Hi!
Okay, I bought a 1992 F250 about three days ago. When I test drove it, I did note that at 60-65 I gunned the gas pedal to see the reaction. The truck didn't pick up speed much but the tone of the engine became a gurgle.
This truck has 44K miles on it and a new motor (not a rebuild) 351W with less than 8K miles on it.
So, being a naive girl perhaps, I assumed that (and still am assuming) that this is a simple problem.
After driving about 80 miles I began to feel the truck surging upon acceleration. By the time I got home (I did not think I would make the last few miles) the truck would not go over 25 mph and sputtered. I pulled over a few times and put it into neutral then blasted it with the gas pedal (in desperation and frustration). The motor would sputter than open with a sound similar to something spraying within the engine compartment.
This truck did sit for a while. I had the fuel filter changed the next day and the mechanic said it was very, very dirty. I picked it up and it drove, but not great. Within 15-20 minutes the problem returned. It creeped home at 25 mph.
So, today, in the freezing snow, I pulled off the exhaust from the muffler back to expose the tailend of the cat. I busted out the front portion of brick and the rear portion was non-existent. The truck seemed to breath better and run better, but after a 15-20 drive the same problem returned.
I just put some injector cleanser in it (Chevron Techtron) and cleaned the distributor points and rotor (they were rusty and had a lot of carbon on them). The truck seems to drive a little better, but there is still something going on. The idle fluctuates up and down and it doesn't want to accelerate very quickly at all.
Seems like I spent my last dime buying this truck and am looking now for resources to fix it myself. I read up on the sensor tests and that looks to be a tricky find.
Anybody with a suggestion? I just find it interesting that it will drive okay (not great) when cold, but as it warms up it quickly deteriorates.
Thanks!

 

If you cound get your hand on a scan tool that displays oxygen sensor readings on the screen then you could tell if the system in leaning-out when hot.Its possible that you need to set the base timing first with computer by-passed and go from there....

 

Thanks! I can probably get my hands on a scan tool. If it IS leaning out, is there a direct relation to any component? I am assuming it would relate to the oxygen sensor. Speaking of which, any feedback on the effects of cleaning out the goat bladder (this does apply to trucks too, right?) and the oxy sensor?

 

I agree about scanning the codes. You can get a EEC IV / OBD I scanner for about 20 to 30 bucks. If you can get the one with the digital display. The other one with the blinking light is a pain in the butt to read.

Since you said that the cap and rotor were not in great shape, maybe all the truck needs is a tune up. Replace the spark plugs, wires, cap and rotor. Make sure to keep the 7 and 8 plug wires separated. They are prone to cross firing.

Since the fuel filter is new thats been eliminated, but it could also be the EGR valve.

 

As TexasGuy001 said get a good low cost reader like the "INNOVA #3145" and not one with the light and buzzer.

The EGR valve would make it run bad cold at idle also. The EGR valve is normally open when the engine is warm and at road speed but not at WOT (when you put the throttle on the floor).
So it does not sound like an EGR valve.

If it is fuel you either have that new fuel filter dirty already or the pump is going bad on you. Do you have two tanks (two fuel pumps)?

If it is Ignition it would one of three things:
1. A bad Ignition Control Module (ICM or TFI).
2. A bad switch in the distributor (Hall effect stator assembly or PIP sensor).
3. The Ignition Coil

The code reader should tell if it is the Ignition Control Module/distributor switch.
The fuel gauge will tell you if it is the fuel system.

 

To Subford: Yes, it has dual tanks and runs the same on either tank, so I don't think that it is the fuel pump inside either tank. But, I understand that there are three pumps. If so, where is the third pump, and could it be that>?

The seller said that his dad had the same sounding problem I am having and it had something to do with the distributor cap, but can't remember what exactly.

I think the best thing to do rather than guess is to perform some guage tests. With the tests that have been suggested by everyone, what am I looking for on the digital read?

Thanks!

P.S. This truck has been like a bad first date, but I find that I still kind of like the guy...

 

"P.S. This truck has been like a bad first date, but I find that I still kind of like the guy..."

"any feedback on the effects of cleaning out the goat bladder"

Gees...remind me to never ask you out on a date! Just kidding. These guys know what they talk about and offer some very good advice. Good luck with your truck and all kidding aside, congrats for wanting to get into it and figure it out. Don't give up on it.

 

There is no third fuel pump on a 1992. They eliminated the third pump starting in 1990.

 

As 88n94 said there are only the pumps in the tanks. Ok we can forget about pumps for now.

He was talking about the switch in the distributor (Hall effect stator assembly or PIP sensor).

Does the CEL (MIL) light on your cluster come on when the problem starts?

There is not one code to look for when you use the INNOVA #3145 it will keep the codes in memory so you can go back inside and read them. Then post them back here and we help you out as to what they mean.
There is a chart in the book but I find that it does not always give the right meaning for the code.
You will like it when you get it running right. The guy you got it from more than likely knew of the problem but could not fix it but with our help I am sure you will fix it.

Good Luck

 

I'm waiting for the mechanic to call me back this afternoon and I'll take it to his shop. From there I will get a read/codes and bring to you the codes so we can hash them out.

As for the man who sold me the truck, I don't think he has tried underhanding me. I am a pretty good judge of character and he has been honest. In fact, I just spoke to him and is willing to pay whomever I hire to get the truck running right. For the most part, we have pretty good people here in Montana -- Some just aren't too, uh, bright...

 

Just got back from the mechanic's garage...
Here are the codes:

126 MAP sensor
212 No Tach to processor spout
556 Air Management Circuit Fault

Had to drive the truck for about 15 minutes for the mechanic to see what I was talking about. He said that the truck is definitely starving for fuel and wants to pull the fuel filter that he just put in to see what it looks like.

Also, the spark plug wires look really old.

I'm starting to wonder about the prior use of this truck. It has a tractor clock in it with 12K hours, though I was told that the truck was used to transport candied nuts (it had a lift gate on it).

I'm wondering if I should cancel my check that was with the cash that I paid for the truck...I noticed, too, that the paint on it is not original, but was some jiffy paint job...

 

OK lets take them one at a time and you did not say what test the codes came from so I will guess that they were all from CM and as the 212 code is only in CM.

126 This one will make the fuel air ratio off and it seams that the wiring or the sensor is bad. This sensor input voltage was way low so the computer is using a know good value in place would be a guess.

It is also possible that you are at a very hi elevation and you have a deep low-pressure system over head (snow).

212 May have a bad TFI module as the Ignition system is not doing what it is being told to do (IDM). Could also be bad wiring here. You could try a new TFI module for this one.

556 The fuel pumps are going off and on when the computer told them to stay on. This could be bad wiring under the fuel pump relay or the relay is going on and off on its own. Could try a new relay here but it is more than likely the wiring connection under the relay socket.

 

Sanford:

It seems likely 556 is the problem. It does feel like the fuel pumps are kicking on and off. Remember that it does this only after the truck has been driven for about 15 minutes starting off cold.
Is there a way to know if this is it? I have a voltage meter... Where do I find the relay for the fuel pumps (remember I have two or three pumps - mechanic thought he saw a third one at the bottom/front of the engine).
Also, just to confirm. The mechanic said that 556 was an "air management circuit fault". ..

 

Oh, by the way, the gurgling sound I mentioned when driving at higher RPMs and punching the gas...The EGR valve assembly has a leak. The mechanic said that is what is causing that sound. Anyone disagree?
This is a lot of fun learning about my new truck. I appreciate everyones' knowledge! Thank you!

 

This is from the 1992 FORD Truck Manual:
CONTINUOUS MEMORY CODE 556: CHECK EEC-IV HARNESS


A Continuous Memory Code 556 indicates that a fuel pump primary circuit failure has occurred during vehicle operation. Possible causes are:

-- Open in VPWR circuit between the EEC power relay and the fuel pump relay.

-- Open coil in fuel pump relay.

-- Open in fuel pump circuit (Pin 22).

-- Damaged inertia switch.

Start engine.

Check for engine stall/stumble while performing the following (also, if possible, listen for fuel pump turning off):
--Shake, wiggle, bend the VPWR circuit between the EEC power relay and the fuel pump relay. For vehicles with the inertia switch in the VPWR circuit (refer to «schematic»), lightly tap the inertia switch to simulate road shock.
-- Shake, wiggle, bend the EEC-IV vehicle harness fuel pump circuit (Test Pin 22) between the processor and the fuel pump relay.
-- Lightly tap the fuel pump relay to simulate road shock.

Key off.

Inspect the processor 60 pin connector and the fuel pump relay connectors for corrosion, damaged pins, etc.
Is fault indicated/found?

Yes
ISOLATE fault and SERVICE as necessary. CLEAR Continuous Memory (REFER to Quick Test Appendix, «Section 5A»). RERUN «Quick Test».

No
For dual HEGO applications with a code 96/543 only:
GO to «J96».
ALL others:
For further diagnosis using the EEC-IV monitor box GO to «Section 7A».
If an EEC-IV monitor box is not available, GO to «J99».




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