F550 V10 cold start issue

[etcetera]

Bumping this because I have an identical situation with my 2012 V10 6.8L shuttle bus.

Cold start - good crank, fuel pressure - no start.

warm start - works just fine. Crank and quick start.

I had the fuel pump replaced, fuel pump control module, was looking into crank pos sensor, camshaft pos sensor, MAF, etc. Just now realized after reading the above it's most likely the ECT sensor.
Does it matter if I get the OEM one or an aftermarket ECT is OK?
Or could it be the TABV (throttle air bypass valve) sticking?

It idles and runs very nice.

referencing this old thread:

https://www.irv2.com/forums/f23/v10-...ue-321644.html

[etcetera]

Could it be the crank position sensor?

Or something fuel related, like an injector leaking?

[craigd853]

Originally Posted by etcetera

Bumping this because I have an identical situation with my 2012 V10 6.8L shuttle bus.

Cold start - good crank, fuel pressure - no start.

warm start - works just fine. Crank and quick start.

I had the fuel pump replaced, fuel pump control module, was looking into crank pos sensor, camshaft pos sensor, MAF, etc. Just now realized after reading the above it's most likely the ECT sensor.
Does it matter if I get the OEM one or an aftermarket ECT is OK?
Or could it be the TABV (throttle air bypass valve) sticking?

It idles and runs very nice.

referencing this old thread:

https://www.irv2.com/forums/f23/v10-...ue-321644.html

Hello and sorry for your issues. If I recall there is a sensor in the block somewhere that feeds information the the ECM to tell the engine rather it's cold or hot and will tell the computer to enrich the fuel mixture and adjust timing accordingly. It might be called an ICT sensor but I won't swear to it. How many miles are on your engine? I ask because if it's over 50,000 spark plugs could have a bigger gap than should be and causing excessive cranking. Also if you take off the cowling inside the rv you should be able to tap into the fuel rail and measure fuel pressure when cranking cold. At any rate it sounds like it will require some trouble shooting on your part. Don't know how mechanically inclined you are but by measuring the fuel pressure at the rail when engine is cold and cranking the engine at least this will tell you rather it's on the iginition side or the fuel side. Good luck and let us know what you find out.

[etcetera]

I've tried all the obvious things. New fuel pump.

2012, and it's a shuttle bus. 53K miles.

There is no ECT sensor in the 2012 version of the V10 engine.

I am going to get a scanner which pulls live data. I think that's the only way it can be fixed.

[code2e]

Originally Posted by etcetera

I've tried all the obvious things. New fuel pump.

2012, and it's a shuttle bus. 53K miles.

There is no ECT sensor in the 2012 version of the V10 engine.

I am going to get a scanner which pulls live data. I think that's the only way it can be fixed.

But, there is a cylinder head temperature sensor. I agree. a good scanner will help diagnostics. You may find the temp sensor showing higher than actual when cold, throwing off the mixture.

[etcetera]

So I ran ForScan and added these values. T

Not sure that I am looking at the right values. I think Camshaft position sensor is cleared. It's not signaled as faulty.
I am not sure which value correlates to the Crank Position Sensor. ENG_CRANK?
I just added everything that seemed semi-relevant. Still no real clue as to what is not functioning. I added all the 10 injectors, they are not flagged as faulty as seen below.
What is the list of items I need to add to the watch list, the max is 28 apparently.




This one is when cranking the engine:





And that's the table view:

[SergioP]

Sure is cold in Virginia right now. Either the IAT is unplugged or defective. Not sure if the sensor is built into the MAF or if it’s a separate sensor in the air box area.

[theoldwizard]

Originally Posted by etcetera

Or could it be the TABV (throttle air bypass valve) sticking?

Highly likely (correct name is Idle Air Control, IAC).

If you get a crank-nocstart after about 10-20 seconds, pause for about the same amount of time. Put the accelerator pedal to the floor and crank. I'll bet it starts immediately !!

[theoldwizard]

Originally Posted by SergioP

Sure is cold in Virginia right now. Either the IAT is unplugged or defective. Not sure if the sensor is built into the MAF or if it’s a separate sensor in the air box area.

-40F will dump a huge amount of fuel in while cranking, flooding the engine. Hold the accelerator pedal to the floor while cranking is called "clear flood mode".

IAT is NOT part of MAF

[etcetera]

Originally Posted by theoldwizard

Highly likely (correct name is Idle Air Control, IAC).

If you get a crank-nocstart after about 10-20 seconds, pause for about the same amount of time. Put the accelerator pedal to the floor and crank. I'll bet it starts immediately !!

Already tried all that and the Ford people are saying the 2012 version of V1 does not even have it. It's all electronic.

[SergioP]

If yours has an electric throttle plate(no cable) it won’t have an IAC, the electric motor controls the idle, basically.

[etcetera]

The only code I get is this:



Watching live data in ForScan, the RPMDSD is apparently the RPM value and it's not moving at all.





I got the repair kit for the MAF sensor broken wire, what apparently causes the error code above but not sure how to install it, will probably get some help with it as I am likely to break it even more:



Video of the super long crank no start:

https://youtube.com/shorts/RWGaP1OCH_U

[code2e]

Originally Posted by etcetera

The only code I get is this:



Watching live data in ForScan, the RPMDSD is apparently the RPM value and it's not moving at all.





I got the repair kit for the MAF sensor broken wire, what apparently causes the error code above but not sure how to install it, will probably get some help with it as I am likely to break it even more:



Video of the super long crank no start:

https://youtube.com/shorts/RWGaP1OCH_U

Your last picture shows no belt driving the alternator. Assume you knew that?

The video shows way too slow cranking speed to start the engine. Low battery? Too high amp draw from starter?

Yes, IAC function is performed by electronic throttle body. Replacing the MAF sensor pigtail is straightforward. The terminals are in a straight line. Only splice one at a time, starting from one end. Mark original connector "up" side, plug in pigtail and begin splicing. Get heat shrink butt connectors with the low temp solder built in. Great for weathertight connections.

[etcetera]

It's the secondary alternator for accessories. It actually has 3 alternators.

I think I picked the wrong variables, will re-run it the test.