Failed 26 year old original db2, what’s inside? What goes wrong?

[IDI-IKE]

I was reading this a few days ago and low and behold I started having some very strange issues with my pump I've never heard of or seen I think its related to that advance seizing up. Saturday I was driving along and all the sudden it sounded like my timing advance stuck full advance I pumped the throttle a couple times it went back normal. Sunday was all good until sunday night I was on my way home and it did it again but didn't go back to normal sounds like atleast 20 degrees btdc. No air intrusion, good fuel flow, the timing arm and cam are good on the side of the pump, I unplugged the cold advance just to be sure, I made sure the return line wasn't stopped up or the return fitting on the top of the pump. Another weird part is with the engine off the throttle is normal but with it running it's pushing back and stiff and also very touchy. I'm swapping pumps I guess its sad this pump has low miles on it always instantly started when hot and felt really good its a original pump I believe

 

[Laine D]

I was reading this a few days ago and low and behold I started having some very strange issues with my pump I've never heard of or seen I think its related to that advance seizing up. Saturday I was driving along and all the sudden it sounded like my timing advance stuck full advance I pumped the throttle a couple times it went back normal. Sunday was all good until sunday night I was on my way home and it did it again but didn't go back to normal sounds like atleast 20 degrees btdc. No air intrusion, good fuel flow, the timing arm and cam are good on the side of the pump, I unplugged the cold advance just to be sure, I made sure the return line wasn't stopped up or the return fitting on the top of the pump. Another weird part is with the engine off the throttle is normal but with it running it's pushing back and stiff and also very touchy. I'm swapping pumps I guess its sad this pump has low miles on it always instantly started when hot and felt really good its a original pump I believe

That’s what my old pump did!! It scared the crap out of me one time

 

[Farmer Rock]

I was reading this a few days ago and low and behold I started having some very strange issues with my pump I've never heard of or seen I think its related to that advance seizing up. Saturday I was driving along and all the sudden it sounded like my timing advance stuck full advance I pumped the throttle a couple times it went back normal. Sunday was all good until sunday night I was on my way home and it did it again but didn't go back to normal sounds like atleast 20 degrees btdc. No air intrusion, good fuel flow, the timing arm and cam are good on the side of the pump, I unplugged the cold advance just to be sure, I made sure the return line wasn't stopped up or the return fitting on the top of the pump. Another weird part is with the engine off the throttle is normal but with it running it's pushing back and stiff and also very touchy. I'm swapping pumps I guess its sad this pump has low miles on it always instantly started when hot and felt really good its a original pump I believe

That happened to me over the summer when I was driving.I sprayed the linkages down and it has been fine since.This pump was also rebuilt recently.




Rock

 

[IDI-IKE]

That’s what my old pump did!! It scared the crap out of me one time

I kept it under 30mph putting along trying to be gentle didn't sound god at all

 

[IDI-IKE]

That happened to me over the summer when I was driving.I sprayed the linkages down and it has been fine since.This pump was also rebuilt recently.




Rock

I tried that right after the first time it did it for the few seconds I thought maybe that timing arm was hanging up but it wasn't hanging up and I oiled it up good

 

[Thewespaul]

When you swap the problematic pump you should pull the 1" advance bore plug out of the passenger side of the pump, remove the cam pin plug on the bottom of the advance bore (1/4" allen), pull the cam pin out and pop the advance piston out the passenger side and inspect it for damage, sounds just like the advance piston sticking in its bore, these are just going to be more and more common problems with these pumps with the dry fuel we are stuck with now.

 

[ISPKI]

Might be able to replace the traditional o ring with an x profile reinforced wiper seal or some variation of that. We use those to seal pneumatic pistons that actuate forward and then rotate their ram at the same time. Used one in a custom collet actuator for a welding lathe I built for work. Still doesn't leak after running it against hydraulic oil and 120psi of air for a few years now.

 

[Thewespaul]

Which o ring? The advance piston bore seals off the housing to piston fit, no o ring or seal since its under load from the injection cycles on the cam ring.

 

[ISPKI]

Which o ring? The advance piston bore seals off the housing to piston fit, no o ring or seal since its under load from the injection cycles on the cam ring.

I meant for the torque screw people were talking about having an actuator to adjust it. Sorry, should have quoted.

 

[IDI-IKE]

When you swap the problematic pump you should pull the 1" advance bore plug out of the passenger side of the pump, remove the cam pin plug on the bottom of the advance bore (1/4" allen), pull the cam pin out and pop the advance piston out the passenger side and inspect it for damage, sounds just like the advance piston sticking in its bore, these are just going to be more and more common problems with these pumps with the dry fuel we are stuck with now.

I will pull it apart and check it out. It's out of the truck now I swapped one of my spare pumps in the only issue with that one is it will high idle normal for the first few minutes after a cold start then it will jump to 2000 rpm or so did that in the last truck I had it in too but if I unplug the advance wire it is normal and doesn't rev way up on it's own.... Any ideas on that?

 

[Dregs Garage]

@Thewespaul I Know your a busy man...but when is part 2 going to get posted?

 

[1madyank]

Super Thorough and in Depth Info! Thanks. I just did my first DB2 rebuild and really wish I had seen this first......I think I put my Pump Rotor Cam with Arrow facing wrong Direction instead of Counter Clockwise.....Crap-Ola! I Also think my Distribution Valve is leaking....How do we check for proper distribution valve assembly torque / setting / Leaking?

 

[Clb]

He's not been here since 21, check his facespace

 

[headhunter38]

My solution (we're getting into part 2 thread material now) is a ceramic sleeve that basically eliminates wear on the advance piston.

Is that something you sell individually for those of us wishing to rebuild these pumps ourselves?

 

[IDIBRONCO]

Is that something you sell individually for those of us wishing to rebuild these pumps ourselves?

No it isn't. Wes hasn't been on here in years.