SASQCH

Are you sure this diagram pertains specifically to the VP44 or is it a generic diagram for most solenoid-valve controlled radial-piston distributor injection pumps like it is labeled? Which part on the diagram is the infamous diaphragm? This is labeled as the high pressure stage, is this implying that the overflow valve is venting the high pressure side of the pump? I'm just a little confused by the drawing perhaps you could clear it up for us?. Jim

I am not familiar with the internal design of the VP44. Do you have any drawings illustrating the chambers and pump? Are you saying that the pump is between the inlet and overflow fittings, or between the chambers and the internal high pressure side inlet? Are you implying that the additional inlet pressure makes no difference in opening the overflow valve because of the pump? Please explain more. Jim

Looks like everyone is seeing things pretty much the same way now, so If I can make my original point again.Since the overflow valve starts to open at 14.5 psi I think that 14-15 psi fuel pressure is marginal for pushing enough excess fuel to cool the pump while going down hill for long periods with the engine idling because it will barely open the overflow valve. I think that 16-18 is better than 14-15 (more volume).I have my FASS95 set at 17-17.5 and haven't seen it drop below 13 at WOT.After this debate I'm considering stretching the spring a little to get it up around 19 psi.Jim

These kinds of debates are always good because they provoke the thought process. There are only winners and no losers.

I'm not trying to be argumentative just trying to reason it out by the laws of physics. To illustrate my point, the rocket engines used in the NASA space program have the nozzles cooled by running the fuel through tubing coiled around the nozzles to take the heat away so they don't melt. The fluid fuel is being pumped at the rate of over 6,000 gal per minute don't know the pressure but I'll bet it's higher than 20 psi, and it still takes the heat away. I must admit that the nozzle temps are a little above a 190 degree diesel engine block though.

Hmmm... if the thermostat is removed from the block, does the engine overheat or does it over cool? I would think the fuel racing through the pump would still keep it cool, perhaps even better because of a greater temp differential between fuel and pump therefor better heat transfer.

Well you would have enough fuel flow to keep it cool that's for sure. The question is would there be enough pressure to force feed the VP44 or would it just run out the return line? If you look at the overflow check valve there are two holes in the output side, one small and one larger. the small one flows fuel all the time, valve open or closed. The larger one only flows fuel when the check ball is pushed off the seat by a pressure of 14.5 lbs or greater. There is a limit as to how much fuel can go through the holes at the max of 20 psi. The restricted holes ensure there is positive pressure in the VP44. I suspect that without a restriction in the return line it would be difficult to maintain adequate pressure in the VP44. Kind of like a garden hose with and without without the nozzle. With the nozzle the line pressure is up without it the line pressure is lower. But I really don't know without someone (not me) trying it on their truck and reporting back with the results. Anyone want to volunteer?

Mike,I agree with what you are saying.Here is something else to think about on fuel pressures.The overflow valve is not a binary valve (just open or closed), it is a spring loaded ball check valve.It starts to open at 14.5 lbs pressure. The more pressure the more it opens.At 15psi it is open a little at 17 psi it is open a lot more.I don't think the volume of fuel flowing through at 15 psi is much at all.I'm thinking that 16-18 is better than14-15 (more volume).It would be interesting to test this theory with an adjustable fuel pump, pressure gauge, and the overflow check valve measuring the volume of fuel escaping from the valve at different pressures for 60 seconds.My worth.Jim

I'm on the second tank of fuel with injector cleaner in it along with the 2 cycle oil.The stalling when shifting into drive has gone away, it no longer stalls warm or cold. The change was gradual after I put in the injector cleaner.The hard starting has also gone away. It stopped being hard to start when I put the smarty #3 program on the ECM and the fuel lift pump don't come on for the 2 second run when I turn the key on. It now starts immediately when the engine turns over hot or cold.Thanks everyone for the input.:thumbup2:Jim

Have you thought about putting one of the thermocouples post turbo to see what the temps are there?If you put both pre-turbo it will be like the man in the old Chinese saying."Man with one watch always know what time it is.Man with two watches never sure." :lol:I've heard that the front plenum to the turbo runs cooler than the rear plenum so if you put a thermocouple in each expect to see a difference in EGT between them.

Well I haven't tried to see what it will do yet. I put the #3 smarty tune on that gives boost fooling, fuel and timing advance. I never turned on the powermax3 on for todays run, but it felt quite a bit stronger than just the truck on stock tune. I'm really looking for better mileage than the stock tune gives. Perhaps this weekend I'll play a little to see what this tune does with the powermax3 stacked. Before the smarty I could easily push 42 lbs on the hx35 and 1600 EGT. I really don't feel I need any more than that so the smarty was to get high idle and better mileage if possible.

Thanks Guys, I did the flash this morning and all went well with the box turned off.Thanks for all the great responses.Jim

This smarty ECM flash don't let the LP run until the engine starts or is bumped and now the engine starts immediately (no initial fuel pressure, no more hard starts). That's what made me lean toward the torn diaphragm theory. So your saying that isn't an indication of a torn diaphragm?

It only did the fluctuations on one start not on any subsequent starts (about a dozen before I got home). When it did it on the one start, it continued to fluctuate between 5 and 12 psi for as long as the engine was running. like the check valve was slamming shut then popping open again over and over until I shut it off.

UPDATE I put a smarty program on the truck (#3) and took it out to see how it ran (normal driving - no wot or anything like it). When I started it I noticed that when I turned on the key the fuel pump didn't run for 2 seconds like it always has before. Once the starter engaged and the truck started the fuel pump came on and The pressure went to 17 psi. I backed out of the garage put the truck in drive and it died (like always) put it into neutral and started it. The fuel pressure gauge started going crazy (first time it has ever done this) the needle jumped from 5 to 12 back and forth never going under 5 and never going over 12 after about 10 seconds of this without stabilizing of going to the normal 17, I shut the truck off. I restarted it and the fuel pressure went to 17 and stayed. I don't know what that was all about, The only thing I can figure is maybe the return line drain might have stuck open???? The hard starting when warm has gone away completely It starts every time now. The idle hunting has also gone away, don't know if it cleared up from the injector cleaner or the new ECM program from the smarty. It idles at 745 rpm according to the scangauge. The last thing is if I let it idle for a minute or longer when warm, it does not die when put into gear. I'm suspecting more and more that the VP44 has a torn diaphragm that is causing the problems over an electrical issue. It's puzzling because the VP44 has never had low fuel pressure because I put in the FP gauge, FASS 95, and rebuilt VP44 all at the same time. I guess it's possible that the VP44 re-builder didn't replace the electronics and diaphragm module when it was rebuilt. As I said before If it's torn I'll live with it until the IP dies. I still need to clean and check the ECM connection.

Okay, thanks. Another question: The manual also says "If you have a performance-enhancing device installed, it must be removed.". I have a PowerMax3 on the truck which does boost fooling and taps the VP44. Question - Can I just set the PowerMax to factory setting (off or 0), or do I need to unplug the boost fooler cable from the MAP, reconnect the factory cable and detach the tap to the VP44 when I load a catcher program to the truck?

Mike, I know I'm not the smartest guy in the world, but just where is there a "Schrader Valve" in the fuel system? Are you referring to the overflow valve on the VP44? If so all of them that I've seen cannot be opened by pressing any pin on them. Wikipedia defines a schrader valve as follows: "The valve A Schrader valve consists of an externally threaded hollow cylindrical metal tube, typically of brass. In the center of the exterior end is a metal pin pointing along the axis of the tube; the pin's end is approximately flush with the end of the valve body. Generally, all Schrader valves used on tires have threads and bodies of a single standard size at the exterior end, so caps and tools generally are universal for the valves on all common applications. A new development is Schrader valve stems with integrated transmitters for tire pressure monitoring systems (TPMS). The valve cap A valve cap is important on a Schrader valve because if one is not fitted, dirt and water can enter the outside of the valve, potentially jamming it or contaminating the sealing surfaces and causing a leak. Rock salt and other chemical deicers used in the winter are especially damaging for the brass components in the Schrader valve. Metal valve caps usually have, in addition to a handy deflating tool, a small rubber insert to permit a good seal against the valve body; a cap of this kind also helps to prevent air escaping from a slightly leaking valve. However, the vast majority of Schrader valves used for tires are fitted with plain black plastic caps which effectively serve only to keep contaminants out of the valve stem." Guess I'm confused as to what you are referring to as a Schrader Valve. Got a picture of one? Thanks Jim

The manual doesn't specifically cover whether the smarty stores the parameters of the stock program or just loads a default one. That's why I'm asking the questions hoping to get someone who has used the smarty to respond with what works and what doesn't. Thanks Jim ---------- Post added at 03:57 PM ---------- Previous post was at 03:33 PM ---------- Here is what MADs electronics site FAQs say: "Smarty does NOT download the complete original software from the ECM and does not store it into it's memory. That is for a simple reason. The protocol in the ECM does not allow to read the flash memory. How can Smarty then return to stock? Simple he has all the latest stock softwares already on board. When you choose to return the truck back to stock, Smarty takes the stock software from it's memory and updates the ECM with that software." The FAQs do not address the other questions I asked. It does not say whether or not high idle is turned on in those stock software programs. Any answers are appreciated. Thanks Jim

I just got my S-03 smarty. I've read through the manual and have an idea on how to use it. However, the manual don't tell me how to just turn on the high idle in the stock ECM program. When I load a catcher program (they all have high idle enabled in them) to the ECM, the smarty stores much of the original ECM program and then vin locks so It can't be used on another truck. I can restore the original program to my truck and then the smarty unlocks so it can be used on another truck. So my question is when the original program is restored to the ECM is the high idle turned off or left on in the ECM? There is no specific function in the smarty to turn on the high idle feature, so how can I turn it on for a buddies truck and still have my smarty to use on my truck? If loading a catcher program on the buddies truck turns on high idle and then restoring his original program leaves high idle on and unlocks the smarty, then all is cool. Just trying to understand how to do it. Oh, the manual also says "If you have a performance-enhancing device installed, it must be removed.". I have a PowerMax3 on the truck which does boost fooling and taps the VP44. Can I just set it to factory setting (off or 0) setting, or do I need to unplug the boost fooler cable from the MAP, reconnect the factory cable and detach the tap to the VP44 when I load a catcher program to the truck? Thanks Jim

I hadn't thought about the ECM connector at all, I'll check it out.I'm putting a scan gauge on it today so I can monitor more parameters on the road.I have a smarty coming also to be able to turn on high 3 cyl idle and also take advantage of the timing added options for better mileage when running empty.

Here is how to do it: http://mopar.mopar1973man.com/cummins/2ndgen24v/reprime-fuel/reprime-fuel.htm As quickly as you can, release the key as soon as you hear the starter engage, and the engine will not even turnover once or start but the pump will run for about 30-45 seconds.

Hey, man you can send me a check for the $100. Nope don't stall in reverse. I have figured out that when it don't start when warm, if I just bump the starter so the pump runs and I wait about 10-15 seconds it will start right up almost all the time. If it don't start, then when I turn the key on and the pump starts running again, If I hit the starter when the pressure gauge hits around 10 psi, it will start. So now I'm thinking there is an air leak in the return line somewhere and the 10-15 second run re-primes the VP. That's why I thought about rotating the connector tubes in the holes to see if an O ring was leaking a little air. Since it only seems to do it when the engine has been up to operating temp (190) and has cooled for a few minutes, my thoughts are now running towards warm fuel being thinner than cold fuel and metal expansion from heat causing larger clearances. (grabbing at straws here) I guess I could put in the old VP check valve on the return line that I replaced when I was having problems before (didn't fix the problem so I kept the old one) and see what that does. I know hard starting is an indication of a torn diaphragm in the VP44. If it turns out the truck has a torn diaphragm in the VP I'll live with it until the VP dies.

Checked and cleaned/re-greased the connections and wiring to the CKP and Cam sensors. It made no difference in the problem. I could find no problems in the wiring (did a lot of jiggling).I'm out of ideas at this point other than to pop the connector tubes and re-seat the O rings into a different position by rotating the tubes a little.Any other thoughts?

JOHNFAK, I was just thinking that it might be helpful to you to find some cummins 2nd gen owners near you to gain some hands on general knowledge from them. I see that you list St Louis as your location, thought you might want to want to post on the MO chapter of the cummins forum to make some local contacts. Here is the url: http://www.cumminsforum.com/forum/missouri/ Just a thought. Jim

:iagree: Yup, Ya got to keep that magic smoke inside the wires, otherwise things stop working.