ITS ClubRacing RX7 1986 with 1989 motor (according to previous owner)






I will be as direct as possible. I cannot prove what series this motor is. and if someone could link to direction to find out (without tearing open the motor and looking at the rotors). my probvlem is with the fuel system, no power to pump no fuel pressure. i will run through my fuel system and remark on what ive done.


Fuel Tank- Removed, drained, scrubbed and soaked.
Fuel Pump- Replaced with a unit that was hotwired to show function
Fuel Sending Unit- replaced with a clean unit, hotwired fuel pressure seemed low.
Fuel Lines- Blown clear with compressed air, no debris or contamination detected
Fuel Filter- Replaced
Fuel Pump Circuit Relay-replaced
Fuel Pressure Regulator- Aeromotive unit-Untested
Fuel Rail- clean and clear
Fuel Injectors- Sent out for service, currently all in working order.
AFM-untested
Fuel Pump Resistor Relay-untested

I also have a question about the last part. In the FSM's they all refer to the testing procedure for this relay



even when in the picture of output devices this relay is pictured


the testing procedures all refer to the first relay.
My car has the second relay pcitured, would this item prevent the fuel pump from getting signal?
I found alot of Rewire threads but they all refer to the first relay. is this procedure beneficial for systems involving either one?

I have done ALOT of searches but please feel free and encouraged to share resources and knowledge.


James
Northern Forest Motorsports
nfmotorsport.blogspot.com

 

Admins, if you feel i will get a better response in another area please move the thread.

 

welcome to the board.

for your pump issue, i would start with these. if the AFM fails, it will prevent the pump from getting power.

here's a fairly decent thread on it: https://www.rx7club.com/2nd-generati...rking-1055010/

for your question about which engine you have, i will prelude any response with this: seeing which rotors you have is important because it was a fairly common practice years ago to stick the S5 rotors (higher compression) into older engines. housings aside, i think the rotors are where the most significant difference lays in as far as the engine itself goes.

that said, your photo shows nothing relevant about the engine itself, so it's anyone's guess.

for starters, i would suggest looking at the intermediate housing. if you see an EGR valve (or block off plate), then it's possibly not an S5 engine. i say "possibly" only because of what i said above. S5 engines don't have the EGR provisions on the intermediate housing.

the intake system is S5. i can't get a clear view of the AFM, but from what i can see of it, it's S4.

 

Thank you very much for your response. can you tell me what to look for to identify the afm? i want to use the correct testing procedure.

Again thank you for your response!

 

AFM is s4. i will test accordingly.

 

AFM tested within specs...

 

Pic#1 is an s5 fuel resistor pack.
Pic #2 is the resistor pack for the S4.Usually located under the S4 AFM (air box location)

You need to establish the impedance of the injectors and whether you are running the engine as an S4 based engine with the s4 harness or an s5 with add ons/or deletion of parts.

The fuel pump won't work in Key ON..it will turbn the Pump on in START position and then when the engine catches the "switch" inside the S4 AFM sends a signal to the ECU to keep the pump on.
You can check the fuel pump by jumping the yellowish connector by the air box(2 female spade type..sometimes has foam around it) with just key ON and the pump should start and continuously run until you remove the jumper.

 

Motor is s5 running s4 afm, ecu and injectors(I believe). All emissions deleted i think s4 wiring harness.

 

I did jump the connector. Fuel pump ran for a few seconds then faded out. Is that normal for that jumper? If not I worry about a bad ground. Also should I have a FPR reading when cranking?

 

I am referencing the FSMS on rotaryheads.com. the second resistor pack is shown as the component on s5 NA cars. in this FSM it gives the testing procedure for the 1st picture. can anyone tell me how to test the Second resistor pack?
i found the case ground of the top of the fuel pump to be very weak. i am addressing that now.

 

http://www.rotaryheads.com/PDF/2nd_g..._non_turbo.pdf


Page F1-4 is the input devices where the second relay is pictured.
Page F1-57 is where the Diag procedure is supposed to be but is for the other pack.

I need Diag procedures for the Second Relay in OP.

 

I see a regulator in the pic.
Is the regulator set up on the return side of the fuel system( it should be)
Filter to rails ....rails back to reg..then back to tank.

Also I see the s5 top manifold.( I never delved into that as I stayed straight s4 N/A engine)

The fuel injectors should be a LOW impedance square head center notch,with the resistor pack at the air box location.Running a N326 or 327 ECU.
This is normal S4 N/A setup.

 

Yes regulator sits between rail and return line. I am running a 326 ecu. the second relay pictures is one my vehicle. I am running s4 red top injectors.

I regrounded the case ground on the fp. No change. I then turned the key to on, heard the pump makin some noise so I waited a couple minutes and tried again, the car fired, idled about a second then died. I was able to get it to stay running by manipulating the throttle. I did not :-/ check the fpg. I will again next try.

If the pump is weak will it not push as much fuel? Or is it a binary system either it works 100% or 0%?

Also if anyone can provide diag on the second relay box pictures please share

Thank you for your reply MrStyx

 

How is that Afm mounted?
it needs to sit so that the door in it opens..well,like a door..not like a drop..or a trap.

Also,mentioned that the Afm sends signal when it gets started to keep the fuel pump in the loop.

Did you check the relay under the steering column?>(yellow base)

 

It is mounted plug up. I want to say it opens vertically. It was raced this way for a long time though.
Yes circuit opening relay is new

 

Thank you RX7Club community for your assistance and volumes of knowledge. She fired today, we have been working on her for 5 months after not being started for ten years!

Nfmotorsport.blogspot.com