Problems Starting

[berning.36]

My 1988 Fullsize Bronco with the 351 windsor engine is having troubles starting. It will start and then immediately die and then not start unless i feed it fuel. It will do this hot or cold. It is a fuel injected model. The fuel pump is new, the fuel filter is new. And the battery is new also. It also runs rough with the engine loping until it warms up. When sitting at idle the engine revs up and down between 700rpm and 1500 rpm in about 5sec intervals. Anybody have any ideas what could be the problem??

 

[Seabronc]

you may have more than one problem. Have you pulled codes? When you say "Feed it gas" are you talking about pressing the accelerator pedal?

Good luck,

 

[BroncoJoe19]

Pulling codes would certainly be a good start.

A surging idle is often a vacuum leak. Here are some tips to help you locate one.

How to locate a vacuum leak

 

[Joplin]

My 94 Bronco just stopped running, thank god it was in my driveway. Fuel pump not making a sound. Check all relays and fuses and they are good. I can jump out the contacts and the pump starts working. Have power to one side of the coil of the relay but it want work. Please help. Oh I have check the fuel shut off switch, not tripped.

 

[miesk5]

yo Joplin,

WELCOME!

For the heck of it; eziest check first;

in Power Distribution Box

swap your Horn relay (assuming Horn Honks)

w/PCM Power Relay (bottom relay)

Ck for Corrosion in Socket(s)

When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM).

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."

Wiring Diagram in a 94 from EVTM, partial (at FP relay)



Ck DG/Y

Source: by Mikey350 at SuperMotors.net

Also, it would be better to start a new Post so we (meaning me) don't get your year/issue confused w/original poster

 

[Joplin]

yo Joplin,

WELCOME!

For the heck of it; eziest check first;

in Power Distribution Box

swap your Horn relay (assuming Horn Honks)

w/PCM Power Relay (bottom relay)

Ck for Corrosion in Socket(s)

When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM).

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."

Wiring Diagram in a 94 from EVTM, partial (at FP relay)



Ck DG/Y

Source: by Mikey350 at SuperMotors.net

Also, it would be better to start a new Post so we (meaning me) don't get your year/issue confused w/original poster

Thanks I will try that when I get home. I will start a new post also, Thanks for understanding the newbie...