3 Questions on Diagnostic tests

[Pat]

1. How good is the CAT tests performed by Muffler shops using a probe and pressure gage? Will it pass a bad cat?

2. Is there a test for COPs?

3. Can a bad fuel injector(s) be identified while still on the engine or must it be tested using bench equipment?

Yes, I'm still wrestling with my car's bogging problem.

[MM_BKK]

1 - That depends on the shop's reputation. Without feedback or testimonial, it's hard to say.

2 - Usually, when COPs are bad, you'll get the symptom of misfire or spark blow outs.

3 - You can test the injector on the car by disconnecting them one at a time while the engine is idling and listen for slight drop in rpm. More accurate way is to have someone watch the scangauge rpm display while doing it. If there's no change in rpm, that injector is probably bad. You can then confirm it with an ohm meter to make sure it's not reading open. Open = Bad
It's very rare that fuel injectors go bad.

3a - You can also test the fuel injector wiring to make sure you're getting the firing signal from the PCM by using Fuel Injectoion Noid light test kit.

Do you have a fuel pressure gauge installed. What is your FP at said bogging rpm?
Better yet, if you have an Xcal 2 or 3. Do some datalog with it and post it here. I'm sure someone can tell if there's something wrong in it.

My hunch is on either weak fuel pressure or restrictive exhaust.

[justbob]

Very good response there^, I agree fully. Get that fuel delivery checked first.

[Spectragod]

1. How good is the CAT tests performed by Muffler shops using a probe and pressure gage? Will it pass a bad cat?

2. Is there a test for COPs?

3. Can a bad fuel injector(s) be identified while still on the engine or must it be tested using bench equipment?

Yes, I'm still wrestling with my car's bogging problem.

1. They will tell you if it's bad

2. Ford dealers have the service equipment to test them individually

3. Several tests can be done, the above posters nailed it.

That said, I have a stock set of cats with 17K on them and a stock set of injectors with the same mileage. If you need them, let me know, I'll hook you up........ dirt cheap.

[Pat]

Thanks, I'm going to do these things.

Regards,

Pat