Ideas needed

[NH2112]

I just finished putting my engine back together - it got "new" heads, new head gaskets and a new timing set - and I'm getting the same problem that I had before as far as diesel rattle, lack of power, etc. What it's still doing is smoking excessively (acrid grey smoke at idle, lots of black smoke even under moderate acceleration), the diesel rattle is very loud, and it's hard to start - the battery is kinda weak, though, and I have to do Dr. Lee's terminal mods as well. My timing light isn't working due to my leaving the box out and it filling up with rain water so I couldn't check the static timing, but with a new timing set I should have been able to just line up the timing marks and be pretty close to good. Well, it didn't work that way LOL I triple-checked both the crank-to-cam sprocket and the cam-to-IP gear alignment and both were dead on. I doubt I'll be able to get the timing light fixed anytime soon, but I will give it another shot once it dries out. So, anyone have any ideas? I've advanced and retarded the pump as far as the lines would let me move it (about 1/16" either direction) but it doesn't seem to make much of a difference - the sucker is LOUD either way. I guess I'll mess around with it some more, maybe get the HPCA working, and see what happens. Man, I'm getting tired of this truck! LOL

[DmaxMaverick]

HPCA? That be a good place to start, and may be all it needs to make that monster go away.

Also....
Make sure your I/P and inj. return lines are not blocked/kinked.
Correct injector line timing (it happens. you can cross a couple)
EGR?? If it has one, make sure it's not staying open.
Rat's nest in the intake. (sounds stupid, huh)
Fuel filler cap venting properly?
Fuel and filter quality. (really should be at the top of the list)

The list goes on, but that should get you started. It'll probably be some stupid thing that got overlooked.

[arveetek]

Did you ever fix the HPCA system that was disabled in the "new" IP?

Casey

[NH2112]

Originally posted by arveetek:
Did you ever fix the HPCA system that was disabled in the "new" IP?

Casey Well, all that I had done to it was remove the plunger from the valve because the needle was bent and the plunger would get stuck. The temp switch isn't hooked up. I do have an ignition-hot wire I can use (electric choke wire - the truck used to be a gasser) but right now it's powering my electric fuel pump....which I'm thinking of getting rid of anyway.....maybe I'll splice into it to feed the temp switch.

[Peter J. Bierman]

Phil,

Check the fuel pressure and the housingpressure in particular, if this is to low your timing will advance more then you can adjust.
Dropping the pressure a few psi will advance 2 to 3 deg, imagine dropping it to almost zero.....

If your cam and pump timing are correct, this could be the answer.

Good luck, Peter

[NH2112]

Peter,

I started thinking about my electric pump being too weak for the job, although I did specify a 6-10psi pump and it should be strong enough to push fuel from back near the tank. I'll probably take it out of the system and hook the mechanical pump back up when I get a chance. Although, I had been running with the electric pump for a while before this problem started, but it was mounted on the passenger fender. Maybe pulling the fuel that far weakened it? I know electrics like to push rather than pull.

As far as it being HPCA-related, I don't think it is because the HPCA has never been hooked up on this engine. Once I get everything else worked out I'll hook it up simply because it should make winter starts easier, but I'm pretty much convinced it's not part of the problem I'm having now.

[Peter J. Bierman]

Phil,

If your lift pump gets fuel to the IP, the transfer fanepump should get it up to the specified housing pressure.

Measurements on various places in the system will tell the true story, otherwise its just guessing.

Peter

PS, as for the HPCA thing, you can try to clamp off ( a bit ) the returnline just above the IP to get some more resistance/ pressure.
Easy to do and you'll be sure its not the HPCA.

Peter

[NH2112]

Well, one thing I did notice was that the advance plunger on the bottom right of the pump isn't making contact with the lever with the throttle in an idle position. So, I figure that it's advancing the pump, which means I'll have to pull the pump - AGAIN - and either disassemble it to unstick it or work a lot of penetrating oil into it to free it up. Anyone taken one of these apart?

[Peter J. Bierman]

Shouldn't there be some free ply between them or is it stuck pushed in?

I had a pump dismantled a few times but do not recall anyting special about the advance plunger.

Looking at the pictures it came back, at the bottom off the pump is a plug, removing this allows you to take out a little pin which connect the camring to the plunger. you have to take it out or you won't be able to remove the plunger.
I guess you have to take out the pump to do so.
You can however take the screwcap out on the leverside and see what is sticking, the big plunger seems not a real likely suspect the smaller one through the seal might, replace the seal wile your at it....
This can be done in truck, so it might be worth a shot.

Good luck,

Peter

[5.7L oldsdiesel]

On the 6.2 diesel pumps i've worked on,there was hardly any clearance between the servo plunger and the actuating arm at the bottom of the pump at idle.Has the face cam screw loosened?If the screw is loose,the cam will slip on the throttle shaft.At idle,push in at the bottom of the actuating arm.Engine speed should decrease and the engine sound will have a different tone.This will tell you if the advance mechanism is working properly or not.

[NH2112]

I guess I'll pull the IP again this weekend and see what I can see about that plunger. One good thing about all this - I'm getting VERY good at pulling IPs! I bet I can have that sucker out in less than 1/2 hour LOL. And that's not using any power or air tools!

Hopefully I'll be able to get it running right, either by freeing up what's in there now or swapping parts from one of the other IPs I have laying around.

[BobND]

Originally posted by NH2112:
Well, one thing I did notice was that the advance plunger on the bottom right of the pump isn't making contact with the lever with the throttle in an idle position. So, I figure that it's advancing the pump, which means I'll have to pull the pump - AGAIN - and either disassemble it to unstick it or work a lot of penetrating oil into it to free it up. Anyone taken one of these apart? What you think is an "advance plunger" is actually a "RETARD PLUNGER".

As the throttle is opened, and the lever is moved by the cam on the throttle shaft, it pushes in on the plunger, and RETARDS injection timing.

At idle, the lever backs away from the pin or "plunger", and the timing is allowed to advance.

The reason for this... as the fuel rate goes up, the plungers in the pump move out farther, with the increase in fuel delivery, and therefore contact the came ring sooner, resulting in the start of imjection being advanced.

The mechanical cam on the throttle shaft acts as a sort of "reverse timing advance", acting against the plungers hitting the cam sooner, and keeps the start of injection at a same time, as the fuel rate increases.

Advance plunger "OUT" = advanced timing

Advance plunger pushed "IN" = retated timing.

[NH2112]

Are there any special tricks to taking this thing apart, or will it be like trying to put Humpty Dumpty back together again? I'd meant to try on an old pump today but never got around to it during break.

[twaddle]

Hi phil,
Have you tried the test that 5.7Diesel suggested.
It will only take a moment and all you need is a screwdriver to push in the lever/plunger?
It will tell you if the plunger is sticking or not.

When you move the IP either way of the lines does the engine run rougher, more or less smoke?
Does the engine exhaust smoke when revving or idling?

I have had a very similar situation once when installing a IP. I had trouble getting the shaft to align with the centre of the gear. I accidentally shoved the gear forward and it "jumped a tooth" out of alignment. Is there any chance that the same may have happened with you.

Good luck

Jim Twaddle
Biggar, Scotland

[NH2112]

There wasn't a discernible difference in sound, smoke, etc, but if the plunger's halfway depressed (it doesn't even contact the lever when the lever's at the end of its travel) then timing's probably so retarded that a few degrees either way (by moving the pump) won't make much difference. I do have a lot less black smoke under load now than I originally did, though.


Tomorrow it's supposed to stop raining, so I'll be able to get out and do some tests. I told myself that after 12 years of freezing, boiling, and getting drenched while operating and maintaining vehicles in the army I'm not doing it any more except at work or when on the trail smile.gif I'm hoping I'll be able to use a pair of needlenose pliers and some PB to free up the partially depressed retard plunger, but if not at least it's a relatively fast & easy job to get the pump out. Although I just realized I forgot to bring my pin punches home from work :mad: , and I'll need one to get the lever off so I can take the mechanism apart...oh well, looks like I'll have as much tols in my truck as I do at work before long LOL

[BobND]

Likely, it is not the short little plunger that is visible that is stuck (although it's possible), but rather it's the larger advance piston that's stuck in it's bore. (The little plunger fits inside the larger advance piston.)