S4 NA RX7 needs more powars....

That's not bad. Thats about what my streetported and exhaust gslse did prior to going megasquirt.

Yea, I was hoping for less. At this point it will be tough to get 10 or 15 more HP.

For the record, I am not shooting for a number. I am shooting for more straightaway speed.

Wow, 14:1??? That's crazy. Yeah, at that point I'd be adding fuel, not taking it away.

Yep. Gonna check fuel pressure to see what's up. I think we are losing some power from lack of fuel.

Be sure to check the obvious stuff, the filter sock on the pump and fuel filter are two places I'd start, in addition to getting the injectors cleaned if you don't know how long it's been.

It has been 12 months since I got the injectors cleaned.

The fuel pump is putting out 50 psi on the stock regulator.

More info: The spark plugs and exhuast are whitish (ndicating lean). The car uses the stock fuel tank and fuel pump to feed a "surge tank". This surge tank is simply a VERY large boat type fuel filter.

A secondary pump pulls fuel out of the filter and sends it to the engine. The return line goes back to this filter. There is a another line that goes from the fitler to the tank. It has been plumbed like this for a year and about 150 track hours.

I do not know how long it has been runnign lean. Possibly for a year.

I am going to remove the injectors and get them sent out / tested / cleaned.

I will check the grounds for the injectors while I am in there.

ANy other ideas?

Thanks!

Rob R.

Just to clarify - there are four fittings on this surge tank/filter thing, right?

No, 2.

One from oil fill pedestal and one from intake. Oh yeah, one from gas tank vent too.

Also, I just now found out that the " boost sensor" line was plugged shut on the intake.

Could that really be the entire issue?

It sure could. The boost sensor is the MAP sensor. The surge tank? I'd need to see a pic of it. There's directions on teh int3rw3bt00bz on how to build a simple 'flash code' diag box, you might want to look into that. If I find it I'll link it.

EDIT: Here's the link. Notice it ONLY applies to S4 (86-88) ECU's. http://fc3spro.com/TECH/HOWTO/ERRORCODES/ZENKI/zerror.html

I made a box for my LED's, it's mounted next to the ECU and has an on/off switch. I used red and amber LED's so I wouldn't have to remember which was which, even went so far as to engrave the codes in the box face, saves digging in a manual if I'm in a hurry. I also added a O2 'closed loop' LED (that's the 'yellow wire' pin they mention).

wvumtnbkr wrote: No, 2. One from oil fill pedestal and one from intake. Oh yeah, one from gas tank vent too.

Okay, what now?

I was talking about the thing in your fuel system.

wvumtnbkr wrote: Also, I just now found out that the " boost sensor" line was plugged shut on the intake. Could that really be the entire issue?

I'm with Curmudgeon, that's a pretty important sensor for fuel control...

Knurled wrote: Just to clarify - there are four fittings on this surge tank/filter thing, right?

Ohhhh. For some reason I was thinking catch can.

Yes, the surge tank has 4 fittings.

update...

Tried a few different boost sensors and vacuum locations. The result is that if I get to 12.5:1 AFR, I lose about 12 hp at the upper end.

If I was to take the engine apart and street port it, what sort of gains could I get? I will still run the stock intake manifold. It is legal for me to run a Rtek ecu now as well.