Hello everyone, this is for a 2005 Ford ranger, 2.3L automatic. After a number of months of figuring out a "crank but no start" issue, a family friend discovered the engine runs fine if he manually did the IAC's job. It was replaced under warranty, got the new one on, and no joy. Some research later, we tried a trick found online: Key on for 5 seconds with one key, switched to a another key, key on for 5 seconds, then switch the key back to the first one and start the engine. The second or third time doing this, the engine started and ran fine for about 4-ish seconds then died. Checking the codes we got p0113 (Intake Air Temperature Sensor 1 Circuit High Input), p0122 (Throttle Position Sensor/Switch A Circuit Low Input) and p0511 (Idle Air Control Circuit).

This sounds like a wiring problem, or a bad sensor messing up the others? Worse case, the PCM. Where do I even start too troubleshoot this?

 

Welcome to the forum

2005 Rangers didn't get PATS(passive anti-theft system) so no transponder keys are needed, Ford skipped just this one year
So disregard the key on and off switching around thing, wouldn't apply to 2005 Ranger

Unplug the IAC Valve's wire connector and use a volt meter to test the two wires
Turn key on and test wires, should see 11-12volts, Red wire is +
The other wire is from the computer, and should be a ground with key ON
If you don't see 11-12volts then test Red wire to engine metal(ground), if thats reads 12v then it is most likely a computer issue, its not grounding the IAC Valve

Do you know what brand of IAC Valve they used to replace the old one?
Only Motorcraft(Ford) or Hitachi brands will work

On cold start the engine should idle at 1,100rpm, then idle will slowly go down as engine warms up, if that doesn't happen then IAC Valve or computer is not working

The other two codes shouldn't cause a running issue, so I would focus on the IAC valve issue first

If you can clear the codes how long does it take for them to come back?

 

Thanks for the reply Ron.

Oh, interesting.

When tested, it read about 11-ish volts (since the battery is running low) and 0 volts. So, looks good on that end.

I got mine from Standard. I was recommended by another to get Motorcraft as well. The price difference is noticeable. I mean, I get what I paid for, but its listed as compatible...

That's the main issue. I haven't been getting any codes for months since the engine would crank, but wouldn't start. It's only with that trick the engine finally ran for a good few seconds, stopped, then the codes showed up.

 

So first thing to do is the 50/50 test, always, when you have a crank but No Start

Spray fuel into the engine/intake
Try to start
If it starts and then dies you have a fuel delivery issue
If it doesn't start/fire, then its a Spark issue
50/50 instant results

Most common issue is fuel delivery, this can be clogged fuel filter or failing fuel pump, yes pump can be intermittent, so turning the key off and on several times might get it to work momentarily, which would explain why that worked
You can hear the fuel pump run from in the cab, a HUMMMMM from behind the cab, it should run for 2 seconds each time key is turned on, so repeated on/off may get it to run


Yes, BIG price difference between Motorcraft and any other brand, Hitachi is best alternative
Yes, other Brands are "compatible", meaning they bolt in and plug in, but electrically they are NOT compatible
IAC Valve can not cause a no start, so not your problem at the moment

 

So, an update here just in case it helps someone out there. I decided to replace the IAC with one from Motorcraft which i had to go direct to Ford to get the part and the gasket. It arrived a day ago, but it in, cleared the codes and tried to fire it up.

Cranks and ran for a bit, then died. However, it sounded so much better and the codes haven't come back up. The non-motorcraft IAC was definitely a part of problem. So lesson learned. Thanks again for the help Ron.

Once the texas heat dies down a bit, i need to trouble shoot a bit more. The enigne is back firing like mad, me and my older bother thinks it sounds a lot like a timing issue. Any more advice?

Heres a list of things done so far:

• Fuel pump is new and works. Pressure is at the rail. Gets proper power.
• Sprak plugs/wires are good and gets spark.
• Fuel filter is new w/ new fuel lines.
• Replaced the Fuel Inertia Switch, gets proper power.
• A family firend replace the crank sensor, stated that the timing was a bit off but half assed the alignment to a "good enough" point. (hmmm...)
• Before the battery died, engine was starting rough with bad back firing or ran for a few seconds then stops.

 

Double check the spark plug wiring and then check it again

Back fire into exhaust means there was a misfire and unburned air fuel mix was ignited in the the exhaust manifold by the next cylinder that fired
And it can also indicate valve issue
Compression test shouldn't be to hard to do on this engine
Pull out ALL spark plug first, then test

The 2.3l DOHC has a long timing chain setup and if it gets a little out of time backfires can happen, exhaust valve opens too soon
Compression test can sort that out, yea or nae, and its done, or its the problem so you don't waste time on non-fixes if its a compression issue

"A family firend replace the crank sensor, stated that the timing was a bit off but half assed the alignment to a "good enough" point. (hmmm...)"
This also peaked my curiosity

You need to install a bolt to set engine at TDC, Ford sells it or it comes with cam alignment tool kit, the bolt stops the engine from turning when its at TDC
The Crank sensor comes with a plastic alignment tool, and you install crank sensor and tighten it up, remove plastic tool and remove bolt, all done, there is no "adjustment", the computer does that