my last hurddle is getting the injectors to pulse.

when i turn the key i have: (on the #3 plug)

main relay:12v
battery:12v
starter switch: .85v

both grounds are good.

but i CANNOT get power to come through the injector wires, what am i missing??

all the grounds on plug #2 are good also.

 

It might help if you gave the full specs of your setup.

 

Yea,is this a stock TII setup or a standalone?

If its stock ECU,then the main relay has two big power wires that feed the 2 main power leads on the big right side harness.One big wire is the common power for the 4 injectors and the other big wire is the common power for all the solenoids in the rats nest and ACV.You have to find those 2 big wires on the big right side harness and run them to the main relay outputs.These wires on the big right harness do not lead all the way down to the yellow ECU gang plugs.They terminate higher up,on a different gang plug that would normally connect to the FC underdash harness.
That way,all those components will have constant "incoming" power, when the key(main relay) is tuned on.The ECU will decide when to activate each item,and does so by grounding the appropriate wire,completing the circuit and activating the injector,solenoid,valve or whatever....

 

S4 stock ecu and harness

you're speaking of the 4 or 5 colored plugs behind the alt, i need to find the one for the injectors and power it up?

 

No,not even close......

The big harness that goes from the engine, into the passenger compartment, and connects to the ECU with 2 large yellow gang plugs.Inside the car,follow that big harness up from the yellow ECU plugs until you come to a couple other plugs that arent connected to anything.There will be two large black wires somewhere in there,going to those plugs.One will have a white stripe and one will have a yellow stripe.The one with the white stripe goes down the harness to the engine and powers up the smog solenoids,fuel pump relay resistor and many of the EFI sensors all over the engine.That wire needs to be connected to the black wire with a white stripe that comes out of the FC main relay.The black wire with the yellow stripe powers up the injectors and the ignition coils.It needs to be wired to the black wire with a yellow stripe that comes out of the FC main relay.

The main relay needs to be hardwired into the FC fuse block through the 30AMP and 40AMP EGI fuses.That is the bulk of the power that the engine uses.The rest of the power used by the ECU and the power needed to actually turn on the main relay,is provided by the circuit opening relay,which is activated by a small 15AMP fused signal wire that comes from the igntion switch.

 

ok, getting very close.

thanks go out to steve for being patient with me.

i only have a few small things left..

the injectors still will not pulse.

i have the CAS wired correctly, and the FC coils firing. knock control box in place, injectors have power, sensors have power, ecu has power and grounds.

what actually tells them to pulse, a combination of the AFM and TPS or is there a system that should provide at least some fuel?

 

The ecu tells them to pulse. The AFM, TPS, CAS, etc. provide all the necessary inputs to the ecu to determine the ms value.

 

so what am i missing from this equation then? power not being applied somewhere?

the ECU is telling the coils to spark, that tells me it should be working somewhat?

 

Is all your engine stuff from the same car?I mean the ECU,injectors,harness and underhood electrics/sensors......

There were two types of S4 engine,the 86-87.5 and the 87.5-88.
The change was to the injectors,ECU and injector resistor box.The early engines had low impedence injectors and a resistor box that plugged into the harness.The later engines had high impedence injectors with no resisitor box and a different ECU.
The harness and injectors had different different plugs so you cant mix up the injectors,but if you have the wrong ECU for the type of injectors,you wont get any injector action....or worse.

Lemme know the "N" number on your ECU,the color of the injector plugs and where the little locater notch is inside the injector electrical socket.Also,be sure the "N" number on the ECU matches the "N" numbers on the various engine parts,like AFM,BAC,ect.......

 

N333 ECU
N318 AFM, boost, knock

injectors have red tops and locator is bottom right.

harness plugs are red and match with the slot

from this ive gathered i have 88 engine/injectors/ecu
so it should be the high impedence that dont require a resistor

 

I really hope you figure out your problem. I hate to see a car so close to completion and to run into a problem like that.

 

That would be an 88 ECU and an early 87 AFM.....no biggie.
Your right,its high impedence with no resistor pack and an offset pin on the injector plug.

I dont know if the injector pulse is tied into this,but I do know the fuel pump activation is........
Try holding the AFM door open a little while someone cranks the engine.On the S4,the door has to open a little before the ECU will fire the pump up....it could be the same for the injectors.If you have any vacuum leaks,or the AFM door is cruddy/sticking,that might be holding you up.

Did you have the injectors tested/cleaned prior to installing the engine?Unlikely that both primary injectors are bad,but not impossible.

Are you 100% sure the fuel lines are routed correctly?It sounds obvious,but Ive caught more than a couple people that accidentally pushed the fuel feed line onto the wrong metal fitting,then couldnt start their engine.They either filled the crankcase with fuel through the vapor recovery line,or they backed up the incoming fuel against the regulator by getting the feed/return lines backwards.

And just to double check........you have one of the big,black "power-on" wires from the main relay hooked up to the main power wire for the 4 injectors,right?
The 4 injectors are fed power from this black/yellow wire,its the same big power wire that runs the 3 coils.On the big right side harness,this injector power wire terminates before the yellow ECU gang plug,on an under-dash plug furthur up the harness.Be sure that power is flowing from the main relay to that big black/yellow wire.
The other big main relay "power-on" wire is black/white and juices up all the smog solenoids.The solenoid main wire is in the same vicinity on the big left side harness.It is very similar to the injector power wire(black/white),so be sure that its not that wire that your sending your power into.....(unless you are retaining all the smog crap)

 

the fuel line thing came to my attention, i originally had it routed with the inlet being the larger of the two pipes. now knowing it should feed the primary rail first i'm going to go double check that it has the proper route.

also i'll try the AFM thing, i tried to patch up a lot of my vacuum leaks but its certainly possible that there are others.

again thanks for all the help

 

ok AFM thing didnt work and i have my fuel lines routed properly.


i have a question about this plug..i beleive it goes to some sort of rich/lean mixture screw on the FC, can i leave this unplugged?
http://memimage.cardomain.net/member...08_67_full.jpg

also do not have an o2 sensor plugged in yet, but not sure if that would completely kill the injectors?

 

Sorry for interupting the discussion, but I have a quick question since its a process that you've aready went through. I'm fixing the passenger side of my s5 harness and I ended up with 2 wires that were cut by the previous owner, I dont know if he cut them before he gave them to me, but I was told that it leads to the "grounds". Is this a required part of the harness, because my spare harness also has that cut...
Again, sorry for the interuption...

ps. Good luck on your swap, sounds like you are almost there.

 

are they black wires near the injectors and other sensors on top of the engine?

if so yes they are required to be grounded.

 

aww crap... do the two black wires end up at 1 plug or is it 2?

 

they come together at an eyelet which gets bolted to the engine as a ground.

 

What color are the wires leading to that plug?My book shows brown/white, brown/black and green black.

I thought(could be wrong) that the later S4 engines didnt have the variable resistor?My 87 TII engine had it,but it was an early 87 with low impedence injectors.
If the late S4 also requires the injector variable resistor,Id bet real money that you need it to be there.The R-L screw controls the injector pulse width at idle,and I would think that having it gone,would affect things.....


Drunken,Im not aware of any grounds on the big portion of the left harness.There are several grounds near the end of the harness,on top of the engine block,near the mess of plugs that run the rats nest.Just crimp on some ring terminals and bolt them down,it doesnt matter if they are seperated or together.
If you can get a picture of the harness and point out the wires,it'd be much easier.

 

colors are correct. i'm wondering if i could simply jumper the connection or if the actual switch would be required...

 

Probably shouldnt jumper them.
The resistor sends a varied signal to the ECU depending on the position of the dial.At no point in its adjustment range is there a closed,no resistance signal sent.
And I confirmed that all S4 cars have the variable resistor,as there was an 88 in the local wrecking yard with the same plug....but no resistor dial.

A cheap part,I say its not worth the risk of damaging the injector drivers/ECU....just round one up from the wrecking yard or Ebay.

 

found a ground strap on my transmission that was hiding. bolts to the top and has a white connector, looks male.

i dont recall seeing anywhere on my harness to plug this sucker in...any insight?

 

UPDATE:::::

propped the throttle all the way open and turned the CAS by hand...primary injectors ARE pulsing.

so it sounds like i've got a severely out of calibration TPS lol. gonna go see what kind of progress i can make now...

 

ok..im at the point where it cranks right up, revs to 2krpm then putters out and dies, the tps is adjusted virtually all the way out...gonna take some serious tweaking

 

Well,thats a start,at least you know they are firing SOME fuel!

The S4 TPS can really screw things up when it gets out of whack.My brother's 86 Base got a little off and the damn thing would barely idle below 1500RPM,damn thing sounded like a bridgeport.......One half turn on the TPS screw, and it was purring like a kitten.

The momentary running,then dying reminds me of a bad fuel pump relay or AFM signal.The initial primer charge to the fuel pump will keep the engine running for just a couple seconds,then is tapers down to nothing and dies as the pressure is bled from the system.
Try jumpering the little yellow 2 wire plug by the pass. side strut tower, with a paperclip.Thats the fuel pump test port,and it will keep the pump running full time when you jumper it with the key on....