Well,

Last night I replaced the fuel pump and fixed a few wiring problems and fuel system got pressure. Car started and even idled under it's own power....granted it wasn't a totally smooth idle as it pulsed up and down and would never drop under 1K rpm.

Found out there was a leak from the fuel hose going to the prim. fuel rail. Replaced it and put it all back together...even pressurized the fuel system to check for leaky injectors and nothing.

However, tonight the fuel system won't pressurize. When the key is turned to the ON position the fuel pump runs and will not stop and I do not have the yellow test plug jumpered in any way. Any idea why it would do this?

Also it has an extremely rough idle...enough that I can' t let off the gas or it will slowly die and it is blowing alot of what looks to be blue smoke which I figure has something to do with burning oil but it wasn't doing it the previous night.

Any help is greatly appreciated and I did do some searching as well.

Mike

 

It's been a while since I've one apart, but I believe there is a seal at the top of the pump that must be installed correctly, or fuel will not be directed into the line. It will bleed back into the tank.

 

Today I plan on going back through and checking lines but there were no leaks as of last night.

I did a compression check as well at it shows alittle of 90 on both rotors as well.

I know that for some reason the dingy yellowish cap is off the Pulsation Dampener but there isn't any leak from there.

Mike

 

If this is the Turbo in the signature it is a S4. What ECU are you running???

The S4 ECU won't even turn on the fuel pump unless it sees airflow through the AFM or the start/crank signal.

and teh cap on a S4 PD, is simply to prevent anything from getting near the travel limit screw in end of the PD

 

Oh my bad on the car.

It is my sisters 86 NA and I am running the N326 ECU.

The engine isn't the original as the previous owners changed them out for some reason.

My main concern first is why the fuel pump continues to prime the system. So it's not an issue of no fuel...it is that the pump continuously runs. Not sure if the AFM will have anything to do with that.

Mike

 

It should be pressuring the system unless there is a jumper in the fuel pump diagnostic plug, or the AFM is open, or the car is cranking.

 

I take it that is suppose to be "shouldn't" instead of should.

I did the jumper to pressurize it the first time after replacing the fuel pump and fuel filter. After that it started up right away with a pulsating idle. Now all of a sudden pressurizing all the time.

Could I swap the AFM from my T2 onto this NA as a test to see if it could be a bad AFM?

Mike

 

sure for testing you can swap AFM, but it will run a little lean leaving the Turbo one in

 

Pull the plug off the afm and see if the pump runs all the time or not. IF it now stops, the vane in the afm is stuck to the wrong side closed.

IF it keeps running then you have a short in the fuel pump check connector wire b/t the connector and the Circuit Opening Relay or the Circuit Opening Relay is stuck in the on position all the time. Or it's seeing the *start signal* all the time. Depin the black/red wire from the circuit opening relay and see what happens. IF that act stops the pump from running then you've a ignition switch problem...maybe.

And in your post you say you fixed a few wiring problems which means????????

You could pull the circuit opening relay and put a meter on the black/red wire that is the *start* signal and see if it has voltage on it with the key to ON. IF it does, that is wrong and you need to find out WHY.

Or you could pull the circuit opening relay and see if there is a gnd on the brown wire or not. IF you have a gnd on it, that is WRONG and you need to remove that gnd. The gnd should only exist is the afm vane is pulled aft or the jumper is in the fuel pump check connector.

I'd look at that gnd first before the other stuff above. IF the gnd is there, and you then remove the plug from the afm and it goes south, then the afm is the culprit.

The circuit opening relay causes the fuel pump to work. The relay pulls in if there is a gnd on the brown wire OR if you hold the key to START and there is batt voltage on the black/red wire.

As you can see, the gnd on the brown wire is only there if the afm vane is pulled aft or the jumper is in the check connector.

The batt voltage on the black/red wire is only there when the key is held to START.

See??? There's several ways to find out what is amiss. See the wiring schematic out of the fsm. The wiring schematic in the 86/87 fsm is much better than the scrogged up ones in the later versions.

 

Well,

the wiring I fixed were splices from the previous owner.

They had actually spliced into the power wire that goes to the Open Circuit Relay for power to a small switch. I assume its the OCR...it's a plug that is hooked right above the steering wheel.

The switch that was spliced in might have come off the car somewhere as well. It was a push style plug and the top had a cross shape like a phillips screw. Part of the wiring coming from the switch was Red with a white stripe.

The previous owner actually cut into 2 or 3 of the wires I guess hunting down the power wire. At first we were getting no fuel and once I took that switch out and put the wires back together we got fuel and it started up fine. Then the next night the pump keeps running.

Mike

 

Alright,

Found the problem of the non stop fuel pump.

Apparantly the previous owner was jumping the fuel pump with a wire and thought a good place to store it was in the AFM. Well the wire wouldn't allow the flap to close thus making the pump run all the time.

Mike