How to test VP44 overflow valve

[dave110]

Just for kicks I disconnected my Quad. No help. I want to try Blue Chip's trick and unplug the VP and give it only 12v. and ground to rule out bad crank, cam sensor. Just trying to wrap my brain around the injector suggestion. I always thought that raw unburned fuel would be black. So a leaking injector would smoke black at startup. I do get a small black puff when it starts easy. The white smoke comes with a hard start and clears up almost instantly, don't have to drive around the block. What does white smoke mean?

Oh, and I learned the smoke from the vent tube was caused by a vacuum leak I created by knocking the line off while doing the other work. Interesting how that works.

[Mopar1973Man]

Well if your worried about injectors then just pull them and have them pop tested to verify there condition. Like myself I'm getting some oil smoke now most likely from bad valve seals. But for hard starts you might have air in the fuel lines or weak compression.

 

More here...

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/40-basic-diagnostics

[dave110]

Finally pulled the trigger on a reman VP and my problem is fixed. BIG thanks to all who helped me on this one. Lots of knowledge on this forum. Now listen guys, I don't mean to call anyone wrong here but I feel I need to explain my findings to help others who may be experience hard starts. I finally broke down and called Doug at BlueChip. I always felt since I started diagnosing this, that his hard start cold and instantly runs smoothly due to a broken diaphragm explanation fit my truck. When I mentioned that on here I was promptly reminded that a pump was torn apart and no diaphragm was found so therefore it can't be true and I dismissed the idea. Wiring the LP to the wiper circuit fixed for awhile but I just had a feeling it was  Bandaid. We talked, he gave me some home work which I had already done and he instantly told me I had a bad diaphragm. I told him the days of the diaphragm are over according to this forum. Partly true he said and this is how he explained. The old style diaphragm was upgraded around 2000-2001. So after that there were no more. But the ones on the shelf and on the road did not get recalled. So there are still some 99-00 trucks out there with low mileage like the one in the local paper @ 79k( which they want 24k for). Say that truck goes down the road another few miles and dies with a 1689 code and the guy buys a reman from a sloppy rebuilder. He takes the pump, replaces the computer and little else, and sends it back out into the world with an old style diaphragm as an upgraded reman. Then here comes a guy with an 02 and buys that pump for his truck and he actually goes backwards because he now has an old style pump he didn't have in the first place. And the cycle goes on and on. Doug says he sees these old style pumps and expects we will see them for as long as these trucks are around. So the VP that Mike pulled apart must have been a new style, or an old style that a good rebuilder properly upgraded. It's still great to have pics of the inside of one and again I'm not trying to stir the pot here but it's hard not to believe since it fixed my problem after I tried everything else. Makes perfect sense when I think about it. At least now I know I have new everything in the return line and new connector tube O-rings and I learned quite a bit to boot.

[Yankneck696]

That sounds viable.

Ed