surging/return line question...

[llong66]

Hello all, I have a question regarding a cpl of issues I am having after my rebuild. Somehow I had damaged the steel return line that comes from the top of the IP and is connected to the returns from the individual injectors. It was crimped and after running for a while, developed a tiny pin hole. I cut the crimped portion out and replaced it with a small piece of rubber line and clamped it together. Everything seemed fine at first, but now I have a surge sometimes at idle or when driving down the road under power. It has also died a cpl of times when I stop, but fires right back up, no problem. I am pretty sure I have a leak in my fuel system someplace, I am just not sure if that is an area I need to be looking into or not. I have an electric lift pump and when I replaced the skid plate that covers the area I put it, where the small sections of rubber line after the tank, I checked all of that out when replacing the plate and did not see any sign of a leak. The motor I got to rebuild had a DB4 pump and the steel line from it will not work on my motor. I may have to search for a line from another, older, DB2 motor if that could be part of my problem.
Any input is greatly appreciated! The search for a leak will be straight forward, I just would like to know if my issue with the return line could be a source of the problems I am having.

Thanks,
Greg

 

[llong66]

Hello! Well I went through my fuel system again and I did find a broken hose clamp on the inlet side of the filter housing, being as I have an electric pump and there is pressure in the line at that point I dont think it is my issue. I also tightened all the lines at the injectors. I still have an odd surge, its when I let off the accelerator at speed slightly, its a fairly strong surge. On the splice I mentioned above, I sealed the joints with some black RTV to hopefully help if it is an issue.
Any thoughts on where else I might look? It fires right up first thing in the morning, or any time its cold as well as when hot. As far as timing, I put the pump back at the same position as it was at when the old motor was in. Same pump, inj, heads, the change is all in the block, new crank, rods, 0.03 0ver turbo pistons, new timing set, and balancer. the only rubber that is not new is the couple of small pieces right after the tank.
Any ideas/thoughts are much appreciated!

Thanks!
Greg

 

[the skull]

Hi Greg,
Just asking, did you eliminate the check ball fitting in the return line in the
top of the pump? Mine does the same thing. The fitting was plugged,
I could not get past 35 mph. Had blue smoke bad. I gutted the glass
ball fitting, and she ran like a scared rabbit. BUT it has a surge very similar
to what you describe. I was told by someone here, the return back pressure
has a "governing" effect on the pump. Maybe a "vibration damper" ?
Please correct me if I'm wrong here people.

 

[llong66]

Hello, I have not looked into the check ball yet, I need to do a little research before I pull the cover off and look into that, I am not real sure about what I need to look for when I do.
Thanks for your reply, I will defiantly look into it since you are having a similar problem and that helped. Is there a gasket that I need to get for the top before I pull it off?

Take care,
Greg

 

[the skull]

Oh sorry mine is surging right now, runs well otherwise. The check
ball is in the fitting in the top of the pump, mine had a restriction.
The surging is a side effect of no backpressure I think. As far as the
gasket, mine was ok. Hope I didn't mislead you. Look and see if the
check ball is there, if it's not plugged, then clean it and reinstall it.

 

[the skull]

And the fitting has an 0-ring where it screws into the top of the pump

 

[llong66]

Thanks Skull, You did not mislead me at all, your post gave me something else to research and check out, thanks alot!

 

[llong66]

Hello all! I checked the check ball on the IP, the ball is there and clean. The truck is running great and I seem to have elemanated the surge. I still have an issue and that is when I am driving down the road and let off the accelerator, it will surge a cpl of times and then be fine. If I stop fast, letting off the accelerator and hit the break, sometimes it dies, it will fire right back up, but I am not sure where to go from here. As I said, it starts right up hot or cold, first start of the day. Sometimes when I am taking off from a stop, it will get a sudden surge of power. Could this be a timing issue? I had marked the location of the timing mark on the pump relative to the housing. I put it back together just as it was. Other than timing I am not sure where to go from here, any suggestions??

Thanks,
Greg

 

[Chief_919]

Your governor is sticking and "under-running" under deceleration because the metering valve is sticking. It is a 75% change it is just dirty.

If it is just dirty you can clean it. Get the Stanadyne Fuel Injection Cleaner and a fuel filter. Change the fuel filter, open the bleeder screw and pour the new filter full of the stuff. Dump the remaining bottles in the fuel tank. Then start the truck, run it for 30/45 seconds, and shut it down. Let it sit for 12-24 hours, start it and run it. This procedure will run the truck just enough to pull a super high concentration of the cleaner into the IP, letting it sit lets it really clean out the gunk and deposits in your IP.

If that doesn't fix it you will need a new or rebuilt IP.

 

[llong66]

Thank you Chief!! I will do that and report back!!

 

[Chief_919]

Thank you Chief!! I will do that and report back!!

Filling the filter is tedious, get a funnel with a tiny end and go slowly.

 

[llong66]

Chief, I could not find any place here in town who could get the Stanadyne stuff so I could order it or try what was available here in town, I chose the latter. I got Power Service Diesel Kleen+Cetane Boost.
I have read good things about their products and reading the bottle and comparing it to the info on the Stanadyne stuff they seemed pretty similar. Filling the new filter was not to bad, I have a small metal funnel that fit right in the port that the bleed screw came out of on the filter housing leaving just a little room to let the air out and keep the gurgling/splashing to a minimum. I added the remainder to the tank, its surprising how much the filter holds! Now I am just letting it sit and will go fire it up in the morning an see how it does.
I changed my CDR valve while I was at it, the old one had a fair amount of gunk in it and I figured new motor, why not change it.
Thanks again for the advice, I cant wait to fire it up in the morning!

 

[llong66]

Well, after letting the Power Service sit for a good 24 hrs, it defiantly made a difference! I am still having some surging and it still will die once in a while. I think my high idle solenoid might be sticking too, it seems to be idling a little high and when I turn it off, I feel the acc. peddle rise against my foot just a tiny bit, even when well warmed up. I am guessing I must be getting some air in some place I am going to try the clear line on the return and see what I get and when I have some day light, look into the fast idle system.

 

[southdave]

http://www.oliverdiesel.com/tech/howdb2pumpworks.htm
Maybe you need to read this before wacking your balls out

 

[llong66]

Wacking my balls out? Lol, I have read that but will revisit it, I had not planned on removing the check ball, it is nice, clean, and clear, I was saying I was going to try the clear line to look for bubbles.

 

[Sharecropper]

Your governor is sticking and "under-running" under deceleration because the metering valve is sticking. It is a 75% change it is just dirty.

If it is just dirty you can clean it. Get the Stanadyne Fuel Injection Cleaner and a fuel filter. Change the fuel filter, open the bleeder screw and pour the new filter full of the stuff. Dump the remaining bottles in the fuel tank. Then start the truck, run it for 30/45 seconds, and shut it down. Let it sit for 12-24 hours, start it and run it. This procedure will run the truck just enough to pull a super high concentration of the cleaner into the IP, letting it sit lets it really clean out the gunk and deposits in your IP.

If that doesn't fix it you will need a new or rebuilt IP.

Perfect advice!