Fuel issues I think

Topic: Fuel issues I think (Read 1396 times) previous topic - next topic

Fuel issues I think

May 13, 2005, 08:47:22 PM

Have 88 thunderbird , my question is when you turn your ignition to
the on position , the fuel pump is suspose to come on for a second or two right? Then cut off right? My fuel pump just continues to run and run . the motor has new egr, plugs wires, iac, temp sensor , air temp senor tps sensor. o2 sensors are bosch and are about three years old. this is a 86 GT mustang motor that ran perfectly fine pass emissions test all the time now that i've done the swap it idles differently. used to idle up at start then come down now it just stays at 1100-1200 all the time and the exhaust fumes starts to burn your eyes.
all wiring connections are right and the car starts up fine no check engine lights are stalling just wierd exhaust smell and idle speed is slightly high the idle stop screw as no effect on the speed of the engine and i don't think it's got a vac leak. this is what makes me think its fuel system related..............help :disappoin

Re: Fuel issues I think

Reply #1 – May 14, 2005, 11:30:48 AM

the only two things i can think of that would keep the fuel pump running is this.

the tan/light green is getting a continuous ground because
the eec on pin 22 is shorted
or
the tan/light green wire located at the fuel pump relay or at the self test connector is shorted to chassis ground somehow.

this wire provides ground to the fuel pump relay and the eec controls it.
this wire (tan / light green) runs from the eec pin 22 to the relay coil.
the other side of the relay coil is a red wire which runs in line with the inertia switch.

is it possible someone maybe jumpered the fuel pump relay to test the fuel pump recently or sometime in the past?
is it possible that a jumpstart might have caused this pin 22 in the eec to short,,?

whatever the case,, swap out your eec and see what happens. there seem to be a lot of signs on your running condition that points to it.

pulled the codes yet?

Re: Fuel issues I think

Reply #2 – May 14, 2005, 05:12:03 PM

You may be in "Limited Output Strategy (LOS) Operation.
Sometimes called "limp home mode"
Which means the software in the EEC has stopped running.
Could mean the voltage (vpwr) to the EEC is low or the EEC is bad.
There is a "watchdog timer" in the EEC that the program has to keep reseting before it times out. If it times out the EEC goes into LOS operation.

This keeps the fuel pump running.
Puts the fuel injectors on a fixed pulse width triggered by PIP.
Among several other things.

Re: Fuel issues I think

Reply #3 – May 14, 2005, 06:42:00 PM

thanks for the info guys will check all this stuff and let you know it goes.........thanks again