the fuel lines hooked up correctly at the pump? Are you getting fuel out at the filter outlet upon cranking? Have you measured your fuel pressure after the filter?

Next, I would try pulling ECU trouble codes: https://fc3spro.com/TECH/HOWTO/ERROR...KI/kerror.html
If you disconnected the battery, than any stored codes were cleared. You will need to try starting the car again to reproduce the codes, if any.
If you get any trouble codes, than that should point you to where the problem might lie.

That's all that I can suggest for now.

 

Okay so fuel pump is wired properly, fuel is coming out of the filter. Right now my only pressure sensor is electrical and will only read once the car is turned on, so I’ll have to go buy an analog sensor at some point.

Unfortunately I can’t get ECU codes because the previous owner for who knows what reason decided to cut the green test connector off. I’m going to double check the wire, but once I find the proper one I’ll connect more wire to it so I can properly ground it out. Unless theres I way I can use the 6 point connector which is still in the car.

Also as a side note, pushing open the AFM plunger and turning the key to ON does not turn the fuel pump on. I’m not sure if that’s only an S4 thing but wanted to throw that in there incase that could be part of the problem.

 

Don't think so. Each check connector utilizes different pins from the ECU.

 

So just to see, I put the old fuel pump back in and to my surprise the car started right up but with the same problem I was trying to fix before. That being, any time I would give more than 10% throttle I would get massive fuel cut. So it seems the Atkins might have sent me a dead fuel pump which really sucks considering it was $750 with shipping. I still need to test the new pump itself once I figure out how, but I don’t see how anything else could be the issue

 

So while the car sorta runs with the old pump and my fuel pressure sensor can actually sense, I might as well throw my original issue in the mix to make sure I’m even on the right track.

My sensor is located directly after the filter

At idle, I get a little less that 30psi of pressure
If I try to rev, it hits a wall at around 38psi and the car starts to bog and backfire like crazy

Any suggestions while I wait for Atkins to help me out with the pump?

 

Use this link to access online FSM: https://www.rotaryheads.com/PDF/2nd_gen/
Refer to 1989-1991 FSM, section 04a, pages F1-13 (Troubleshooting of each system), and F1-48 thru 53 (Fuel System).

Page F1-13: I would refer to the Lack of Power and the Afterburn columns for guidance. First thing I would check would be spark plug wire condition and making sure they're hooked up correctly. Next, check the igniters.
F1-48 thru 53: There are a bunch of pressure measurements you can do to assess the condition of your fuel system. Page F1-53 shows that fuel pressure at idle should be 27-33 psi. Looks like yours is within that range.
Also, I would try to check your ECU for any possible trouble codes. I know you had an issue with the check connector wire, but if you can access the wire just hookup a jumper and ground it to the battery.

 

It’s going to be raining most the weekend but I will try and test the FSM pages as much as I can.

For the test connector looking at pictures I’ve seen an orange wire and a black wire connected to it. I can only find the orange wire, from what it looks like the previous owner cut the connector to supply power somewhere. Do you know if I can just jump the orange, or do I need both?

 

I've never paid much attention to the color of that wire (only looked for the single pin green connector), but according to the S5 wiring diagram it's listed as O for orange. BTW, just so there's no confusion, it's the wire right next to the battery by the fender well. I usually just jumper it to the NEG (-) post of the battery.

 

I was born & raised in IL (Oaklawn area). For some reason, the weather there always sucked.

 

Here's a photo of the green one pin test connector on my S5. The wire is orange in color. IDK what the other green connector is for as I've never had the need to use it.

 

it'll spit out the error codes, and there is an o2 sensor test port. so you can hook up an LED, and see the o2 sensor cycle

 

Interesting. After searching the forums, I now see that you can use a 12v LED plugged into that S5 green 6-pin test connector to pull ECU trouble codes. The S5 green 6-pin connector only has 3 wires, i.e., B/W, B/Y and Y. Plug the Pos (+) lead of LED into the B/W (black/white) wire connector and Neg (-) lead of LED into B/Y (black/yellow) wire connector. Ground green 1-pin test connector and turn ignition switch to the "ON" position. LED will flash short and long pulses corresponding to the ECU trouble code(s). If you're looking at the 6-pin green test connector from the front with clip at the top, the B/Y wire is at top left and the B/W wire is at top center.

Of course, you can always resort to the light in the dash as an alternative method.

This will only work on an S5. For an S4, there are 4 wires attached to the green 6-pin test connector and you will need two 12v LEDs.


.

 

Alright I’m back on this thread, I started a new one before even checking this one with new info because I assumed this would be dead. After dealing with trying to get broken pump I was sent replaced, I finally got it in and the problem is still here. I’m going to try using the 6 pin connector method like you said, I gotta find a little LED first though.

i really appreciate the help, I was losing a lot of motivation but seeing all the responses got me back into the the groove.

here’s an image of the connector situation I’m dealing with. I’m going to try and add a wire to the end of the orange so it can reach a ground and hope that works.

 

I got an LED coming in the mail hopefully sometime this week, I will update once it’s in and I’ve tried the 6pin connector method

 

Video 1

the first few seconds is pressing the throttle very lightly. You see it can rev out fine

after is a few quick throttle blips to over 15%, the engine cuts out instantly.

At the end is holding the throttle a little longer, you can here as soon as I let off it backfires which leads me to believe it dumps fuel as soon as that happens


Video 2

Here you can see my fuel pressure while this occurs.

You can hear the engine start to die out while I hold the throttle at the start. I do this twice over 15% in this video. The pressure rises while the engine gets no fuel

The second half is holding under 15% while the car revs out. The pressure hardly changes. I can’t remember how high I revd out to but I think it was 4-5k



Is this what LIMP Mode looks like? If so I’m beginning to think my OMP or ECU went bad. My LED to test should be here tomorrow, expecting to see an OMP code

 

Hmm... have you checked the TPS? Maybe you have dead spots after your 15% throttle.