Grunswald

Hi,

This morning i've had a strange issue.

Basically I went to work and on my way i refilled the tank.
I parked at work and one hour later when i had to leave to another place, the car wont start.

After checking during my lunch break, the issue was that the fuel pump was not receiving the +12V.
So it's look like it's either the plug of the harness, the harness itself or i suppose the relay.

I finally have it working again with no real explanation. What i notice was that while it couldn't start, i couldn't hear the relay switching and once the car managed to start, it was ticking.
I wonder where this relay is, and how could I test it. is it one the 4 install on the front crossbeam, in front of the radiator ?

diabolical1

iTrader: (3)

Hope this helps: Google results for FC pump relay

You can also download a copy of the FSM here: Foxed.ca

Hot_Dog

The fuel pump circuit opening relay, which cuts the fuel if the engine stalls, is located under the dash next to 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 low 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.

Grunswald

i was posting will you replied.

Thanks that helps.

Basically what i've done was measuring voltage at fuel pump connector on the black/white wire.
there was nothing and by tinkering next to the connector, at some point it got a solid 11V that allowed to start the engine afterward.

I would have said the harness is at fault, but even when moving the harness it doesnt cut now.

So i've seen the method to test the resistor and it seems feasible.

Grunswald

Quick update, just drove back from work, the car ride smooth as usual...

I remembered one thing, while I drove back from the petrol station to my job (5min drive) two times i've had the warning buzzer going for maybe half a second.
So i suppose it's because the fuel pump got "offline" for a second.

If one of the two relays discussed above would fail, would it turn on the buzzer alarm ? would either of them turn it on?

Hot_Dog

No. Check your coolant and oil levels.

Grunswald

i'll check but for the oil, i have a baffled oil pan so i dont really have issues with oil ( but i agree that if there aint enough oil anyway i'll have an alarm).

For the coolant it's even weirder... recently i've changed the radiator and the piping. I had previously an aftermarket radiator from another car cutted and welded by a shop to fit on my car... more or less a piece of ****...
On this one, they had removed the coolant level sensor because there was no place to install it (and also the original radiator brackets...). I suppose they put a jumper in the harness plug and hided it cause i can't find where it is.
Basically i've now a proper koyo radiator where the new coolant sensor that i bought additionily is only used to cap the top passenger side hole be cause i don't know where is the harness plug

Jose A.

iTrader: (40)

The wire for the coolant sensor should be right by that hole where you put your new sensor.

Jose A.

iTrader: (40)

Look under your air box /air filter for that wire , maybe they just wrapped it and put it under there somewhere.

Grunswald

ok...

i've had lot of work and the rx7 was driving correctly, so i didn't really took care of it.
But now, she doesn't drive anymore so i've checked it.

First thanks for the picture of the coolant probe harness, i looked and it seems to have been completely removed...

I removed the fuel pump resistor and measured the resistance. here is what i have :
A-B : 0.04ohm
C-D 79.5ohm
E-F 1.2ohm

so i believe that i'm good for A-B and C-D but E-F seems toasted (should be between 0.70 and 0.94).
Am I correct ?

If I am, that means that only the resistor with the fins has to be replaced, the relay seems ok.
Is that possible (and cheaper) is it factory sealed to the little bit of harness ?

Grunswald

Now for the fuel pump circuit opening relay:
it behaves as described in the FSM except that it seems to deliver only 10.9V

i've checked the resistance :
STA-E1 gives 26 ohms
B-FC gives 140 ohms
B-FP gives infiny

so this is perfectly in bound.

I've checked my battery and it says 11.3V... I hadn't expected that, moreover than when it first broke it was after a 30-45 min drive where it started perfectly before.
I'm charging the starter booster to see if it helps but it's weird... or my multimeter is shot...

Grunswald

so since my last post the car was in running order (don't really know why) so i didn't really cared...

This morning i went to start the car and it was not starting again...

i will order the a new fuel pump resistor and hope it fixes it.

additional question : while it was running this month, my idling speed was at 2000rpm when cold and it lasted until the oil reach 90°C.
Can it be linked to the resistor somehow ?

Grunswald

Ok, so i received the resistor and changed it but the problem is still there.

Yesterday when leaving work the car wouldn't start. I tried several time with no chance.
I went in the boot and moved the fuel pump harness in hope that if it's a short cut, i'll have contact at some point.
didn't work.
I have a battery booster in the car so I thought i would try using it.
So I pop the hood And then (before installing the booster) i hear this sort of ticking noise. I know it's the sound of something fuel related (the pump priming ?) so i try to start the engine and it works.

this ticking noise comes from what ?
a mechanic friend of mine told me to inspect the neyman contactor before going further. I believe it's a good idea but i don't know how to do it. Do you have a procedure ?

Grunswald

any idea on what should be the way forward ?

Grunswald

Hi... I desperatly need some help...

I'm waiting to receive my fuel pump circuit opening relay and replace it.
I thought it would be a probable cause.

But recently my girlfriend told me "how by the way, last week i believe that even with your car parked, your dashboard was still lit...". Of course i went to check and my battery was dead, but that also be due to it parked for a long time now... so i couldnt check.
I would have suspected either the ignition switch or the alarm.

That's were I'm in trouble. I've checked my ignition switch. The harness has been modified by the previous owner to fit the alarm (a cobra model, if necessary i can provide the model number). Therefore now i just have 2 connectors and one wire going directly to the alarm.
For me it makes absolutely now sense, as there should be 4 connectors... As per the FSM, i still have the connector for Acc, IG2, B and IG1. The additional wire link directly to the alarm is black with red stripe (i do believe that would be the ST wire).

I've had a quick look and the wielding seems in ok condition and well insulated. The behaviour of the ignition switch on the existing connector seems ok as well.
When i tried to start the car, the starter was always going well also so i believe the ST wire is working correctly.

1st question :
- the other pin that i can't find are :
L
E
K1
K2
Do you know what they do ?

2nd question :
can the central unit of the alarm be faulty ?

3rd question :
I'm considering getting rid of the alarm, but it seems that most of the harness has been cut and welded to install the alarm, so I suppose i'm missing the connectors to simply unplug it and close the circuit. Is it possible to get just the front harness ?

please... save my car...