Idle Problem / Squealing 93 F150 4x4
02-23-2016, 05:01 PM
#1
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Idle Problem / Squealing 93 F150 4x4
Hi gang,
Here's the scoop:
I bought a 93 F-150 with 180k miles on it about a month ago. I was told it had an exhaust leak, and a minor valve cover gasket leak. I've replaced the exhaust manifold (Driver Side) and now I can hear something other than a loud put when I accelerate
. However, thinking the CEL was related to the exhaust (back pressure/02 sensor?), it still throws the light when the truck is warmed up. I live in the mountains of Boone NC, and it starts and idles fine when cold. But as soon as it warms up, the CEL comes on and it idles rough when at stoplights/parking lots. (In P, N, D or R). No tachometer on this model, but it sounds like the RPMs drop to about 400 or so, sounds like it is going to stall, but never does. Just drops low, then revs high, then evens out. Doesn't do this consistently like it's a misfire, just sporadically.
I've done research and considered a dirty IAC, dirty throttle body, bad TPS, or vacuum leaks. I've cleaned the IAC, still no luck. It may need replacing, but I'd rather isolate other options before buying parts. I got an OBD I scanner and have codes 33, 13, 25, 52.
I have now....
Replaced the IAC with a brand new one, put new motorcraft plugs all around, new air filter.
Still the same rough idle, and now when I give it gas sometimes it will have a loud squeal like something is metal is getting spun around against metal. Doesn't happen in idle though, only when revved in drive actually going down the road. (could this be a bad plug?)
Idle problem still happens when it warms up. Seems like it takes it longer to develop though now that I've replaced the IAC.
Thoughts?
Here's the scoop:
I bought a 93 F-150 with 180k miles on it about a month ago. I was told it had an exhaust leak, and a minor valve cover gasket leak. I've replaced the exhaust manifold (Driver Side) and now I can hear something other than a loud put when I accelerate
. However, thinking the CEL was related to the exhaust (back pressure/02 sensor?), it still throws the light when the truck is warmed up. I live in the mountains of Boone NC, and it starts and idles fine when cold. But as soon as it warms up, the CEL comes on and it idles rough when at stoplights/parking lots. (In P, N, D or R). No tachometer on this model, but it sounds like the RPMs drop to about 400 or so, sounds like it is going to stall, but never does. Just drops low, then revs high, then evens out. Doesn't do this consistently like it's a misfire, just sporadically. I've done research and considered a dirty IAC, dirty throttle body, bad TPS, or vacuum leaks. I've cleaned the IAC, still no luck. It may need replacing, but I'd rather isolate other options before buying parts. I got an OBD I scanner and have codes 33, 13, 25, 52.
I have now....
Replaced the IAC with a brand new one, put new motorcraft plugs all around, new air filter.
Still the same rough idle, and now when I give it gas sometimes it will have a loud squeal like something is metal is getting spun around against metal. Doesn't happen in idle though, only when revved in drive actually going down the road. (could this be a bad plug?)
Idle problem still happens when it warms up. Seems like it takes it longer to develop though now that I've replaced the IAC.
Thoughts?
03-17-2016, 04:54 PM
#4
Sounds like a pulley may be bad or one of the accesories. Take the belt off and turn each one by hand, might help identify if that's the issue.
Take a look at code 33 first - EGR valve not closing properly ; that could give you some idle issues.
Most of the things like egr, pcv, purge valve etc. are set up to not operate when the engine is cold or idling = so as not to mess with your idle mixture, which is much more sensitive than the mixture at rpm.
One of your codes is power steering pressure switch, which may be just the switch (if you even have one, but with a code showing up and a squeal out of the accessories (possibly), I'd pay particular attention to the P/S pump when I was checking all those pulleys up front.
Take a look at code 33 first - EGR valve not closing properly ; that could give you some idle issues.
Most of the things like egr, pcv, purge valve etc. are set up to not operate when the engine is cold or idling = so as not to mess with your idle mixture, which is much more sensitive than the mixture at rpm.
One of your codes is power steering pressure switch, which may be just the switch (if you even have one, but with a code showing up and a squeal out of the accessories (possibly), I'd pay particular attention to the P/S pump when I was checking all those pulleys up front.
03-17-2016, 07:38 PM
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Thanks For the response Chris. My mechanic said the PS pump was going bad. I plan on replacing it, but can it really make such a loud squeal? It's not a whine, and doesn't really complain when I turn the wheel. Just when I tap the gas. After climbing the steep 2.5 mile(ish) hill on my way home, it sounds like a metal screech by the time it gets into the driveway. Thought maybe something in the driveshaft/wheel hub assembly.
03-17-2016, 10:24 PM
#6
Possible. If something's rubbing on one of the driveshafts it should be making a shiny spot.
Could also be the motor torquing over and rubbing a pulley against ??? a trans line ?
Or a brake part rubbing on something.
The motor having to be under load makes it sound like driveline or pulleys (things that turn).
I'd crawl around looking for something close to something else that could touch if things moved a little. Then look for shiny metal where it should be rusty or dirty.
Could also be the motor torquing over and rubbing a pulley against ??? a trans line ?
Or a brake part rubbing on something.
The motor having to be under load makes it sound like driveline or pulleys (things that turn).
I'd crawl around looking for something close to something else that could touch if things moved a little. Then look for shiny metal where it should be rusty or dirty.
03-17-2016, 10:29 PM
#7
Senior Member
A couple of things from an old guy. EGR cannot be open at idle. Loosen EGR valve and insert a piece of gasket to cover ports (holes), retighten EGR mounting bolts. Start engine and notice how it performs. If OK, repair not closing EGR valve. If still idles rough, you need to look further. The power steering code could be not cycling the PS during the self test (operator error).
Describe the squealing more, try removing the belt and run engine with it off. I said to run the engine not drive the truck. Extended operation needs the water pump for cooling.
Describe the squealing more, try removing the belt and run engine with it off. I said to run the engine not drive the truck. Extended operation needs the water pump for cooling.
