Was I wrong doing this conversion?

icemanjc1

icemanjc1

Joel's Diesel
Joined
Jul 17, 2009
Messages
289
First off..... Merry Christmas people.

I've had my Ppump conversion completed(kinda) for about 9 months. It has never ran right since first crank. Symptoms are: Bunch of white smoke on start up when cold. Takes forever to start it after sitting over night (cold or hot). When it's at operating temps, it lopes horrible with the 215hp pump, idles smooth with my 160 pump (or 175??). Absolutely no black smoke. The only time I see some black smoke is when I rev it up (cold), let off, it chokes for a second, then I see a puff as it comes back up to idle. Needless to say, serious lack of power. I can't get more than 12 psi of boost out off it. I've tried various timing settings from 12.5* up to 25* on both pumps, no change other than it gets even harder to start after 20*.

I'm running 100hp jammer nozzles (VP pressures), .084 mild steel lines, airdog 150 27 psi at the inlet, Helix 2 camshaft, sportsman springs, 3k GSK kit, #10 plate or no plate. Like I said, I have two pumps, 215 and 160. 181 dv's. New relief valve. I've put seal kits and turned the barrels on both, didn't help at all. Shut off lever is a manual choke.

Guys are getting away with running vp injectors alot, maybe my setup requires a lower pop off? 2 bad pumps in a row? Kinda doubt that. One thing, I get bubbles and foam from the line nut at the injector connector tube no matter what, the main reason I pulled the mechanical lift pump and replaced it with the air dog. Please tell me what I'm missing.


Joel
 
the p-pump does not produce the line pressure that the vp or cr pumps do you need to change the injector pop pressure you are not getting the volume of fuel into the cylinder as you would be with a vp pump. the pressure is what opens the injector if the injectors are set at a vp pop pressure it means that the injector will open late and close early due to the p-pump not producing the pressure to open the injectors.
my buddy has his 24v p-pumped and it runs great his injectors are popped for a p-pump.
 
The pop off presure is not the issue. there is tons of back and forth on that topic, but im going to go with the direct inperson quote Van Haisley gave me "dont waste your money". It sounds to me like you have a fuel pressure issue. 27-30 is low for a p-pump. should be in the 40's to 50. did you address the lift pump when you converted? a VP lp will not do the job for a p-pump.
 
I originally tried a mechanical 12v lift pump, didn't work very well. Later I decided that it was my root problem(sucking air). So I purchased an Air Dog 150 for a 12 valve and slapped it on. After that, it would actually rev up to 2500rpm+, but all the other issues remained.
 
nick2001 said:
The pop off presure is not the issue. there is tons of back and forth on that topic, but im going to go with the direct inperson quote Van Haisley gave me "dont waste your money". It sounds to me like you have a fuel pressure issue. 27-30 is low for a p-pump. should be in the 40's to 50. did you address the lift pump when you converted? a VP lp will not do the job for a p-pump.
Click to expand...

false... maybe for a dedicated puller, but you don't need 40-50psi for a p-pump to run right!

12v trucks didn't come with 24v pop pressures on the injectors for a reason :bang

match the injectors to the pump from the get go... you're chasing your tail otherwise IMO
 
Dumb question, but do you have a boost line hooked up to your afc? You could try gutting the afc to see if it could be causing low power. Have you checked for boost leaks?

Have you watched fuel pressure while your driving it to see what it drops to, if it drops below 20psi get a stiffer spring and raise the pressure.

How do you have the airdog wired in, key on hot or through the stock lift pump connector? You could let the airdog cycle a few times before you try starting it to eliminate the low pressure side losing prime. If that helps with the starting issue check your connector tube o-rings.

The pop pressure shouldn't be causing an issue, I've heard of pop pressures from 260-330 bar on P-pumped 24v's.
 
I agree on the pop off pressure issue. (it's a non-issue) My hard starting issues were caused by the return line on the back of the pump. Mine had a crack in it and lost prime every time it was shut down for more than 15min or so. Hang in there.
 
Injector pop pressure is not going to cause the problems you have.
Definetly look at the afc and check you return lines for leakage.
 
Maybe get a different set of eyes to scan over everything. Maybe you are overlooking something minor.
 
Thanks for all the help guys. I'll go over it again today, all I've got is time. I have another relief valve and I'll gut the AFC, see what I come up with.

The Air Dog is hooked up key on hot. I do let it cycle a bit before I crank on it. I'll put a gauge on, check it again.
 
pop pressures do make a difference. Not this drastic but there is a noticeable difference.
 
Thought I'd bring this up, I've been looking for leaks for awhile. I have never been able find any diesel leaks anywhere. Surprising, since after it cools off (pistons are cold), it's a pain to start. If it's warm it starts up fine at 18*. I thought I had a leak on the high pressure side somewhere. Back then I condemned the 215 pump for having leaky barrels/plungers thinking they were in charge of holding pressure when shut off. Not the case. I finally figured the delivery valves are in charge of holding the fluid circuit to the injectors for the next start up. Kinda why I'm leaning towards pop off pressures. If I'm getting barely enough of a fuel charge to run the engine decently when warm, how am I supposed to get enough fuel to ignite on a cold piston at a short window of 4700psi? I'm just thinking of duration. Any how, my lunch is over, time to get back to work. It is possible I'm missing something minor. Thanks again by the way.
 
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