Possible internal Engine/Pump damage ???

[8v-of-fury]

At about 4100rpm's the motor experiences a stumble, loss of power and smoke out the tailpipe. Prior to my incident, spinning 5400rpms was no feat. Holding it out when the stumble commences just makes smoke out the tail pipe and loss of power... WEIRD

Last week I had a no run problem, For some reason the pump was not pulling fuel from the tank. On occasion it would start after a long time of cranking but only run for a few seconds if that.. I guess on one of those times I had my foot to the floor, I know it doesn't do anything to help the starting of these particular engines.. but its habit from my carburetor'd '67..

ANYWAY! I had just done the GOV MOD to this pump so it not having any internal governor anymore.. I think it spun up quite a few rpms and possibly damaged something.. I Don't know if it was the engine or the pump that got the flack.. I dont think timing was affected as it still starts fine with no smoke and runs ok (minus a lack of power) under 4000.

From what I have heard the gasser 1.6's can spin up to 8000 no problem, these engines being more robust should be able to theoretically do the same.. I doubt it got over 6500, but i think maybe the springs inside the head of the pump were damaged.. and now they cant force the plunger back quick enough. Any support that theory?

Please tell me it is the pump, I have a TD pump that was just resealed not to long ago.. also got a ko3/manifold, and TD intake just taking up space on my TDI motor and need an excuse to turbo this 1.6 n/a

THANKS GUYS

[R.O.R-2.0]

im kinda stumped on that one..

did you get it hot and stick a ring? i know that you gotta have your foot in it to turn these engines 5500.. and you will be building some heat.

[8v-of-fury]

Naw it was a cold start, in neutral rev to the moon..

I don't think it even had enough heat for full combustion! let alone to stick a ring..

It doesn't show ANY signs of anything until just after 4000 rpms.. Its odd. I might just swap the td pump and lines on tonight for fun to see if it changes..

[nathan_b]

do you cold rev all your motors to red line??

[8v-of-fury]

do you cold rev all your motors to red line??

Do you ever read original posts??

Have you ever pushed the pedal of a properly set up Gov Modded pump? They spin their rpm range QUICK.

[truckinwagen]

try advancing timing and see if the stumble happens later in the RPM range.

my car acted like that when it was running out of advance up top.

-Owen

[CRSMP5]

what was the no run??? when the alge slug grew on my screen inside the tank.. it would do that... took less then 3 years to grow it at that...

probally also your no start issue.. pull the float and remove that screen..

[8v-of-fury]

the no start is still a no clue. Car has only had diesel in the tank since late Feb (used to be gas) and is daily driven, so fresh fuel every week. Put a puller pump up in the bay before the filter, and pulled some fuel up and pushed it back down the return a few times, then the car started fine.. and didn't need the puller pump to run.. I still have it hooked up as I have read good things about supplying the pump with a few psi instead of making it work.

Also I swapped out the pump tonight for a TD one, put my n/a pump top and fully shimmed governor assembly in it. With the N/a pump after my rev incident there was a lack of power.. so something inside the pump was definitely off.. There is a substantial power increase over what there was this afternoon. Yet it still seems to start to stumble at the same rpm (pretty sure I timed the new pump to exactly what the old pump was..)

I have it currently timed at 0.40", would the jump to 0.41" be a significant amount? Or maybe jump right to 0.42" right away and see what happens.. I am pretty sure you cannot physically damage the engine with a little bit too much advance. The fact that it is happening in the same spot with two different pumps though.... Leads me to believe either injectors, or valves.....

[Alcaid]

Had similar problems on a TDI earlier, check your case pressure relief valve (solved my issues):
http://forums.tdiclub.com/showthread.php?t=238872

[8v-of-fury]

Hmm good idea, but it happening on two different pumps of completely different age and everything.. leads me to believe engine damage..

I'm going out right now to bump the timing.

[CRSMP5]

will you please pull the float unit and remove the screen for me?? use a piece of coat hanger as a hook and grab it and yank straight up.. see if that helps.. since diesel fuel likes to clean things... it is possible it cleaned the top of the tank inside and allowed crap to fall to the bottom.. then plug the screen up...

then add in a beetle style fuel filter in reverse before the main filter.. this way you can see the crap it catches and those cheap like 2$ each to replace instead of contaminating your 10$ main filter..

[Smokey Eddy]

This is most odd that it does the same thing with both pumps. I was going to say definitely a GOV mod issue doing that... like you bumped something or it didn't go back together properly or something fell loose ...
Hmm
Damaging the insides would only cause no start/burning oil when running + no power.

[8v-of-fury]

Well something is off, but your right if i fubar'd the internals there would be power issues.. which there isnt with the new pump. I got power back with the new pump, but still stumbles around 4300 give or take..

The gov mod didnt start the problem.. before the cold start and rev, the engine did 5500 no problem. Now it still rockets to 4200 but stumbles after..

[745 turbogreasel]

Lamed a valve spring?

[burn_your_money]

Fuel supply issue... Delete the lift pump and then change the filter. Or hook a vacuum gauge up to the supply line and see what it is doing around 4000