OK so a friend of mine who owns an FD came over a few saturdays ago and we got rid of his rat's nest, plugged up all the vacuums on the LIM and UIM that are not used for vital things and now the car will not rev past 3k rpm. It was fine before that (mostly, It had a lot of issues that we fixed when we removed the rat's nest like bad o-rings on the primary injectors, cracked vacuum hoses everywhere...etc), now it idles perfect, it purrs like a stock FD should, picked up a lot of lost torque from all the vacuum leaks, re-adjusted the throttle cable since someone had messed with all that when they couldn't keep the car idling because of all the vacuum leaks so now the car cranks great, starts right up, idles great, backs up fine, take off....BOOOOGGGG!!!! @ 3k rpm. BTW this all happens right at 0 psi the point at which I think the secondaries come on.

What we have done so far: installed wideband to see if we were leaning out or not boosting, afr gauge reads super lean when this happens which tells me secondaries are not firing. We then took off the UIM and i checked the connections to ALL injectors, they were fine. I put a voltmeter with the ignition switch to the ON position and ALL injector pins on the wiring coming from the ECU measured 12.5 Volts (battery voltage). I even Ohmed the injectors they all came back at about 15 ohms. This car used to be automatic but now it is stick so I swapped out the ECU and put in a N3A7 which I believe is a JDM 93-95, and nothing, changed the boost sensor with the one that is on my car which i know works just fine and nothing, took resistance readings on both boost sensors and they both read the same ohm at the same conditions.

What we have not done so far: I have not read the codes from the ecu, I'm sure there would be many as many things have been deleted but I have not done that yet.

The car is as follows: '93 FD used to be automatic, now stickshift, stock twins, air pump, only mods are cat back, air intakes, and alternator under drive pulley, that's it.

To me it feels as if there may be some "arming" feature for the secondary injectors or something but i'm not well versed in OEM ECU knowledge, I have PFC on my car and Microtech's on my other but from what I can see there is power to the secondaries they are just not coming online when they're suppossed to. HELP!?!?!?! Thanks in advance guys!

 

3k is where the secondary fuel injectors start to come in. First thing I'd check is that they're plugged in properly and the wiring to the injectors isn't broken.

Get some noid lights, they're little lights that plug into the injector clip and will flash when the injector fires. Unplug the secondaries, plug the noid lights in, start car, rev, see if they are flashing.

Everything look correct on the sensor check screen in the PFC?

Dale

 

Well that is just the thing... I have a PFC my friend does not... this is my friends car.... About htose noid lights... where can I get them? I've never heard of that name... are they just LED's?

 

im having almost the exact same problem right now. mine bogs at 4k rpm and says its running super lean. i am single turbo though. im going to try the same things you have tried today and also change my coils out and check fuel pump. one guys thought is that it is ignition because its breaking up around 4k and dumping raw fuel in so its saying it running lean when its really not since the wideband wont read unburnt fuel. anyway ill let you know if i have any success on mine.

 

There are two relays in the fuel pump power circuit. Under part throttle/low load conditions, the first relay is closed and current to the fuel pump flows through a resistor. Under full throttle/heavy load conditions, the second relay closes and bypasses the resistor, upping the voltage to the pump. You might want to check the voltage at the output of the second ("speed") relay, which is a white wire with red stripe coming out of the relay box hiding under the intake air guide. The "speed" relay is the relay at the far right end of the relay box (B1-04). For max fuel delivery you want +12 volts on that white/red wire, but only for heavy load conditions. At idle or part throttle, the voltage should be lower (don't know the value, sorry).

 

Thank you, I have done the fuel pump re-wire modification to my own car so I'm well aware of what you're talking about and from what I remember it is somewhere around 9 volts that the pump gets only but this is different. I'm pretty sure i'm not dumping fuel since (1) I don't smell any and (2) I don't see any clouds of black smoke coming out of the muffler. I really like the blinking lights idea... I almost tried something kinda similar were I was going to swap the connectors on the injectors and run the secondaries as primaries and the primaries as secondaries just to see if the car started but undoing the wiring wrap is a PITA and in the end that would just prove that the primary wiring works and that the secondaries work WHEN FIRED which thinking back to when the car showed up to the house is all true anyways... I'm more inclined to the lights test just because I feel like after we ripped everything out it is almost as if we eliminated something that is needed for the secondaries to fire which boggles my mind because I'm pretty sure that there is no "initial condition" or "arming" that happens with secondaries...at least not how they were meant to work from the factory. I don't think TPS has anything to do with it...unless it just went bad from one hour to the next???? Where can I get these NOID lights?

 

well i changed my coils and checked votage at my injectors and they checked out good and the coils didnt help. any possibility that the pump or filter is bad? im going to see what my pressure is from my pump tomorrow. sorry for kinda jacking your thread, but i have another one going in the single turbo section and no one is replying, so i thought i could just go along with yours if thats okay.

 

Lol... dude it's cool no worries that's what we're here for... Anyways I'm going to rig up some noid lights or something similar next... it's the only way for me to know if the injectors are actually getting the signal to open... once I find that out I can move down the line....

 

thanks man, i am wondering on the operation of the noid lights though. i was just reading about them and as far as i can see all they do is what you can do with a volt meter. wouldnt we need to know if the secondaries are functioning around 3k rpm when they are suppost to open? so what if you just use a bulb, a socket and just extend it to your cabin so you can see while driving.

 

well im just thinking that injectors get pulsed so fast that most voltmeters would have a hard time "seeing" it. The lights allow for better way as all you have to do is see blinking!

 

ok so I'm sure that the secondary injectors are firing, read the codes from the ecu and the only thing that came up that wasn't related to what we did was the one that says the BAC is not wroking right....well I checked and there is no BAC!!!! But I'm not sure this has anything to do with the problem or does it? I thought for sure I was gonna get codes 71 and 73 or at least one of them but now, plus I rigged up the lights to it and they're fine. Can anyone chime in on this?

 

did you pull the injectors out and make sure they are opening? i talked to one guy that had the same problem as were having and he said his injectors were stuck and was also bogging. i pulled mine and hooked them to a battery and mine function okay, but the voltage at my injectors is only about 9 to 10 volts so im hoping they needed 12 volts to unstick them and now hopefully they will work okay. im also thinking it worked cause after i did this and put it all back together my car flooded super bad. i havent got it started yet so i cant tell you if it worked or not, i think im going to have to pull start it.

 

I didn't think of that, no I didn't pull them out and manually cycled them or anything. Voltages seem good too like 12.3 volts at the injector but never thought that they may not be opening. I will have to check that. I don't understand why after doing what you did your car would flood so bad i mean its not like they fire during cranking or anything....

 

well my map was way rich cause the guy tuning my car kept adjusting when it was on the dyno. i think it flooded so bad cause i pulled my primaries also to check them and when i pulled them i heard alot of fuel run into the case. so when you pull yours maybe pull your fuel line first so that doesnt happen.

 

Lol yeah I usually take off the gas cap... that helps relieve the pressure built up in the fuel system...

 

oh well yea i didnt think of that so that why i have to pull start it now.

 

I had a problem similar to this that was the relay that switches the fuel pump voltage. Cleaned the contacts, solved the problem. Not sure if it's the same issue though. If you want to try it you can also take out the fuel pump resistor by jumping the clip under the cruise control and it ends up being the same thing. Or just tap the fuel pump straight to the battery.