Ok, for those who haven't been following my other thread the car is a 83, the engine is a 90 JDM 13bt. I've done the FC style in tank fuel pump setup, and am running the stock (n374 JDM) ECU. Anyway, tried to start it today, it cranks over, and has leading spark (not sure why no trailing yet) and the fuel pump runs, and the fuel makes its way through all the fuel rails, but dead heads at the FPR, is this normal? Also it doesn't seem like the fuel is making its way to the combustion chambers, how can I check the injectors to make sure they are firing? I realize this is more of a second gen section question, but there are plenty of people here that are running these engines, so I'm posting here. Thanks in advance
Sean

 

You should be able to use a stethoscope type probe on the injectors and hear them "ticking" while its being cranked if they're in fact working. Sometimes a screwdriver will work, put the tip on the injector, and ear to the handle if you dont have an automotive stethoscope.

On another note, is it possible that they arent firing because there is no trailing spark? Maybe since the ECU isnt getting a signal from the trailing spark circuit its not firing the injectors?

~T.J.

 

sounds like your fuel lines are backwards, fuel should be able to flow all the way through.

 

I posted this in the second gen section as well, and that seems to be what those guys are saying as well. Just seems odd that on the US cars the FPR is that last thing the fuel sees before going back to the tank and on the JDM engines it would be the first thing the fuel sees. I won't be able to try anything today, but I'll switch those lines first thing tomorrow and see what happens...

 

The FPR is always after the fuel rails. If it's stock it should be on the end of the secondary fuel rail. Fuel should flow through the primary rail, then through the secondary rail, then the FPR and finally back to the engine.

You sure you don't have it confused with the pulsation dampner? That's the device on the end of primary rail nearest the fire wall.

 

The FPR has a vacuum line where the pulsation dampner doesnt right? Is thats true then I have the hoses run correctly. A few people in the second gen section are saying that the fuel lines are reversed anyway, but that doesn't seem to make sense to me. Hmm, this is confusing the hell out of me.....

 

I'm sure you probably have, but dl the S5 FSM and follow the routing diagram. I don't have an S5 one to look at and help with that, but it never hurts to recheck your work. ReTed also has an upgraded fuel supply system on his website, fc3s.org, iirc. I'm not sure if it covers the S5 or not.

I'm suprised that you're getting the fuel pump running w/o trailing ignition, unless you bypassed the fuel pump relay, or did you go standalone?

 

I was in the same situation as you, only i had a standalone computer.. Your fuel lines are backwards...For some reason the US cars are routed differently then the JDM ones. Also, if you dont have trailing spark, there is a good chance that the injectors are not firing. So switch the lines and see what happens. If it still doesnt start, remove the plugs and see if they are wet. If they are totally dry, then the lack of trailing ignition may prevent the injectors from firing.

 

I too was suprised that the fuel pump runs without trailing ignition. since the trailing gives the tach its signal I kinda figured it took care of the fuel pump as well (like on the S3 cars) but low and behold the pump goes on after a few seconds of cranking and continues to run for a few seconds if the key is left on. I'm running the stock ECU btw. I'll switch the lines around today and see if I get a full loop of fuel or not. I'll also stick a test light on one of the primary injectors and see whats up.
I have the S5 manual, but since its for the US cars i'm not sure how much help it is as far as the fuel routing goes...

 

Ok, update. switch the fuel lines didn't help, now the fuel just stops at the FPR (the first thing it sees in this configuration) and doesn't go anywhere else. I've taken the fuel rail off, hooked its vaccum line up to my other car (a 12a that has plenty of vaccum) and the FPR does nothing. I've tried blowing air through the rail in all different directions, both with the vaccum hooked up and without. Nothing happens. In addition I took the fuel rail from a NA s5 engine that I have and tried the same tests and again nothing flows as it should.
I'm very sceptical that both fuel rails would be bad, but then I also wonder how the hell does the fuel get back to the tank??
As for the tailing problem I cleaned all the connections on the coils themselves (the eyelet connectors with the 7mm nuts holding them) and checked them with a test light. Oddly enough they have power going to them, however the trailing still doesn't fire. Using a test light doesn't yield any results when probing the leads coming from the computer (but it also doesn't on the leading, which in this case works) How do I go about testing the signal through these wires?
Lastly, I checked the injectors and the primarys are indeed clicking away when I crank it over, so now I'm really confused, I can get fuel to the injectors, and they click, why the hell wouldn't it fire up?
Sorry for the long post but I'm getting frustrated....

 

your lines should be configured in a way that fuel will flow all the way through both rails and out the other line. if it hits the FPR and stops it's backwards.

your TPS may also be way out of adjustment, or the AFM could be bad.

 

Either way I configure the fuel lines the fuel stops dead at the FPR. I'll have to look at the tps. How do I adjust them?

 

Yet another update, I borrowed a timing light and a fuel pressure gauge (both snap-on) from a mechanic I know, and my timing is dead on, and fuel pressure is 35psi. After cranking it over a few more times I pulled the plugs and they don't seem to be getting fuel. Yet the injectors are clicking, which is what confuses me. If there is enough fuel pressure, and the injectors seem to work shouldn't the engine be getting fuel regardless of whether the fuel is returning to the tank or not??

 

Yet another update, I was finally able to get it to fire last night! However now another problem has cropped up haha as soon as it fires it screams all the way to redline. I'm pretty sure this has to be caused by either a massive vaccum leak or a falty BAC valve (which would basically be a massive vaccum leak as well...) I'll be testing the BAC later on tonight. I'll be sure to post the results...
Thanks again for everyones help, gotta love this forum!

 

Well a vaccum leak wouldnt cause the car to rev that high.....Maybe the butterflies are jammed? (happened to me in the past) So what did you end up doing to get it to start anyways?

 

Yeah, definately check the butterflies.

 

Damn must be telepathy, I just got in from fiddling around with the throttle body and here are two guys telling me to check the butterflys. Anyway, I think that may be the source of my problem although I could be wrong, this is the first T2 TB I've done anything with, so I'm not sure how they are supposed to look. I have attached pics (crappy ones, sorry)
Now I realize the primary butterfly (the single top one I assume?) is supposed to be slightly open, but shouldn't the bottom two be closed? Also, the second pic shows that the throttle mechanism isn't even close to touching the little stop (see red arrow)
Also, the TPS that is in front (towards front of car) isn't even touching anything, and the rearward one is half extended
Before I go pulling the upper intake again I wanna confirm that this is indeed messed up. (seems logical that it is the problem)
To get it started.... I feel like an ***, but I didn't have the I/C piping from the ic to the tb on (so I could get to the plugs easier) so the maf wasn't seeing any vaccum and thus not moving. As soon as I manually operated the MAF it fired almost immediatly. DUH! *smacks forehead*

 

Ah yes, I should add that the throttle cable has been disconnected at the gas pedal for these shots, so its not the cable holding it open like that....

 

Ahhhhhhhhh..........
Sorry, but you are an ***!......J/K ;-).......but seriously,I wouldnt have asked if the intake piping was all hooked up,thats usually a given.Glad to hear thats what it was.

About the butterflies....
The two secondaries you are seeing at the bottom, are the secondary-secondary butterflies.
They stay closed when the engine is cold,to prevent you from beating on the engine until its warmed up.If you open them up and look down the throat,youll see the actual,primary secondary butterflies that do the real air metering to the secondary ports.They will start to open up after the primary has traveled about 1/3 of the way open from its idle stopper.The little thermal vacuum pot on the TB controls the secondary-secondary butterflies.Deleting this complex and slightly restrictive system is what is commonly know as "the throttlebody mod" to 2nd gen guys.I did it,cant say it made much/any difference,but I dont miss them being there,and I dont beat on a cold engine,so I saw no reason to keep them.

Get all your throttle mechanisms cleaned and WD40'd,then get that TPS contacting and close to its proper range.The S5 TPS's are self correcting and dont require setting usually,unless you install a new one and your off by a mile.....or of course your not touching at all and are off by a mile,like in your case.

The throttle gear wont sit on its idle stop until the engine is warmed up.Right now,the thermal wax fast idle cam is engaged because the TB is cold.When the engine is warm and coolant is up to temp,the thermalwax plunger will let the throttle retract to the idle stop screw and the primary butterfly will be fully closed.Air for the idling engine is then metered out by the BAC valve on the other side of the intake,instead of the butterflies.This allows the ECU to adjust idle air flow/speed independantly of the TB,to account for sudden,automatic loads on the engine, like powersteering drag ,A/C and electrical drains.

 

Thanks again for the help everyone. Fiddled around with the TB some more and got the butterflys to close as they should, and thats what was causing the racing engine. It still has some idling issues, its either "hunting" or just plain stalling out, but at least i'm getting somewhere. I'm getting tired of engine work for the moment and I think I'm going to move on to body work for the next few weeks and come back to this.
As for the fuel not getting past the FPR it seems to be flowing as it should now, since one of the rubber hoses on my return line burst yesterday, so at least I know fuel is flowing back through the return I have since fixed the line obviously.
One thing though, in order to get the thing started I have to push the maf all the way in, otherwise it just cranks and cranks (and this is with all the intake piping hooked up)
There is surely other stuff wrong with the engine that will need attention, but I'm tired of wiring/plumbing etc for now, I'm gonna start doing body work, Once I get a "second wind" for the engine I'll make a new post with new questions. Thanks again everyone!
Sean