What do I check next? (this has gotten ridiculous!)

[gavio]

Hey guys:

I'm having a strange surging/lagging/bucking problem, most evedent under low-speed light load conditions. It's detailed in an earlier post, but here's the latest:

The most repeatable symptom is when sitting in the driveway idling, if I rev it up to maybe 1200-1500 RPM or so, it'll then takeoff on it's own and jump to like 2000 RPM or more. It doesn't entirely run away, it levels off at some point.

It doesn't seem to have this problem when it is still cold, although obviously I can only test this for so long before it warms up.

It happens with the HPCA disconnected and also if I disconnect the cold advance solenoid it still happens. It also happens with the lift pump disconnected (I have only an electric lift pump - no mechanical).

It starts exactly the same as always both cold and warm, the fuel filter's pretty fresh, the lift pump is working.

There isn't any evidence of any leaks, except for a little bit of wetness at a valve I have where the factory secondary fuel filter would have been (i.e. between the lift pump and the IP) but since it's after the lift pump (i.e. pressurized) could that even be a source of air? And if so, wouldn't it cause starting problems and behave the same cold as well as warm?

Only other things I'm aware of, probably not related, but maybe:

Voltage when running at speed shows 14.6 instead of 13 or so - it doesn't go over 14.6, but does drop down significantly at idle;

and there is a strange vibration to the idle at times - haven't quite identified the pattern, but it's like the idle speed doesn't quite drop down to 650.

I'm in the middle of moving and financially strapped (when else would the truck break?) and I need the beasty back to normal PDQ. I just don't know what else to check.

Any help sincerely appreciated.

Thanks, as always.

[ 01-28-2004, 04:24 PM: Message edited by: gavio ]

[NH2112]

I had something similar happen - mine would all of a sudden jump ahead like a jackrabbit even though the "throttle" was steady - and after giving the outside of the IP and the inside of the cold advance solenoid a good cleaning with carb cleaner it stopped. My diagnosis? Either the "light load advance lever" was sticking, or else the check ball in the cold advance solenoid was sticking and caused timing to advance, although I never paid attention at the time to see if the clatter was more pronounced like on a cold engine.

[gavio]

I don't think the clatter changes when it surges, although I'm not positive as it always clatters a little anyway.

I'll try a little cleaning - but specifically where do I focus my attention? Sorry if that seems a little dumb, but I still lose track of what is what.

Thanks so much...

[Peter J. Bierman]

Sounds to me that governor weight retainer sticks a little one in a wile, thats the only thing controling RPM other then the trottle.
It is however hard to check, you have to open the pump and see inside.
One other possibility is the throttle linkage inside the pump, the movement off the throttle is linked inside with a couple off springs and links. if one or more get stuck it could start a life off its own.
In both cases you have to go inside. :(

Peter

[rthomse]

had the same surging problem with mine.The Injection pump was starting to self distruct.

[gavio]

This IP only has about 12k miles on it, so I sure hope it isn't failing already! :eek:

I'm goin' in now to have a look 'round. We'll see what happens.

[gavio]

OK, so I cleaned up everything on the outside of the pump and....

the problem remains.

I confirmed that it for sure ONLY happens after the engine warms up and drops into low idle. Does that mean anything?

If I pop the cover off the injection pump, what am I looking to do in there?

I looked inside my spare pump and I see all the bits, but I just don't see what you would do with them - I mean assuming they are all in place which they must be since it's been running all this time.

:confused: :confused: :confused: :confused:

Help!?

[dieselbegreat]

May I state the obvious and suggest you swap the injection pumps? Seems reasonable.

[gavio]

I somewhat misspoke myself when I called it a "spare" IP. Actually it's my old one and it leaks like a seive and was definitely behaving very badly indeed.

Otherwise, your idea just might have worked! ;)

[Peter J. Bierman]

Look for little brownish pieces off plastic, if you find those is probably the governor weight retainer.
Move the trottle and see if everyting moves smoothly all the way.
On the injectorline side in the bowl you see a lever pivoting around a axle like thing in the center, this axle is what actualy controls the fuel injected.
See if the thing with the springs on it moves smoothly on the rod and if the linkage is free and all the springs in one piece.
The movement might be getting a little stiff when it warms up?

Other wise I don't know :confused: ...... Britannic???

Peter

[britannic]

Remove the governor housing cover on the IP and check that the metering valve (rear of pump towards the engine bulkhead) rotates smoothly in both directions without binding (use the accelerator linkage or have an assistant press the go pedal from the cab).

To check for governor ring failure (front of IP) use a screwdriver and rotate the governor weight retainer in both directions, it shouldn't move more than 1/16" either way and it should return to its original position.

When you replace the housing cover, don't start the engine yet, but instead energize the shutoff solenoid with 12v and make sure it clicks, else the metering valve may be jammed open, guaranteeing a runaway engine that may destruct upon startup!

[gavio]

Thank you so much for the detailed information.

I'm hoping to have the time to check it out tomorrow - if not, it'll have to wait until Sunday. I sure hope to get this puppy back to normal soon - I had to drive it a little today and it was a pretty strange ride. :eek:

[Larry Andrews]

Maybe this is just it's way of telling you that it's tired of being on the vegan diet? :D J/K!

[gavio]

Hey! Bite your toungue :D

Besides, it gets some diesel #2 mixed in in the winter to prevent gelling.

Hmmmm, maybe, just maybe, it's telling me that now that it's used to fresh golden nectar, it really doesn't like stale old dinosaurs anymore! :D

We shall see, we shall see.....

[dieselbegreat]

Maybe it thinks it's butter, but it's not! :D You probably have margarine coating the inside of your pump which is messing with your metering and advance. Shortly after I got my Suburban, my wife gave me a half full gallon can of olive oil to dispose of. It was a summer day and I was headed out on a 250 mi highway trip, so I threw it in the tank! I tested it first to make sure it would mix. All was well until a storm blew through and the temp dipped below 60 deg. Going up hills my "Water in Fuel" light started coming on (clogged filter) and got progressively worse. I made it and the next day was hot so the olive oil liquified again and never had another problem. I definitely would like to use biodiesel as an additive at least because of its high lubricity and detergent qualities. (and I like the smell of french fries) :D

[gavio]

OK, so I've got the pump open, at last.

The mechanism all seems to work smoothly, no kinks or anything of that nature. Everything in it looks like my old pump's innards.

I'm having trouble identifying the "governor ring" or "governor weight retainer". Wherizit?

In my shop manual, there is one of those crude illustrations that seems to show a sleeve or cap on the end of the governor apparatus but both of mine just have exposed springs. I noticed that the photos in the Diesel Page manual show a setup like mine.

The difference is that the end of the governor spring seems to contact the plate connected to the metering valve apparatus in the photos and on mine, there is a space there, unless I manually move the metering valve apparatus backwards. Did that make even a tiny bit of sense?

In other words, moving the throttle lever doesn't seem to directly result in movement of the metering valve assembly unless either the metering valve bit is moved back, or the governor weight is moved out by hand. Is all this correct?

I have found no broken bits or bent things or non-working wizbangs.

What else am I looking for in here before I stick it back together?

Thanks for any help.

[britannic]

The metering valve is at the back of the pump towards the bulkhead and the governor ring is at the front toward the radiator.

Without the cover on, the shutoff/governor linkage should be acting as though the shutoff solenoid is retracted and all throttle movement should actuate the metering valve in the rear of the IP. If it doesn't, then something is sticking or the springs have become weak. How about trying a comparison between the old pump and new to see if throttle movement is the same?

Is there any possibility that the veggie oil has gelled in the pump somewhere?

Check out David Oliver's site for information and pictures on how the IP works: How the DB2 Works (http://www.oliverdiesel.com/tech/howdb2pumpworks.htm)

[gavio]

OK, so the deal is...

The movement of the metering valve apparatus is pretty much the same between the old pump and the current one. What happens is if I push forward on what I think must be the governor ring (it's on the main shaft just ahead of the governor weights) that causes the metering valve linkage to be engaged with the throttle linkage. I can then open up the throttle and the metering valve opens smoothly with it. Then if I close the throttle, the metering valve does not move back - instead the min-max governor spring assembly moves back with the throttle, but becomes disengaged from the metering valve linkage. I can re-engage them by manually moving the governor ring back forward. The ring on the old pump seems very sloppy, on the current pump it's not so bad but the overall action of it all is the same.

Does this explain anything?

The problem is unlikely to be due to veggie oil as it has been running a mix of #2 and commercial biodiesel for some time before the problem occurred. I discovered a design flaw in my veggie system and shut it down until I can install a new type of filtering apparatus which will heat the filter better.

A post on the veggie forums says you can clean the metering valve (on Fords, anyway), but I can't seem to figure out how to remove it as the throttle shaft seems to prevent the linkage from lifting enough. Are these set up differently than Fords somehow, or do I just not know the correct trick?

Thanks for the help, as always.

[Peter J. Bierman]

On the rear off the pump, just below the cover mating face, is a hexagon bold.
This is the guigepin or whatever it is called.
If you unscrew this bold and take is out, you must be able to remove the metering valve.
Be carefull, if you take out the guidepin the springs and so come loose too.
Don't drop them inside!

Good luck, Peter

[gavio]

Unfortunately, the linkage which controls the metering valve is trapped where it runs forward under the throttle shaft. I'm hoping there's some trick to it 'cuz I'd like to try everything possible while I'm in here.

It's not very scientific, I know, but time is at a premium as I'm moving in two days and have not even packed yet!

[britannic]

FYI (you may already know this): to remove the accelerator/regulator block, after the guide rod is slid out, rotate the accelerator and tip up the block until you're able to pull it free of the accelerator shaft.

[gavio]

Say, Brittanic, does my description of my throttle/metering valve operation seem copascetic, or is something off there?

[britannic]

Gavio, since both IPs behave the same way, that seems to check out - unless the original IP's problem was the same as the newer pump :D . The behavior would be different if the pump was running, since the governor weights would move the governor ring.

How much pressure is the lift pump putting out? One possibility is that it's not putting out enough pressure, so that when the vane transfer pump in the IP compensates at higher rpms you get the weird behavior.

You might try calling Tim Wagner @ Accurate Diesel (http://www.accuratediesel.com), mention my name to him and discuss the symptoms. Ask him whether or not the IP needs recalibrating - you'll find Tim to be very honest and he won't just say it does need work to get your business.

[gavio]

:mad: :mad: :mad: :mad:

Well, I finally finished trying everything anyone suggested to check out and clean and what-not and I'm putting it back together and I feel the anticipation building and I'm tightening the screws that hold on teh governor cover, after having of course made sure that everything was clean and in the right place and working, and I'm thinking "this just MIGHT have worked, by golly" and then it happened.

One of those %#^&@%$#^! screws actually snapped off. Worse yet, it snapped off level with the top of the IP housing, so there's nothing to grab. :( :( :(

Tell ya, in moments like that, I wish biodiesel had a lower flash point so I could at least have the FANTASY of throwing a match in the fuel tank!

What's really annoying is that I drive this van around all the time and then on my moving day, I have to borrow my neighbor's!

OK, I'll stop venting now. If anyone's listening, thanks for the attention. And if any of you are the folks who provided help - thanks for that, too.

After I move, I guess I'll figure out what to do with the van - the ingrate - after all I've done.... :D

[britannic]

Was it level with the top of the cover, or the actual housing? I'm feeling your pain :mad: !

[britannic]

Just had a thought, based on a re-read of your symptoms, this may not be a pump problem at all: how much engine oil residue do you have in the intake manifold from the CDR connections? To rule out the CDRv as the culprit (once you get the engine restarted), try disconnecting the CDR altogether and see if the symptoms repeat over 10 minutes of running.

I had to drive 10 miles before the last of the excess oil was purged from my intake after replacing the CDR.

[gavio]

Well, the bolt snapped level with the pump housing. After I move, I'm gonna try using a really small extractor if i can find one. If that doesn't work, then I don't know what to do - don't really have the dough for a rebuild of my pump right now.

I thought of the CDR thing, but there is just the barest film of oil residue in the tube and the inside of the intake is not oily at all. When my old CDR was bad, there was quite a bit of oil in there.

Oh, wouldn't I just be SERIOUSLY annoyed if it turned out not be a pump problem at all!?