Joshh

hey guys,

So ive got a 1993 FD3S that is converted to single turbo. all was working just fine in the fall when I parked the car for the winter. over the winter I removed the UIM, and unclipped the engine wiring harness.. I cut off all the unneccesary connectors from the rats nest and capped each wire. Now I have plugged all the conncectors back in to the proper connections.

When I turn the key in the ignition to the 'on' position without cranking, usually the fuel pump would prime the fuel system.. but now the injectors (all four of them) are stuck open and are continually spraying. I have searched for a short in the harness to no end with no luck.

Does anyone have any other ideas? or any other ways to check for a short other than visual inspection that may be more thorough?

Thanks for the help!

XLR8

iTrader: (52)

There may be a few things going on here. I will try to advise in order of each one.

1. When you performed the single turbo wiring harness over the winter, you only removed the plugs and "capped" the wires. I know some have done this, and I find its not a good idea. Wire "caps"come loose, work their way around and can cause issues. The engine, drivetrain and harness see's constant heat fluctuation and vibration. You would be surprised how things move around. When I performed my single harness I removed ALL wires that weren't used and depinned them from the ECU plug. I would suggest the same to everyone. I realize it's extra work, but it greatly reduces the possibility of floating leads.

2. I have had my injectors stuck open. In fact, my car did the exact same thing as yours. Every time I turned on the key, my re-wired fuel pump kicked on, flooding my engine with fuel. The easy fix for unsticking injectors is this. Take a 9v battery, attach leads to both positive & negative on the battery, pull off each injector plugs and apply the leads to each pin on the injector. Polarity doesn't matter so you can't get them backwards. You should hear the injector snap open and closed when voltage is applied and removed. This SHOULD free them up. Deflood the engine by removing the plugs, pull the EGI fuse, and crank it over. The gas will spit out so if you want to put a towel down there. Replace everything and it should fire up. If the injectors don't free, then they are physically stuck and will need to be removed for cleaning/replacement.

If you snap the injectors as outlined above, and still have flooding issues then there is a wiring problem. Essentially, the injectors are given a constant voltage. The ECU toggles the ground to make each injector open during operation. If the injectors are constantly open while the key is on, then its possible the firing wires are getting grounded in some other way. An easy way to test this is get a stethascope and put it on an injector while a friend turns on the key. If the injector snaps open, it's an obvious wiring issue.

Hope this helps..

Joshh

Thanks for the reply!

So I confirmed it to be a wiring issue. I just pulled off the injector plugs and turned the key to the on position. the fuel pump ran and the injectors were not spraying fuel this time. so that confirmed that they are closing at least.

However one question I have is normally prior to these issues, when the key was turned to the on position, the fuel pump would run for only a few seconds and stop. now it is continually running, could this be somehow causing this problem?

I have been told by a friend as well that the ground in the passenger footwell that attaches next to the ECU should be left unplugged. Is this accurate?

I will pull the harness this weekend and pull those wires out. if it was possible that this was a short, could this have now damaged my power FC? more specifically the injector driver in the PFC?

Thanks!

XLR8

iTrader: (52)

The ground that attaches next to the ECU is the ground for the ECU. Not only should it be attached, but I re-enforced it with a strap from my relocated battery. I noticed a more stable idle.

As far as damage to the PFC goes, I don't know. The 4 trigger wires the ECU uses are neutral with a triggered ground. If it received a + signal, I don't know if the EGI fuse would blow or if it would effect something internal.