83 280ZX floods out

[scottsman]

Hello to all! I am working on an 83 280ZX that was running fine for a month and suddenly went to flooding out one day when the owner tried to start it. The owner said it was great until this happened. I have had the entire fuel injection system off and sent out the injectors for service, all new hoses, fuel filter and great fuel pressure. I did all this prior to the problem. It came to me originally as a no start. That turned out to be poor grounds to the body and the alt not putting out good volts after start. Now all the fuel injectors flow all the time the key is on. If I unplug them they stop, (they all ohm good) I found some corrosion in the ECM from a windshield leak, so I tried another ECM, no luck....any idea's here??? Scatching head :lick: Curt

[BuDavid]

what about the way the engine run after starting it? too much fule? black smoke? u might have wiring problem, coz only one injector should flow when the key is on before starting (the seventh for the cold start right after the throttle valve on top)

but i cant c that u noticed that any wiring modifications??!

[zmom99]

You might check into your fuel regulator. The diaphram goes and you get stuck open and all your fuel goes into your injectors rather than excess returning to your tank.

[scottsman]

I might not have been clear in previous posting. The vehicle ran well no smoke or overfueling then one day suddenly it would not start and flooded out so badly, it hydrolocked the engine. When I got it I discovered that all six fuel injectors flow fuel all the time the key is on. I had not been able to shut them down until I unplugged each injector wire. It acts like the injector driver in the ECM is failed, but I tried another ECM with the same results. So here I am still scatching my head Curt

[kenz240z]

Have you tried another set of injectors? Doesn't seem likely that all 6 would go bad at once, but maybe they are stuck open?

[BuDavid]

it would be good to find an osciloscope, but in regular case u can use an AC volt meter a connect it with one plug of one of the flooding injectors, check weather the signal varies while u start the engine or u can just open the flow meter cap and manually turn the flap anti clock wise to see if there will be any difference in th evoltage feeding the injectors!

sorry if i could not help

Mohammed

[Arne]

I'm not all that familiar with the ZX injection (even though my 240Z had it in it when I got it) so I don't know whether there are any other inputs that might override the ECU. Failed thermo-time switch? Bad cold start assist system? Since changing the ECU doesn't help, I'd be looking for anything else that can send an 'open' signal to the injectors.

[scottsman]

Progress!! Today I found that a noid light attached to any FI wire will flash dimly and then go steady very brightly on cranking the engine and stay that way as long as the key is on. I am going to unplug each sensor crank it and see if the condition changes, I suspect a short in the ECM harness now but didnt have time to it check further. I will post a fix when I get it.

Oh thanks for all the inputs so far! Curt

[scottsman]

Hello to all ZXer's Well at last I found the culprit. After my last post I went down to shop saturday morning (the only time I have for fiddling lately!) I had determined to find that elusive short and started with unplugging each sensor and turning on the key to see if the condition changed. After about 30 mins the fuel pump quit and the noid light fizzed out suddely! I smelled smoke from inside the car! (I was shaking the wiring harness a lot) I guess I made the short worse, the ECM went up in smoke! At this point I was :surprised

oh no!! I didnt want to cook my only remaining ECM so I resorted to ohming wires to find it. After another hour I noticed the MAF wiring harness was real tight in one area. As I looked closer I could see the a/c discharge line going to the condenser had the harness smashed tightly to the engine comp wall on the driver side just in frt of the strut tower. I cut the tape off and found the B+ feedback wire from the MAF (white/green stripe) had been cut into by the hose crimp on the a/c hose which also was firmly againt the wall. I would have never found this had I not resorted to ohming each wire. I dont how many hour I looked for this thing :stupid: Sorry for the long post I hope this may help someone else some day. Curt