skatingsamurai

post by HAILERS

"

Nornally, the fuel pump only runs if the engine is running or the key is HELD to START. It does not run just by turning the key ON.

There are exceptions. If you jumper the fuel pump check connector and have the key to On or better, then pump runs. Or if the key is ON and you push the vane in the afm aft at least an 1/8" the pump will run.."



so how voltage is suppost to be sent to the pump if you jumper the fuel pump check connector. and if it is 12v, could this be a bandaid fix till i get around to the fuel pump rewire?

and what is the best/ fastest way to take the voltage of the fuel pump while it is running?

arghx

iTrader: (3)

the fuel pump check connector grounds the circuit opening relay I think (maybe some other relay). it's not going to provide "extra" voltage if you have degraded wiring.

HAILERS

Jumpering just puts a gnd on the Circuit Opening Relay to pull it in and feed the pump. The fuel switch in the afm does exactly the same thing. Puts a gnd on a coil in the Circuit Opening Relay to pull it in. Both do the very same job.
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and what is the best/ fastest way to take the voltage of the fuel pump while it is running?****************************************** ***********************************

I have two 12' meter leads with bananna jacks and alligator clips. I put the meter on the passengers seat. Run the neg lead to a gnd point like the ECU attach bracket. The positive lead backprobes the large BLUE wire in the fuel pumps connector on the back of the left rear strut tower. Then go drive the car.

In other words backprobe the Blue wire on the fuel pump connector. It's Blue on the R harness side of the plug but turns Black/White on the fuel pump pigtail side of the connector.


12vdc when starting.............drops to approx 9vdc while idleing (sp).........back to alternator output when you have a load on the engine.

EDIT: I forgot to add the Circuit Opening Relay feeds the Fuel Pump Resistor/Relay which in turn feeds the pump. Sorta left that out in the reply at the top of this post. But you knew that anyway.

What you really want to do, is go into boost and read what's on the Blue wire. Then do it again with the headlights on and maybe the heater fan on. That's an thought I got from Ted. You Really need to do that.

skatingsamurai

see its a vert...sooooo its going to be a pain in the ***. see the reason im so curious is because my wide band is showing some wierd signs while cruizing...ill be driving along maybe 20%throttle and i will let off just BARELY a little bit and and it drops alot from 14.9ish to 17.8ish. and i feel serious power loss. then when i put that same throttle or a little more back on it, the afrs jump back to 15ish. BUT any more throttle then that all , all the way up to 70% or so, the afrs stay at around any where from 15.5 to 18 and i know they should be dropping to about 13 or so? maybe this is wrong.

so the injector sizes might be a problem 550/720, turbonetics hybrid, walbro pump, rtek 1.7, and safc. so i really dont see why it should be leaning out real bad just under small load from the injectors. but rather fuel pressure.

HAILERS

With or without ACV, airpump and converter?

None of the above? Try disconnecting the 02 sensor and repeating your drive under the same conditions.

It sounds a little screwy. Usually if I drive along at a steady speed, then just barely lift off the throttle, the afr will drop a full point, say from 14afr to 13afr. This is because when you just barely let off the front rotor gets cuts fuel and only the front rotor (see Training Manual)
IF you let off quite a bit, then both rotors have fuel cut off and the afr goes to ?????21-22afr. Depends on the widebands range.

Just an aside: Now when you let off just barely, and one rotor has it's fuel cut off, the afr actually goes richer by a point. THAT I do not understand at all. I would have thought the afr would get leaner. It does this on all three of my cars so it's not a single car issue. If anybody knows why the afr gets Richer, tell me why.

skatingsamurai

hrm interesting.
it seems to have gone away for the moment. this occured while it was raining and while i had my heater full blast. ill replicate the conditions again see if it happens. but it was only on the highway where the engine had time to "set" into a steady driving mode.

arghx

iTrader: (3)

Question (and slight hijack): I had this idea of running an autometer voltage gauge to the big blue wire so I could monitor fuel pump voltage in the cabin easily while driving. I cut open the stock electrical tape type stuff on the harness leading from the strut tower to the pump ( that is, between the fuel pump itself and the fuel pump connector). I stripped back the insulation on that blue wire and tapped the wire for the voltage gauge into it. The gauge is now reading off the charts-- like pegged at 18 volts. Is this a flaw in the gauge or did I tape the voltage form the wrong place? I checked the FSM and it seemed like it was the right wire.

HAILERS

Hard to see eighteeen volts on a twelve volt system. I'd think the gauge is off. Put that same gauge on the battery and see what it reads with the engine running. One lead to neg one lead to pos terminals.