Stalling Issue

[Broosedamoose]

So a few weeks ago I had to replace a blown head gasket on my 2007 4.0L. I had them both replaced and the heads milled. I got the truck back and it was idling rough and would stall 90% of the time I went from drive to reverse. Took the truck back in and it was tested for vacuum leaks but none were found. Turned out to be the timing was off just a tad bit. The truck idles and drive good now but it's still stalling out! When the e-fan kicks on the RPM's drop and a couple times the engine stalled. It's mostly when I go from drive to reverse that it stalls. It idles at around 700-750 RPM's which is normal. I don't understand why the fan knocks it down as it's an electric fan! Anyone have any ideas of what else could be wrong? How do you use brake cleaner to check for vacuum leaks? I want to double check the intake because the engine did get quite hot after blowing the head gasket.

 

[RonD]

After engine is warmed up and idling, unplug the 2 wire connector on IAC Valve
Idle should drop to 500rpm or engine may even stall either is good, confirms no vacuum leaks
If idle doesn't drop then there is a SMALL LEAK, but shouldn't effect performance much

Air increase RPMs, the point of the throttle plate, so a vacuum leak increases idle RPMs, at 700-750 warm idle I would not suspect a leak, but I would expect 800 for an automatic

I assume it idles at 1,000-1,100 when cold which means ECT and IAC are both working

Is the e-fan factory?
If so it should bump up the idle when it activates

Same bump up of idle should occur when shifting from Park or neutral to D or R
Or when turning on AC

 

[Broosedamoose]

The e-fan is out of a Taurus. Never dropped the idle before. I get what you're saying about the RPM's and a leak. So what would cause the RPM's to drop so low all of a sudden? Could it have anything to do with the plugs? I had them changed while the heads were off. I don't see how that would cause the drop in RPM's though. Even if they were not gapped right I would have a rough idle.

 

[RonD]

Turn heater fan off
When engine is stone cold, remove fan belt, so no alternator or water pump
Start engine
Check battery voltage, should be 12.1-12.6 depending on how new it is
Manually start the e-fan and see if rpms drop and check voltage at battery, that will tell you the amp draw of the fan

If voltage drops below 10 then time for a new e-fan motor
A starter motor uses 60amps and only has a 2.5volt drop

 

[gaz]

Broose,

You have the OHC engine, how much material was milled from your heads; 0.030" will definitely change your cam timing in an OHC engine, not a ton but enough to cause issues. Also, was your lower intake manifold milled to match the heads.

So what happens is the timing geometry gets changed since the distance the chain travels has been shortened. What I have had to do to correct this is advance the cam gear (s) 1 tooth; this results in an advance but between the undesired retard and purposed advance, I'd take the advance.

Rule of thumb:

0.030" mill shortens the distance 0.060" (both sections of the chain) causing a 4° retard on a 39 tooth sprocket (9° per tooth). So you may need to compensate for the head work, advancing the cam sprokets will leave you with +5° instead of -4°.

 

[Broosedamoose]

So I have an SCT handheld tuner I can use to advance or retard timing. If I use it to adjust the Global Spark Timing, should I advance it 5° and see what happens?

 

[Broosedamoose]

I tried adding the 5 degrees and the engine ran terrible! I talked to the mechanic and he said that if the sprocket was keyed it might make a difference but where the sprocket is just pressed onto the camshaft it doesn't matter. Using the tool from Ford to set the timing sets it back to the stock location. I don't know what the hell is wrong with it! Ran like a top before the head gasket blew and now it runs like sh*t and no one can figure out why!

 

[Broosedamoose]

What are the symptoms of a cracked head? I'm wondering where the engine over heated so much if I cracked a head. Would that be something that would have been noticed while milling the heads? Would it cause the issues I'm having?(Rough idle, stalling when going into reverse)