[nimnoi]

Hi guys,

I'm new to the forum, so maybe you've already answered this somewhere, but I've got a 1990 Ford F-350 with a 7.3 ltr diesel that stalls if I lift my foot rapidly from the accelerator. It will restart easily, and it doesn't make any funny noises, it just dies. It will idle, you just have to lift your foot slowly enough so that it doesn't die. I've had it recently serviced, new fuel filter, no obvious fuel or air leaks. Does anyone know what might be causing this?

thanks

 

[cdnsarguy]

How many miles on the IP........is the trans manual or auto.
Does it stall at corners if the clutch is disengaged?
What is your curb idle set at should be 650 manual in nuetral or auto in drive.

 

[nimnoi]

How many miles on the IP........is the trans manual or auto.
Does it stall at corners if the clutch is disengaged?
What is your curb idle set at should be 650 manual in nuetral or auto in drive.

It's automatic transmission (newly rebuilt). As far as the IP's mileage, I'm not really sure, but probably many. The odometer reads 102,000, so probably that? Also the truck had been sitting for seven years when we bought it; we've had a lot of problems with other parts failing on us. It doesn't seem to stall at corners in particular, but often at stoplights and sometimes even when coasting - it idles at closer to 600 and sometimes as low as 500. I think the low idle is the problem.

Any idea how we might fix it?

 

[nimnoi]

OK, my husband talked to a local diesel mechanic, and the fix was so simple I'm still in shock! It's not shall we say EPA approved though.... we just dumped a quart of tranny fluid in the gas tank. Worked like a charm, didn't even have to drive very far before the problem went away. Has something to do with a little valve on the fuel pump (I think) that needs lubrication, and since diesel fuel has pretty much been delubed by some law or other, this switch tends to get stuck from it's lack.

Therefore tranny fuid = lube = FIXED!!!! Yaay!

 

[cdnsarguy]

Better to use a diesel fuel additive with every fill than trans fluid..... Trans fluid is not a lubricant.

Hayes diesel treat, Stanadyne pro, Power Service(diesel) and there are many more.

If it has been sitting that long the old fuel may have bio matter in it......

 

[drinkypoo]

Better to use a diesel fuel additive with every fill than trans fluid..... Trans fluid is not a lubricant.

You're probably right that it is better to use a diesel fuel additive, but you are 100% wrong that trans fluid is not a lubricant. Like motor oil, it is made of crude plus additives. IE, it is virtually the same thing as motor oil, though it has more additives; mostly more of the same stuff, just in different proportions. If you look inside of your Ford C-II power steering pump you will find that it is a high-friction design with slippers on a rotor running around inside a cam. If trans fluid were not a lubricant then the pump would grind itself away in no time. (Conversely, if you run your P/S pump empty, you will destroy it in fairly short order.)

Diesel fuel has had lubricity additives since it became low-sulfur. So you really shouldn't need to add anything... but adding motor oil or trans fluid certainly should increase the lubricity of your fuel.

 

[LMJD]

Has something to do with a little valve on the fuel pump (I think) that needs lubrication

It's a metering (spool) valve that can hang up. If the problem returns, it's probably scored but can be replaced and its bore smoothed but that requires a IP overhaul. Besides a lube, ATF has a very powerful detergency additive. Even works on humans, We used to overhaul lots of heavy truck Allison automatics and no matter how dirty our hands were, when tearing the trans down and wading around in the ATF a while they'd soon be clean as a brain surgeon's.:icon_wink:

 

[chuckster57]

Even works on humans, We used to overhaul lots of heavy truck Allison automatics and no matter how dirty our hands were, when tearing the trans down and wading around in the ATF a while they'd soon be clean as a brain surgeon's.:icon_wink:

Never liked it as shampoo though :lol:

 

[LMJD]

Now that was a good one!:lol::lol: