Ford Zetec Fuel pump

[Deaninkc]

I've been asked to look into piggybacking a MS onto a Ford Focus with a 2.0 Zetec. One of the first things that comes up is the Focus has no return line and uses voltage variation to control the fuel pump and fuel pressure. Anyone familar with this? Does it use a pressure transducer to keep the fuel pressure at the proper level? Does it map fuel pressure along with pulse width to adjust the mixture? Would it be easier to design a separate circuit that used a pressure sensor to keep the fuel pressure at a constant, say 45lbs, level instead of incorporating it into the MS?

[MegaDave]

Are you sure it doesnt have a regulator in the tank? Mechanical pressure regulators work pretty nice without all that hassle.

[97EscortLX]

Ford got a stupid idea and decided to make the pump PWM on 98 and up escorts, both Zetec and SPI alike. If you go turbo, you'll definite want it gone.

You have 2 options

1. go to a local junkyard and grab the fuel lines, the fuel rail and the fuel pump\float assembly including the mounting ring out of a 1997(HAS TO BE 1997!!!) Escort with the 2.0 SPI engine. It has a vacuum controlled pressure regulator on the fuel rail. If you turbo, id recommend replacing the pump with a walbro 255 LPH model.

2. develop an addon for MS to control the fuel pump via PWM. Probably a lot more difficult than swapping out a few components seeing you'll have to find another chanel free which can handle a large power draw (probably 5 or more amps) and make Ms sense the fuel pressure with an additional sensor input and make it vary the pulse length to maintain the set pressure. I imagine it can be done, but it'd be a lot more of a pain in the @$$.


Have Fun and good luck.

1997 Escort LX, soon to be turboed/MSnEDIS'ed

[jacowilson]

On this same note, can the non-loopback (post '97) rail be used on a non-turbo engine? Will there be enough fuel pressure and cooling capacity to keep the engine alive? I have a 2003 2.0L Zetec, but not sure I would want to put a pre-'97 rail on it if possible. This is going to be using an in-line pump for my 1974 Capri Mk. 1. Thanks for any info.

[MegaScott]

I think someone needs to look into this a little further, doesn't the returnless Ford fuel systems have a seperate pump controller that regulates the fuel pressure on it's own, based on a transducer mounted on the fuel rail? on these systems the ECU just sends the pump controller a signal to turn on the pump? I say these systems need a revamped fuel system in order to cope with boost, but not much work has been done in this area. Still lots of guessing, but until somone actually tears into it and can say the thing can work with X amount of boost, It's an unknown at this point.

[andereck]

It has a pump driver module, but it gets its commands from the ecu. We have a boost proportionate pump speed controller that controls an auxillary fuel pump for these pwm systems. The fuel pressure sensor has to be relocated behind the auxillary pump for it to work. In a piggyback application there is no reason this couldn't be made to work. An auxillary pump is plumbed in parallel with a check valve. The aux pump is dormant until boost is sensed by the controller and it starts to regulate the speed of the pump via pwm to increase volume to the engine as boost increases. This takes the load of the stock pwm pump as its now being sucked on and it speeds up while being commanded to 100% dc by the ecm to maintain pressure. This increases volume through the system to make power under boost.

http://216.242.145.16/products/product.phtml?p=32

[ModMech]

In this case, it would be easier, and you would get a better end-product if you just did all the tuning inside the stock Ford EEC.

There are some VERY knowledgeable people around that can provide you with all you would need to make the required and proper changes in the factory EEC.