You're reaching about the same conclusion I have. Sometimes the engine seems to be lacking a little power at times, and thus feels like there's a fuel delivery problem.

I was investigating the switches in the relay. There are actually 3 resistors in there, two of which power the switch which gives power to the fuel pump (I practically have the blasted circuit diagram memorized from trying to get a solid conclusion on this :-P), one for the ignition switch in the starting (cranking) position, and another for the "on" position. The other resistor closes a switch which diverts power to the ECU itself, the crank position sensor, air flow sensor, oxygen sensor, and whatever else... The only thing between the battery and the first switch (w/ the fuel pump on it) is the ignition switch; however, on the same circuit, that source of power goes to the ignition coil, distributor, etc.., and also on that circuit is the check engine light.

I've been all over this thing with a multimeter, and the voltage to the second switch (air flow, crank pos., etc...) drops from ~12v to ~9.5v when the throttle is opened up. The other switch gains maybe from ~12v to ~13v. I'm not sure if that's normal or not, but the one that drops doesn't seem to be the problem.

The way the routine works is when cranking, the one resistor closes the fuel pump switch, and the other switch also gets closed for the sensors and ECU. When the engine is running, the ECU completes the ground of the remaining resistor, which also closes the one with the fuel pump on it.

So basically, unless there's some electrical issue which causes the ECU confusion or power loss or something, perhaps on that circuit with the check engine light...or if it's possible the fuel pump itself is going and the check engine light is coming on because the ECU detects a fault via other sensors (this is what makes me uncertain, and my conception of electricity is peaking around these bloody diagrams hehe), then the ECU looks to be the next logical culprit. Mind you, I got that replacement relay off a 92 in the junkyard, and of course, it's computer would not work because it's the DOHC engine.

So yeah...if I were taking a test or something, I'd guess ECU at this point....just neither me nor my friend (whose car this is) are made of money, and I'd hate to have him blow $250 (cheapest I can find new) on a new ECU if I'm not absolutely positive.

I also took the ECU out and had a look myself...and I would feel better if I too, had seen black deposits or something, but all I saw was a small bit of dust, which I blew out, and maybe the tiniest bit of corrosion...but nothing suspect...but then again, we know from these machines we type on here, that circuitry does not need to be black to fail...*shrug*... I guess the other thing keeping me uncertain is...well ECUs don't typically fail, do they? Ah well... I guess it's time to flip a coin or two.

This sounds familiar!

Had the same problem with my Magna a couple of years ago. Intermittent brief cut out/stalling hesitation with associated clicking sound from behind the glovebox area.

For me it turned out to be the ECU.

Almost the same problems as with mine (http://www.mitsubishi-forums.com/t27497-clicking-from-g-box-and-stalling.htm), especially the clicking from the fuel regulator. I have changed the coil, distributor, plug leads, plugs and regulator itself. I am changing the engine computer in the next few days. I am willing to bet my left nut that it was the computer all along and probably same thing your encountering at the moment. Save your money get a new engine computer, trust me on this one it's not anything else i can think of apart from the fuel pump but this problem i have mainly happens when i try to start the car and it clicks and after shutdown it does that click again and then about 7 seconds later click again. I think finally i have it licked. Will leave an update about how it went in case it of help to you.

I've been brushing up on my electricity knowledge and going over the circuit diagram, and I'm having one heck of a time believing it's anything but the ECU as well. My friend found one for $65 on ebay (let's hope the used part is not a jinx), and it should arrive in a couple days. I'll also post the results when it arrives and I install it.

Mine turned out to be the ECU so maybe it could be the same with yours

Tailfin after fitting the ECU and it runs again

you can wash the dirty marks and smudges
we put on your car while we all had a go at fixing it :grouphug: :thumbsup:

G'ah...sorry forgot all about putting a reply up here. Actually, the ECU came, I installed it, behavior did not change a bit!

I'm suspicious of the alternator after all this. I did test it, and it was over 13v, but just barely. I did not think that was enough to cause such a mess, but perhaps it is. I can't think of anything else even remotely related save the fuel pump. Madness, it is...but attention has gone away from this vehicle, as the transmission is feeling like it's going. I saw in the manual that there is a specific fluid to use with these engines, so that might be worth a shot, but otherwise, this thing is turning into a story to be told around a dinner table full of car nerds. Thanks again for the assistance. I'll keep this thread in the back of my mind in case anything further develops.