RoninRX7

I just installed an Rtek 1.7 ECU code N332 into my 88 10th AE which originally came with an N333. Along with a set of 720CC LOW impendance injectors. I wired in a 10Ohm/10watt ceramic coated resistor into one side of the injector clip on each side. Then after doing that was when i installed the ECU with the battery disconnected.

Now, when i try to start it, the rpms go to about 1500-2000 rpms and hover there for a few seconds, and then the car will turn off. I tried pressing the gas pedal, but i still cannot keep it running.

Can anyone help? Im really stumped. Thanks

RoninRX7

Okay, i got the car to stay running, it turns out there is one point in the throttle where it will stay running. Once it gets warmed up it idles fine.

HOWEVER, when im driving the car, i can feel over 3 grand when it doesnt have the secondaries on. At some points in the throttle it does turn the secondary injectors on. I have a narrow band gauge in the car right now and it wont even show a reading over 3k until the secondaries momentarily turn on, then it says about the correct AFR, and once they turn off again it goes back to very lean.

What do i need to do to fix this? Thanks

SureShot

I thought the S4's had a resistor block already in the harness under the air cleaner.
You may be adding redundant resistors.

-Bill

t04tii

Can you post a picture of how you wired in the resistor...10W may not be big enough without a heat sink. Are the primaries still hi-impedance?

SureShot

10 Ohm 10 Watt resistors worked great on my S5.
You'd have to run WOT at full load for a few minutes straight to get them very warm.

RoninRX7

heres how it was wired. The top wire is done, and the bottom is not in the first pic, then the second and third show them connected to the harness.

t04tii

That will work, but I have the feeling the resistors may get to hot. The resistance can be off or you can ruin the resistor if it gets too hot. I'll look though the FSM and see if I can wire a resistor pack up for you to just plug in. I'll send you a PM later today.

Wanked_FC

iTrader: (1)

A lot of guys wire the resister by the ecu in the cabin. No worries about heat and engine bay stuff.

RoninRX7

nice! thanks, im pretty clueless on how to fix this thing.

RoninRX7

it was running really low fuel pressure after i installed the 720's as well. Something like 15psi when i start the car up. i turned it up to about 28 at idle, but after 3.5-4k the AFR gauge will go from rich all the way down to lean progressively, and the engine kinda shudders.

thashogunlpc

im doing the same thing to my 10th ae.
do you know what colour the injector wires are at the ecu?
i want to put my resistor in there so theres no heat porblems.
thanks

t04tii

The issue is not with the heat of the engine bay hurting the resistors. When you resist electricity things get hot. The issue is that the RESISTOR will get hot an fry itself. It needs to be in a heat sink to dissipate the heat (Just like the stock one is hugely overkill in size and is in a aluminum housing to help dissipate the heat. Do this the correct way and wire in the stock resistor pack.

If I had a stock s5 around I would do a writeup. Searching does nothing but show me people either don't know what impedance is or how to fix the injector issues.
I'll look around at the s5 wiring diagram and see if I can give you more info.

RoninRX7

so does that mean i should move them to the inside of the car? Do you think they fried because they were in the engine bay? I have a series 5 vert parts car, is there something i can take off of that? Also, i have access to an S4 N/A, is there a way i could take the resistor box off of that? How would i hook it up to my 88? thanks.

gxl90rx7

iTrader: (1)

I have 6 ohm resistors on mine due to staging hesitation problems, a few have been seeing problems with the 10 ohm resistors. FYI The stock resistor pack uses 6 ohm resistors, measured them myself

you dont need heat sink even with 10w resistors as long as you have them in the cabin, not the engine bay.. if you do the calculations about 1.12 A will be going through the resistors at 100% duty cycle (14V/12.5ohms), which comes out to 15.68 watts (1.12A*14V). But this only occurs at 100% duty cycle. the ECU only puts out 85% max, and that only briefly. you will only get problems if you are wot at max boost for like several minutes straight, higly unlikely

but you should definitely move the resistors to the cabin to prevent them from overheating. the FSM should have the right wires to cut into

JWteknix

iTrader: (2)

i thought s5 only had to run resisters my s4 doesnt have any resisters in my injector wiring and it runs perfect

gxl90rx7

iTrader: (1)

i think only 87 and early 88 models had stock resistor pack. if you have it stock, it would be next to the AFM on the strut tower ibelieve

ziig

iTrader: (1)

does anyone know the part number for the resistor? I have one home but not sure where it goes