gxl90rx7

iTrader: (1)

if its unplugged doesnt it default to like 40% or something? you wont have decel fuel cut and closed loop wont work, but other than that it will run like normal, right?

sharingan 19

iTrader: (16)

good question...

Sorry, been busy, haven't really driven the car much, or checked plugs...will soon though. In general it seems to be running better now that I have dropped the pressure.

sharingan 19

iTrader: (16)

Pulled the plugs today, no help. The leading plugs were light brown, the trailing were half brown, half black.

I spent the afternoon scraping off the petrified uim gasket and replaced it. Searched high and low for vac leaks and found none.

Went for a rest drive, and the issue is still there. St this point it seems most likely that the ecu is sending the signal for the secondaries to fire, but at least one if them are not. What is the most effective way to verify this?

gxl90rx7

iTrader: (1)

you could check the wiring harness by disconnecting the injector connector at the ecu and with ignition turned to ON, check for 12V at the secondary injector pins. check the FSM for pin #'s. if you get 12v the harness is good

if that checks out ok, try disconnecting the vacuum line to the boost sensor (and plug the engine side). rev it above 3800rpm and if a secondary injector is bad, it should stumble or change tone above 3800. if the secondary injectors are firing, you shouldnt notice a difference above 3800. Ive never tried this myself, but i think the theory is sound haha

lastphaseofthis

iTrader: (8)

i would start spec'ing parts at this point. starting with the boost sensor.i mean Ohm them out and check there out put voltage at the ECU.

sharingan 19

iTrader: (16)

When I replaced the injector clips I checked for 12v on all the injector clips.
That other method sounds interesting, might have to try that.
I replaced the boost sensor and it made no difference.

???

lastphaseofthis

iTrader: (8)

make sure the replacement was also a good part, somebody pulled it out of a good car for a reason. maybe it's bad too, i would check them, look in the fsm for the ECU pin out for voltage ins and outs.

sharingan 19

iTrader: (16)

This just in:

I recall racing a friend of mine the week before I put in my clutch/flywheel/diff (this was weeks ago). I did not have this problem, in fact I had to feather the throttle to keep it under 10psi. I had to break in the clutch so I didn't boost at all for weeks , that's why I'm just recently finding the problem. (other than that race I didn't boost much before that either as I'm waiting to have my bov installed)

This leads me to believe that something related to the clutch/flywheel job is the source of all my trouble. If anyone has any ideas as to what that could be, I'm sure it would be helpful.

sharingan 19

iTrader: (16)

New Info:

I pulled the uim (again...) And checked the injector clips w/ acc on. One of the prongs reads batt/ecu voltage (12.2v) the other does this count down thing ie; it starts @ 10v then trickles down to 1v within about 10 seconds. Is this normal? I was thinking it should be 0v as I always assumed the other injector write was a ground....

R.O.D

iTrader: (3)

im kind of out now, the only other thing i can think to check is grounds, like the one from block to firewall.
someone here told me that a ground issue might cause some of the things ur getting now.

other then that, im useless with out my fsm or rx7 bible ive compiled..
hope u find it soon

gxl90rx7

iTrader: (1)

each injector is wired to 12V, and the ECU grounds the other wire to turn the injector on, so that is normal. what you want to do is check the injector wires at the ecu plug and see if you see 12V.. that will verify the wiring is ok from the ECU back through the injector and to the 12V

sharingan 19

iTrader: (16)

True problem had been found! Low fuel pump voltage:
8.6v idle - 8.4 cruise
7.4 accelerating - 10.2 wot

I changed the ecu setting to 550/550 and surprise surprise, it actually ran! So it wasn't the injectors...

Rewired the pump using the 1300cc.com writeup and now I see:
10.2 idle - 10.0 cruise
11.5 accelerating - 13.5 wot

Switched back to 550/720 and now ity drives much better. Its still down on ower when the secondaries come on, but that is probably because of the FD fuel pump, 30psi idle pressure (stock is 28) and higher voltage to the pump.

At least now I can use tuning to improve performance instead of hunting for broken parts. I'll start by taking off 5% fuel from the secondaries and see if that helps. Time for ther wide band.