What happens when you turn your key on?

[ahuggins6]

im working on putting a 99-00 engine and PCM in my early bronco. I'm using a Moates quarter horse to bypass the PATS and delete the rear o2 sensors and emissions stuff. So far, The only programming I've changed is the PATS option.

However, I must be one of the few to try this with EEC Editor. I'm not sure it's getting the full programming. When I turn the key on, I can feel the PCM relay click on, almost simultaneously turning on the fuel pump relay, which goes off after 1 or 2 seconds. This is not long enough to tell if the pump is actually pumping (the line is open into a bucket in the right front fender well area) and the tank I built keeps the pump VERY quiet. I also can hear the IAB pop open about 2 seconds after I turn the key on.

I plugged a 1996 PCM in, turned the key, and almost immediately had fuel flowing.

So, the question, what happens when you turn your key on? Shouldnt the fuel pump push fuel immediately?

 

[koda2000]

The '96 and '97 used a return-type fuel system (a line from and a line back to the tank) FPR on the fuel rail. Later models used a return-less style fuel system (one line from the fuel tank) with the FPR in the fuel tank. IDK when the return-less style was introduced.

When I turn the key to ON in my 2000's and 2001's my fuel pumps run for about 2 seconds and then shut off. When the engine starts presumably the pump runs as needed. I don't recall if my '97 also runs for just 2 seconds when the key is turned to ON. I think it does. I can verify tonight. I believe the 2 second run is to prime the system and bring the pressure up in preparation for engine start. As many times as you turn the key from OFF to ON you get the 2 second FP run.

The return-style system runs at around 35-40 PSI. The return-less style system runs at around 65-72 PSI.

 

[ahuggins6]

I think you'll find tonight that it does run for a couple seconds. I can't see an Efi system programmed to start without fp. My dad and I were learning about Efi years ago and decided that it's best in s fuel injection vehicle to key on and wait 2-3 seconds to make we have full pressure before cranked. We thought it just HAD to be healthiest for the vehicle.

I think ive got issues tho. With a 96 computer, the pump runs, but with either of the 99 pcms, it doesn't... It's got to be in the programming.

Just for future reference, anyone wanting to use a quarterhorse from moates, should seriously consider a package from coretuning. They seem to have their stuff together, using binary editor. Here I am trying to be cheaper using EEC editor, and while Paul Booth is doing his best in providing a free service to the automotive world, there just aren't enough people using his product with this particular binary (of possibly any explorer binary) to get anywhere very quickly in troubleshooting.

 

[koda2000]

Are you using a return-less fuel system? If you're installing a '00 engine with it's '00 fuel injectors, I'm thinking you need to have 65-70 PSI of fuel pressure at the rail.

I believe you are correct in that my '97 runs the fuel pump for about 2 seconds when you turn the key to ON. I replaced the fuel pump in that vehicle 2 months ago and that's what I recall it doing. It's not a bad idea to wait for 2 seconds before trying to start the engine, but I don't think it's necessary, or particularly helpful.

IDK about your PCM issues. I don't know what year Ford switched to the return-less style fuel system, but I know my 2000's/2001's have it. As the '96 and '97 PCM's run the fuel pump with key ON and the '00 and '01 PCM's also do the same I would think the '99 PCM should also do it. It might have something to do with PATS (began in '98) because that's how PATS prevents the engine from being started (by turning off the fuel injectors).

 

[ahuggins6]

So far... I've found that there was not enough fuel in the tank to pump out... With a test light, I can see that the pump has to be running, but there's nothing to pump. So I think everything is working as it should... I'm having transmission issues with my DD so I'm off this project for a bit.