Committed a Cardinal sin

[FiatFan]

I have a crank but won't start issue and I am not real clear on electrical diagnostics. I was checking resistance with an OHM meter and touched the probes to the harness which I later read never to do? My question is how do I check to see if I damaged the ECU or something else? I was messing with the Cold Start Injector and the Fuel injector connectors? Help

[spider2081]

I was checking resistance with an OHM meter and touched the probes to the harness which I later read never to do?

If you used a digital ohm meter I doubt you damaged anything. Most digital ohm meters are designed to protect the circuits they are used in.
Also the ECU is a pretty bullet proof unit. They are not easily damaged and seldom fail.

[FiatFan]

Thanks, so I have a crank but no start where should I start?

[mighty7]

there is a really nice flow chart in the service manual that walks you through what to check and how to check it for a car that won't start. I used it a couple times. Once it was a relay, another the fuel pump. Both issues prevented fuel getting to the cylinder. With cranking and not starting it is either no spark or no fuel (that's it). If there is spark and fuel it will combust. It may not combust well if there are mixture and timing issues but if there is spark and fuel it will combust.

See if you can't get a service manual and walk down the flow chart. It will quickly direct you to the issue.

[spider2081]

Thanks, so I have a crank but no start where should I start?

Not knowing the cars history its hard to say
I would visually inspect the ignition switch connector that is about 6 inches behind the ignition switch. I would remove remove the distributor cap and inspect inside. After cranking for a bit remove the spark plugs and inspect. Especially look for indications of fuel.
As previously mentioned using a troubleshooting guide is very helpful.
If you are not a member of Mirafiori.com I would join that site. They have a reference library that is very complete. You have to be a member to view the library.

[aj81spider]

There is also a FI diagnostics manual. If you don't have it you should pick it up. I have an electronic copy I can email you (it's not in the most convenient format, but you can print it out). If you'd like it, PM me with your email address.

[FiatFan]

Thanks, so I have a crank but no start where should I start?

Not knowing the cars history its hard to say
I would visually inspect the ignition switch connector that is about 6 inches behind the ignition switch. I would remove remove the distributor cap and inspect inside. After cranking for a bit remove the spark plugs and inspect. Especially look for indications of fuel.
As previously mentioned using a troubleshooting guide is very helpful.
If you are not a member of Mirafiori.com I would join that site. They have a reference library that is very complete. You have to be a member to view the library.

Where do you register I don't see a button to sign up?

[spider2081]

If you are on the home page click on Forum there you sill see the "register" click on that.

[kimu]

I have the same issue, all signs pointing to a bad ECU.

I have an full FI diagnostic and Electrical Troubleshooting manual with colored wiring. PM if you need it.

[stuartrubin]

Why would touching anything with a multimeter probe be a cardinal sin? There's probably 10 or 100 mega ohms across the probes. I'm curious what the fear is. Thanks!

[TX82FIAT]

As other have mentioned, there is a problem solving flowchart. Stick to the basics. Are you getting fuel, air and spark. You know you have juice to the starter so work your way forward to the plugs. The check fuel and finally air. Has the car sat for any period of time? when was the last time it ran and what has changed since then?

[DieselSpider]

Why would touching anything with a multimeter probe be a cardinal sin? There's probably 10 or 100 mega ohms across the probes. I'm curious what the fear is. Thanks!

Most would probably get into trouble trying to check resistance with the system powered up so that they were creating a short circuit. A lot depends on the meter being used as some even high quality meters still use a fairly high amperage fuse instead of protective circuitry that would prevent you from creating a short in the first place.

[stuartrubin]

Oh, I see. Measuring resistance with a "live" circuit could definitely cause problems (and at best completely throw off your measurements)!