DI1974

For anyone who has commented and anyone new to the thread .....

My 1994 Ford F156 has been a mess the past few months. The easiest thing to do is to refer you to my past posts --

Yesterday I received my new MAF in the mail. I cleaned the throttle body, MAF installed and works great (or so says the multimeter), but when I drove it the only thing that was new was the check engine light did not come on. The knocking/misfire, slow to accelerate (or deceleration), and then jumping into acceleration was still happening. When I got home and lifted the hood and let it idle - I noticed that the idle pulley would stop while the serpentine belt kept going over it. Then it would start moving. If I put my foot on the accelerator it would always stop. I turned the engine off and noticed that the belt was a little tight but that the idle pulley was hard to move. In fact, it would stick.

I have looked all over the place and from what I've read most resources say that tension pulley or idle pulley will cause the belt to break or whine (there is no whining) - does anyone have experience with this and does anyone think this could be the cause of the current issues? Or - does anyone have any other suggestions?

(I didn't take a video but I will take one later of the idle pulley stopping and starting to let everyone see what I am seeing)

To date -
_The water pump and hose have been replaced.
_I used UV fluids to pinpoint that there was overflow from power steering fluid (but no leaks) I haven't been able to fully flush it but was able to get a lot of the old out and replace some new.
_The throttle body has been cleaned
_ A new MAF sensor (and assembly) has been installed.

Now the idle pulley is sticking and the serpentine belt is still running over it.

kd3pc

replace, after testing the idler pulley...the pulley should turn very smoothly through multiple 360 degree motion with just your fingers.

It should also spring/rebound when you push against, again quite smoothly.

Sounds as if the serpentine belt is glazed, so check it out while you have things apart.

Once your belt is operating smoothly, I would check the TPS and IAC both are pretty easy to test, with a meter. Both are relatively inexpensive to replace and can be done easily.

wde3477

Whew, amazed by the number of problems you're up against, impressed with the dogged determination.

1) HVAC damper problems - not sure if this is resolved, saw the good advice about vacuum problems, didn't see mention of a likely suspect - the recirc damper actuator vac line, typically white in color, in the engine bay back toward the passenger side firewall on top of the HVAC enclosure - several folks, as well as myself, have found this line failed, where repair solved the changing airflow outlet problem.
2) EGR problems - in addition to the advice already given, suggest to check out the solenoid supplying vacuum to the valve. Located on the driver-side rear portion of the intake manifold. This has a little foam filter stuffed in a port on its underside for admitting air to the system allowing the valve to close. The filter can be plugged up, causing slow response and eventual Check Engine faults.
3) MAF sensor - not sure where this is located, a member of the previous MAP generation here - but perhaps inspect for any way air could be getting into the engine without passing through this sensor - such as a hole or crack in the plastic air piping. May consider lifting the (-) cable from the battery for about a half-hour to erase the learned operating parameters, starting over from default values. Engine may run a bit wonky for a few minutes until it re-figures things out.
4) Idle pulley - suggest to replace, these do eventually wear out, some newer vehicles recommend changing the pulley at each belt change. Can't remember, but the pulley bolt may have left-hand threads - that is, instead of counter-clockwise to loosen, it may be clockwise..?
5) Knocking - I didn't catch it in the previous threads, but has the timing been verified? Going a ways off on a tangent, if a previous owner was a die-hard fan of premium fuel, may have carbon deposits in the cylinder that may need to be cleaned out with a simple SeaFoam treatment or similar.

Good luck, and continue to keep us posted.

DI1974

My truck now reminds me of when my ex-husband bought a used BMW when we lived in MA and I had a guy come up to me and said he once had a car just like mine and warned me that when they go bad - they go very bad!! I truly think the problem with my truck is that it never had any real maintenance.

I need to try to get out early today and get a video of the idler pulley so you all can see what I am talking about. I have a feeling that it is this or possibly the timing belt. My last few posts I have had a ton of good help with deciphering what might be going on and while Ford did say the water pump was leaking and fixed that - it came back from them after 3 weeks worse than before! The majority here guessed MAF and sure enough - no power. Changed if a couple days ago and cleaned a very dirty throttle body and now it finally reads on a multimeter! So one issue down. I figured out that the dripping fluid was power steering and hopefully by (lazily) pulling out as much old as I could and refilling to the right place will fix that issue. But when I started it - the idle pulley was a clear problem - only thing is that none of my research said that the idler pulley as causing the issues that I am having but the timing belt does "If your timing belt is not properly tensioned it will not keep the valves timed properly to the lower end and this will cause misfires, loss of power, bucking, and could even cause a no start condition.". Luckily, because of all of this (and the fact that they broke my drivers side mirror!) Ford will do a free diagnostic. I think with a little nudge - they may see the problem more quickly and fix it. I've never changed pulleys or even the belt and I'm not sure about doing this myself right now.

I just uploaded some photos of the throttle body when I took the hoses off - the first 2 shoe how bad the bottom one was and how I got it mostly cleaned. The hoses and tubes were also oily and very dirty! Ugh!!!

Also- my engine was MUCH cleaner but with all the fires nearby in CA - there is so much ash -it is creeping in everywhere - including my engine! So it looks like it needs another cleaning again!

wde3477

Just to clarify - this engine does not have a timing belt, it still uses a timing chain, so not as prone to the problems mentioned. One of the reasons for the quizzing about checking the timing - if it's very far out, could be indicative of jumping a tooth or so on the sprockets - or that someone previously just set it wrong. FWIW, I changed the chain at 170,000 miles. Engine was running well, just happened to have things tore apart to correct a coolant leak and saw the free play was over the max recommended.

If you're seeing ash inside the air hosing - suggest there's a leak somewhere, getting back around to ensuring all air going in the motor passes by the MAF, and in this case, also all air going through the air filter.

*Edit* ah, the idler pulley. Not seeing this as part of the described engine problems, figure when it locks up or lets loose, would be like when the A/C compressor engages / disengages with only a slight blip in idle speed. Concern here is the damage to the belt, and the pulley eventually coming apart / failing completely, leaving one with no water pump pumping, power steering powering, alternator alternating, etc.