92-95 F150 bucking hesitation modification

[user removed]

Not many here own one but I found something today that worked nice. Mine is the 300 6cyl and 5 speed with a 2.73 rear end. These trucks were notorious for bucking and hesitation on light acceleration, even when new.

Apparently mine had been to a dealership for this problem before I bought it, had new Ford (Motorcraft) plugs, distributor cap and plug wires. Only 85k on the odometer when I got the truck. Smoothest idle of any vehicle I have ever owned.

After searching the web for any solutions, I found a thread on one of the F150 forums about the possible solutions to this issue. The thread was several pages and the solution was to add a restrictor to the EGR circuit to lower the tip in volume of EGR.

It cost me a whole 11 cents at True Value for a 1/8 inch ID 3/4 inch OD galvanized fender washer. The nut holding the tube to the EGR valve had not been touched since 1992, and it was hard to even get and turn on it with a 15 inch crescent wrench, wouldn't budge. After some gentle persuasion with a hammer and some heat from a MAP gas bottle, a hammer whack on the wrench got it to move. Installed the washer (perfect fit) between the EGR tube and the valve body.

I had learned to just step on the gas more to avoid the nasty bucking, so it took awhile to get used to ignoring my previous solution and drive it like a diesel, since it's geared that way. The difference is astounding. There is no CEL and I can feel just the slightest amount of hesitation on very light acceleration, just enough to know there is still sufficient EGR.

Might be worth a try if you have one of that era of F150. I'll check to see if the mileage improves, although it was not that terrible before. I just don't drive the truck that much anymore, maybe 100-150 miles a month or less.

regards
Mech

[E4ODnut]

If you're ever tempted to go programmable EFI I've been running my 300 E150 for about 7 years now. Love to have some company.

[slowmover]

Wish we'd known that 20-years ago. That's the last Ford I'd have wanted to own. Thanks for posting it, and glad you got that sucker free'd up to install it!!

If you're ever tempted to go programmable EFI I've been running my 300 E150 for about 7 years now. Love to have some company.


Have you a thread or posts on this? Would enjoy reading more. Much as I enjoy V8 engines I always seem to wind up with straight sixes. Gas or diesel they really do offer what is needed for a work vehicle.

[user removed]

While I would like the idea of a programmable EFI setup, it would probably cost as much as I have in the truck. Highway mileage at 70 average speed is 20 MPG. Now it will be fun to see what I can do overall, without the stump pulling torque destroyed by bucking and misfires at the perfect rate of acceleration to take advantage of the enormous low end grunt of the old tech 300-6. No air, rubber floor mats, not even a radio, combined with the lightest weight of the short bed and smaller differential. Heck I might even make an aero cap for it now!

I find myself liking the combination of old tech engine and new tech (relatively) multipoint EFI with cat and feedback systems with the Mazda transmission (.80 OD 5th). Another neat thing is it was build in Norfolk Virgina, the same city where I was born 61 years ago today. Plant has been closed for years now.

regards
Mech

[E4ODnut]

The really good thing about programmable EFI is that it allows you complete control of fuel mixture and ignition timing with resolution simply not possible with a carburetor and conventional ignition.

But!

The really bad thing about programmable EFI is that it allows you complete control of fuel mixture and ignition timing with resolution simply not possible with a carburetor and conventional ignition.

The bad part is that you really do have enough rope to hang yourself, but there are rewards if you don't screw up.

Having said that, from my experience, generally the OEM has done a very good job of balancing power, economy, and emissions concerns with any of their EFI engines. Any gains you can make in one area will be offset by losses in another. I've gone to a lot of effort to try squeeze a bit better economy out of my 300, but I've found it very difficult to do. Also even harder to document, because the vehicle is my daily driver and service van which tends to gain weight, which in turn will offset any economy improvements. Ethanol blended fuel doesn't help anything either, but that's another subject.

Why do it then? You might ask. I suppose because I find it interesting and challenging. But it's pretty lonely out here. Most programmable EFI is used by the go fast boys. Not much interest in economy tuning, and even less with the Ford 300. There is a pretty level headed bunch over on Fordsixperformance forum, but even there I've found no one else experimenting with it in this way.

The 300 produces very good torque, not massive, but very good. What sets it apart from most engines is that it will produce this torque right down to about 1200 RPM. It behaves more like a naturally aspirated diesel then a gas engine. The problem is that it's Brake Specific Fuel Consumption numbers simply aren't very good so it's pretty hard to gain much. I've found I can run my engine relatively lightly loaded with A/F ratios between 17:1 and 18:1 before it starts to complain. This should result in economy gains, but in my application I'm hauling so much weight that I'm very rarely in a light load cruise situation.

So, I suppose, it's not so much the destination as the journey, but it would be nice to have some company along the way.

[user removed]

This truck according to my calculations goes 46 MPH at 1200 RPM. 28 inch diameter tires, .79 OD 5th gear and a 2.73 differential. That's some serious tall gearing. Heck you can let off the gas pedal and it will go 25 MPH idling in 5th gear practically forever, which works out to 650 RPM. Even with the not so good BSFC engine it should be able to do pretty good for mileage. The manual says not to go below 42 MPH in 5th, but the EGR mod allows it to cruise at lower than 35 in 5th. Go to low and you can hear the gears in the tranny rattling.

I'm going to fill the 16 gallon front tank tomorrow and see how it does now that it is finally running right.

regards
Mech

[E4ODnut]

I have an E4OD in my van, but it's running on my own controller so I dictate when the torque converter clutch is locked up or not. I have it set to unlock automatically below 1200 RPM, but I can pull down to 1200 even under full load smoothly, no bucking but, no EGR either.