My 97 Escort recently started blowing the 30 amp fuel injection fusable link when accelerating hard. These fuses aren't cheap.

It runs fine otherwise. Any ideas?

 

I think the fuel pump may be shot. When you accelerate hard the pump seems to pull to many amps.
Look at this:
Good luck!

 

When the fuse blows the pump stops because the fuse powers the fuel pump relay so no voltage goes to the pump. A new fuse and all is wll again for a while. The video assumes the car won't start due to a questionable fuel pump.

Is there a way to test the current draw of the pump?

I thought the fuel pump always worked the same and the excess is returned to the gas tank. Shouldn't the current draw stay the same no matter how hard the car accelerates?

 

The Alt/Gen internal regulator is circuit protected on that 30. How long during a hard thrttle till it pops? If quickly, you might unplug the connector and see if it still blows...

 

It takes maybe 5 seconds of hard throttle to blow the 30 amp. I took the alternator off and had it tested. I'm told it's ok.

If the fuel pump was bad, wouldn't the 20 amp fuel pump fuse blow instead of the 30 amp?

 

I won't comment here since you are in good hands with Hayapower and bluewind.
It's always nice to see the light come on upstairs when you start asking good questions.

 

That 30 link protects the Alt reg,,, and feeds the CCRM for the internal PCM power relay (load side), which when closed,, also controls the fuel pump relay (relay coil side 12v~ PCM in charge of grounding to close relay) within the CCRM,, as well as control for the cooling fan.

Most of the engine controls are fed through the 30 link with the injectors and IAC direct through the closed PCM power relay. The MAF, EVAP can, EVR, EVAP sensor IMRC all pull through the 30 link. If the fuel pump was to overload, it 'should' blow the 20.

 

Now you're scaring me. Almost anything could be going wrong from what it sounds like.

Would it prove useful to gently drive the car to the parts store and have them read the codes?

A local mechanic suggested putting in a larger link and see what fails. He was serious. That does not sound like a plan to me. I'm hoping to avoid a potential fire. It was also suggested that a frayed wire could be the problem. I haven't found any yet but I would expect a frayed wire to cause the link to either blow instantly or intermittantly. This problem is both predictable and repeatable.

 

twj:
Electricals are not my forte but I have some experience. Hayapower really knows the circuits.
Here is what I would do based on my experience: This is an old car and therefore it is possible that the charging system is on the fritz. (Hayapower says the 30amp is protecting the voltage regulator) So check the charging system, including a load test for the battery. Make sure the battery poles are clean and all ground connections are good.
Trouble with the charging system can manifest itself in mysterious ways.

While you are under the hood check all connectors for dirt and corrosion crud, and check the wires for chafed insulation. Wiggle the harnesses while idling the engine.

(I wonder what Hanky would do if the light upstairs starts flickering?)

 

I haven't found any bad wires or poor connections yet but I have found a few dried out, cracked and broken vacuum hoses. The engine should run smoother once it is fixed.

Someone suggested a bad throttle position sensor or crank shaft position sensor. I have no idea how to test them and would rather not just start replacing parts hoping to find a bad one.

Am I barking up the wrong tree?