Okay, just like the title says this is my problem. It starts with surging, around 55 mph when cruising RARELY, then the wideband will flash lean quickly, and the rpms will drop. It makes it impossible to keep speed, and eventually the car will shut off, because you cant keep it running. After it dies, with the key still in the on position, you can hear the fuel pump relay and even feel it clicking on and off. After it sits for a while its fine.

I checked, cleaned, and re did my ECU ground, and its perfect.

My coils check out and are in spec as per FSM.

The fuel pump relay is good, because its clicking on and off.

The tps is adjusted properly, the timing is set correctly, the fuel pressure is at 39 psi, and the idle is correct.


WHAT COULD BE WRONG?

Thanks

 

Too hard to say why. The switch on the AFM vane causes the Circuit Opening Relay to pull in or not pull in, which in turn feeds the fuel pump. THAT should not effect the tach UNLESS you talking about how the engine has no fuel and now the tach falls....who'da thought type thing.

IF you mean the tach and the Circuit Opening Relay are dying at the same time, I'd GUESS that MAYBE the MAIN RELAY is opening/closing for some reason. Like the lack of power to the relay from the ingintion switch. Just too much to guess at to say.

 

Well my AFM is at a slight angle, to do having a custom TID, its also not too securely mounted, but its not flopping around either.

Also, i know that the tach is dropping because of the relay shutting off, and same with the leaning out, they all happen at the same time due to the relay turning on and off.

What i cant figure out though is why my fuel pump relay (the gold one behind the passenger headlight) is clicking on and off wildly when it happens.

 

It might help if we knew which if the three completely different cars in your profile you're talking about...

 

Ok. I see. That relay.

Well if it's completly loosing power, on and off, then it has something to do with the Main Relay not supplying power to the Fuel Pump Relay and Resistor.

The power from the Main Relay, pulls that Fuel Pump Relay and Resistor in, IF the Fuel Pump Relay and Resistor are getting a gnd signal from the ECU's pin 3D. This gnd exists IF there is no load on the engine as sensed by the boost/pressure sensor.

Once the boost sensor senses load, then the gnd on pin 3D goes away and the Fuel Pump Resistor Relay relaxes.

Those are the conditons to make the relay pull in or relax. You have to have 12v from the Main Relay and a gnd signal from the ECU's pin 3D.

But then again, the power for that relay comes from the Main Relay. If that power is interrupted then the relay won't pull in. But all that means is that the fuel pump will get full voltage all the time, load or no load.

Look at the schematics for EGI Emissions and Control System. All I'm saying is, is if power is lost or the gnd is lost to that relay, the worst thing that can happen is that the fuel pump will recieve full voltage ALL the time the key is to On and engine running.

If it's clicking, it means the gnd from the ECU pin 3D is coming and going or the volgtage to the relays coil is coming and going for unknown reasons.

If you lose both power and the gnd to its coil, then the relay will provide full voltage to the fuel pump all the time the engine is running. It's sort of a fail safe mode so to speak.

It's ONLY when the ECU sees no load on the engine and applys a gnd to pin 3D of the ECU that the relay pulls in and supplys only approx 9vdc to the fuel pump. That's a normal condition. If you get under boost the gnd signal to the relay from pin 3D disappears and the relay relaxes and the fuel pump now sees full voltage to the pump.

There's the possibility that the signal from the boost sensor (brown/red wire) is not getting to the ECU all the time. Or intermittently. That would explain a clicking Fuel Pump Relay and Resistor.

Yeah, the Circuit Opening Relay wouldn't have anything to do with the other relay clicking on/off.

A simple thing to make the relay NEVER click, would be to depin the green/red wire either at the Fuel Pump Relay and Resistor or at the ECU's pin 3D. Then it would supply a full 12vdc to the pump all the time.

I sort of rambled in the above, eh?

 

Sounds alot like my car except i dont hear clicking. Maybe my car is too loud for that. It will surge like its going lean rich lean rch then really lean and cut out and then go again. Seems to not be so bad when it is cold outside, i'm thinking maybe it's the fuel pump relay as well, 87 GXL.

 

Sorry, its the 10th AE, the only one i have problems with I hope i can straiten it out though.

 

My battery terminals are CRAP, im beginning to wonder if that might cause in intermittent power surge? That would mean the to the car, i am turning the key on and off really quickly causing the fuel pump relay to click like it does at start up.

Would that be it? Because all my sensors seem to check out. Unless im really missing something.

 

On start up the outfit puts out 12vdc. Once started the relay pulls in and now it puts out nine volts until the boost/pressure sensor sees a load. No matter what or whether it's pulled in or not pulled in, it puts voltage to the fuel pump.

If the battery cable was bad, then the headlights would also flicker on/off and any other thing. Such as the radio.

 

yea when it starts clicking the lights dim just slightly. I dont have a radio, so i cant tell that way. when i try to start the car sometimes it will click then all the electronics go dead, so i have to pop the hood and pound on the terminals until they get a good contact. That means it wouldnt be out of the question for the vibration of driving to cause a bad connection. Would that make the relay shut on and off like i was bumping the key?

 

It sounds battery terminal/battery related more than anything.

 

alright, i just replaced the terminals today, and it does the same thing. So i ordered a new fuel pump main relay, you know the one behind the passenger light. Its on its way from mazda to the tune of $97!!! Ouch. Should that fix it? I think it will, because the FSM says that from:

A-B= 0 ohms
C-D= 68-92 ohms
E-F= .64 ohms

MINE is

A-B= .4 ohms
C-D= 78.9 ohms
E-F= .9 ohms

 

were their any replies to if this worked??

 

Yeah. The point four is reasonable. The meter leads were probably causing that point four. By zero ohms they meant it was a closed circuit with little to no resistance across the contacts.

The other two figures are well within reason.

The fuel pump resistor and relay...............the relay is CONTROLLED by the gnd from the ECU. A green/red wire from the ECU. No gnd from that wire means the relay might as well be hard wired across the circuit from A to B. That means full voltage when there is no gnd on the green/red wire (pin 3D on the ECU if memory serves).

 

Iam having the same problem have a whole assembly relay and resistor to see if this will fix my problem.....
Also what would cause me to have no fuel in the secondary rail.

 

also my resistor gets super hot is this normal.

 

yea my resistor was getting really hot too, but i just replaced it. The one i just put on was used, but the specs were EXACT. Mine was a little out of wack, and i think thats why it was intermittent.

The new to it resistor and relay work perfect, and solved my problems since the battery terminals didnt fix it.


As far as not having fuel in the secondary rail, thats not possible. If you have fuel in the primary, the only thing that connects the two is a rubber hose. If it is clear, there is fuel in the rail. HOWEVER, if your FPR is bad and some how stuck open, it wouldnt build any pressure, and the primary rail would use all the fuel before it got to the secondaries.

If you still think there is no fuel going to the secondary (UPPER) rail, jumper the connector, disconnect the hose from the front side of the upper rail and turn on the key. You will get a face full of fuel. If not, the filter or lines from the tank are clogged.

Good Luck!!!

 

hooked up the new relay and resistor also and wah lah it works!!!

 

The resistor is supposed to get hot. If it didn't, it wouldn't be working.

 

then why would this solve my problem???? just curious??? I say this as so far by the way.

 

Also heard that you can wire it in away that it would supply full voltage regardless....

 

Pointless. The pump runs at reduced speed when the engine's at low load (most of the time) and full speed when the engine's at high load. Running it at full speed all the time will mean richer mixtures at low load, so your fuel consumption will go up. There are no benefits to doing this.