gorms

I wouldn't be afraid to tell them what you're going to do, if it might save you the downtime. It's your truck and your pump afterall, and you have a video of what it's doing right now. Maybe they can provide a checklist of things you can do so you don't waste any time, in case it is something simple.

Dumb question maybe but you are sure the shutoff solenoid is up all the way right? AND that it's turning the shaft all the way also?

Andy505

Well I dug into the pump, pulled all the governor springs, cleaned everything. Nothing looked out of place or out of adjustment, put everything back together. It runs better, but it will still lope and then settle into a steady idle...kind of. It will randomly increase is rpms by a 100 or so, then lope a little, then settle back into a steady idle at roughly 850 rpms.

Still doesn't seem right. As far as I can tell everything is tightened the same, unless the weights are out of balance it should be running normal. In the morning I can try adjusting the keeper nuts a couple of clicks each way to see if that makes any difference.

Also, its not the shutdown solenoid. I'm running a pull cable for shutting down the engine and the lever and shaft rotate freely.

etn550

Have you measured fuel pressure? Especially as the loping is happening?

I'm not 100% convinced this is a pump problem, although it could be.

If it is a pump problem most likely a governor issue, wrong springs, slack in the mechanism, or sticking parts.

The normal governor lope sounds like a miss. It;s very fast and the tach doesn't move, only the ear can tell. That is no issue, just insignificant instablility at low idle.

By the way, white smoke or black smoke at high idle is usually governor instability. Some systems like the old DB2 on the 80's Fords and GMs were that way as designed and built. Since no one runs high idle in a truck they never addressed it.

If you have to pull the pump again replace all the hoses in the system, if not already done and consider eliminating the fuel heater or replacing it with a Racor heater / filter.

Andy505

I did check the fuel pressure when I initially changed the pump, I don't remember exactly what the pressure read, but it was well within the normal range. After messing with tension on the springs I took it out for a drive yesterday, and other than it loping at idle, it runs fine at highway speed and make its typical 32-33 lbs of boost. So I'm fairly confident that it isn't a fuel pressure issue.

Also, my messing with the springs ended up being me just tightening both of them 1 click. Now the idle lopes from 900 ish to 1100 ish. It is still hard starting, but at least it doesn't stall.

I did notice, although at the time I wasn't sure if it was a problem or not. I noticed that there are 0 shims in the governor spring assembly for any of the springs. Based on my reading online, the large spring controls idle and when installing a GSK that large spring isn't replaced and must maintain the shims. So I assume this is idle related? Another thing I notice is that the lope is only below 1100-1200 RPMs. Above that speed it acts mostly normal and will hold a relatively steady rpm. Above 1500-1600 it seems a steady RPM as normal and drives normal.

etn550

Well with that information I think you are hitting on the problem area. I know from experience on other diesels that the set up and adjustment is important for the idle quality. One thing that concerns me about the video is that the rate of rise and fall is slow and sluggish. I'm no expert on the p7100. is there any damping adjustment on it to make it quicker acting at idle? Unless you figure it out and it is totally fixed I would consider swapping it for another. What does the seller say about this?

Andy505

Well I called US Diesel Parts today, told them what I was thinking was going on and why. They didn't seem to happy that I dug into the governor springs....go figure, but I can't say that I'm too happy about this situation. So after a little banter back and forth I got them to send me a set of shims, so hopefully that works. Otherwise I'll have to send it back. I don't need to take this pump off and more importantly, I don't need a couple of weeks down time.

biohmmwv

Did the shims solve the problem, or did you need a new pump?

Andy505

Shims didnt fix it. So I sent it back. They told me there was some debris in the governor assembly. They told me the debris came from a couple of blind holes used to fasten the AFC housing in place. (I removed the housing to fill pump with oil) and used fasteners off of my old pump to replace the housing. (since I still had both pumps in my possession at the time) They told me the fasteners were too long and push material making the blind hole into the governor assembly. The fasteners on my old pump must have been too long? IDK. It didnt cause a problem with the old pump that I know of. And they didnt charge me to fix it...just shipping. They also adjusted the timing pin location to be set at 16.5 degrees and tightened up the fuel delivery tolerance between each piston. (I was complaining about a rough idle that was non-existant with the old pump)

Coincidentally, a couple of months after I got the pump back from this fiasco. My idle started dropping slowly. Eventually it wouldn't run. It turns out that a bolt that is used to clamp the throttle lever onto a rotating shaft was missing and the throttle lever had worked itself loose. I replaced the fastener a little over a year ago and I have had zero problems wtih the pump since.

biohmmwv

Thank you for the update. That helps me with figuring out my trucks problems.