fuel injection problems

[88hatchblack]

ok, here's the deal- it's long and kinda complicated so sorry.

I have the non-HO firing order motor from my sig rigged up to run with a fuel injected computer. i just switched injectors 5 and 3, and injectors 4 and 7. which means though the injectors fire 13726548, they are in different places so they fire 15426378. i did this by extending the injector harness wires and switching them around. this seems like it should work- does anyone see a problem with it? the car is definately not running like it should. i'm pretty sure it's a fuel-injection problem. if you unplug injectors 1 or 2 the car dies at idle. if you unplug any of the other ones, no much happens. also, what should the injector voltages be at idle? aren't the injectors ground triggered or something? so i should get some voltage between the injector gound and the positive battery terminal at idle- right? sorry so many questions and soo confusing. Thanks in advance; ANY input will be appreciated!

 

[88hatchblack]

anyone?

 

[88hatchblack]

cmon...

 

[jrichker]

The injector red wires run at battery voltage, and the computer grounds each injector to fire it.

The computer does not furnish power to any actuator, only ground. That prevents a lot of problems and keeps the computer from being easily damaged from faults in the wiring.

Drawing Courtsey of Tmoss & Stang&2birds.

Do a cylinder balance test to locate cylinders that are not functioning properly.

Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 99 for everything OK, or the number of the failing cylinder such as 22 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures. Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at Walmart.