Fuel supply problem Ford 460

[PaceMaker96]

Hi, I am new here. I just bought a 1996 Pace Arrow with a Ford 460 engine in it. I would like to pick up on this older thread: http://www.irv2.com/forums/f23/460-f...ems-94486.html.

Shortly after buying the motorhome (my first, dealer tags are still on it) this is happening: it starts to bock and jerk. If I ease off the accelerator it smoothes out but continuously loses power. Climbing hills becomes impossible. The dealer agreed to have the tank dropped and cleaned thoroughly, replace the fuel pump (aftermarket, O'Reilly's), replace the fuel pressure regulator, replace the fuel filter, clean the injectors, do a tune-up.

Ok, so then I went on my first trip from Las Vegas, NM to Hot Springs, AR and the whole problem started up again as I was leaving OK, getting into AR on US70. Loss of power, "check engine" light, back firing especially when trying to accelerate. It totally feels like a restriction in the fuel supply somewhere, but what's left?? After all the work that has been done?

Whenever the problem occurs and I stop for 15 or 20 minutes and let everything cool off I can go on at normal speed for about 5 to 15 minutes and then the problem reoccurs and with every time it seems to get worse.

It got so bad that I had to be towed the last 70 miles into Hot Springs.

At this point I am at a total loss! I am open to any suggests, advice, anything.... coil pack going bad? fuel pump again? Do I need an additional inline fuel pump?

[JohnRR]

Sounds more like a clogged exhaust system to me (catalytic converter included) think of it as a clogged toilet if you can't flush the burnt gases from the engine it will not be able to take in a fresh charge of gas.

[89sandman]

have the ecm scanned, this would be the place to start. if the check engine light is on there is at least one code stored.

[stisdal]

Also sounds like it could be electrical. My old Ford used to eat pickup coils and would act that way until a 30 minute cool down. Sounds like you have the fuel system pretty well replaced...

[CLIFFTALL]

Welcome again. I've moved your thread here to get some input from our Ford forum members. Hopefully you'll get more responses here. Cliff

[subford]

As said above when ever the MIL lamp (check engine) comes on you need to see what codes you have stored in the memory of the PCM computer.
You can do this by grounding the STI wire near the self-test connector and counting the flashes the MIL makes in the cluster. You can ground it at pin #2 of the self-test connector.

It also sounds like the RV dealer tryed to get off cheap by putting an aftermarket, O'Reilly's fuel pump in it. He should have put the up-dated Ford turbine fuel pump in it.

I would say either you have a fuel pump getting hot and quitting or a bad PIP sensor inside the distributor.

To check the fuel system you need to put a fuel pressure gauge on it and drive it to see what the fuel pressure does. It should be 30-34psi at idle depending on the engine vacuum and around 40psi at WOT.

The PIP sensor should set a code in the Computer memory if it is the problem.

I would dough that you would have a bad ICM (Ignition Control Module) but if you or they replace it make sure it is Black in color as most places will try to sell you the wrong one. The wrong one that they will try to sell you is Gray in color. The last Ford to use the Gray one was the 1993 Ford Trucks and F53's. There computer will tell them that the Gray one will fit yours but there look up system is wrong at all auto part stores and some Ford dealers.

If you do not want to count codes then this is the code reader to buy, it is only about $30.00 at O'Reilly's. Every one with the 460 and the EEC-IV system needs one of these anyway. It works with the F53 460 through 1997. There was no 1998 F53.





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[jamesrxx951]

As mentioned above, some diag will be needed. I definitely would have protested using an aftermarket fuel pump. What is an unknown is if the strainer filter on the pump was replaced. Most aftermarket fuel pumps are just the pump and motor. Not the entire assembly that includes the filter strainer. In the majority of fuel pump issues, it is not the pump itself but the strainer is clogged with debris from the tank.

Definitely check what codes are in the PCM but don't just rely on those. For instance if there is a lean code (O2) stored, 95% of the time it is not the sensor but just reporting what it is "seeing". Low fuel pressure, vacuum leaks, and other scenarios can cause that to set. At minimum fuel pressure needs to be checked, check the distributor cap and wires for any damage. A tune up with good Motorcraft plugs, wires, cap/rotor and possible coil may also be needed. But it will need to be identified how everything is working. Checking voltage back at the pump may be needed also. Low voltage at the pump may allow you to have the pump run but may not be enough to allow the pump to keep up with the demand.

[PaceMaker96]

Originally Posted by JohnRR

Sounds more like a clogged exhaust system to me (catalytic converter included) think of it as a clogged toilet if you can't flush the burnt gases from the engine it will not be able to take in a fresh charge of gas.

Thanks John and Cathy for the input. It doesn't have a catalytic converter and a heat test resulted in a rather cool running exhaust after about 20 minutes of driving.

[PaceMaker96]

Originally Posted by 89sandman

have the ecm scanned, this would be the place to start. if the check engine light is on there is at least one code stored.

thanks 89sandman. The mechanic put a scanner on it: no codes stored.... Since then I learned that on older models the "check engine" light has to be on when scanning. Mine goes on and off.

[PaceMaker96]

Originally Posted by stisdal

Also sounds like it could be electrical. My old Ford used to eat pickup coils and would act that way until a 30 minute cool down. Sounds like you have the fuel system pretty well replaced...

Thanks. I will have the coil pack checked.

[jamesrxx951]

Originally Posted by PaceMaker96

thanks 89sandman. The mechanic put a scanner on it: no codes stored.... Since then I learned that on older models the "check engine" light has to be on when scanning. Mine goes on and off.

That is not accurate to a point. There will be a continuous memory codes stored code for a certain amount of drive cycles. After a certain amount of drive cycles with no faults, then it will clear out. If you disconnect the chassis battery, the code will also be cleared out. The truth about only giving a code when the light is on is mostly true when performing a key on engine running test and key on engine off when it does an on demand test. However there should be something stored in memory.

[Mekanic]

Originally Posted by PaceMaker96

...... Climbing hills becomes impossible. The dealer agreed to have the tank dropped and cleaned thoroughly, replace the fuel pump (aftermarket, O'Reilly's), replace the fuel pressure regulator, replace the fuel filter, clean the injectors, do a tune-up.
........
Whenever the problem occurs and I stop for 15 or 20 minutes and let everything cool off I can go on at normal speed for about 5 to 15 minutes and then the problem reoccurs and with every time it seems to get worse.
.......

Did the mechanic spray any cleaner in the fuel line from the tank to the fuel filter? if not I bet all that "stuff" is now in your new fuel filter. I'd actually think about changing once more
There is one more mechanical device that controls fuel pressure and is the fuel pressure regulator. It has a vacuum hose attached to it and its on the fuel rail.
Right next to where you check the fuel pressure.
There is no fuel pressure sensor for the computer, it will usually just show as a lean code.

[89sandman]

I didn't notice yours was a 96, is it obd 1? do you know if the mechanic checked for current codes and stored codes? I would assume he would but you never know. the older obd 1 computer system is shall we say very lacking as compared to the newer obd 2 system. I would hook up the scanner and take it for a drive, you should be able to catch the code as soon as the light comes on.

the system runs on open loop, meaning in runs off a predetermined set of parameters, until the engine reaches operating temperature. then it actually starts to run off of the feedback from the sensor's or closed loop. could be many different things but I'd start by getting the code from the computer first. if that code is not helpful its time to start trouble shooting. could be something as simple as a bad cap and rotor to a vacuum leak or ??? letting it sit and then it runs fine for a little while could be a clogged/improperly installed fuel filter. the backfiring tends to make me think it is probably an ignition problem, but from here its hard to tell

[PaceMaker96]

Originally Posted by jamesrxx951

Most aftermarket fuel pumps are just the pump and motor. Not the entire assembly that includes the filter strainer.

The whole assembly was replaced by an O'Reilly pump. If I had known better I would have insisted on a Ford pump...