I'll be curious what you find, I am having the exact same problem with the truck not idling because its running rich.

 

Well husky your not the only one who's interested. I am too!!

It seems that somehow I'm getting closer but just not there.
I played with the EGR some last night. At idle there is zero vac. When I bump the accelerator I get 5 in-Hg.
The EGR will hold vac set it at 5 in-Hg and left it and after 4 or 5 min it leaked down to about 3 in- Hg.
While playing with things I pulled the vac conn on the PCV and well idle smoothed out. But I also noticed that the muffler next to the canister was not having air pass thru it. I put vac on the valve and got air to pass. So I checked vac at the canister got 16 to 17 in-Hg at idle. Was getting dark so I'll recheck today to see for sure the measurement. I am getting exhaust from the back left corner of the motor rising up from near the firewall. Used a mirror and can't see anything leaking yet.
There are two air check valves ?? there so some of this may have something to do with this!!??
Anyone know what these are?? Rla2005 or Subford wanna chime in on this???

Can this be clogged? And cause weired problems like this? It seems highly unlikely but the more I played around it seemed to help the idle and smoothness of the motor. It is hard to start but if I unhook the EGR vac line it starts easier.
I have been wondering about the little valve?? In line with the PCV valve and the canister. What is its function in this setup. I cannot find any real good information on this area of the motor so if anyone knows where to get it, i'd love to learn more about it.
Sorry for the long posts. But I figured the more I say the better someone may understand or recognize what the problem might be.

Any and all help, ideas, comments, observations, anything very welcomed at this point!!!
I am really lost at what to do. So I'm really just playing with this and just seeing what happens if I do this or that. Just to see what happens if I do this or that. Does it get better or worse dose it help or not?? I'm guessing my butt off!!! Just hoping I'll stumble or get lucky and find something that works!!!

Thanks for any help etc. Cause I need it!!! LOL!
Charlie

 

Not sure if this will help or not, but here's the pinpoint testing for a CM code 334. It's for a 1993 with the 302, so I'm not sure if it applies to a 1994 but maybe something will stick out.

 

Thank you for the test. That's awesome info. East302 thank-you very much. I don't know if it applies either but gives me something to try that I haven't yet. Maybe someone will let us know about the test!!! HINT Hint!!!!
Well while playing with vac lines I pulled the vac tree. I had a cap gone from one of the ports. They have all been replaced today. I retested the EVP sensor it failed ohmed out at 3781. Took back to parts store and swapped for a new one. Before I left store I checked ohmns on it and got 4787. Haynes says should be close to 5k. Figure close enough. D the
Replaced se nsor and warmed it up and ran KOER. Prior to this I cleared all codes. Results 126,173,and....
Yep, you guessed it 334!!! I also tested the new EGR and it passed the test.

So now I gotta test the O2 sensor and the MAP again. But seems we are making progress sorta!!!
Wish me luck! Cause I need it!!
Pretty sure gonna have to replaced the O2. She is definitely running rich. Can smell the fuel in the exhaust.
But if bad map??? May have to replace it first. Then chek cO2 again.

Well that's the results for now. I will post as I get info. Till this DANG thing runs like she should. I'm in it now and I'm not quitting.

Thanks everyone!
Charlie

 

You can get the factory test procedures for each DTC through an online subscription to alldatadiy.com. It's around $20 a year and isn't bad if you don't have a Ford shop manual.

 

Have you tried unplugging the MAP sensor yet?

 

Great info east302!

Ian, since I changed the PCM not yet. I have tested it tho and got conflicting results two different Hz readings. Both tested in a good range for a Ford MAP sensor. But now that I am reviewing everything I am wondering if this test is valid. What is the proper test procedure for the MAP sensor? Haynes has a test using rpm so I know I did not use it due to not having an idle!

Like I said I'm checking everything including test procedures to make sure of the answers I am getting even if I know I'm right before I do it!! Once I check procedure. I am writing down my answer so that I don't confuse old #s with new ones. I'm doing this in case new PCM has a problem and so I don't get confused with thinking I tested that and got ### and am wrong.
It is on the list to do when I test the sensor in the next day or so. Due to the bad PCM I don't want to confirm a part without double checking my results testing and not trusting anything to memory.
So I am moving slowly forward again just cautiously. As can be seen I have found something's by doing this so its worth it!!
Thanks
Charlie

 

86 that Chilton's. You need a Ford service manual. Most of the stuff Chilton's has had you do has led you astray.

 

Agreed. Ford's pinpoint tests make troubleshooting these DTCs so much easier.

 

Anyone have a good source for the manual. I never had need for them before!! She seriously has never had any real problems till now!
I've always been able to figure out any problemsthis truck has had fairly easily. So I am on new ground here!!
Thanks
Charlie

 

Hi,
I found all 3 of the FORD shop manuals for my 89 F-150 on the Bay for $75+shipping and jumped on them!

Glad now I did....A LOT better than Chilton's or Haynes!!!!

 

The MAP Sensor can only be tested with a vacuum gauge and a multi meter capable of reading frequency.

The best thing to do for a quick test is to just unplug the electrical connection, and see how the engine responds.

 

Ian
That is how I tested it.
I use my fieldpiece by Fluke ( I use this for HVAC work ) and a vac pump..

I received the motorcraft IAC and put that in. Idle much better. Not completely smooth, but better.

I did not retest MAP, but I did unplug the MAP sensor.

Idle went high but very smooth. The way it was a month or so ago.

I just ordered a motorcraft MAP tonight. I'll get it Mon or Tues.


Then hopefully I can get to sort out the rich smelling exhaust. I'm thinking it's the ECT. Tomorrow I'll pull it and test on the bench..

You called it right.

I'm searching for shop manuals. I forgot to say no longer have access to them cause I don't work for that shop anymore. I used to use them and forgot about it. I mainly use the Haynes I have for torques and pics of specifics to see how they are put together. But y'all are right I do need them. I've just been putting it off.

Thanks for everyone's help. It has been greatly appreciated and needed. I just got lost when the outer was bad and I needed a kick in the pants to clear my head.

Being diabetic doesn't help either. It makes me forget stuff that I know well for short periods of time. It is very frustrating. It gives the biggest case of CRS anyone ever had.
So if I appear thick headed at times it's not me. I'll get it but I have to stop and think and forget it and have to start over again. Many other people who are type 1 like me have had years to learn how to adapt but I have only been diagnosed for about a year and a half.

It's not an excuse I know!! But it does affect me wether I like it or not. So I really do appreciate everyone's patience with me.

Thanks
Charlie

 

Alright guys time to update again!

So far mostly waiting on parts to come in. As they come in I am replacing them and waiting for something else. But we are getting there.
So far I have replaced the following : PCM and then
Plugs, wires, cap and button, ACT, IAC, MAF, EGR and EVP (twice).
I am now waiting for a fuel pressure regulator.

I tested fuel pressure 52. On both tanks same answer.
I did unplug vac line.
So I should hopefully get a clear bill of health ( no codes) after I get FPR tomorrow.
It is running better and smoother than before but running very rich. Can smell fuel in exhaust and O2 code tells me that it is rich so...

All-in all this has been a very long haul to get here. Once I get FPR in I will drive it for a good 20 miles since I am clearing codes by battery disconnect. I will verify before I start to see if I get an all clear code.
We shall see if I get any codes from there .

Thanks
Charlie

 

You got 52 PSI of fuel pressure?