86 rx7 wont start fuel problem
 

115,xxx miles
new spark plugs
cranks but no fuel
fuel pump not pumping
Checked all fuses in engine bay and under dash
cleaned and or replaced fuses
I need a new main fuse for my engine bay box.
the 80amp one has/had a 100amp fuse in it, but this fuse was damaged and I may have broken it open with pliers and then smashed the connections points together to create a continuous current....yes that probably most definitely happened .

tried jumpering yellow fuel check pin connector on the passenger side of the engine.
didnt help

blew out the fuel lines with air comp
drained 12 year old gas, and replaced with 5 gallons premium
removed inspected and re-installed fuel pump (was able to hotwire and it came on)
Ran hard/hotwire outside of car from battery to fuel pump and it comes on
HOWEVER...pressure is low, like really low. over 25PSI out of spec

Checked relay under dash, it clicks when key is turned so suppose it works.
HOWEVER
my mechanic said no power was coming past that relay, even though the connector on lower driver strut tower in trunk has power and continuity.


I do not want to be forced to sell this car
it is my dream car and has been since I was a young boy growing up in my dads 1st gen rx7.

Granted this is 2nd gen but I aint complaining...except that it wont start..

please and thank you

So, you're not getting any power to the fuel pump? Have you checked this...?

hit it with some starter fluid to get the car to fire up then see if it will idle.

The wires at the relay under the dash ought to behave as follows. Black/White wire top row far left position has voltage w/key to start only. Black/White wire in top row center position has voltage w/key to on. Blue wire has voltage w/key to start or has voltage w/key to on and fuel check connector jumpered or has voltage w/car running. If it has the first two then you need to check to see if the pump in the back is connected to the Rear harness properly and that the Blue wire in this harness is also passing voltage through the connector to the wiring coming from the pump pigtail. If it does then make sure the ground wire is properly grounded.

I believe we have checked everything you mentioned, I will make sure though when I run out to the shop today. Thanks

To answer the other questions, yes the fuel pump is not getting power, yes we have checked this, and yes we have TRIED using starter fluid with no success.

Have you proved that you are getting spark as well? The pressure you got from the fuel pump when hard wired was low you stated. Was this pressure measurement taken before the fuel filter, just after it or taken from the fuel return line coming out of the engine?

Ya she is getting spark, plugs are brand new and sparked when tested.

The fuel pressure was tested after the fuel filter I believe, before it hits the engine. He may have tested the return line as well. I will have to ask on that. I was in the trunk listening for the fuel pump to turn on and they were testing the pressure in front.

We did blow out the lines with the compressor and fuel vapor shot out, so they were not blocked and the fuel filter is not clogged in theory.

I did a price check tonight on ebay and i can get a cheap pump motor replacement brand new for 24$ free shipping to my door
I can also get a new fuel pump relay (the opening relay under the steering column) for 24$ used though not new.
and finally the fuel pump resistor relay for 28$ used .

SO
about 75$ worth of parts

:scratch:

Didn't know your car was a turbo as it wasn't mentioned, but if you have the Fuel Pump Relay and Resistor it could be bypassed by disconnecting the plug to it and jumpering one of the Blue/Red wires to one of the Blue wires in the plug. Also, if the Circuit Opening Relay tests out okay there would be no need to replace it? The fuel pressure is to be close to 30 psi so if the pressure was measured in line after the filter and it was 25 psi out of spec that would imply the pressure was about 5 psi or so?

Its not a turbo, N/A .. does that mean it does not have that resistor relay?
The circuit opening relay is clicking when you turn the car over, but there is no power coming past it.

I believe the psi was more around 50 or 40ish as opposed to the 80psi my book says its supposed to be.
I have tried jumping that yellow check connector on the front passenger strut tower bottom with a piece of wire, supposed to turn on the fuel pump and bypass the maf sensor.
didnt help.

An 86 NA will not have a Resistor Relay. Also, there is a different way to jumper the fuel check connector. At the Circuit Opening Relay there is a Black wire and a Brown wire on the bottom row. Jumpering these two wires is the same thing essentially as jumpering the fuel check connector except it is done at the relay itself and bypasses some possible faulty wiring between the check connector and the relay so try this and see if it makes a difference. Again, B/W on top row far left has voltage w/key to start and the B/W wire in the top row center position has voltage w/key to on. Which of these wires is not behaving as it should? If they are both functioning properly and the jumper is in place at the relay then the Blue wire should have voltage w/key to on.

i can sell you a good main relay fuse box if you did bust that one

Thanks for the info on the resistor relay.

The circuit opening relay under the dash is clicking when key on so i assume it works, but I understand what your are saying to jumper it so I will try that when I head out to the shop today.

Some bad news, before we had spark no fuel. Now we have no spark no fuel. Brand new plugs, all fuses brand new, dunno what happened between spark and no spark..

I compression tested the block, and after priming the spark plug holes 2-3 times each with oil. I was able to raise the compression in the rear cylinder to close to 100psi, the front however would not budge past 50-55psi...

Those numbers do not sound like they are within specs...

Any ideas on why no spark? Special fuses? Relay's?? I am almost 99% sure that the ignition coils are in good working condition.

The fuses involved would be the Main fuse and EGI INJ fuses in the Engine fuse box and the 15 amp Engine fuse in the inside cabin fuse box. If the engine turns over then the Main fuse is okay. If the Main relay clicks w/key to on then the Engine fuse is good. The INJ fuse powers the coils such that the Black/Yellow wires that power the coils w/key to on are powered by this fuse. No 12 volts on the B/Y wire w/key to on means the INJ fuse is bad (this assumes the Main fuse and Engine fuses are good). You can check the B/Y wire for voltage w/key to on at the leading coil. This wire is found in a White two wire plug. Another possibility is the EGI COMP fuse in the Engine fuse box is bad as this powers the ECU and a non powered ECU will not allow the coils to fire.

A reading of 50 or so on the front rotor is quite poor to say the least.

And the Circuit relay has two wires that should have power. One w/key to on and the other w/key to start. If one had power w/key to on but the other did not have power w/key to start that would not be good.

oh sounds low , washed out with fuel maybe?

I am going to head to a scrap yard tomorrow and see if I can pick up an air cleaner top/lid. Mine is missing.

Apparently this lid has a sensor that goes in it for the air temp or something along those lines.

Mine has no such sensor, however when I removed the lower air cleaner box and the MAF I noticed a 3 prong green plug with nothing plugged into it.

When reviewing the MAF removal tutorial in my Haynes manual I noticed this plug was also unplugged in the pictures provided. Therefor I assume it is supposed to be unplugged and is for diagnostics of some sort.

THat being said, time to find an air temp sensor

The sensor you speak of is inside the AFM.

I have attached a picture of my engine bay
and a picture with what I believe is the sensor I am missing:scratch:

The Green plug is a check connector used for setting the TPS/Relief and Switching solenoids using the LED technique. This plug would have a Black/White wire, a Blue/Yellow wire and a Blue/Red wire.

And your car is/was an automatic transmission.

IAT is not in the AFM, its a two prong sensor in the TB elbow area. There is no sensor connected to that green plug.

Pin 2J and pin 2L are both connected to the Intake Air Temperature sensors where one is located at the Dynamic Chamber (he does not have a turbo) while the other one is in the AFM. Information garnered from the control unit pinout in section 4A, page 31 of the FSM.

The series for RX7 does not use the afm for STARTING the engine. But does use it after the rpms get over 500 rpm.

That's an automatic transmission car, isn't it?

Yes auto tran.

Yup, you are right on that one. However if the AFM is pugged in then that sensor is plugged in. That green connector he highlighted does not plug into the AFM.

When I removed the AFM from the bottom of the air cleaner box it had only one large black connector plugged into it. I left this plugged in.

After I removed the AFM I discovered a 3 pin green connector that was unplugged just laying there. I did not see anywhere for it to plug into and assumed it was missing the pig tail connector for the green sensor I circled in the picture. Is this not the case?
It is next to the jumpered check connector for the fuel pump.

You are right, it doesnt connect to anything. Most green colored connectors in the FC are Diag plugs.