Engine surge after startup

[Fantom]

This is the second time this has happened with my truck since I had the 36k service done. Don't know if there's any correlation between the two.

After warming the glow plugs as soon as the truck is started the engine "revs" twice really fast to about 2k. It's never done this in the 5 years I've owned it until about 2 weeks ago. Anyone else have this happen or know why it does it?

The truck is a 2001 F550 7.3/auto Mileage is about 38k

[mschn99]

Originally Posted by Fantom

This is the second time this has happened with my truck since I had the 36k service done. Don't know if there's any correlation between the two.

After warming the glow plugs as soon as the truck is started the engine "revs" twice really fast to about 2k. It's never done this in the 5 years I've owned it until about 2 weeks ago. Anyone else have this happen or know why it does it?

The truck is a 2001 F550 7.3/auto Mileage is about 38k

does it have a PTO for the dump bed???

[Fantom]

Nope, not PTO. The dump bed is eletric over hydraulic.

[mschn99]

sorry then, ive seen that with pto trucks...but ive never seen that with a non PTO unit......thought i was onto something...

[super_stroke]

does it smoke? howa bout glow plugs? relay? shot in the dark.

[Fantom]

Originally Posted by mschn99

sorry then, ive seen that with pto trucks...but ive never seen that with a non PTO unit......thought i was onto something...

Not quite the answer i was looking for. I wanted something along the lines of "sounds like your torque flange doohicky valve, they do that all the time"

Glow plugs seem to be doing their job. After running all day, she does tend to blow little whisps of white smoke. Not enough that you'd really notice though.
It doesn't do it every time I start it, although I'm sure it's a "dealer couldn't duplicate problem" situation.

[mschn99]

only thing i can think of is either a bad copper washer on the injectors, or an injector itself leaking down sometimes.....

[ProGunProgressive]

I've noticed a similar problem; a couple times now on cold start up it'll buck and surge until I blip the gas pedal.

wonder if I'm seeing the early signs of that filter clogging thing people talk about all the time.

I've noticed that on cold, cold starts--like literally only the first start of the day--the motor will buck when you first start it up. You wait for the glow plugs to warm up, you fire it up, and as soon as it catches and turns over you release the ignition key just like you always do. At that point it'll buck pretty noticeably...imagine a big lumpy cam but slower. Vrum, vrum, vrum, vrum....like it's coughing and gasping for fuel. Give the gas pedal a quick blip and it levels out immediately and it doesn't happen again no matter how many more times you start it for the rest of the day.

I drained off a bunch of water from the water separator the other day, so it's probably not that. My guess is that a little bit of stuff has probably congealed on the filter and that it loosens up when the motor warms up, but that when it's a cold start the motor is gasping for more fuel. I'm going to pull the fuel filter and see if it's gunky. If that's not it, anyone have any other ideas about what causes it to buck at cold start idle?

The rest of the time it runs like a dream--quieter than ever, smoother, making more power than it ever has, so I don't think I've got an injector or fuel delivery problem for the most part.

[jeshoyt]

Originally Posted by ProGunProgressive

I've noticed a similar problem; a couple times now on cold start up it'll buck and surge until I blip the gas pedal.

wonder if I'm seeing the early signs of that filter clogging thing people talk about all the time.

I've noticed that on cold, cold starts--like literally only the first start of the day--the motor will buck when you first start it up. You wait for the glow plugs to warm up, you fire it up, and as soon as it catches and turns over you release the ignition key just like you always do. At that point it'll buck pretty noticeably...imagine a big lumpy cam but slower. Vrum, vrum, vrum, vrum....like it's coughing and gasping for fuel. Give the gas pedal a quick blip and it levels out immediately and it doesn't happen again no matter how many more times you start it for the rest of the day.

I drained off a bunch of water from the water separator the other day, so it's probably not that. My guess is that a little bit of stuff has probably congealed on the filter and that it loosens up when the motor warms up, but that when it's a cold start the motor is gasping for more fuel. I'm going to pull the fuel filter and see if it's gunky. If that's not it, anyone have any other ideas about what causes it to buck at cold start idle?

The rest of the time it runs like a dream--quieter than ever, smoother, making more power than it ever has, so I don't think I've got an injector or fuel delivery problem for the most part.

My truck is doing this when I start it also. But what's weird is it only does this on probably 1 out of 10 starts? I am pretty sure it's not the fuel filter because I just changed it out a couple of weeks ago. It was doing the bucking thing with the old filter as well. My truck runs great the rest of the time also, just does that bouncy thing sometimes when I start it.

[ProGunProgressive]

Yeah, it's not really a problem, the truck drives great, idles great, doesn't smoke, makes a ton of power, etc. It's just that A) I've recently switched to B100 and B) noticed that I had to drain the water from the separator. I had to do that once before when the truck was still on petrodiesel. My thought was maybe I've got that problem that you hear about with bio, that I've loosened up some gunk in the tank or fuel system and it's congealing on my filter and starving it...and then going away as the thing warms up.

But I've noticed that as soon as you blip the throttle with your foot, the problem disappears instantly. Like you're jump starting fuel delivery or something. Interesting. Certainly not a problem I'm going to spend hours hunting down, but I just want to make sure it doesn't portend future troubles.