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I just cleaned my TPS and throttle body, hoping it would give me better MPG and fix the rpm drop off when I depressed the clutch going down hill. Unfortunately i'm now experiencing erratic idle while the vehicle is sitting still but everything else seems normal. I only had to replace the throttle body gasket when I cleaned it. I have checked for vaccum leaks and don't seem to have any so I don't think thats the problem. The question I want to pose is, could it be the computer that's causing the problem and should I reset it anyway to make sure it isn't still trying to get IAC readings from a dirty throttle body and TPS.
First question is what did you clean the throttle body with.
If you did not remove the TPS and used anything other than mineral spirits, the TPS has failed. This will give an eratic idle. The TPS has one way fasteners, but with a little persuasion, they can be removed. Also, the TPS control an air blled hole in the TB. This bleed hole may be plugged, also causing an eratic idle.
First question is what did you clean the throttle body with.
If you did not remove the TPS and used anything other than mineral spirits, the TPS has failed. This will give an eratic idle. The TPS has one way fasteners, but with a little persuasion, they can be removed. Also, the TPS control an air blled hole in the TB. This bleed hole may be plugged, also causing an eratic idle.
Carb cleaner and yes I did take the TPS unit off the throttle body and cleaned it to. So if what you're telling me is correct I guess I should be out looking for a new TPS. Now would that be the sending unit or the whole TPS. But before I try and find one, where exactley is the air bleed hole located on the throttle body and how do I clean it.
Well, if you used carbb cleaner or even throttle body cleaner on the Ford throttle body, you might as well make a trip to the stealership and pick up a new one.
There is a special coating on the Ford TB, I think it is teflon based and carb cleaner and off the shelf TB cleaner will remove it. Once loosened up, it will migrate to the air bleed holes and stop them up. The cleaners will also screw up the TPS and any sensor downwind of the TB. That is why I said mineral spirits. It will remove the buildup and not hurt the downwind sensors, but the TB sensor has to be removed to clean out the air bleed. A standard pipe cleaner soaked in mineral spirits will do the job quite nicely.
I don't wnat to sound like a butt, but I screwed up a $450.00 racing TB for a 5.8 a few years back by using TB cleaner. It not only screwed up the sensor, but also removed the coating in the intake and deposited it on the intake valves, not counting shorting our several other sensors. I had to tear down the entire top to clean that mess out. It cost over $900.00 in parts just by using a $3.50 can of TB cleaner.
Well, if you used carbb cleaner or even throttle body cleaner on the Ford throttle body, you might as well make a trip to the stealership and pick up a new one.
There is a special coating on the Ford TB, I think it is teflon based and carb cleaner and off the shelf TB cleaner will remove it. Once loosened up, it will migrate to the air bleed holes and stop them up. The cleaners will also screw up the TPS and any sensor downwind of the TB. That is why I said mineral spirits. It will remove the buildup and not hurt the downwind sensors, but the TB sensor has to be removed to clean out the air bleed. A standard pipe cleaner soaked in mineral spirits will do the job quite nicely.
I don't wnat to sound like a butt, but I screwed up a $450.00 racing TB for a 5.8 a few years back by using TB cleaner. It not only screwed up the sensor, but also removed the coating in the intake and deposited it on the intake valves, not counting shorting our several other sensors. I had to tear down the entire top to clean that mess out. It cost over $900.00 in parts just by using a $3.50 can of TB cleaner.
Well I guess I'll have to wait and see what happens. As it turns out it's running alot better now. It stopped hunting but still had a bit of a rough idle so I started checking for vaccum leaks. I heard what sounded like one around the christmas tree so I changed a couple of hoses put on the original MAP sensor and it seems to have helped. Since alot of these problems were present before I cleaned the throttle body I'm hoping that I haven't fried my Throttle body. The one thing I did notice was that I could smell propane so I know the system is running rich. With any luck it could be my propane mixer that's shot if thats any consolation since it's a vialle and getting rebuilt parts is next to impossible.
Anyway thanks for the tips and I'll keep my fingers crossed and hope I don't have to shell out for a new throttle body and TPS.
None of the 4 EFI 300's I've owned have said anything about not using carb cleaner on the TB. Even the ones that do have the sticker don't seem to be hurt by cleaning the throttle body. I've done dozens of them and never had any problems.
Six years and 110,000 miles of using carb cleaner on the TB of my Explorer hasn't caused any problems whatsoever...starts and runs like the day it was new.
check to make sure the TPS is calibrated right first, since u did remove it, it may have been bumped and now reads a little wrong.
I don't think I banged it, but then again anything is possible. Although I was under the impression that the TPS on these fords weren't adjustable, but if they are that may be part of the problem. If they are adjustable how do you adjust it? I know about doing the voltage reading to see if they are shot but other than that, I'm in the dark. I also talked to a ford mechanic who told me about after market TPS units that had an adjust screw on body but I guess mine is original since it doesn't have that.
Thanks
F.O.G.
Last edited by FreakinOldGuy; Oct 29, 2006 at 03:02 PM.
The OEM style without the screw are adjustable by rotating the TPS to adjust the voltage. Cleaning it like you did with TB cleaner will not hurt it at all. I would suggest that you check your PCV valve to make sure it is not stuck and causing a lean misfire condition.
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