Engine stumbles & dies on steep upgrades (Ford gas v10)

geoffff · 07-31-2008, 10:16 AM

My mechanic is having trouble diagnosing this, and I'm wondering if anyone else has had this problem.

I was recently in the Whiskey Dick area of eastern Washington with some friends. We were several long bumpy hours from any kind of pavement or town when my Sportsmobile's engine started stumbling and cutting out when driving slow steep uphills, maybe 5-10 MPH. At the top of one upgrade, the engine finally died, and it took quite a while (and lots of black smoke) to get it started again.

No, I wasn't low on fuel. And no engine ODBII trouble codes were set.

With this problem, I'm afraid of getting stranded far from help. I need to feel confident about my Sportsmobile if I'm going to use it the way it's intended!

One suspicion -- I just got my fuel pump replaced this past winter. I hope that isn't the problem again.

Thanks for any ideas!
-- Geoff

Ford_6L_E350 · 07-31-2008, 11:12 AM

Wow! That shouldn't happen.

Did it die at the top (level-ish) or near the top (still steep) of the incline?

How steep was the incline? Could you duplicate the steepness with a jack and blocks under the front of the van? The run it at a similar RPM for a similar time to make it fail? Of course that doesn't solve the issue, but being able to duplicate the problem is the biggest step towards solving strange problem.

I don't know the interior of the V10, but could the hill have been steep enough to have oil build up in the valve cover and maybe go into the PCV valve? Or some other place it shouldn't go?

Maybe there is some restriction in the rear oil drainback hole on one head or the other. And it is normally no problem because the oil drains out of the front drainback hole also. But, a steep grade causes all the oil to drain to the rear hole only and then the oil fills the valve cover until it causes a problem? That might account for all the smoke on startup also.

Good luck and keep us informed with any more information you get.

Mike

John Kalmbach · 07-31-2008, 11:19 AM

Hello Geoff,

While I haven't heard of this issue going uphill, I have seen it happen regularly on long descents when in low range with the V-10. The sustained high engine RPM without fuel being supplied to the injectors would cause a "shut-down" mode, not what you want to happen on steep grades.

The best thing to do is stop occasionally, let the engine idle for ten seconds or so (until smooth), and then continue repeating this process. It's not as much of a hassle as you would think. This short idle time does allow the computer to sense that fuel is flowing to the injectors and the engine will not shut-down.

I know this is opposite of what you're experiencing, but I wanted you to have the info anyway. It could be that the long uphill grades are causing sustained excessive RPM (at least not in the parameters of the program) and causing a similar "shut-down", but that is only speculation. You might try the similar stopping occasionally approach and see if it makes a difference.

I hope this helps!
John K.

geoffff · 07-31-2008, 12:38 PM

Thanks for the input!

Most of the time, it would be OK after the steep uphills once the trail leveled out. During the climb, the engine stumbling would come in sporadic bursts -- a second or two of stumbles, then 10-20 seconds or more of running just fine.

The time it died completely was just after climbing a steep trail (with some stumbling), and the trail had almost completely leveled out again. When it wouldn't start, I waited a few minutes, then just cranked it a whole bunch (10 seconds cranking, wait, repeat...) until it finally started with lots of black smoke.

I haven't had any problems with the downhills.

If my mechanic can't figure it out, I'll try doing some experimentation as you recommend.

-- Geoff

NRL · 07-31-2008, 02:29 PM

I had a similar problem when we did our DIY Transflow install.

In my case, it turned out to be the check valve that keeps the fuel pressurized and by design prevents the fuel to flow back into the fuel tank on a steep incline or on startups. I needed to add the check valve after I replaced the whole fuel pump assembly.

I may not be 100% accurate but I recall older vans (Pre-97), the fuel check valve are in the gas tank was the fuel assembly and newer models it's up in front. (Please check your service manual for exact location on your year and model)

Also, when you replace the fuel pump, did you get a peek at the replaced unit? In my case, my old fuel pump assembly had a little reservoir that holds a bit of fuel right underneath the actual fuel pump(which goes into the fuel tank).
When we put in our modified 97 fuel assembly onto the transfer flow tank, it was missing that reservoir that was holding the extra fuel.

I guess from 97' onwards there is no reservoir that holds that extra fuel for inclines. Don't know exactly how the new model fuel pickup works inside the fuel tank, especially when your on an incline.

geoffff · 07-31-2008, 03:45 PM

Hi NRL, was your '97 a two-tank system? (My 2004 is a single 46 gallon tank.) I gave the Transfer Flow people a quick call and the tech mentioned issues back with the 2-tank systems. But otherwise he couldn't think of any likely problems.

-- Geoff

geoffff · 07-31-2008, 03:50 PM

I didn't get a look at the fuel pump when the Ford dealer replaced it, but I do know my tank takes the stock Ford unit.

NRL · 07-31-2008, 03:57 PM

Quote:

Originally Posted by geoffff

Hi NRL, was your '97 a two-tank system? (My 2004 is a single 46 gallon tank.) I gave the Transfer Flow people a quick call and the tech mentioned issues back with the 2-tank systems. But otherwise he couldn't think of any likely problems.

-- Geoff

Yes, I have the one tank 46gal using a 97 Ford fuel pump assembly with a 96 pump.
They only sold the transferflow for gas quigley for 97 and up.
We made it work for a 96 using the 97.

Christopher Thwaites · 08-08-2008, 03:58 PM

No one has mentioned the fuel filter as a possible culprit! Anybody have an opinion? Under power(steep climb) and with a filter that is nearly plugged the angle of the filter might cause fuel starvation that would not show up on level ground. I have a V10 and haven't had any issues. I replaced the filter at 46,000. How many miles on your filter?

NRL · 08-08-2008, 04:12 PM

Quote:

Originally Posted by Christopher Thwaites

No one has mentioned the fuel filter as a possible culprit! Anybody have an opinion? Under power(steep climb) and with a filter that is nearly plugged the angle of the filter might cause fuel starvation that would not show up on level ground. I have a V10 and haven't had any issues. I replaced the filter at 46,000. How many miles on your filter?

Good call. Heard it was easy if you have the fitting tool.