Self-teaching myself engine repairs and curious what this part is. Is it the air intake valve? I removed both hoses while the truck was idling and did not notice a difference connected or disconnected. Is there suppose to be positive pressure at these two connections, and if so, what should the pressure be? Thank you.

 

That is the Idle Air Control motor.

 

OOPS, I didn't look at the arrows closely. The tubes are for coolant to flow through the base of the throttle body and warm the air a little. It is only really needed in cold climates.

 

Thank you Weskan. Been troubleshooting my truck these past 3 weekends when the issue started. Bought a 1993 F150 4.9L, 6 cylinder, single cab, automatic new and it now has 350,000 miles. Up until 3 weeks ago as soon as I turned the key the engine would crank & start immediately. Now it takes about 20 seconds of cranking before it starts. The starting time increases when the engine is cold but will start immediately if the engine is hot (up to temperature). Tried just turning the key several times (not cranking it) with same results. Checked the battery, alternator, starter, fuel pressure: all good when I tested it, Auto Zone, Ford Dealership and an independent mechanic shop. No check engine light or fault code. I used a HEI spark tester during cranking and healthy spark appears when cranking. Ford Dealer mechanic said to replace the distributor & ignition module and I did with no change. Check vacuum today and its 18 inches of Hg. Plugs, cables, battery a year old. Air filters good. Battery is 12.6 volts, 11.7 volts when cranking, alternator is 14.6 volts, no voltage drop across starter cable during cranking. Any suggestions?

 

My general advice is to check the basics first. All engines need air, fuel, compression, and ignition. In your case, it seems fairly obvious that you have air, fuel, and spark since the engine does run. If the engine is original and has never been overhauled, I would check the compression when cold, then check it again after it is warmed up. This will help you find out if the engine is simply getting worn out.

Then check the fuel pressure under the same conditions. I don't think there would be a difference between hot/cold readings, but at least you will know for sure if the problem is fuel related. Sometimes things happen or malfunction without setting a code or CEL.

 

Good post!

 

Good information and will pickup again this weekend. I had the truck at the Ford dealer and they said it was the distributor & ignition. I changed both components but same issue. Changed the fuel filter two weeks ago and always change the oil & filter every 3,000 miles.
The mechanic at the dealership and an independent auto shop did not mention weak compression and they drove the truck several miles but the engine has never been overhauled.
I used a HEI spark tester while cranking seeing/hearing a healthy spark. Have a fuel tester probe coming this week and will see if the fuel injectors are firing while cranking (fuel pressure is 50-55 psi). I read the idle air control valve should be wide open when the engine is started. Could the valve be sticking partially closed when the engine is cold? Measured 10 ohms resistance across the coil and might be a good idea to remove it & clean it. The truck has 350,000 miles running smooth at any speed or at idle. No slip or slop when taking off.

 

I would still check the compression even if it is just for peace of mind. 350,000 miles is quite a bit by anyone's standard. Severe blow by has other indications, usually oily residue in the air cleaner.

But for diagnosis via the internet, knowing the condition/operation of the basic systems helps eliminate bunny trails of remedy. There are folks here that have much more knowledge and info than I do when it comes to diagnosing the electrical side of the engine operation.

 

Hit it with a snort of starting fluid first thing in the morning (cold start). That will at least tell you if it's fuel related or ignition related. Won't really tell you much about compression, though.

 

Thank you both for the suggestions and work on this issue Saturday. The positive is I have learned so much about engines and this is a good mind exercise for me.

 

I'm pretty sure that the hoses and the hose fittings in the picture are for the canister purge system (fuel tank vapor recovery). If they were the lines connected to the cooling system, you would have had antifreeze everywhere when you pulled the lines with the engine running.

Did you check fuel pressure first thing when it's cold or did you check it after trying to start it?

 

Yes it is the air intake (control) valve (IAC).
No pressure or vacuum at idle but they should/may have vacuum on them as the throttle is opened.
As EPNCSU2006 said above they are for the fuel tank vapor canister purge hoses.
I would guess you either have a bad ACT or a ECT sensor.
I would check the codes but when one these two sensors go bad they do not give a code most of the time.
Could be empty fuel lines (a bad fuel valve to the tank) but the shops should have found this if it were the case. Besides turning the key on and off should have filled the fuel lines.

 

Eric, your right thats not the coolant hoses for the throttle body, those two should hook into a Y and go to the vapor recovery tank, or charcoal canister, Is it possible that the fuel is leaking past the check valve in the tank and it takes time for the engine to build the pressure back up and start? Did you leave the fuel gauge on overnight and make sure in the morning you still have pressure in the system? If the fuel drains back it could take a while of cranking to get the prime, fuel thru the filter, hoses, fuel rail, and injectors, a good pump should be able to do that in 6 or 7 seconds but maybe yours is a little weak. Something to check.