Another quest ….

[aldive]

No, not a Quest for 40 ( or more ), but a quest to get a perfectly smooth idle on my 4.0 SOHC motor.

The 4.0 SOHC is infamous for a somewhat “irregular” idle. And it drives me crazy.

Before I outline what I have done so far in this quest, please, let’s discuss potential causes and remedies.

Look forward to your input ….

 

[aldive]

No one else have a rough idle?

 

[spindlecone]

No one else have a rough idle?

Not Me

 

[BrooklynBay]

Did you check your MAF? How is that new coil pack? You mentioned that it helped it little.

 

[aldive]

Did you check your MAF? How is that new coil pack? You mentioned that it helped it little.

Yes, the new coil pack definitely helped the idle. I let a friend drive the truck yesterday and she asked if I had done a tune up; she said it idled ed better th am the last time she drove it.

The MAF is clean; I clean it monthly.

It is idling better than it ever has currently.

I have never been in a V6 that had a great idle, but I continue to work on it.

 

[prerunner02]

I know you said your plug wires were good but, did you do a resistance check on them?

I work with a sprint car team and wires should be checked for resistance when new,we check the resistance after every race and you would be surprised at the idle difference that good wires make, even if there is no HP difference. a slight resistance drop in one wire can make all the difference in smoothness.

It surprises allmost everyone that a new set of wires out of the box ,more often then not, will have a different ohm reading per wire. not very good for smooth idle and acelleration under load(or lugging). The most consistent wires ive ever tested are performance distributors live wires.

Test the resistance of each wire, and please post the results, ill bet atleast one will be off.
Hope this helps with your new quest.

 

[aldive]

I have not tested the resistance of the wires. You have a good point; thanks for your input.

 

[410Fortune]

V6's are notorious for this, especially the 60 degree cologne engines.
Good luck!

 

[BrooklynBay]

Maybe the CPS has to be realigned to correct the timing.

 

[aldive]

Maybe the CPS has to be realigned to correct the timing.

What is a CPS?

 

[Turdle]

Crankshaft position sensor.

I removed my 102k mile pulley (when I replaced my engine) to find it is vulcanized, in that the Keyway-sprocket shaft is seperate from the pulley-sensor wheel assembly. Mine was more than a few degrees off, due to movement over the years. Is the v-6 pulley similar?

 

[aldive]

Thanks Jon, my acromyms sometimes leave me.

When I installed my underdrive crank pulley/dampner, the sensor appeared fine.

 

[Turdle]

Yes
I went to look, and it appears you replaced the whole shebang, trigger wheel and all. The sensor is a work - no work thing, with no adjustment I am familiar with, so this area is good IMO.

Timing would be more easily adjusted thru tuning, although I have seen an adjustable ( movable) Crank sensor bracket for mustang engines.

 

[aldive]

Jon, the idle roughness is an issue with the stock computer tune as well as over 20 other tunes I have used.

 

[SkanlaxJMO]

subscribing

 

[aldive]

I have done the following to help the idle:

new DPFE
new EGR
new coil pack ( http://www.explorerforum.com/forums/showthread.php?t=169182&highlight=coil+pack )
cleaned IAC
cleaned MAF

the idle is remarkedly better, but not where I want it.

Yet to do:

new plugs ( gapped to 0.060" )
new spark p[lug wires

 

[churd69]

Al, you are the Peter Jackson of threads. Good luck, I too understand what you say about the idle, i changed plugs, wires, cleaned the IAC and MAF, and changed fuel filter and it smoothed it out a lot. I think some of my problem is due to the aftermarket intake. It seemed to idle a little smoother with the stock box on.

-Rich

 

[aldive]

Forgot to mention - I also have a new fuel filter.

 

[spindlecone]

I have done the following to help the idle:

new DPFE
new EGR
new coil pack ( http://www.explorerforum.com/forums/showthread.php?t=169182&highlight=coil+pack )
cleaned IAC
cleaned MAF

the idle is remarkedly better, but not where I want it.

Yet to do:

new plugs ( gapped to 0.060" )
new spark p[lug wires

lose your 4.6 TB, is not compatible to your application

 

[Doubt Incarnate]

i dont notice any rougness. a little hunting over a hundred rpm or so once in a while, and a wet fart sound from condensation in the exhaust. I'm un-modified, but the first thing i'd check for is all vacuum or intake connections being 100% leak free, maybe water in under hood connections or a loose ground.