I have a new to me pair of 49HOs. One doesnt idle well and takes a few tries to start. Fuel filters fresh, fuel pumps work, tank vent clear.

Hooked up Rhinda and get no codes other than trim, fuel tank level, and other non-hooked up sender things.

Would Rhinda pickup a bad IAC, Fuel injector, or plug spark issues? I hate to do parts swaps blind if it knows and can pinpoint issues.

If not I will test each plug for spark and replace IAC before pulling injectors and plugs for a clean up.

Thanks - Swampy

You should be able to use the Techmate to do a cylinder drop test, where you deactivate one cylinder at a time, and see what happens. If there's one cylinder whose deactivation does not worsen the way it's running, then that cylinder is likely misfiring or not firing at all.

You can also use the Techmate to "exercise" the IAC, to run it to the inner and outer limits of its range of motion.

Thanks DR! I will try both before I start swapping stuff. Good exercise as I need to learn this stuff for when I go to bahamas and keys and need to be self reliant. Learning!

FWIW - I also had that motors water pump replaced. Figured out this weekend that the New pump doesnt have a port for the water PSI sensor so nothing is plugged in .... going to fix that situation tonight and see if anything changes there. Not sure if water PSI on raw pump could put it into some sort of safety mode.

Pretty sure the low water pressure will put it in safe mode but shouldn't make it hard to start.

Correct... guardian mode should limit overall power but should not make it hard to start at all.

Rhinda shows 100% available power without the water PSI info....weird...but I made an adaptor so I can plug it back in to the new pump this weekend. This will be step one.

Since these are new to me motors, I dont know how old the plugs are, how healthy the injectors are, or anything. I agree that the water PSI thing should not cause starting issues.

The IAC test on Rhinda showed numbers all over the place 40-99% at idle. Will replace IAC since I have one. This will be step two and will see if anything changes.

Then plugs and possible injector cleaning.

Swamp,

Do the new plugs and injector cleaning. Just because. Same as the IAC. Cheap insurance and "new" injectors never hurt anything. Smitty does AMAZING work.

Thanks. Brad.

Replaced water PSI sensor....seems a little better. RPMs still "hunt" until it warms up so will do IAC next. Need to order plugs - do I really have to pay merc $15 each WTF? Can someone cross reference them for me so I can get em from summit?

Swamp,

THIS is what’s in mine.

Thanks. Brad.

Thanks Brad.
Plugs and oil change this weekend....see what's up then. IF she smooths out I will try the Rhinda test each injector thing and see if I can hear the difference and ID if a bad injector.