94 4.0 bogging under throttle
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From: SW Va
Its really important that you have the Specified MAF sensor in place & that it be kept squeeky clean by the air filter & not get contaminated from blow-by crankcase fumes, so the PCV system needs to be in good repair & plumbed correctly.
So, did you make sure that the store gave you the correct MAF sensor, that the specified one was in the box & that it tested ok before leaving the store with it???? Sometimes things get packaged wrong, or swapped into the wrong box when folks are looking at replacement parts at the store.
While your backprobing the MAF sensors Sig Return voltage, also check to make sure its B+ Reference voltage is up to spec.
So, did you make sure that the store gave you the correct MAF sensor, that the specified one was in the box & that it tested ok before leaving the store with it???? Sometimes things get packaged wrong, or swapped into the wrong box when folks are looking at replacement parts at the store.
While your backprobing the MAF sensors Sig Return voltage, also check to make sure its B+ Reference voltage is up to spec.
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Of course you know whats going on, the computer is telling you that its unhappy with the PID feed back that the MAF sensor is giving it.
So, break out your multimeter & repair manual & back probe/measure the MAF sensors signal return voltage at its electrical connector & if its ok there, measure it at the computers firewall connector.
Edit: Give the connector & wires a wiggle test to see if anything is intermittent, or giving a low reading from a bad electrical connection.
So, break out your multimeter & repair manual & back probe/measure the MAF sensors signal return voltage at its electrical connector & if its ok there, measure it at the computers firewall connector.
Edit: Give the connector & wires a wiggle test to see if anything is intermittent, or giving a low reading from a bad electrical connection.
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From: SW Va
Ok, good post on the vacuum gauge test. The vacuum level looks good & its steady, so you shouldn't be having blow-by problems & don't need to do a compression test, unless you just want too!!!! It doesn't explain all of the oil deposits in the intake manafold though, unless they were there before you purchased the vehicle & before you replaced the PCV valve.
Are you using the specified 5W-30 viscosity????
I can hear a tic come & go, after you goose the engine, so keep a check on it as time passes, to see if the Mobil-1 will tidy things up enough for it to quiet down, or stop. Next time I'd opt for a Motorcraft FL-1A oil filter.
"So why aren't the other codes showing up now"???? Maybe you haven't driven it enough after the last battery disconnect/KAM wipe for them to re-set, or maybe the Trans Tune has done a tidy up action on the 3-4 shift solenoid, so it no longer hurts enough for the computer to say it does.
If you've been busy checking, cleaning, improving the battery, body, engine/tranny ground connections, maybe you fixed a problem you didn't know you had?????
Are you using the specified 5W-30 viscosity????
I can hear a tic come & go, after you goose the engine, so keep a check on it as time passes, to see if the Mobil-1 will tidy things up enough for it to quiet down, or stop. Next time I'd opt for a Motorcraft FL-1A oil filter.
"So why aren't the other codes showing up now"???? Maybe you haven't driven it enough after the last battery disconnect/KAM wipe for them to re-set, or maybe the Trans Tune has done a tidy up action on the 3-4 shift solenoid, so it no longer hurts enough for the computer to say it does.
If you've been busy checking, cleaning, improving the battery, body, engine/tranny ground connections, maybe you fixed a problem you didn't know you had?????
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Update:
Truck has been running great for the most part but still acts up from time to time. I noticed that the MAF seems to get really hot so I modified the intake so that the MAF and the filter are farther from the engine and down where they can get some colder air. After doing so she started acting up again so I pulled the MAF plug and then slid the plug in and out a few times in an attempt to maybe clean the contact surface of the pins and after doing so she fired right up and ran fine so maye I'll go ahead and replace the pigtail. I'll try cleaning the old one with contact cleaner first and see how that goes. I'll say this though, when she's running right she has loads of power and torque so she's well worth all the time and effort!
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From: SW Va
OK, good trouble shooting. As long as its throwing the MAF trouble code, stay with it until it stays clear. The computer needs an uncorrupted PID from the MAF sensor, to properly calculate fuel injector squirt time/fuel trim. It'll need uncorrupted input from the MAF, IAT, O2, TPS, ECT, TRS, sensors to properly do that & make it run good all the time.
Did you figure out what was going on with the engine temp gauge???? The computer uses a seperate (two wire) temp sensor, from the dash temp gauge, whos sensor has one wire. So you'll need to monitor it with a scantool that'll read PID's, or to measure its resistance when the engine is at operating temp or test the coolant with a thermometer,, to know if the thermostat is stuck open & the engine is running cold, or if the gauge or computers engine temp sensor is faulty. If the engine really is running cold, the computer will keep the air/fuel ratio too rich & that'll cause driveability problems, a drop in mpg & can carbon foul the spark pugs & all that can cause driveability problems!!!!
Did you figure out what was going on with the engine temp gauge???? The computer uses a seperate (two wire) temp sensor, from the dash temp gauge, whos sensor has one wire. So you'll need to monitor it with a scantool that'll read PID's, or to measure its resistance when the engine is at operating temp or test the coolant with a thermometer,, to know if the thermostat is stuck open & the engine is running cold, or if the gauge or computers engine temp sensor is faulty. If the engine really is running cold, the computer will keep the air/fuel ratio too rich & that'll cause driveability problems, a drop in mpg & can carbon foul the spark pugs & all that can cause driveability problems!!!!
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Ok so the whole way to work and back the truck acted rediculous. I had to pull off the road a few times and the last time for whatever reason I decided to pull the plug off of the MAF, tps, and iac and apply dielectric grease. I did so with the truck running and the only time it acted differently was when I unplugged the iac. Which makes sense so I didn't think much of it until a lil ways down the road. So when I stopped at our mail box I decided to unplug the iac completely and it drove like a brand new truck (other than the crappy idle). So basically with the iac plugged in she idles ok but runs like ***, with it unplugged she idles like *** but runs like a beast so I guess I'll pull the iac and check the ohms? What else should I test it for?
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From: SW Va
Check the IAC as outlined here. Ford Truck Enthusiasts Forums - View Single Post - 1997 3.0L v6 Ranger HIGH Idle
Seems to me, as the IAC is closed, unless the computer sends it a variable pulse width signal, to cause it to stay open longer, the only way for the IAC to mess with the vehicles power at throttle up, would be if the computer is sending it bogus signals for some reason, to open up.
After 7 pages it seems you find a new problem every time you drive this vehicle, but never seem to post that you've solved any of them. So its becoming more difficult to try giving trouble shooting suggestions as its difficult to try & figure out how past problems may be affecting the latest problem.
So, again, go back to the lowest trouble code number & fix it so it doesn't return & work your way up the list & post how it goes.
Seems to me, as the IAC is closed, unless the computer sends it a variable pulse width signal, to cause it to stay open longer, the only way for the IAC to mess with the vehicles power at throttle up, would be if the computer is sending it bogus signals for some reason, to open up.
After 7 pages it seems you find a new problem every time you drive this vehicle, but never seem to post that you've solved any of them. So its becoming more difficult to try giving trouble shooting suggestions as its difficult to try & figure out how past problems may be affecting the latest problem.
So, again, go back to the lowest trouble code number & fix it so it doesn't return & work your way up the list & post how it goes.
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Ok so the mechanic finally got a chance to look at my ranger. He said it ended up being the MAF pigtail so he replaced that and she's running a lot better but that once she gets up to temp she pops a code for some kind of circuit input an he seems to think its an issue in the ECM so once I pick her up from him I'm going to see if I can track one down at a salvage yard and see if swapping it makes a difference.