O2 sensors have their own codes, and you didn't report any O2 sensor codes, so I wouldn't worry about O2 sensors until you are getting all pass codes from the computer without resolving the problem.

 

thanks, that helps to know.
Right now I'm working on the EGR valve, trying to clean it up.
Looks like it has been shut for a long time.

That wouldn't effect idle would it?
isn't the valve closed anyway at idle speed?

I'm still not giving in, something is whack and I'm bound to get to the bottom of it. or I'll deal with it, which ever comes first

 

From my best understanding, the EGR opens up until the engine reaches a certain temperature, then closes. It wouldn't surprise me if that's part of my issues as well, as it takes quite a while for mine to warm up. It may or may not affect idel, it all depends on how it being seized shut (I'm guessing that's what it's doing?) affects the computer. Are you sure you got all of your vacuum lines routed correctly, and that there are no other vacuum leaks?

 

As far as I know, I have no vacuum leaks and everything is routed per the diagram under the hood. I'm kinda thinking I may just have to deal with it for now. I don't know where else to look and for the life of me I can't figure out why it's running so rich at idle.

One thing I have not tried is to take the air filter hose off the throttl and see if anything changes.

plus that o2 sensor, but I don't have a code for that so I'm assuming that it is functioning properly.

20 years old, 175000, I guess I shold be lucky that this is all that's wrong

 

Plugs !!!!

I haven't checked the plugs.
Durrrr !

That's my last hope.

If that doesn't work, well........

I'll be back

 

If it's running rich at idle ALL THE TIME, the computer is getting bad signals, you may have some junked up injectors, as well as the intake sensors / parts could probably stand a good cleaning. Plus, not to mention, you may have some gunked up plugs and/or need a tune-up. You're going to have a "rich" condition when the vehicle is cold, until it warms up. Bad thing is, the EGR setups on these probably create and contribute more problems than they help anything!

 

your right about that !!

To be honest, when you first start it cold it revs up to about 1300 like it always did, runs without stumble for about 2 -3 seconds and then instantly drops down to about a 1000 rpm and starts to gag.

For years it reved up to 1300 and after about 15-20 seconds it would idle down and run great. I just thought it was normal

Would the eec coolant sensor make this problem exist ?
Can they be volt tested?

I just learned of the second temp sensor today.
Thanks !

 

Yes, the ECT for the computer can be tested, can't remember if the Read First/Tech section has the procedure or not, but I know I have seen procedures somewhere, maybe on TRS. Your situation isn't near as bad as mine, mine will start up, rev up to 13-1500, run for a few seconds, and drop down and sometimes die and I have to restart. I've always been told it's more than likely due to things needing to be cleaned, especially the IAC. Thing is, it should high idle until the engine warms up, which leads me to believe the ECT could be screwy, IAC could be screwy, EGR or hot air tube, etc. Lots of things to look at, including tune-up and fuel delivery / injectors / etc. I think when I start really worrying about mine, I'll pull the upper intake off and port match upper and lower intake as well as the throttle body flange, as well as put new injectors in and clean up / replace parts, etc. I also eventually want to do a 5.0 throttle body conversion, among other things...

Anyhow, back to the ECT... check out the Read First / Tech articles on here, as well as check out therangerstation.com's tech area. Lots of good info, and it tells you how to check all of the sensors, if I remember right. Hope this helps!

 

Seems to be functioning, drops voltage like it should, spit a code when i messed with it, which is good I guess.

Nice and tucked away, that was fun.

Changed the plugs, didn't change much on cold start.
Drives a little better when it's warm.

I'll keep lookin'....

 

UPDATE:

Well, ran out of time to work on it for now so I've been just dealing with it.

Today it rained real hard and fast enough to flood the streets pretty good, and when i went through some bigger puddles, I started to stumble pretty good like the engine was cold. It just would not go, kind of chug chug.

Makes me wonder about the O2 sensor, if the water cooled down the tailpipe
it would think it's running cold.

I'm speculating, but maybe it's not heating up ??

Still no o2 codes present.
Also going to change the temp sensor.

 

You may want to make sure your distributor and plug wires, etc. under the hood aren't "holding moisture / water", that could be part of the problem. Can't remember if this issue was already addressed...?

 

My truck had the same symtoms and I found it was a bad ground. The negative wire from the battery to the side of the engine block stops on the frame and has unique clamp bolted to the frame. This connection was totaly coroded. I replaced the wire, but I used a continuse wire from the battery to the block and I used a seperate cable from the frame to the block. The way I found the problem wasto use a volt meter at the cigarette lighter and noticed a voltage fluctuation while driving and it got worse when I turned on the fan motor or lighting load. Check it out....

Good Luck!

 

Well, continuing on as time allows,.......

Today I decided to unhook the o2 sensor.
Dropped the code for sensor out of range, but the truck ran exactly the same.

No black smoke no change in anything, exactly the same. Lean...

i'm assuming that the coolant sensor tell's the computer what to do at cold start untill the o2 heats up ??

I checked the voltage on the coolant sensor, but that means crap sometimes.

What happens if you unhook the coolant sensor ?

 

Not sure, but it may run rich, since it won't sense a temperature at all. Wonder if both sensors are bad, or if the air intake temp sensor is also a problem. You may also want to check the battery/cables closely. How old is your battery? That may have something to do with it as well. I plan on putting in a new(er?) battery and replacing the cables, at least the negative cable on mine (I believe it's the original!), among other things. I need to do a serious once-over on mine as well.

 

well, the o2 sensor is broken, didn't notice that.
the temp sensor seems ok, I unpluged it and the truck went nuts, but that doesn't mean spit.

I do have this "clicking" noise that I cannot isolate, I'm sure it's not a lifter.
it seems to be centrally located.

Do injectors make noise when they are bad ?