charliegt

A while ago I found out that a previous owner of my car (94 touring model) had cut the wires at the ECU that go to the rear injectors. Then, taken the wires from the rear primary and secondary injectors and spliced them into the wires for the front injectors (primary to primary, and secondary to secondary).

They had then taken the primary and secondary rear leads coming from the ECU and combined them into one wire, that was run through the dash to the driver's side.

Does anyone have any idea what the purpose of this would be?

-Charlie

dgeesaman

iTrader: (7)

It's something that wasn't gonna work.

[edit] The reason it shouldn't work is because like spark, the fuel injectors alternate firing (front-rear-front-rear). If the wires to one rotor short or open circuit, you can't run both rotors with fuel injection at the same time. I'm not a pro on that subject, but my first impression is by injecting fuel into both rotors at the same time, it will cause bad performance, excessive unburned fuel, detonation, or something. As nasty as this idea sounds, I recommend buying a new engine wiring harness or fixing what you have.

Dave

charliegt

I agree it makes no sense at all. I found out about it a year ago and re-wired it to normal. The strange thing is that it ran perfect both ways. The only reason I even found out about it was that the wire on the driver's side came unplugged from whatever it was hooked to and caused the ECU to throw a code (since there was no feed to the ECU from the rear injectors).

Now, a year later I am having problems with my car running rich - and although it is a long shot I figured I'd ask about that to see if there is any known reason that someone would do it.

-Charlie

maxcooper

Is it true that both primary injectors don't fire at precisely the same times? I can see that it might be better to time the injector firing relative to the port opening for each rotor, but I am not certain that is what the stock ECU does. Anyone know for sure?

-Max

dgeesaman

iTrader: (7)

The chart on F-164 shows injector pulses - one labeled "FP" and another "RP", and the pulses are 180° out of phase with each other.

Assuming F stands for front, and R stands for Rear, then there's good evidence.

Dave

DaleClark

iTrader: (55)

He might have had an injector pulsewidth monitor in, or maybe a device that would cut fuel due to some event.

That is odd, though.

Dale

sonix7

I want to know too. Anyone know what this would do exactly. I am surprised the engine ran good like that. There is something we don't know or a strange phenomenom.

charliegt

The car was almost completely stock when I bought it (downpipe and exhaust were the only engine related mods).

When I contacted the previous owner (the guy who owned it right before me, there was one other owner that I don't have contact with) he said the only thing he could think of was that he thinks the rev limiter was removed at some point.

I never really thought about it too much after fixing it, but it doesn't make any sense - especially since the injectors most likely fire at different times.

-Charlie

nopistons94

removing the rev limiter is retarted though

scratchjunkie

we have a rev limiter?

maxcooper

Good to know. I'm convinced.

-Max

maxcooper

~8200 RPM in the stock ECU.

-Max

IRPerformance

iTrader: (41)

The injectors do share a common power wire. It should be black with a yellow or white stripe. If just that wire was cut, maybe there was an internal short in the harness and he took power from elsewhere? Either way, I would replace the harness or repair it the proper way.

GUITARJUNKIE28

the fc's cut fuel to the rear rotor in case of overboost.
do the fd's cut fuel to the rear rotor too?

if so, he might have been trying to up the boost.

firing both injectors at the same time is no bigggie. that's what the e6k does. you do get slightly better performance when they're fired sequentially, but i don't know if you'd be able to tell much difference.