RX200013B

ok up till 5500 rpm, then it seems to hit a rev limiter( sound like a drag car at the light).

did the search, but no answers are found, seems once some one fixes it they dont post again in that thread.

s4 swap , emissions removed, rebuilt harness

idles good, solid, goes good untill just before 5500.

injectors were just cleaned, fuel pump battery powered.

sugestions?

beefhole

iTrader: (29)

That's the RPM the VDI kicks in. Removing your emissions you may have removed an actuator/solenoid that controls that system.

RX200013B

it's a s4, not a s5. i dont have VDI!

beefhole

iTrader: (29)

D'oh! Missed that!

RX200013B

if i free rev it will go to 6-6.5 k rpms, have not tried to go past
1st gear will goto 6-6.3 pretty good, have not tried to go further( just got the swap ready to drive) 2nd and 3rd goes to 5500 and then sound like a rev limiter. swaped afm's and it would go to almost 6k and do the same.

any solutions?
please help.
thanks RX200013B

RX200013B

NObody has any opinions! great

RotaryEvolution

iTrader: (30)

try inspecting your secondary injector connectors.

you also didn't list what your swap was into, is this an S4 into an S5 chassis? in which case did you install the injector resistor block?

RX200013B

S4 N/A engine, n326 ecu, w/resister pack, all injectors are 2.9 ohm's, stock block, 90 psi across, swaped into a b2000 mazda pick-up, stock fuel pump key switched to battery power, stock fpr, emissions removed,

ItsFun

iTrader: (25)

I would say secondaries. I know tehre is a way to test the seals, I believe you remove a sensor (ask karack im sure he knows) then let it idle in your driveway. The sensor you remove will let your secondaries come online with no load. get some propane or starting fluid and rev it to about 5 k or wherever your stumble is noticed mostly and spray the propane, butane, or starting fluid on the secondaries(while its revving) . If its leaking you will notices a stumble from the fluid being combusted...... thats how I found my hesistation problem and now my ride runs great. hope this helps. Someone correct me if im wrong but isnt the rubber they give you on refurb injectors to hard causing leaks? thats how mine were.

RX200013B

also, the idle is good, sits at 800 no bouncing, but the rich/lean adjustor is almost all the way rich.

if that helps


which sensor is that?

the boost sensor?

ItsFun

iTrader: (25)

I could not tell you right now if my life depended on it, I will search.

HAILERS

Variable resistor for idle only.

Molotovman

iTrader: (49)

If it seems like you're hitting a wall, check the ECU Ground on the Rear rotor housing. Search for Rear Rotor housing ground.

I had a car do this, and I checked the ground when I had the manifold off. Either way it loosened up. This was on my 88' GTU. I ran through everythign because i felt positive it wasn't that ground. Turns out it was, I was able to take the solenoid and UIM mount off of the drivers side and clean the ground up & resolder it. Put it back on, Absolutely no problem anymore.

Have you checked this?

RX200013B

yes, i have. i completly rebuilt the harness for the swap(into a b-2000 pick-up) all grounding locations were cleaned with new terminals (took me a couple of weeks to do the wiring install cause i wanted to make sure everything looked good) alot of my ground wires loop from one connection to the next, and the ecu wire is grounded to chasis and to the case.

the only thing i have not done is use a stisiscope to listen for the sec inj.

(no i cant spell, i'm from idaho)

tweaked

iTrader: (4)

I have this same problem. Just did a swap and it showed up. I haven't gotten around to trouble shooting yet. Been caught up with suspension work.
Have you found a solution yet?

HAILERS

Kinda sounds like just one of the secondary injectors is not working/coming online. Just a guess.

There is a method in the 1986/87 FSM fuel and emissions section on how to make the secondary injectors come online in the driveway. I believe you remove the vacuum line to the boost/pressure sensor and block the line off. Then unplug the TPS and leave it uplugged. Then rev the engine over 3800 rpm. The engine will stutter when over 3800 rpm 'cause the secondarys come online (primarys duty cycle cut in half as the secondarys come online makes the stutter).

That kind of sucks. I'd put a meter on one of the secondary injector wires in the ECU small plug and observe the volage. Should be batt/alt voltage til you hit 3800 where upon the voltage should make a big drop ...indicating the injector came online. Then do the same with the other injector wire. In both cases the voltage should drop as you go over 3800 rpm IF and I say IF the engine is under LOAD.

The problem does sound injector related in some fashion. It's all a guessing game to some extent.

RX200013B

found the problem! when building a new fuel tank, don't forget to vent it!!! lesson learned (the hard way)