Belt Tensioner

[peakcomp]

Broke off while driving. Replaced the entire belt tensioner assembly. Just replaced the belt itself less than 4 months ago. Didn't think I need to replace the belt...but, how would one tell that it needs to be replaced?

Also...the 95 Ford Explorer OHV with 127,000 mi on it...has trouble starting and idling often. I am not 100% convinced it is only when it is warm...but, seems that way. When it's 100% cold, especially in the winter..no trouble starting or idling..but, after it warms up and gets driven some...when it it turned off and sits for about 30 mins or so...it has trouble starting..and when it does start..rough idle for about 1 min or so...then something 'kicks in' and it idles fine.

I did replace 1 oxygen sensor...the after cat one...was thinking it could be the other o2 sensor...or maybe even the Thermostat..the vehicle may not know the car is warm...so it keeps changing stats to match a cold car..thus causing the idling problem?

I know one thing, the idle problem is causing me a headache...

Oh, I cleaned the IAC already.

Any advice is appreciated.

[1998Exp]

The secondary O2 sensors (downstream from the catalytic converter) have no effect on engine operation, because they are 'out of the loop', and for monitoring emissions only.
As far as the thermostat goes, it could certainly be bad, but you got the story backwards a bit: the thermostat is responsible for controlling the engine coolant temperature, but not for reporting it to the computer. There is a sensor (called ECT) for that purpose.
Your story sounds like you may have a defective IAC (idle air controller), but I don't have any experience with your engine, so definitely can't say that for sure. Others will certainly help you, but will like to know the trouble codes. Even if the CEL is not on, you can have it scanned and see if there is anything stored.

[peakcomp]

It is a 95 and obd I. Therefore, no scanning. I did use a paperclip trick on it, and there are no codes being displayed or reported.

[1998Exp]

Sorry about overlooking the model year!
OBD-1 has poor self-test ability, but it can still tell you something before you throw more parts at the problem.
You can use your paper clip to run KOER (on-demand diagnostics with engine running). Essentially, you start a previously warmed-up engine with that paper clip in place, wait for a cue (a long pulse if memory serves) and help it test itself with a few maneuvers: something like briefly stepping on the accelerator, stepping on the brake and turning the steering wheel). The details may be specific to your model year. I am sure you can find them (and the interpretation of the resulting codes) on the internet. Hopefully, someone with Ford 'emissions and engine electronics' book or CD for MY95 will chime in here and provide them. The usual wisdom is to service the first code in the list, then re-test.

[peakcomp]

I have already done the paper clip, no codes listed other than the All system okay code.

[windsors03cobra]

If cleaning IAC didnt help I would replace it.

[Carguy3J]

First, there is an easy way to test the IAC. With the motor running, and with it idling "poorly", disconnect the IAC electrical connector. Did the idle improve? Then there's your problem. Also, with it idling "normally" do the same thing. Does the idle drop, or the engine "die"? That should confirm that the IAC is functioning. If it is bad, just replace it. I've never had a "bad" one come back to life by cleaning. Is it possible? Yeah, if the stepper motor is fine, and there is just a bunch of carbon buildup. However, it is nearly impossible to get into all the cracks and crevices to clean it.

Second, Ford ecm diagnostics have 2 different sets of codes:
1.) KOEO (key on, engine OFF) - this provides what is called "Hard" codes. Any of these codes should be addressed first, in the order that the computer spits them out.

2.) KOER (key on , engine RUNNING) - these are "soft" codes (also know as continuous memory codes). These codes, if any should be addressed AFTER addressing any "Hard" codes.

If you've erased the codes by pulling the fuse or the battery, then you'll need to drive again for a while to allow them to set again. If you don't have the proper test equipment, it would be a good idea to take it to a shop w/ the proper scan tools. Explain to them what is going on, and just ask them to check the computer for codes. If you shop around, you should be able to find a shop that will run the scan, and maybe do a quick diagnostic, for a reasonable fee. You can then go ahead and do the actual repair, that they recommend, yourself. If you're honest with them, upfront, that you intend to do the repair yourself, and just need a little help w/ figuring it out, many will be willing to help. Stick to small, local shops. The chains (STS, Firestone,etc..) are usually jerks, who won't deviate from company policy to save their grandmother's life.

[joe doe]

are you losing antifreeze?have you looked?whenever i see a post about a funny idle for a minute then it clears up i am reminded that i have a cracked head.
because thats what explorers with cracked heads do.....
after sitting for some time(like overnight)a cracked head will leak a small amount of antifreeze into a cylinder,when you start it up that first time the engine will idle rough until that antifreeze is burned off,then it smooths out .

watch for misfire codes and lost antifreeze .

hope i didnt scare ya too bad ,but thats what mine does and i have a cracked head.

every other month i have to change plug number 4 because the insulator cracks on the plug .

just keep an eye out ,thats what i,m sayin.its a common ex problem

[1998Exp]

Originally Posted by Carguy3J

....
Second, Ford ecm diagnostics have 2 different sets of codes:
1.) KOEO (key on, engine OFF) - this provides what is called "Hard" codes. Any of these codes should be addressed first, in the order that the computer spits them out.

2.) KOER (key on , engine RUNNING) - these are "soft" codes (also know as continuous memory codes). These codes, if any should be addressed AFTER addressing any "Hard" codes.

If you've erased the codes by pulling the fuse or the battery, then you'll need to drive again for a while to allow them to set again. If you don't have the proper test equipment, it would be a good idea to take it to a shop w/ the proper scan tools. Explain to them what is going on, and just ask them to check the computer for codes. If you shop around, you should be able to find a shop that will run the scan, and maybe do a quick diagnostic, for a reasonable fee. You can then go ahead and do the actual repair, that they recommend, yourself. If you're honest with them, upfront, that you intend to do the repair yourself, and just need a little help w/ figuring it out, many will be willing to help. Stick to small, local shops. The chains (STS, Firestone,etc..) are usually jerks, who won't deviate from company policy to save their grandmother's life.

For what it's worth:
The OPs MY95 vehicle is OBD-1. As he mentioned, the only 'diagnostic equipment' needed for this system is a paper clip (to ground the test pin of the diag connector). The codes are flashed on the CEL. To erase them, there is no need to disconnect the battery; one simply pulls that clip out while still in diag mode. Similar to OBD-2, it takes more than one occurrence of a malfunction for a code to turn on the CEL, so yes, it won't be back immediately.
KOEO and KOER exist, but they are are much more primitive. Same paper clip enables them.

[peakcomp]

WOW! Cracked head? we did replace the plug this year...one was cracked. Didn't notice any fluid in the plugs tho...maybe that is the problem...is a cracked plug...would that be due to the cracked head?

Originally Posted by joe doe

are you losing antifreeze?have you looked?whenever i see a post about a funny idle for a minute then it clears up i am reminded that i have a cracked head.
because thats what explorers with cracked heads do.....
after sitting for some time(like overnight)a cracked head will leak a small amount of antifreeze into a cylinder,when you start it up that first time the engine will idle rough until that antifreeze is burned off,then it smooths out .

watch for misfire codes and lost antifreeze .

hope i didnt scare ya too bad ,but thats what mine does and i have a cracked head.

every other month i have to change plug number 4 because the insulator cracks on the plug .

just keep an eye out ,thats what i,m sayin.its a common ex problem

[peakcomp]

Now the top radiator hose was collapsed, and after replacing it..refilling with fluid..the temp gauge fluxuates from normal (1/4) to a half (1/2) and back and forth slowly...

people are telling me air bubble, radiator cap replacement maybe..water pump...thermostat....any definitive ideas?

[joe doe]

when you have a head crack the plugs "insulator" will crack .thats the porceline
that surrounds the center electrode .heres one of mine for example.

see the crack,thats what a cracked head will do to your plug.this happens to mine every other month or so .plus i am still losing antifreeze .


Shot at 2010-07-13

the fluxuation in your temp gauge sounds like a stuck open thermostat.

[Carguy3J]

Originally Posted by peakcomp

Now the top radiator hose was collapsed, and after replacing it..refilling with fluid..the temp gauge fluxuates from normal (1/4) to a half (1/2) and back and forth slowly...

people are telling me air bubble, radiator cap replacement maybe..water pump...thermostat....any definitive ideas?

I just went through this w/ my Ranger. Mine would also "thump" when it warmed up, almost like a car driving by w/ the bass cranked up. I could've / would've swore on my life that there was no air in it. I thought maybe a brand new thermostat was bad. Several people agreed, some said air.

Well, Achem's (also spelled Occam - after the guy who said it first) Razor prevails here. The simplest explanation is usually the right one. It was a massive air bubble.

Remove the radiator cap. Start the truck and let it warm up a bit. Make sure you have the heat on high, to get any air out of the heater core as well. Now hold the throttle open some (maybe 2000rpm or so). Keep your face away from the radiator filler. It's gonna start puking out the air at some point, in a big shower of anti-freeze. After it doe sit once or twice, let it idle again while you top off the radiator. Do this until it stops "burping". Problem solved. Well, except for that big mess you just made......

[peakcomp]

Thank you. We replaced the themostat, after draining the fluid..and it the temperature gauge seems to be holding so far. It's only been a few days tho. We will see.

Ken

Originally Posted by Carguy3J

I just went through this w/ my Ranger. Mine would also "thump" when it warmed up, almost like a car driving by w/ the bass cranked up. I could've / would've swore on my life that there was no air in it. I thought maybe a brand new thermostat was bad. Several people agreed, some said air.

Well, Achem's (also spelled Occam - after the guy who said it first) Razor prevails here. The simplest explanation is usually the right one. It was a massive air bubble.

Remove the radiator cap. Start the truck and let it warm up a bit. Make sure you have the heat on high, to get any air out of the heater core as well. Now hold the throttle open some (maybe 2000rpm or so). Keep your face away from the radiator filler. It's gonna start puking out the air at some point, in a big shower of anti-freeze. After it doe sit once or twice, let it idle again while you top off the radiator. Do this until it stops "burping". Problem solved. Well, except for that big mess you just made......

[peakcomp]

So far, proves to be true. Replaced. Temp gauge holding so far. It's only been a few days tho..

ken

Originally Posted by joe doe

when you have a head crack the plugs "insulator" will crack .thats the porceline
that surrounds the center electrode .heres one of mine for example.

see the crack,thats what a cracked head will do to your plug.this happens to mine every other month or so .plus i am still losing antifreeze .


Shot at 2010-07-13

the fluxuation in your temp gauge sounds like a stuck open thermostat.