Hi Guys, 2nd gen S4 Question...

I think the previous owner of my car did some re-wiring and eliminated the yellow jumper for the fuel pump circut. Is there any other reason why my fuel pump would run while my key is in the 'ON' position? I can't seem to find this yellow connector, I belive it is supposed to be by the passenger strut tower. If someone has a pic of what their's look like, that would be great.

It's an '86 S4 N/A rx7, and has a walbro fuel pump installed by previous owner. All emissions systems are also removed.

So is it okay to have the fuel pump running with the key in the 'ON' position before I start it, or should I 'fix' the 'problem'?

Thanks - Richard.

 

The flapper door to the AFM if opened could cause the pump to run w/key to on.

Post #3 last pic is the check connector for the fuel pump. Post #6 first pic is the Circuit Opening Relay which powers the pump. W/key to on if the Brown wire in the relay has a ground to it then the check connector is jumpered or the flapper door is open. If the Brown wire does have a ground as stated then the Blue wire would have voltage and it is this wire that runs to the fuel pump.

https://www.rx7club.com/2nd-generati...erence-671004/

 

Thanks satch, I'll check that tomorrow.

Can the pump being on for a few seconds before start cause problems in the long run?

Also I did find the check connector, it is there, just hidden (to me) in that rubber boot. So i'll have to check the circut opening relay to see if it is grounded. But more than likely it could be the AFM flapper. I'll do a search on it, if you know of any threads about it, please post a link here.

Thanks again - Richard.

 

I wouldn't think so unless the injectors (primary) were leaking.

 

Okay well I don't think I have any injector problems. I let the fuel pump run for a while, and there didn't seem to be any flooding/starting issues. I know it's not the most professional way to check, but I don't feel like taking my intake system apart again...lol.

I'll check all the things you mentioned tomorrow and post an update for sure.

 

Just wondering: are you having any problems with the car?
start up or running issues?Or is this fuel pump thing the only concern?

 

I'm 'ressurecing' it. It's been sitting a while, so I wouldn't doubt the AFM flapper has some crap in it and doesn't close all the way or something. It doesn't idle well until warmed up for 30 seconds to a minute, but other than that it runs smooth, but extremely rich.

 

I got a vert and the AFM flapper door was corroded and would not move freely.I had to literally take it apart and "buff it".
That may be part of your problem.
Here Try this link as it is written by a Guy we all "look up to" for advice..(God was not available!).
Mr Aaron Cake!
Removing An RX-7 From Storage, Dealing With Improper Storage

 

Yeah thats a good link everything I've read from Aaron Cake is always good stuff.

 

Hey Guys, new update...

Jumper is not jumped...
AFM Flapper moves freely...

In the first attached pic (my car) notice the circut openning reley has two blue wires with yellow dots, and two black wires with yellow dots. Which is different from the second pic (other guy's car). Coming from the pump itself, there are only one of each type coming.

I don't know much about 12V electical but what the heck?

Maybe I should just leave it lol. I don't wanna mess things up.

Richard

 

scaryy dog . lol nice!!

 

Yeah he's just making sure all the connections in my ECU are all good ;-) iPhone flash makes him look like he has laser eyes.

 

The two Blue wires eventually merge into just one wire that powers the pump so this is not a problem at all. As stated earlier, if the Brown wire in the relay has a ground w/key to on and the check connector is not jumpered then the possibilties are the Brown wire is accidentally grounding out thus it has a fulltime ground when it should not or the other possibilty is that the fuel switch in the AFM is stuck open enough to ground the wire because that is the role of this switch or the flapper door is open. Now the door might not be stuck such that it can move freely, but that doesn't prove the door is not fully closed w/the engine off.

 

I'm going to put some hours into this tomorrow after work and come up with a new update for you guys.

In the mean time, is there a way to isolate where the brown wire might be accidentally grounding off itself off? I have a multimeter I just dunno how to use it lol. I'm a noob with electrical.

I will likely take a closer look at the AFM and take pics before looking into where the brown wire may or may not be accidentally grounding itself off. Those pics should be up tomorrow night.

I've always wanted to learn more about vehicle electrical, I guess this is one good way

Thanks again satch and everyone! - Richard

 

You could unplug the plug to the AFM. Having done this you can measure the voltage of the Brown wire inside the car w/key to on and it should read 12 volts. If it does then you know the grounding earlier was a function of the AFM. To measure the presence or non presence of voltage at the relay you place the Red meter lead to the Brown wire and the Black meter lead to the solid Black wire in the same relay plug (not Black/Red or Black/White, but the solid Black wire as this wire is a ground which is necessary for the meter to measure volts). The meter should be set to DC voltage. Your problem could also be a Circuit Opening Relay problem.

 

Thanks for the great instructions, I will preform these test tomorrow and narrow down the possibilties.

 

So I tested the the brown wire there, and its the same wether or not the AFM is plugged in 0.010 V, 35 ohms resitance. Does this help you guys with my diagnosis?

 

Was this, the voltage test, with the key to on?

 

Yes. 0.000V when it's in any other position (I didn't test start)
Since the previous owner installed the WALBRO pump he might have bypassed the relay somehow but I don't know what to look for...

I could take pics at the pump (and remove it) to take a peek...

 

I doubt the relay was bypassed. So it appears the Brown wire has the ground due to that wire being grounded or a fault in the relay.

 

Okay well thanks for the help!! I'll post here again if I make any more progress.

Richard

 

If you wanted to take it a step further you could disconnect FEM-02 which is located above and to the right of the ECU. FEM-01 and FEM-02 are side by side and both Orange. FEM-02 is smaller and has 7 wires in its largest row, where this 7 wire row has the Brown wire in the middle of this row (3 wires to the right of it and 3 wires to the left of it). You want to check the Front harness side and not the Emission side. The Front side has two Black/White wires side by side next to the Brown wire (other side, Emission side, does not have these two B/W wires but only one of them). W/key to on the Brown wire of the Front harness when unplugged should have 12 volts w/key to on. If it does then the grounding is coming from the Brown wire from Emission side of the connector or the relay itself.

And I found this a bit confusing. "Yes. 0.000V when it's in any other position (I didn't test start)"
The on position is not what makes the engine turn on, but is one position before the start position and one position after the ACC position. Is this what you understood it to be?

 

Sorry to be clear - 0.000V in the lock and acc position, and 0.010V in the on position (one after acc). I did not test the wires with key in the start position. Hope that makes sense.

I might try the other things you suggested but it will be likely a day or two before I have time. I might get my cousin to give me a hand since he knows this DC stuff slightly better.

 

Okay I think I'm learning a bit about electrical, but starting to get a headache from this LOL.

To review:

- Fuel Pump Running w/ key in on position.
- Flapper door checked, and still runs with AFM unplugged.
- Fuel pump circuit terminal is NOT jumped @ the Bb-19 connector.
- Testing the brown wire @ the circuit opening relay (plugged in) yeilds 0.010V
- Testing @ the X-16 connector front harness side, after the circuit opening relay (unplugged) yeilds ~ 12V.

So satch, according to the tests I've done, its either the relay itself or some accidental ground on the EM side?

I don't understand how I can get 0.010V @ the relay, but 12V on the Front Harness side at the x-16 connector (which you called FEM-02). Perhaps it is my limited understanding of DC, but it makes no sense to me lol....

I'm tempted to replace the relay and see what happens lol.

Thanks again for all the help, I'm learning alot, and very glad I have a paper copy of the FSM ^_^ The pic attached is of the x-16 connector I tested today.

Richard

 

So in doing your tests, you unplugged FEM-02 (on an S5 they call them different names such as X-???). Getting back to the issue if the Front side of the harness has 12 volts on the Brown wire w/key to on did you test the voltage back at the relay on the same wire w/key to on while the connector was still unplugged or not? I'm guessing you did not and if I guessed right then the ground is coming from the Emission side of the harness and not the Front side of the harness.