I have hooked up everything and i am getting spark but the
computer is not opening the injectors, there is power to the injectors
but the computer is not switching the ground, what have i missed?
any suggestions would be appreciated, except the suggestion of
getting a after market computer to run it

matt

 

I am not sure of other causes but the factory ECU does have a 'Limp mode' if its not getting readings from certain sensors this is what it does. It won't allow the engne to rev to well. Maybe something like this??

 

wont run at all, everything else looks to be working, the computer starts the fuel pump
supposed to, it powers up the ign and fuel relays
checked the power to the computer and it seems to be correct, guess i have to check the rest of
the inputs to the computer, just thought someone here might know where i should be starting to look.

matt

 

thats what happened with mine. double check everything there must be something plggend in wrong or maybe it thinks your in gear??

mike

 

interlock would keep it from cranking if it was in gear. but beleve me i will try that to.
i really dont think that the dash is needed to run the motor but i could be wrong

 

it shoudn't be fd's run fine without the dash. are you sure the ecu is grounded right?

mike

 

You need to give us a lot more information on your set-up.
FD?&nbsp FC?
Stock ECU?
3 rotor, right?



-Ted

 

yes ran an extra ground,, for some reason the computer is not ground switching the injectors on.
the only thing that i am not 100% sure on is the direction of fuel flow, its not really clear which is the return and which is the feed lines, one of the metal fuel tubes has a white dote on it, i would have assumed
that the one with the dot would have been the feed line but that one goes to the secondary (top) set of injectors 1st.
what happens if these are hooked up wrong?
i don't think connecting the fuel lines up wrong would stop the computer from trying to open the injectors.

matt

 

<RETed> it is a cosmo 20b on the shop floor, trying to get it to run with the stock computer and wiring and trani.

matt

 

Do you have it hooked up to the transmission right now?

 

yes its in one big piece.

 

the actual direction of fuel flow shouldn't keep the injectors from firing. im thinking maybe the injectors have a seperate ground and its not hooked up, or it thinks your in gear or something

mike

 

<j9fd3s> the injectors are switched on the ground side from the computer, and i think there is power to the injectors.
I have not tried yet but i think if it was in gear it wouldnt crank at all, but i might try that later just to see.
matt
matt

 

Try and get the ECU to spit out error codes - I'd bet something is not plugged in right.&nbsp The bitch has a LOT of things that can trigger fail-safe...



-Ted

 

reted> I cant find the check engine light in the wiring diagrams, i have asked a couple cosmo owners to point it out to me in the diagrams , hope to hear soon, and hope it helps

 

Are you running stock turbos? If I'm not mistaken the way the fuel injectors work is during regular or light driving only the primary injectors are used and once you floor it and get into the upper rpm range the secondary injectors spray, could it be possible if the fuel is not being feed to the primarys @ start up it will not start even if fuel is being supplied to the secondaries, that might be what is happening if the feed lines are not hook'd up correctly

 

would any damage occur if i tried the fuel lines the other way around?


matt

 

I don't know if this will help you but on the FC's and FD's motor the line closer to the firewall or the rear one is the return!

crispeed
87 Rx-7 TII
9.20@150mph
2600lbs

 

crispeed> that is what i thought and that is the way i hooked it up,,

thanks
matt

 

also that didnt answer my question .
would any damage occur if i tried the fuel lines the other way around?

 

It would probably start and idle with the lines hooked up the wrong way but it would not run right if you try to rev it! With the feed line from the fuel pump hooked to the bottom or return side of the regulator the motor would actually get less fuel as you decrease vacum(increase load) because the regulator would close the return.
This is an assumption being that I've never actually tried it!

crispeed
87 Rx-7 TII
9.20@150mph
2600lbs

 

OK I tried switching the lines around, among other things, which made no difference at all
then I connected a test light to the injector wire at the computer and see now that the light does flash, so I am guessing that the injector is getting signal,(my fluke must have been to slow to see the pluses),, checked the spark on all 3 plugs at the same time, I am getting GREAT BRIGHT SPARK! while the plugs were out I thought I would check the compression and all sides seem good at 60psi dry and 80 wet (oil). I think the next thing I am going to try is to ground one of the injectors for a couple seconds to run some fuel while I am cranking this should make it fire on that one.
any other suggestions?

matt

 

You should be able to HEAR the fuel injectors click, if they are operating properly.&nbsp If it's too noisy, hold your finger up to the fuel injectors, and it'll noticeably "buzz".




-Ted

 

I think I might know what the problem is.
will post what happens when test my theory.

matt