83 Ranger Idling at 20 BTDC

[Jason_1984]

Thanks again for the help. I do have a compression tester. All cylinders where at 100psi +/- 5psi when doing a dry compression test. Ill work on getting myself a vacuum tester. When I was at firestone the vacuum needle was steady and reading 22 but ill double check that here as soon as I get the vacuum gauge.

 

[Big Jim M]

Yeah but!

Thanks again for the help. I do have a compression tester. All cylinders where at 100psi +/- 5psi when doing a dry compression test. Ill work on getting myself a vacuum tester. When I was at firestone the vacuum needle was steady and reading 22 but ill double check that here as soon as I get the vacuum gauge.

NOW that it is running badly do BOTH tests to see if something has changed.

A poorly installed gasket will eventually LEAK.
A poorly adjusted carb will eventually burn a valve.

As a side note I have never in my life allowed anyone to do a valve job on any of my engines. A "valve job" is artificial WEAR on both the head and the valves.
When having a burnt valve I have simply replaced the offending valve with a new one and "lapped" it in place with diamond dust.
The "non-offending" valves I have left alone. Many times I have not even loosened them from the springs.

Then when reinstalling the heads I always replace the same pushrods Back in the same position as they came from. The same tips back in the same rocker arms and lifters. I HAVE NEVER HAD A LIFTER NOISE FROM DOING IT LIKE THIS.

Big Jim

 

[Mark_88]

I thought about the links that are on YouTube and other sources and wanted to take a look at what they had to say about rough idle. I found two that might help, the first one looks like the one I put on my truck once that ran beautiful but had terrible idle...the second one is for an older carb used in the 6 cylinders...

The guy is actually rebuilding an old carb, but he explains things pretty good so you will understand the symptoms better and troubleshoot it more effectively...




https://www.youtube.com/watch?v=kimVLqWgobw

Hope one of them helps!

 

[Jason_1984]

It was wasn't running good when i originally did the compression and vacuum tests in the past. I did the vacuum test again today. Steady at 20. When I rev the engine it immediately goes to 5-7 then goes immediately back up to 28-29 when I let off accelerator. drops back down to 21 after about 3 seconds then about 15 seconds goes by and during that time it steady drops down to 20 and stays there.

 

[Mark_88]

Sounds like it is running fine as far as valves go and everything else for that matter. Did you get a chance to view the videos or find something relevant?

I have a Motorcraft 5200 2 bbl and intake that came off a 78 Mustang II...it worked way better than my original but when I was having problems with it I could not find any information...then out of nowhere I found a complete tuning and rebuild guide that helped me quite a bit. I've since gone to fuel injection on a 2.5...still not finished that yet.

Anyway...it would be good to hear if this worked out for you or if you still have the rough idle!

 

[94RoadkillRanger]

I bought a rebuilt carburetor but had to adjust it every week after it began to sputter. Finally, I put some thread locker on the idle rich screw.

You may also have some dirt in the line that randomly messes with stuffs.

 

[Jason_1984]

Well thanks for the help. It sounds like going into the carburetor is the next step. I am not familiar with the insides of carburetors and am a bit nervous about cracking her open. If anybody has any insight please let me know. Otherwise I will keep you posted with what I find out.

 

[Mark_88]

Before you take the carb apart (because I doubt there'd be an internal problem so fast) try adjusting it if you can...I've only ever had to remove my carb a few times and usually only had to pop the top off to get at the float and jets...

Your truck is otherwise running fine except the idle...so I would give that an honest attempt first.

Otherwise...take your time and if you can watch a few videos and keep them keyed up and ready to roll if you get lost...

Most important is use the right size screw driver for the screws and don't let them skip on the threads...best to use a ratcheting screw driver if you have one...just push it hard into the screw head before turning...once they are "broken" as in the tension is released from the farthest in position, they come out easy...but some of them may be a bit longer than you'd think so the ratcheting driver saves the WaT (wear and tear) on your body parts...

If you need to replace any gaskets (this should be the new or rebuilt carb you just put on) they can be ordered but you need the little tag from the carb...they can find the right gasket set faster that way...

 

[Jason_1984]

That's kind of what I figured. That it shouldn't be out of adjustment already but I don't know what else to try. I have tried to adjust carb (external) in past and just cant get it where it idles smoothly. I adjust the air/fuel at the base of carb. then I go to idle speed on the side but it never idles smooth. I am leaning towards the computer messing with the idle. Im not 100% on this though. One reason I am leaning this way is because its about the only thing that hasn't been replaced or adjusted. 2 because it goes from idling smooth to idling rough in about a week after adjusting the carb. I don't notice that the screws on the carb are turning themselves with the vibration. I sure wish I new how to test the PCM on my vehicle. I tried to scan with OBD1 but I cannot find the single wire.(I think its called pip signal) I can only find the plug. Honestly I wouldn't have an issue getting rid of all the emissions and computerized stuff if it was possible to bypass. Anybody have any insight please don't hesitate to share.

 

[Mark_88]

Well, I can understand your frustration by all means...been there many times and usually had to come to TRS for input...and many times I did receive helpful info...but sometimes nobody knew what was wrong.

That was partially why I wanted to know what carb you had. There are a few people on here that have extensive knowledge of the carter carb you are running but they tend to hang around the 4 banger section below and not here but sometimes they don't show up for a few days/weeks. What I found on Youtube wasn't exactly what you need and I watched most of it...just didn't hear what you were experiencing.

Now, the computer, so to speak, that your truck has would only affect the idle directly by something like a choke if automatic and possible idle kick down if present. The base idle is set by the little screw and arm on one side of the carb. That is totally manually set and not affected by the computer.

The idle kick down and choke only apply when the engine is cold and only till the engine warms up. That is when you hear the idle drop and you can rev the engine with noticeable increase and no excess fuel smells. Once the temperature of the engine reaches operation levels the feedback system of temperature will tell the ICM (computer or idle control module) to open the choke and drop the idle.

That is something I meant to ask before...have you watched the choke during operation and driving to see if it is opening properly? The butterfly on the carb top should be fully opened when operation temp is reached. If the butterfly is only partially opened you have restricted air flow...I'd imagine this was the case simply because your fuel consumption would jump and you'd smell the excess in the exhaust...among other symptoms like sluggish acceleration and bogging...

To bypass the computer, you simply disconnect any wires that go to the carb. There seems like a massive amount of wires for such a simple task, but it's sort of like the older computers that used to fill rooms...not needed with solid state printed circuits and all that...they work on a simple open/close gate principal to allow a set amount of current to activate a single switch or a couple of them...if you have a manual choke and no kick down idle then the computer is redundant...and can be removed completely.

Older carbs used that sort of system and could run without any input...my 5200 had no choke (I removed it) and I removed the idle kick down when it stopped working to no noticeable effect. The truck would start in cold weather with the help of a block heater...and it would idle around 900 rpms using the idle screw...

 

[Jason_1984]

I was going through my wiring diagram yesterday. I noticed an Idle speed control motor, idle fuel solenoid, and fuel control solenoid. I was able to locate 2/3 components. I cannot find the idle speed control motor. When I go to the auto parts store there is a Idle speed control motor listed for my vehicle but I cannot locate it on my vehicle. I guess I assumed this part would be on the carburetor but I cannot find it. Any ideas?? Also on the wiring diagram there is a PCM and an idle speed control. They look to be separate on the wiring diagram. I am unable to find the Idle speed control location. On the wiring diagram it almost looks like a secondary PCM. It has multiple wires running to it. I also was looking for clarification on coolant temp sensor location and I am unable to locate that as well. I did find the sender but not the sensor. Not by thermostat. (could be buried under my intake where I cannot see it) Any help on the specific locations of these components is greatly appreciated.

 

[Mark_88]

What book did you find this in? I have a Haynes manual and it outlined my vehicle exactly as per wires, but because there were two or three different carb verstions (2bb, 1 bbl and variations of such) it would have to specify what carb it is referring to.

The stock Asian 2bbl was found on 87-88 2.0 engines...the stock Carter yf 1bbl was also on some of the 2.0 engines...the 2.3 I'm not really sure what it had in 83, 84 and 85...

I will go find my Haynes manual and take a boo at the wiring diagrams...I can even take pics and send them to you if you'd like...if you have something different.

 

[Jason_1984]

I found the wiring diagram in the Haynes Manual. Specifically for 83 Ford ranger 2.3. If I knew how to post images i would post the diagram, but it keeps asking for URL and since it is a picture off my phone it does not have a URL. (not a computer guy) I did look at the vehicle again and still unable to locate the coolant temp sensor (just to test to be sure its functioning properly) I also still cannot find the idle speed control motor or Idle speed control. (perhaps it just looks like 2 PCM units on the wiring diagram but maybe its all in one unit) I would like to perform a test on the mixture control solenoid wiring but not having any luck. I did test the unit itself and it does click when I apply and remove 12V. But says I am supposed to test dwell/duty cycle. (no experience testing dwell) But not sure how to test the wiring either. (using my stethoscope I do not hear a click when vehicle is running or turned to on position) I think one wire on the mixture control solenoid goes to PCM and the other goes to a barometric pressure sensor. Any ideas how to test the wiring. (just so I can cross it off the list or replace if needed)

 

[Jason_1984]

http://www.autozone.com/repairguide...DIAGRAMS/WIRING-DIAGRAMS/_/P-0900c152800781b2

Should be 3rd diagram from top. Fig.3 ------- 83 ranger 2.3


I don't have a lot of experience with a Multimeter other than voltage tests.


Questioning
idle speed control (location)
idle speed control motor. (location and testing procedure)
Coolant temp sensor(not sender)(location)- not by thermostat. found sender on block but unable to find sensor.


Found Idle fuel Solenoid on carb. (curb idle)- unsure how to test.
I believe the fuel control solenoid is my mixture control solenoid on carb. - Need to know how to test wiring to sensor and also the correct procedure to test the solenoid itself. (other than applying 12 V and it clicks)

 

[Mark_88]

Most people (non Premium Members) open a photobucket or similar account and that allows you to post the URL to specific photos. I have a Premium Membership and can post pics to TRS but I also have a Photobucket account just because I lost a whole bunch of photos to a computer crash. Your choice...I always recommend the PM just because it promotes the site but the PB is free...PM costs $10 a year...not a bad price.

My best suggestion for the wiring is to simply go by the color listed and trace them to where they go...sometimes can be a pain when grease covers them or those plastic wiring containers need to be prodded (be careful because 30 year old wires can be brittle) but it really is the only way...

The Temp sensor...usually on the intake manifold but could be on the block...driver side usually but 83 was the first year...it has a Light gree/yellow wire and goes into the Idle Speed Control (that mess of wires on the passenger side) but also has another wire that is Black/Light Green and goes a body ground somewhere close by...probably the front cross member beside the rad...but who knows!

Its usually best to have a supply of clean rags and some cleaner handy to clean the wires...the first color is the main body of the wire...the second color is a stripe usually...and very hard to see sometimes so you may need to clean a large section of the wire and roll it a few times...good glasses or a magnifier and some strong light are needed...and best to do it at night so the sun doesn't blind you...a garage would be ideal.

Finding the Microprocessor Control Unit (MPCU) may be easy if you can find the O2 sensor listed as the exhaust gas oxygen sensor...these are usually on the exhaust manifold and yours shows a wire running from it directly to the MPCU....it shows it as Dark Green/Purple...so trace that wire and you will find the MPCU

As far as testing the sensors...they are usually only 5 volts but may be 12...you can just test them during operation by measuring the voltage...may be gradual or may go direct from 0 to 5 or 12 volts when activated...you may need to puncture some wires to test and, again, be careful especially near the sensors...damaging the wire too close to the sensor can mean you may need to actually replace the sensor...

Finding out what voltage they should be may be another matter...not sure where that information could be found...RonD who often posts on here or in the 4 cylinder forum usually has the information...or it may be in the Haynes manual under troubleshooting...not sure because I can't find mine right now...

Maybe post another question in the 4 cylinder section below...or Personal Message RonD...with the direct question...there is a way to do that once you find the person...although I'm not sure if he'd appreciate it...he is very helpful and this is a fairly specific question that probably only a few people might know...

There is no Tech Article currently that I'm aware of on sensor voltages as to what they are and what their range is when functioning properly...so it might be a good one to build some day...