ebay7

The fsm manual for 89-91 models show the same spec for fuel pump pressure. But Mazdatrix shows 2 different model #. So how different how they, sturdier, better built, etc. My NA pump ain't puttin out, and hold pressure is way under spec.

scathcart

Nope. TII pump is higher output, hence the reistor pack. Flow and pressure are different things, keep in mind.

DaleClark

iTrader: (55)

The TurboII pump does flow more - they are regulated to the same pressure, but the TII pump can produce more flow at a given pressure.

I would check other things before swapping the fuel pump - fuel filter, junk in the gas tank, etc. The pumps are pretty darn hardy, and rarely fail.

Dale

DaleClark

iTrader: (55)

Oh, but to answer the original question - yes, you should be able to use a TII pump in an NA without any complications - the FPR's are pretty much the same.

Dale

ebay7

The fsm saids hold pressure should be @ 50psi after 5 minutes with the gauge plumbed right after the fuel filter. It read only 35psi, so the pump gotta be leaking, no? I hope it's just a drop in and not having to worry about the resistor pak.

scathcart

The resistor pack lowers voltage to the pump at idle and low throttle positions. This is to prevent the fpr from becoming over run, and rasing the fuel presuure at idle, causing it to run even richer, compunding a carboning problem on a car which already has issues with it. It was adde to the turbo cars b/c they run the same fpr, but have added flow from the pump, and when the least amount of fuel is being used (idle), the fpr can't flow enough to keep the fuel pressure at the right psi.

ebay7

Sounds like I oughta stick with an NA pump then. THanks for all ya help.

Suds7

I have put a TII pump in my N/A, without the TII relays. How much should I lean it out (With S-AFC) or a better question is at what RPM, idle through 3k?

scathcart

you can't really do that.
A fuel pump flows a certain amount at a certain voltage. The fpr flows a variable amount to maintain a relatively constant fuel pressure. The amount the fpr flows out is proportional to the amount of fuel being used by the injectors.

Thus, if you lower the injector pulses at idle and low load, the injectors are firing in less fuel, and thus the fpr has to flow more fuel. Since it is already over-run, the fuel pressure will increase even moreso, cancelling out the effect of lowering the injector pulse.

You need to wire in a resistor pack from a TII, or better yet, get an aftermarket FPR.

HAILERS

Why do I get the feeling that EBAY has taken a fuel pressure gauge and plumbed it after the fuel filter but not dead ended it. As in having a tee instead of just a run straight to the fuel pressure gauge and no where else. Its the 35psi that caught my eye. Too close to normal fuel rail pressure when there is a loop.

Tell me I'm wrong EBAY. I just thought maybe you had made a mistake. Happens to the best.