Loud engine bay

[ChildIdenticant]

After years of my car sounding like a freekn harrier, and seeming almost adiabatic in its performance (literally could drive an hour at highway speeds, park, and safely place my hand on Air Intake Manifold ), I've decided to address the issue. It had never occurred to me that my lower than expected power across entire speed range could be due to the fan always being engaged, but being 500 miles past a complete engine rebuild with improved but still eh power, I have no other suspects in the system. So I have a couple of questions for this great forum.

#1: Is the clutch fan actually supposed to turn off completely at some point during operation of the vehicle?I know electronically controlled fans do. Mine doesn't , I don't remember if it ever did, and I haven't seen a definitive answer on this. The roar is my normal.

#2: Can a constantly engaged clutch fan significantly sap enough power such that traveling on a 5% grade requires gradually increased throttle just to maintain speed of 55 mph with WOT necessary after ≈1mile?

#3: Is there another , non-transmission related, non-vacuum related, non-misfire/ nofire related, plausible explanation for the behavior described in question 2?

1994 2wd
167,200 miles
≈500 miles since complete engine rebuild
≈2200 miles since fuel filter replaced
FuelPumpPressure= ≈30@idle, ≈35 city, ≈41 highway.
vacuum = okiedokie

 

[Turdle]

On some of our trucks, when the gas pedal is floored, the throttle body plate is not open all the way. Remove the air intake tube and have a helper press the accelerator pedal. when it is floored you should see the throttle plate completely horizontal. If not, you can fix it by taking up some slack of the throttle cable using the "zip tie mod"



Also, the throttle position sensor can be checked at this time. Less than 1v at idle, greater than 4.3v at WOT

 

[974X4BLACKSPORT]

If your fan roars going down the road, you need to check and make sure it has not ssiezed up, it should spin by had with some ressistance with the engine OFF.

 

[ChildIdenticant]

Uh huh, uh huh. Yes, checking the throttle cable slack from where measurements actually matter.Brilliant! That helps, thanks much. My WOT was really HOT. Half open, that is. The performance difference is almost exactly what I expected could be gained. Zip ties... so inelegant. I'll be so self conscious if it gets stolen. Hoping nobody looks down there.

My roar persists though. Every cold start , most warm starts, until just about 40mph. Then it quiets a bit , not as noticeable among the other ambient and engine noise, but it is still there. Engine off and I can move the fan by hand, but by no means is it free spinning. It ceases the moment I stop touching. And I still think it never turns off while the engine is running. So is it failING , partly failed, or considered to be failed, in a way that it also performs what it was mean to do?

I do think I can consider the main issue here thankfully solved, though.

 

[Turdle]

Ok, the "heavy duty" fan clutches are a bit more noisy than the standard duty. It should not "free wheel" , rather it should spin with a tight feel. Like you describe. It will not free wheel but as the temp rises should grab harder like a clutch, and roar louder until the excessive heat is dissipated. Mine will roar real loud after a heat soak period.


You might try another fan clutch from a junk yard just to see if there is a difference.



Zip ties might be "inelegant" , but they fix many problems well enough they get forgotten in the rest of the mess. Many of our trucks have zip ties in private places--

(the word inelegant only came up 3 times in the forum search, I am going make it my new favorite word )

 

[Mart1n]

Uh huh, uh huh. Yes, checking the throttle cable slack from where measurements actually matter.Brilliant! That helps, thanks much. My WOT was really HOT. Half open, that is. The performance difference is almost exactly what I expected could be gained. Zip ties... so inelegant. I'll be so self conscious if it gets stolen. Hoping nobody looks down there.

My roar persists though. Every cold start , most warm starts, until just about 40mph. Then it quiets a bit , not as noticeable among the other ambient and engine noise, but it is still there. Engine off and I can move the fan by hand, but by no means is it free spinning. It ceases the moment I stop touching. And I still think it never turns off while the engine is running. So is it failING , partly failed, or considered to be failed, in a way that it also performs what it was mean to do?

I do think I can consider the main issue here thankfully solved, though.

Hi, did you ever find the answer to your fan issue. I have a similar case. My fan works too much for no reason (although it will stop at times). I also lose power when this happens. I've read about the PCM / TCM issue.

 

[ChildIdenticant]

Hi, did you ever find the answer to your fan issue. I have a similar case. My fan works too much for no reason (although it will stop at times). I also lose power when this happens. I've read about the PCM / TCM issue.

I have not yet determined the cause of the fan roar, as I have a quart oil disappearing every 600 miles with no tail smoke and not a drop on the driveway, and the cabin fan has started turning on automatically at about 40mph. I gotta call the (real) ghostbusters. I don't know about the PCM /TCM issues you mention.