Running Rich Injector

[hodunwun]

92 Metro, AT with l ltr engine. Has single throttle body fuel injection. Will not start due to excessive fuel passing by the injector when trying to start up. I mean a lot of fuel. It will run if the fuel line is taken of the throttle body and plugged and the feeding gas down the throat of the throttle body. Does any one have the specs for doing a bench test on the injector? Has anyone run accross this problem before that might have clue? So far I have tried three used injectors and another (used) throttle body assy from the exact same model setup. I have not tested the pressure valve sensor as there is no specs to do so. The book says that it is calibrated at the factory and not servicable. I have tried two used ones already. Nor have I tested the throttle position sensor. I am about the send the ecu in for testing but I thought someone here could send me in the right direction for this specific problem.

Doug V

[geozukigti]

The pressure valve is run by vacuum, but won't flood an engine if it's faulty. You're probably looking at a bad fuel injector resistor.

[hodunwun]

Thanks Geo for the info. Is the injector resistor in the ecu or some other place where I can check the resistance?
Doug

[geozukigti]

It's the big heat-sinked piece of metal behind the drivers side strut tower. It should have a big round plug attached to it. Can't miss it.

[hodunwun]

Geo, I got it off and put an ohm meter accrossed it - 2.3 ohms. Pulled another off the car I drive (93 Metro 1 ltr.) that I know works. I got the same ohms measurement. Ofcourse this test is not under load, but still it suggests strongly that the resistor is ok. Any other ideas please? I am about the send in the ecm for testing. What do you think?
Thanks for your attention.
Doug

[geozukigti]

Perhaps find a place than you an stick a scan tool on it, and see what's causing the rich mixture. Besides the resistor, the computer could be to blame also. Check the vacuum lines on the fuel pressure regulator also. Could also be the fuel pressure regulator is no good.

[hodunwun]

The latest for anyone who might be following this thread. Sent in the ecu for testing and it was fine. Blew out fuel return line thinking that if it was plugged or check valve was not working this would back up fuel from the injector but air blast to line to tank had the gas in tank bubbling. Still have to test the return fuel passage in the throttle body itself. After installing the ecu I will check for code though I don't expect any to be there. Since the throttle body now on the car replaced the original that was floodiing and it still floods with this second throttle body, I am assuming the pressure regulator is ok. But I will set up a pressure gauge to check out the actual pressure which is suppose to be around 11 lbs. If it isn''t then I will open up the pressure regulator which is in the throttle body. I find it hard to believe that both pressure regulators, the one in this throttle body and the one in the orginal throttle body would both be bad, but could be. Any other ideas please. The car still floods a half inch of gas on the throttle plate when trying to start the engine.
Doug

[hodunwun]

ECU came back from testing place with a clean bill of health. Still floods. Tried changing the spring tension of the pressure regulator valve in the throttle body. No help. I have noted that the injector floods the throttle body even before I turn the engine over with the starter. Got the car to run in idle cause according to the tbi diagram there is a small gas bypass for the idle circuit. At idle I have a constant 12 volts to the injector. So I am still thinking ecu, the injector control circuit. So I will call the outfit that tested it in Texas and see what he says. Maybe someone local can bench test for just that circuit. Or maybe just go ahead and get a rebuilt ecu. Any feedback. ??