5.8l engine to start.

I pulled codes but cant remember what they are, Im going to have to do it again.

But in the mean time, Fuel pressure is 32 running 39 not i believe.

It idles rough and when the engine is cold, and also does what i would call hesitating/surging when accelerating. I will give some throttle and the truck will kinda act like it isnt getting enough fuel and to much air and then WHAM!!! all the ponys are there and the thing screams. I would say 1-3 second delay from throttle depresed to actual response.


It goes away once the truck is warm. I did put a new thermostat in it because the old Tstat was swinging bad. It would go from cold to hot and back again, never stay in the middle. The new motorcraft one holds it on the cold side and barley ever gets to 195. I get hot air out of the vents, but i dont think its hot enough personally. Regardless it will warm the truck up.

Could the Temp sensor affect anything in the truck as far as engine managment and driving? It seemed worse with colder temps 0-10 degree. Now being 20-30 its not as noticible.

My MPG still suck though 8-10 driving 6-7 miles to work. 3.55 rear 33in tires, reg cab short bed.


I will get codes again as soon as possible. I remember it was saying one of the banks was lean and also a fuel pump secondary circut was a problem.


Anyways thanks for any advice thus far and we will see as i get farther into this.

 

fuel filter?

 

94 f250 runs rich - Ford Truck Enthusiasts Forums
I had the exact same problem as your explaining. You'll find all the answers your looking for there

 

ya i seen that thread. Its deff possible.

 

Don't get me wrong I started with all the problems the codes were giving me. Once I was done replacing all those parts its still ran the same, I put a new computer in and still did the same. Come to find out the computer that I bought was bad.. I would start with the obvious things like o2 sensor, map sensor, fuel pressure regulator, and the temp sensor. from what I have learned those are the basics to fuel air mixture. Depends on what the codes read

 

Does the temp sensor play into the control system at all? Thats what i want to know.

 

yes it does. If the temp sensor is not working correctly it could thow off your fuel air mixture. If it is faulty it could prevent the system from going into a closed loop telling the computer to give more gas than air or less gas than air..

 

Is there a seperate temp sensor for the computer and the gauge or are they the same sensor. Also where are they located. Becasue im going to change it to see if that corrects my running rich issue. Its very possible the truck never goes to open loop and dumps extra fuel in thinking its warming up.

 

If I remember correctly, The coolent temp sensor is located on the front of the motor bolted on the intake. And yes the coolent temp sensor is for both the gauge and for the computer. I found this out when I changed mine. Once I put the new one it the gauge started working again.

 

No that's not true.. you guys are your own worst enemy. The dash gauge sensor is seperate, it's a little single wire thing in front of the #5 injector on the V8 trucks. The computer sensor is on top of the thermostst housing.. usually in the coolant tube feeding the heater core.

As for solving the rich problem, start with the codes and try to eliminate any problems there. Note the self test has to be performed on a warm engine otherwise the temp sensors will be incorrectly flagged. Also check fuel pressure and for a leaky FPR, and also make sure the truck doesn't have the fuel transfer problem if 2 tanks are present.

 

This is why in my first post I took him to my thread, because its pretty much the same issue I was having. Started with what the codes said and went from there. Just because the codes say one thing don't mean thats the exact problem. Connan Your right tho I would start with what the codes say and go from there other wise your on a wild goose chase.

 

Chilax bud. I will get the codes, i know the procedure. I have already been down this road with this truck, just didnt get far enough into the problem to get it fixed. It was to damn cold out.

Regardless im going to fix my temp gauge issue, so thats why im going to replace it. And needed to know if it was the same sensor or if there was 2.

Codes will come tomarrow im hoping as long as i get home to my scanner.

 

I only found one temp sensor today. Its on top of the coolant houseing. I switched it out and the gauge reads slightly higher but still swings from Middle of normal to below the N pretty fast. Normally it hovers right below N of normal.

Would the intake charge sensor have any effect on these issues?

Im going to autozone to get my codes tomarrow as i didnt make it home to get my code reader. Well see what they say.

 

I got the codes pulled by auto zone today. They only did KOEO test. they got codes 172 and 173.

Lean engine condistion and rich engine condition.

I do have a small crack on my passenger side of the truck where theres a small tube comming off the manifold or down pipe (cant remember) i also cant remember if its upstream or downs stream from the O2 analyzer.

 

those codes could mean just about anything. p 172 Fuel Trim too Rich (Bank1) p173Fuel Trim Malfunction (Bank 2)
My father's explorer had p172 codes come up on his explorer and turn out we had to change the over head cam. Once we changed it truck has been running awesome. If I were you I would take it to a shop and spend the little money for them to tell you exactly what is causing those codes to come up. other wise your playing a game of trial and error which could end up costing you a lot of money in the end.