1987 4 cyl MJ Rough running condition

[jeepogeek]

Please elaborate on your idea as I am unfamiliar with it.  when you said you thought the truck hadn't been serviced in a long time; I'd have to agree with you.  All the components and sensors I've looked at thus far appear to be original.  with over 230k on the clock, to me, its probably time to change at least the sensors that could be the cause of rich running.  So tell me more about your "steam clean idea" please.  Thank you. 

[eaglescout526]

3 minutes ago, jeepogeek said:

Please elaborate on your idea as I am unfamiliar with it.  when you said you thought the truck hadn't been serviced in a long time; I'd have to agree with you.  All the components and sensors I've looked at thus far appear to be original.  with over 230k on the clock, to me, its probably time to change at least the sensors that could be the cause of rich running.  So tell me more about your "steam clean idea" please.  Thank you. 

So steam clean or water decarbonization as others call it involve getting the engine to operating temps and using a squirt bottle with the throttle body or the vac hose to the booster to ingest tiny amounts of water in which when water enters the combustion chamber, it blasts the carbon deposits off with the steam that was created. There’s a few videos out there that shows it working pretty well enough to give it a shot. I wonder if you have sticking valves. How filthy would you say the

engine bay is? 

[jeepogeek]

Well, there is quite a bit of oily crud stuck to the block, but, for me, thats pretty normal for an engine this old.  when I rev the engine to WOT it sounds pretty strong. Like the stumbling almost goes away.  Conversley though there is quite a bit of clatter from the valve train at idle.  however, it always starts right up.  not that that has anything to do with the problem at hand.  I'm about to change the O2 sensor and CPS.  Best I can tell these guys could have an effect.  but who knows?  What do you think?    

[Ωhm]

If it starts and runs I'd hold off on that CPS. Now that O2S has a lot to do with fuel control. Does your REM show CLOSED or OPEN Loop?

[jeepogeek]

Unfortunately I haven't mastered the REM yet but I will try to get that for you.  

[jeepogeek]

So I think it's in open loop but I'm not sure.  Like I said all this technical stuff is rather sketchy for me.  I'll check it again if you can help me learn which buttons take me where.

[Ωhm]

58 minutes ago, jeepogeek said:

I'll check it again if you can help me learn which buttons take me where.

 

Can't help on REM navigation.

[jeepogeek]

Okay thanks anyway.  That O2 sensor looks like the original so I'm going to replace it anyway as long as I can get it off the exhaust.  Probably will need to use heat on the pipe since running the engine up to temp didn't work.

[eaglescout526]

I have original NOS AMC 2.5L O2’s if you’d like to go that route. 
 

The REM is easy to navigate. Nicks instructions for the device are pretty easy to follow. I believe it’s the bottom left button that will show each individual read out of each sensor. 

[jeepogeek]

You are probably right but I'm not the sharpest knife in the drawer when it comes to this stuff.  I'll get it eventually.  This is the first computer vehicle that I have ever worked on.  I'm much better with cars of say, the 60's.  But I'm usually pretty patient and will persevere.  In the end, it's a learning experience for me.  How much for the sensors you have since all I'm able to find locally are Denso?  Thank you

[54bobby]

On 10/1/2020 at 9:54 AM, eaglescout526 said:

There’s a universal throttle body rebuild kit that I used that has a new pressure regulator diaphragm in it. It’s made by standard and I believe it’s just called a TBI rebuild kit. 

the pressure regulator kit alone was, if i remember right the same or more in cost than the entire tb kit, go figure.