91 class c e350 460 motor rig

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technerd88

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Anyone have a class C here with the 460 7.5l EFI? Doesn't have to be the same year as mine as they are virtually all the same with this motor I believe
So some back story before you ask me why I just bought it. Has roof leaks but nothing I can't rip out and fix myself. Needed a new place to live since four mechanics have told me my current rig is scrap since they(tow company) bent up the front cross member so bad it mashed the oil pan(which was a milkshake already) and drug it without taking out the drive shaft which likely overheated the transmission even though I asked the guy if you were supposed to remove it. Been sitting in this parking lot for a month so I found the 91 e350 tioga arrow with the 460 EFI for sale with only 54,000 something miles and brand new tires. The guy at the shop I bought it from thought it was carb not EFI. Took me 1 second after opening the hood to know it was EFI and bought it right there on the spot for dirt cheap. Here's my problem. I understand VERY little about this EFI stuff. I know its a feedback system where it gets the water temp and manifold pressure, O2 sensor data to make the injectors pulse to fire and how to get codes from it now but thats about it. It had the check engine light on when I drove it away, but it went out after 10 miles with fresh gas. I thought that's why it died on me a few times but immediately restarted when I turned the key. It drove a little funny, almost as if there was either too rich or too lean where it would stumble a little at 40mph ish I think but it didn't die again. Parked next to our broken down rig the day before the historic blizzard up here in Buffalo NY hit and didn't touch it for a few days because you couldn't see outside. So while waiting it out I researched a bit and thought it was going to be the fuel pump in the tank because the guy did say it took a bit of cranking to start(guy thought it was carb'd lol) and from the research I did the fuel pumps on these rigs are a common issue. So its that right? I just throw parts at it. Nah, not my style. Finally had a decent day today where I could go outside and look at some things on it. First thing I had to do was clear huge snow drifts to be able to open the hood.

So first thing I checked was the air filter after I figured out it was 4 flat head screws to open, and its dirty. So I added that to the list with a fuel filter to get for it plus oil change stuff. Then I noticed the starter battery is completely dead and someone wired the coach battery as the starter one somehow :/ that explains why there's no power besides for the engine and transmission...all the "van" stuff. Strange because the coach already has the facility to do that with the press of a button. Checked the coolant, and oil, everything is good. Even has windshield washer fluid. I then proceeded to clear out the snow that got into the engine bay to see how it would act when I started it. 16 degrees outside I thought it was going to be trouble but surprisingly no. Started instantly after sitting for 3 days. Didn't bog or anything like when I first started it to drive it back. I think that pretty much rules out the fuel pump being the problem. I did put injector cleaner in the tank. I'm leaning towards a wiring issue now that I seen the hackery with the batteries under the hood and maybe some of it was dirty injectors from sitting? I don't know. The CEL never came back on and all I get is the code for everything good when I put it into diagnostic mode which is everything good. Was going to do the engine running test but will just wait till tomorrow(I didn't know there was a key on engine running test on top of the engine off key on test) but first I probably should figure out what the heck they did with the wiring. I noticed disconnected ring terminals and bad aftermarket wiring. That stuff I do know very well. I really have no idea why they'd do that nor why they'd put an ac delco AGM battery into a ford lol...I know it doesn't really matter. If it had a bad fuel pump I don't think it would have started like a brand new car at 17 degrees f lol literally as quiet as one and smooth too running.
I don't plan on using the coach battery anyways as I already have 1200ah lifepo4 bank I built out of bare cells, but I think I probably should fix that wiring so at least the generator can start and make sure the drivetrain connections are all good then. Only other reason I suspected wiring was because the gas gauge pegged and other gauges weren't working right at first. I think a bad connection like that could definitely make the PCM do nutty things on EFI correct and I made it make good contact again when I brushed all the snow out? It had plenty of oooooph when I drove back. Like it felt as if it were a truck with nothing in the bed, barely had to touch the gas to accelerate only went 40 though. I think the fresh gas made all the difference with the cleaner in it. Does anyone here have any experience with these old coaches or have one you can send me a pic of the wiring under the hood so I can put it back to factory? I looked but couldn't find any. The engine looks well taken care of, not a single leak of anything and it looked pretty much brand new when I removed the doghouse to look all those glorious 460 cubic inches. I'm pretty sure its a E4OD transmission as well. All the electronics make me nervous and I was a network engineer by trade before I became disabled so there's that.
 
Sounds like you got a good start on fixing it. Pump pressure can be checked but most likely new fuel, injection cleaner added and a new fuel filter will straighten out the fuel system. Usually electric pumps work or don’t work at all. All fluids, filters and rubber hoses, belts and flex lines will need to be changed, checked or replaced. Many times there is paper work tucked away in closets or drawers also check inside fuse panels or compartments for the coach wiring, you may get lucky! Coach wiring will be gotten from the coach manufacturer and Ford factory wiring should be pretty much the same as the same model commercial van cutaway. Good luck! Can’t imagine doing work in the cold. 78 degrees here in southern Arizona today just so you know!
 
The engine control computer in that Ford's era is notorious for blown capacitors. My '94 van was a real deal, with many parts replaced when purchased, and it took me a while to find and replace those bad capacitors. It idled poorly, and had inoperative gauges. An internet search will show those bad/leaking capacitors. I bought a Cardone brand from a parts store as a spare. Mine is a 5.8. Both ECU's provide the same fuel mileage.

The fuel pump circuit begins at the fuel pump relay, through the inertia/rollover switch, to the fuel pump(s).

You have a good one. Great engine, with basic fuel injection, with very few sensors involved. It does require some old school troubleshooting for almost everything but the fuel injection system, so you can't relay on a code reader to tell you everything, especially distributor/ignition problems. It is probably an OBD1 system, and an Innova 3145 code reader works for me. The connector is in the engine compartment near the starting battery on mine.

Hopefully you have one 35 gallon fuel tank instead of two. Possibly a 130 amp alternator also. Since it has a house battery, you may have a continuous duty relay to connect the start to house battery when running for house charging. My relay is hidden underneath the start battery box, with a battery cable running in front of the radiator to the house battery. I finally found that relay by removing a headlamp and looking through the hole.

A generic shop manual for your van is helpful, and if you can find a wiring manual, even better.

Brrrr.
 
I would add that if they fiddled with the wiring, double check all grounds. A bad ground can make for all kinds of wacky fun.
 
I don't have a Ford chassis, but I do have a '94 P30 motorhome with 34,000 miles that I purchased this summer. Luckily the previous owner didn't add or change anything, so there was no amateur electrician wiring to contend with. I would recommend getting the factory manuals for your chassis, I don't know about Ford, but Chevy has several manuals that cover my chassis. I would search for the body manuals for your class C as well, many of the big manufactures have this information online. It may also be helpful in restoring your wiring to original.

The Chevy wiring diagram manual has been very handy as this motorhome had uninvited guests (mice). They didn't damage much by chewing on things but they left evidence of their stay (poop and piss). They occupied the space on top of the fuse panel and a large junction block soiling these areas. I had a no-start problem shortly after purchasing the motorhome that I was able to chase down with the help of the wiring diagram manual. What I discovered was that the fuel pump wasn't getting 12v. I was able to trace the wiring from the fuel pump to the fuse panel and the break was at the junction block. The block was full of some nasty, black, mouse gunk. I cleaned the junction terminals with electrical cleaner spray, used Q-tips and small files to remove all the gunk and corrosion. The problem was resolved after cleaning and reassembly. I wouldn't have been able to easily troubleshoot this problem without the manual, other than physically chasing down the wiring.

My understanding of fuel injection is that an engine can start fine with low fuel pressure, but may not run well from part to full throttle. Fuel pump, filter and pressure regulator are the usual suspects. I'd replace the fuel filter since you have no idea when it was last replaced. I carry a spare fuel pump with me just in case. Check your spark plugs, rotor and distributor cap. I also recommend finding all of the engine grounds and cleaning them up as was suggested above.
 
It was the fuel tank causing my issues. They seemed to of had a problem with these years where the inside of the tank rusts and the fuel pump craps out. Confirmed this by adding an additional in-line one before the high pressure one on the rail and it doesn't miss a beat now so I can at least get by till I get a replacement tank and pump. Makes me seriously wonder why ford used an in tank low pressure pump rather than a in line external one close to the tank which works great. Edelbrock makes em if you ever are in this situation for 70 bucks at autozone,oreily, advance....etc
 
Glad you got it figured out. Night want to keep an spare inline fuel filter or two until you can clean out the tank or replace it.
 
Update? How's it going now? Lots of rv systems to work on too, if one gets bored, ha ha...
 
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