Hi! Please help me figure out what is going on! Here's the history:

I bought a used 2002 F250 SD w\ the 7.3l PowerStroke diesel and automatic tranny in March of this year. Shortly after buying it, my stepson "topped off" the tank w\ 10 gallons of regular unleaded (there was about 20 gallons of diesel in the tank at the time). Fortunately he realized his mistake right away and didn't drive it (except the 1\4 mile home). I siphoned out the tank and refilled it w\ diesel, replaced the fuel filter, and it didn't seem any worse for the experience.

A month or so later, he blew the transmission. I had rebuilt w\ all HD components and had a cooler added.

My check bettery light came on last week. I had the alternator tested- it was pushing 308 amps(!) and 12.1v. I replaced it.

So- I have 3 potential contributers to my problems- gas in the tank, something botched in the tranny rebuild, or electrical gremlins from too much current.

Now- here's the problems I'm having:

Starting about a month ago, when I got down to about 1/8 of a tank the engine would start behaving as if I was running out of fuel. Refuel and it ran no problem. I figured maybe I still had some gas in the tank, so drained it completely via the fuel pump and changed the filter again, but did not help. It also sometimes didn't seem to quite have the power it should, but wasn't missing or anything.

Last weekend I pulled a trailer w\ a Jeep Grand Cherokee from Phoenix, Az to Moab, Ut, which involves an elevation gain of about 6000 ft., and it was awful! Shortly after starting into the mountains I had a dramatic loss of power and the truck started bucking like a manual transmission in too high of a gear. The only way I could go up a significant incline was to hit it running and downshift as I lost momentum, ending up in first or second gear at the top (I probably should have turned back then but there was no way I was going to miss that weekend!).

Over the course of the drive, I found that the truck runs almost normal when the tank is >3\4 full. If I really push it uphill w\ the trailer w\ a full tank, it will slowly lose "oomph" (like it's starving for fuel) and the check engine light will come on. Get to level ground and it will go back to normal after a few moments and the check engine light will go out. Get below 3\4 of a tank and I lose almost all power and can barely limp to the next station unless it's downhill.

To make things even more interesting, my transmission was randomly overheating. It mostly would overheat if I didn't turn off overdrive, but would sometimes get a little temperamental in 3rd. It didn't seem to matter if I was on a hill or not- If I ran it in OD for any length of time, even on level ground, the transmission would act normal for a while, then rapidly overheat. To cool it off I tried turning off OD while driving, pulling over and idling in park and in neutral, with and without OD on- the only thing that seemed to work was to pull over and turn the vehicle off for 30 minutes or so, then drive slowly w\ OD off- once it started to drop it would go back to normal rapidly. If it was engine temp., I would say it was acting like a faulty water pump, but I don't know if that's a good analogy with an automatic transmission.

I talked to the Ford dealer in Moab- they said it sounded like the fuel pump, but didn't have time to look at it. I don't like "throwing parts at it", but went ahead and replaced the fuel pump anyway. It seemed to help a little, but definately did not solve the problem. I limped it back to Phoenix yesterday, fortunately this way is downhill. Just to keep things interesting I had a trailer tire blowout an hour from Phoenix.....

When I unhooked the trailer, it drove exactly as it did before I left- normal above 3\4 tank, almost normal, just maybe a bit short on power below that.

So- I have no idea what's going on. The possibilities I see are that the gasoline ruined something due to lack of lubrication (that's why I went ahead and replaced the fuel pump), or that there is some wierd electrical fault stemming from a fried sensor or some such. I can't figure how the transmission figures into this- I think it may be a seperate and unrelated problem. One person (autozone salesperson) told me there is a pickup or sending unit in the tank which may be bad ($800ish...ouch!), but the dealer said this isn't so. The problem DEFINATELY is affected by the fuel level in the tank -above 3\4=almost normal, below=yuck- so you'd think something in there was the problem, but I'd also think the dealer would know what they're talking about.

My ODB II doesn't pull any codes, and I haven't been able to have the dealer hook up their computer yet.

This has me stumped! I'm thinking that whatever is inside the tank is the problem, but the price tag is a bit steep to just start replacing things and hoping it works. Any help is greatly appreciated!!!

 

Your OBDII reader won't work as you need an enhanced OBDII reader with manufacturer specific plug ins. This is not something you're going to find laying around outside a shop.

Your son driving it for 1/4 mi on a 33/66 mix of gas probably did some damage to the fuel pump, and could have possibly scored the barrells and plungers in the injectors. Only way to know for sure is a disassembly and inspection, but its not cheap. I would suggest pulling the valve covers and check the injector harnesses. There is an update out there which helps keep the plug seated. If it comes undone a little it can cause some injectors, or an entire bank to die. Check for scorched pins and an unseated connector. As for running stronger over 3/4 tank you're probably sucking air. Mine will run slightly stronger over half a tank because of this. My guess is that something in the tank was damaged by the gas. Might as well drop the tank and do the prepump/intank mod as well as the harpoon mod. Have you changed the fuel filter lately?

When the trans failed the first time what went out? If they did not flush or replace the coolers then there could be crud still in there. Its common practice to replace them instead of flushing as that is not guaranteed to get it all out. Sounds more like a crappy rebuild of the trans. I don't know why you haven't taken the truck back to the place you bought it from and have them fix it instead of sitting on it. That would be the first thing I'd suggest. Most likely a problem with the clutch pack slipping in OD causing extra heat.

 

I'll have to read up on what those mods are. It has a brand new filter.

I was told the front pump seal went out and a chain reaction from there pretty much ruined it. It was supposed to have been completely rebuilt with all HD components, all new clutch packs, new cooler, etc.


Private party, no recourse. Besides, I don't really feel I should hold the seller responsible for problems that may have arisen from gas in the tank.

I'll search for info on the mods you suggested. Are there any sites you recommend for info?

Thanks!

 

Your tranny issues are in no way related to running gas through the truck. I don't know how it could ever be thought to have caused it as the systems are separate. Running gas through the engine will only damage fuel system components. The trans getting hot I'll wager is from a poor quality rebuild. Should have gone to BTS for your trans. It would run $3800 or so when its all said and done, but you're guaranteed you'll never have to buy another trans for the truck.........EVER. Brian dares the high hp guys to take the truck out and actually TRY to blow up the trans. Not many succeed. Go to http://www.dieselinnovations.com/di....products&cat=2 and you can order the intank/prepump mod there about 3/4 down the page. The harpoon mod is when you look in the fuel tank you'll see the plastic breather line that sticks down about 6". Cut it down to 1" using a pvs cutter so you don't get shavings in the tank. This allows you to fill up with fuel all the way to the filler neck without having to dribble it in. After the pump kicks off you can usually get 5 gallons or more in the tank due to the position of the breather being too low.