Bought a S5 NA witha S4 T2 engine installed in it. It runs rich as can be and I remembered that the person that I bought it from said that he had upgraded secondary fuel injectors. I pulled the injectors out and found red-top high impedance in the primaries and black-top low impedance in the secondaries. I am curious aout which ones should really be in there. The engine harness is a S4 Turbo and I assume that the rest of the car is wired S5 since they all use round connectors.



Any input would be greatly appreciated.

what year harness is it?



the main thing is if it has the resistor pack (the yellow thing near the passenger side headlight).

What ECU is the car running?

ECU is N333. It does have a resistor pack installed on the car. As I can remember, my 87 T2 had a pack on it because I remember playing with it when I installe dmy microtech. But I was always under the conclusion that S4 had low-impedance while S5 had high impedance. My frilends 88 SE did not have a resistor pack. So I do not know.



As far as I can tell, the body harness is that of a S5 because all the connectors are round, not square. Tahts how someone told me to check, but I dont know.

Well, i found this site http://www.rotaryresurrection.com/rotary%2...r/injector.html and it appears the the High impedance injectors I have are from a S5 NT and have know idea what the low impedance ones are. The entier injector is black also. Those are the ones that he said that he upgraded.



If I put a high impedance injector on a circuit that has the resistor pack installed, would that make the car run rich. The injectors do pulse (Had the injectors off the car, but on the rail and saw the fuel spray) but the all black ones look like they spray more. I also switched the injectors around and the car ran alot worse with the low impedance as the primaries.

Without some sort of fuel computer, the upgraded injectors are just going to dump more fuel with the ECU giving them the same injector pulse as the stock ones. How many psi boost are you running?

I dont know how much I am running because I havnt been able to drive the car. It is an extended street port with solid corners and 3mm apex seals, so I can run whatever I want, but with the stock ECU, I am planning on running 15 psi.



But the upgraded injectors are only the secondary, not the primaries. I thought that the secondaries only kicked in at 3500rpms and x amount of boost or whatever, not at idle, which is where I have a problme right now.



Reading some more on that site, the N333 is a high impedance ECU, so I will check and see if the resistor pack is installed I guess by using a continutity tester, and if it is, I will leave the secondary injectors hooked up to the resistors (low impedance black ones) and just run a jumper wire to bypass the resistors for the primaries (high impedance red-top) then in theroy, the ECU will see both as being high impedance.



Also, I am still wondering if having a high impedance injectors with aq resistor will make it put out 2x as much fuel. When I was cranking on it to see if the injectors were even flowing, I noticed that they were shooting alot of fuel out for a long time. But the low impedance looked like it was still shooting more fuel, but for a shorter time.

WEll, the resistor pack that I always thought of isnt there. There is ones, but it isnt a 1 input, 4 output one like I rememebr on my 87 T2. So I guess that it does not have a pack on it. I also just ran the numbers on the side of the injectors and came up with them both being 550s, 2 low, and 2 high. So since I guess that the body harness is a S5, it wouldnt have the resistor box, so I am just going to wire some 10K/10w resistors inline with the low impedance and see if that helps.

that should work

Well, it wont even start now. It actually seems like my fuel pump isnt kicking on all the time. I had a clear line in between the fuel rails, and no fuel was flowing through it when it was trying to idle. So I am hooking up a fuel pressure gauge in the morning and see whats going on. Damn these conversions.