Fuel Pump Choice

[Ken 77]

Have a 1996 Newmar Mountain Aire.....very good outside & inside condition.. But 43000 miles and 18 years are taking a toll on running gear...Picked up bus in Jan of this yr in TX at Ft. Worth filled up with gas & drove to Rockport about 300 miles.. ran fine... traveled around Austin next & back to Ft. Worth..noticed seemed to lose power when I stepped on it.. Because I was worried about old tires ONLY PUT ABOUT 30 GALLONS OF GAS IN AT TIME. On way home to Wis. 1000 miles the engine would log down on the hills when I put peddle on the floor...Got to mechanic in Ill. & he couldn't get a good read out of Computer,..when got home had it rebuilt (no new ones anymore) & when I got it on took a test drive...great for about 5 miles of putting engine under load...& rattts started doing nosing over when pushed for power again... not fixed.

Reading post here & around .... sure sounds like I have the old fuel pump & its failing .... or the sock is full of dirt..... anyway advised with the history of the 460 F53 that I should put new fuel pump on regardless.......My question of group is spend the $1000 bucks on down to have it replaced or just put another fuel pump on the frame & leave old one alone... & if I do that do I cut the wires to the old pump so it doesn't operate???? any recommends appreciated. Ken

[jamesrxx951]

If the sock is plugged up no amount of fuel pumps on the rail will help. If the inlet is plugged, you will not get enough fuel in the fuel system. Before you get to crazy (unless you just want to do preventative maint) I would install a fuel pressure gauge on the fuel rail to see where your at. Expect around 32 PSI at idle and over 37 PSI (if I remember correctly) at wide open throttle driving. Checking voltage and ground at the fuel pump will also be necessary to verify the pump is getting everything it needs.

If you do have low pressure and need a pump, be very careful. Some tanks have studs and nuts that hold the fuel pump in. In most cases the studs will break if proper precautions are not followed. They are weak and small. Broken easily. The best way I have removed these nuts without having to charge a customer a few G's for a new tank is to fully drain the fuel from the tank. Partially fill it with water. Get a bunch of wet towels and full cover the tank only leaving the area around the nut to be removed. A good presoak of penetrating oil like Kryoal is a good idea also. However when a single nut is exposed I use a small mini torch and heat up the nut. It don't have to be red hot but really warm. Use a small wrench and wiggle the nut loose. Look closely at the stud. Make sure it is not moving. If it looks like it is going to spin with the nut, heat up the nut some more. Just heat and slight movements of the nut seems to break it free from the stud for me. The oil also tends to get deep in the threads. I have also use the oil, heated it up and cool the nut with the oil. The heat it up again to remove the nut. If this tank has small bolts, use hand tools and also be careful.

[cb1000rider]

Ken,
A 96 Should be OBD-II, so I'm not sure what "couldn't get a good read" on the computer means.

My advice: Don't dig into the fuel pump yet. You don't know that this is an issue. And you're throwing money at it right now.

First, after about 1995 - we really don't need by ear or guesswork diagnostics anymore. You're 1996 Is Ford EEC-V, which is OBD-II (the common spec), but may have a Ford-only diagnostic called "Mode 6". You need a Ford specialist and/or a Ford specific scanner. IF the 460 E-350 supports mode 6, it'll tell you what is going on.

Missing at WOT can be the fuel pump. It can also be aged plugs - or in the case of the V10 crappy coils... You've got a 460, so I'd suspect ignition, but I want to verify first. Bad fuel pump - I'd expect it to thrown lean codes across both banks. And I'd expect it to miss on random cylinders, not specific ones.

Ford EFI doesn't give fuel pressure in 1996, so you'd need a manual gauge to measure while driving...

Have you done the fuel filter? Every Ford motorhome I've had - awful fuel filters as early as 20k miles.



And let me 2nd James' advice. We lost a fuel pump last year while on a trip. Ford pulled the tank, broke the studs - they said they'd rusted. The retail cost for a new fuel tank was $2k, so replacing that fuel pump cost me over $3000. IF you had to replace it - there are better fuel tanks for about half that price. I would use a retail ford pump though...

[BFlinn181]

Originally Posted by Ken 77

.....Reading post here & around .... sure sounds like I have the old fuel pump & its failing .... or the sock is full of dirt..... anyway advised with the history of the 460 F53 that I should put new fuel pump on regardless.......My question of group is spend the $1000 bucks on down to have it replaced or just put another fuel pump on the frame & leave old one alone... & if I do that do I cut the wires to the old pump so it doesn't operate???? any recommends appreciated. Ken

Triage is the process of determining the priority of patients' treatments based on the severity of their condition.

I'm amazed that you think it's a fuel supply issue, but had the ECU rebuilt as a first step. Next you want to replace, disable fuel pump(s) as a second step. You ponder fuel sock in tank clogged with dirt. No mention of changing fuel filter. I guess I tend to solve problems in order of expense and labor needed. Eliminate the easy fixes before moving on to the expensive ones.

Fuel issues? Put a pressure gauge on the fuel rail and monitor during driving. Still fuel issues? Replace fuel filter, they almost always need change. Analyze what's in the filter. Clogged fuel sock? Use compressed air to blow back into the fuel line and dislodge particles in the screen. If the screen and filter give evidence of rust, drop and clean fuel tank. While tank is dropped, a test of the internal fuel pump can be done. When reinstalling, replace fuel lines that could be aged and replacement prevents need to drop tank again soon.

[subford]

Originally Posted by cb1000rider

Ken,
A 96 Should be OBD-II, so I'm not sure what "couldn't get a good read" on the computer means.

Wrong the F53 was not OBD-II until 1999.
His is an OBD-I.

Originally Posted by cb1000rider

First, after about 1995 - we really don't need by ear or guesswork diagnostics anymore. You're 1996 Is Ford EEC-V, which is OBD-II (the common spec), but may have a Ford-only diagnostic called "Mode 6". You need a Ford specialist and/or a Ford specific scanner. IF the 460 E-350 supports mode 6, it'll tell you what is going on.

Wrong again, his is a EEC-IV and not EEC-V.

And Ken do what James said above, he knows what he is talking about.

Also your fuel pump should have a return shuttle valve in it for the return fuel that is operated (opened) by the fuel pressure from the in tank pump. I do not know if an inline fuel pump on the frame can open this valve and if not your fuel pressure may go too high. So no I would not advise you to installing one on the frame and cutting the wires to the one in the tank.

However other have in stalled a frame inline pump to work with the tank pump and it has helped on hills and such.

That said if the OBD-I scanner or code reader can not read the codes than you may have a Computer problem as your running problems may be a bad computer. You can open it up and check the caps to see if they are leaking and replacing the caps may fix your problem if they are leaking.

[cb1000rider]

I stand corrected.. Cars and light trucks went OBD-II in 1995. Apparently the big vehicles didn't.. I tried to find that info before I posted it.

My last experience with EEC-IV was the Ford Mustang - and I believe it's capable of setting "bank lean" codes. I'd expect to see one of those codes if he's running out of fuel, so I wouldn't just go in and replace the fuel pump without getting some sort of confirmation - at least a fuel pressure drop below spec at WOT.

[Ken 77]

appreciate answers given on my fuel pump question...looking around at things on my 96 fuel pump... lots say replace now cause at 40,000 plus miles its due to fail because so many have had it happen with it... the new style turbine one 97 & on seems much better.. so probably going to do it... Took bus to an RV repair shop, only guy yesterday.. like 15 bus around yard being serviced..... He said not care what you read, we will go through diagnostics to find reason and not spend unnecisary money.. But what I read it should be replaced.
I did have the computer send in and rebuilt.. Of course on my 100 mile trip up to the shop it ran great cruising at 60mph... & only a little chugging when I floored it..??? I'm trying to be pre-emptive on all the running gear stuff & house stuff I can deal with... I been told by Richard in no uncertain terms to put the Mechlin all steel Ribs on bus but repair guy was no fan of Mechliens...
But I think still going with them... 16" tires.... will post back here when we get bus back from repair shop..... Ya.. & to old and decrepid to crawl around under the bus.. & to dumb to work on engine.... but do like to travel & live will in a MH... Ken

[cb1000rider]

Ken, I think you're getting good advice on going through the diagnostics. We had an F53 with 75k miles - no fuel pump problems. And a 2005 V10 Class-C that had the pump die at 23k. Low fuel pressure should be pretty easy to sort out without dropping the tank.


I'd question "rebuilding" the computer too. I don't know of anyone who rebuilds ECUS. A few companies do things like replace problematic (leaking) capacitors, etc in ECUs where those are a problem, but the ECUs are generally proprietary... It may be that a specific component failed and could be replaced - otherwise, I'd want to know exactly what was "rebuilt". Usually, I'd just replace it with a used unit. Did the "rebuild" fix your problem?

Michelins are the top of the line RV tire...

[89sandman]

obd-1 computers do not give lean bank codes. these did not come until the obd 2 computers.

[jamesrxx951]

Originally Posted by 89sandman

obd-1 computers do not give lean bank codes. these did not come until the obd 2 computers.

That would be incorrect. Any system that has an O2 sensor for fuel mixture monitoring will give a lean/rich DTC if necessary.

http://www.fordf150.net/howto/eecivcodes.php
I would post a Ford PCED manual but it is not available via OASIS anymore for that age of vehicle.

[89sandman]

obd-1 computers do not give lean bank codes. these did not come until the obd 2 computers.

[89sandman]

you are correct obd1 will give a lean or rich code. You are incorrect that it will give bank codes as i had posted. The obd2 system only gives bank 1 or 2 codes.

[jamesrxx951]

Originally Posted by 89sandman

obd-1 computers do not give lean bank codes. these did not come until the obd 2 computers.

Depends on what you are specifically referring to. There are in fact lean codes with EEC IV. I4 and I6 engines only have one bank so if you are hanging on the "bank" portion it does not matter with an I engine. If a V8 has a single O2 sensor for both banks then you will not get a bank specific lean DTC. In many instances models like the 302 Mustang and Mark VII have 2 O2 sensors. Since I brought up Mustang that gave me a thought, and yes the PCED does come up for an EEC IV Mustang

129 Insufficient MAP/Mass Air Flow (MAF) change during dynamic response test KOER 136 Lack of Heated Oxygen Sensor (HO2S-2) switch during KOER, indicates lean (Bank #2) 137 Lack of Heated Oxygen Sensor (HO2S-2) switch during KOER, indicates rich (Bank #2) 139 No Heated Oxygen Sensor (HO2S-2) switches detected (Bank #2) 141 Fuel system indicates lean 144 No Heated Oxygen Sensor (HO2S-1) switches detected (Bank #1) 157 Mass Air Flow (MAF) sensor circuit below minimum voltage 158 Mass Air Flow (MAF) sensor circuit above maximum voltage 159 Mass Air Flow (MAF) higher or lower than expected 167 Insufficient throttle position change during dynamic response test KOER 171 Fuel system at adaptive limits, Heated Oxygen Sensor (HO2S-1) unable to switch (Bank #1) 172 Lack of Heated Oxygen Sensor (HO2S-1) switches, indicates lean (Bank #1) 173 Lack of Heated Oxygen Sensor (HO2S-1) switches, indicates rich (Bank #1) 175 Fuel system at adaptive limits, Heated Oxygen Sensor (HO2S-2) unable to switch (Bank #2) 176 Lack of Heated Oxygen Sensor (HO2S-2) switches, indicates lean (Bank #2) 177 Lack of Heated Oxygen Sensor (HO2S-2) switches, indicates rich (Bank #2) 179 Fuel system at lean adaptive limit at part throttle, system rich (Bank #1) 181 Fuel system at rich adaptive limit at part throttle, system lean (Bank #1)

So im not sure where you got that information but no one let Ford know about it.

[jamesrxx951]

Originally Posted by 89sandman

you are correct obd1 will give a lean or rich code. You are incorrect that it will give bank codes as i had posted. The obd2 system only gives bank 1 or 2 codes.

I see you changed your original post but mine still shows the correct details.