460 Ford engine stalls when put in gear

[Geocritter]

Hi all y’all,
Wouldn’t you know it, I’m ready to start out on a 900 mile journey and my previously good running 1994 Ford 460 V8 engine decides to act up. Here’s what I know:

When I purchased the RV last April it ran fine, I parked it at a friends for a few weeks and whenever I had to move it, it started and ran fine. In June I drove it 1/2 mile to a nearby RV park where I’ve lived in it since. Once in July I started it up and drove it a short distance to take on propane, it ran fine. Since then I’ve started it up periodically maybe every other month. I’d let it warm up and then turn it off, it’s always run fine (of course all I did was idle it).

Yesterday I started it up to drive it the 1/2 mile back to my friends place and it started up after a prolonged cranking. After it started it seemed to idle okay but it had a miss when I’d feed it gas and the exhaust smelled like it was running rich, though it was not blowing any soot or anything like that, just a tell-tale odor. I let it warm up and the minute I put it in gear it died. Tried again several times until finally I put my left foot on the brake, raised the RPMs slightly (no tach, so I don’t know how much). With the higher RPM I was able to get it to stay running in gear, whereupon I carefully drove it to my friends, never letting the RPM’s drop to idle when I’d stop.

I haven’t torn into the engine yet, I’m hoping for some useful input before I do that. At this point I’m thinking it might need a new O2 sensor or some plugs and/or plug wires or the coil has gone bad.

I hate to ask for help with this, I’ve worked on gasoline engines all my life, even professionally while I was in college, but I just don’t have the time to do a lot of guessing at this point and I really don’t have the money to take it to a mechanic.

Steve

[Geocritter]

Thanks all y'all for your support, technical advice and good cheer. I've done nearly all my own car repairs for over 50 years and to say that these RV things are a challenge is an understatement! I'll check the engine ground cables and straps and hopefully when I get the shakedown problems shaken out of this thing I can do some quail hunting. For the next few days it's off in my Caravan to LA for Thanksgiving with my daughter.

BTW have a wonderful Thanksgiving everyone!!!

Steve

PS since I'll be in Tucson until April the gas treatment sounds like a great idea.

[doxiemom11]

When we sit - sometimes for 6 months at a time, we add fuel stabalizer to the gas tank and them run the engine and generator for awhile to mske sure the stabalizer get into all fuel lines, engines etc. We have done this for 3 years now and so far no problem. After you get this taken care of you might want to do that. We use Stabil.

[bobman]

Ha that sucks these things are a real learning curve are you going quail hunting in AZ?

[John_Joey]

That's great news Geocritter, the more you use it the better it will run. Like I said in a prior post my rig didn't "break free" for well over a thousand miles of constant use.

BTW, I swapped out the fuel filter yearly for the first three years. They are cheap and easy and the problems with a bad filter on the road can be a real PITA. Also if I sat for much more then 3 months I would park with a 1/4 tank and Seafoam it. If I didn't do that it took a few hundred miles before the engine would kick up her heels.

On Edit:

On your starter problem. Make sure your ground strap is in good condition and has clean ends. It should be located by the alternator.

[PaulJ2]

RLS7201 wrote:
Steve, Check the Idle Air Control (IAC). It's responsible for setting the correct idle speed. It's mounted on the front of the upper intake manifold, under the two hoses attached to the throttle body.
When idling in neutral, remove the wire connector and see if the idle speed changes. If it don't change, you have an IAC problem.

Richard

My thoughts axactly! Probably varnished and sticking from old fuel.

[Geocritter]

This is an update. I just finished driving from San Marcos TX to Tucson AZ (through a miserable early winter ice storm I might add). Apparently, my stalling problems were due to old gasoline. The farther I drove the better it ran. I did have one hiccup going up a long grade outside of Benson AZ. The engine stalled right near the top of the grade, acting as if it was running out of gas. I let it sit for about 15-20 minutes and it started and ran fine. I suspect that I have a dirty gasoline filter that wasn't allowing enough gasoline through to keep up with engine needs on the long grade.

I also had an ongoing starter problem, with the new 750 amp/hr battery and newly rebuilt starter barely cranking the engine. I suspect that the switch that isolates the battery has dirty contacts and is not allowing enough juice through for the starters needs. As a test I'm going to pull some cables off the coach system and jump out the switch and see if that helps.

Anyhow, that's what happened with the stalling problem, when the engine starts, it runs great!

Steve

[cbr46]

Geocritter wrote:
BTW the electrical system has a parasitic drain that I haven't been able to find, fortunately there's a switch to isolate the battery.

Steve

My 02 Fleetwood has a parasitic drain off the chassis battery as well, about 40 ma total. I isolated it down to 3 sources - 1.) the electronic control center for various coach levels (electric, propane, tanks), 2.) the Scan Gauge engine monitor and 3.) I can't remember, but it was another coach function.

Try isolating your drain by pulling fuses and watching the current meter, then figure out what that fuse supplies. To keep from pulling cables off the battery you can "short" the disconnect switch with the current meter, just remember to have the switch in disconnect mode. To identify circuits be sure to turn on the main switch or you might blow a meter fuse.

Good luck,
- bob

[RLS7201]

Steve, Check the Idle Air Control (IAC). It's responsible for setting the correct idle speed. It's mounted on the front of the upper intake manifold, under the two hoses attached to the throttle body.
When idling in neutral, remove the wire connector and see if the idle speed changes. If it don't change, you have an IAC problem.

Richard

[John_Joey]

This goes with the "don't sweat the small stuff," but as I remember the fuel gauge is electronic based, it eithers works or it doesn't.

You may be right in it is a stuck float that will break free on it's own. Till then figure on 300 miles from fill up to 1/4 tank. That was pretty much what I got given an 80 gallon tank and mostly driving with a tail wind.

If you have overhead map lights keep an eye on those switches. Sometimes when you turn off the lights, but leave the main rocker switch "on" (on the dash) that is where the drain is coming from. The driver side rocker switch charges the relay which drains the battery even though the map lights are turned off.

BTW, if you can afford the SeaFoam more of it will surely help.

[Geocritter]

John&Joey wrote:
Is that year carb'ed or EFI? If carb'ed wasting a $2 can of WalMart carb spray isn't going to hurt a thing and will make things look nice and clean.

Also an old trick is to lightly mist over the intake, if the engine speeds up then you are running lean (could be varnish in the bowl, or out of adjustment.) Also spraying lightly around the intake manifold will show a leaking gasket by again gaining rpm's

It's EFI. I just finished driving to the gas station this morning and took on 67 gallons of gas, apparently I have a malfunctioning fuel gauge too (heavy sigh). Hopefully it's nothing more than a sticking float which the new gasoline may remedy in a while by dissolving varnish.

Once the engine's completely warmed up it runs a lot better and at cruising speed is very smooth. Maybe it's wishful thinking but I'm starting to feel more and more that what I've been mainly dealing with is old gasoline.

I also need to get a new battery. The battery I have is only good for a very few starts and then you're out of luck. I always buy 700-800 amp/hour batteries. I may be cheap but I learned long ago not to skimp on batteries. BTW the electrical system has a parasitic drain that I haven't been able to find, fortunately there's a switch to isolate the battery.

Steve

[John_Joey]

Is that year carb'ed or EFI? If carb'ed wasting a $2 can of WalMart carb spray isn't going to hurt a thing and will make things look nice and clean.

Also an old trick is to lightly mist over the intake, if the engine speeds up then you are running lean (could be varnish in the bowl, or out of adjustment.) Also spraying lightly around the intake manifold will show a leaking gasket by again gaining rpm's

[Geocritter]

I did do some work on the rig today.

-I put in two cans of SeaFoam
-I checked the EGR valve for a cracked diaphragm (it was okay)
-I replaced the air filter and the crankcase ventilation filter (which looked like it had never been changed), probably not the problem but they both looked pretty dirty.
-I searched the engine for bad vacuum lines and didn't find any
-I replaced the spark plugs, again probably not the problem but they looked like they were due to be replaced.

The engine is running better now, though it still wants to stall without my raising the idle while stepping on the brake. And, I seem to have less gasoline than I thought. I don't know if it's because of an inaccurate gas gauge, theft, or evaporation. Anyhow I'm taking it in for a fillup bright and early Sunday morning when the traffics light. See what a tank of fresh gasoline does for the old gurls spirit.

Steve

[falconman]

Could be the TPS (throttle pos sensor if its EFI).

[John_Joey]

Geocritter wrote:

Bird Freak wrote:
You can add all the additives and cleaners you want. Drain the tank and put fresh gas in it. I deal with this a lot in my business.

You might be right but I hope not. What can I do with 50 gallons of old gas in the tank and only 5 days away from the start of my journey. What I should've done was syphon my gas 5 gallons at a time and burned it in my car (augmented by 15 gallons of fresh gas in my 20 gallon tank). Why is hindsight always 20/20?

Steve

Don't waste your time draining it. What happens is you get varnish build up in key area's. the SeaFoam will dissolve them, when the tank gets to half then fill her up with some good stuff (i.e. Chevron with cleaner already)

My old 460 that I bought sat for about 5 years in a heated garage prior to me buying it. That engine didn't "break free" until I got to Mobile, AL from MN. All of a sudden I could feel the power returning.

I try not to sweat the small stuff, so here it goes. If you did what you did how could anything "major" have broken? Now yes a vacuum hose may have dried out and has a cracked end, a critter may have chewed a wire, or something may have corroded shut. The last being the worst case, but you starting the engine and letting the oil circulate I doubt if that happened.

More then likely it's varnish in the fuel system causing the engine to run funky. Now with ethanol in gas, the life span is about 2-3 months prior to it breaking down. Over do the Seafoam, wait 24 hours, then drive the beast for 5 to 10 miles. At that point you should have a good feel if it's simply the gas, or more major.

Don't sweat the small stuff, and everything is small. Good luck.