'89 240 DL - Gas Flooding Problem

[Craign]

1989 240 DL, 205,000 mi., 65,000 on re-built engine. Car is driven 5 days a week. Recently driven off the freeway after 15 mi. to a stop light. Turned right onto street and car sputtered and died. Gas was leaking from the air intake duct. Technician has told me he spent 5-6 hours diagnosing problem. Says that it is a combination of the cold start fuel injector mechanically failing and that the computer that controls the injectors is bad. He said that taking the computer control off the injector that he manually operated the fuel pump and the cold start injector is not closing off and fuel is being dumped through it. This did not make sense to me. I asked if the computer also controlled the closing of the injector as well as the opening of it. He said that without the computer to control it that it should still shut. He said that the other injectors are dumping fuel into the cylinders and that's why he believes the computer to be bad. Is this an accurate diagnosis, or could this gas flooding problem be some other problem?

[billofdurham]

His diagnosis may be correct - it should be if it took him that long to do it.

He said that taking the computer control off the injector that he manually operated the fuel pump and the cold start injector is not closing off and fuel is being dumped through it. This did not make sense to me.

I am a little lost with this statement. Did he mean that he took the computer control off the cold start injector or one of the other injectors? If it was the cold start injector it should not be affected by the computer and he was not testing it the correct way. If it was one, and only one, of the other injectors he should not assume that they are all faulty because one is.

As fuel was coming out of the air intake duct I would suspect that the problem would be the cold start injector as it is located in the intake manifold just down from the air intake.

The correct way to test the cold start injector is to remove it with the engine cold, leaving the fuel and electric supply connected. Hold the injector over a container e.g. a glass jar, switch on the ignition and run the starter motor. With an engine temperature of -4F the cold start injector should spray fuel for about 12 seconds. Obviously, at this time of year, the engine should not be this cold so the fuel spray will be less but it should spray fuel up to an engine temperature of 95F. When it has stopped spraying fuel stop running the starter motor but watch the injector to see if it is leaking. This is a test that any competent person can carry out in about 10 minutes.

To test the injectors they should be removed with the fuel lines connected.
Go to the airflow sensor, which is located above the air filter and underneath the air pipe to the manifold. With the ignition on but the engine not running, lift the airflow sensor plate so that the fuel distributor opens allowing fuel to pass to the injectors. The injectors should not leak more than one drop of fuel every 15 seconds. Any injector leaking should be replaced. Again a fairly simple test which should not take a competent person too long to carry out. However, if all the injectors are leaking the reason may be excessive rest pressure in the system. This can only be checked with a suitable pressure gauge.

Hope this helps.

Bill.