Hello, I would appreciate it if someone would answer a question.


first, i have a 96 6.5, changed the injector pump twice, (once was free, used one from a dealership, the second one was rebuilt from somewhere up north, I found them on the net.) The truck ran fine for a while after both of these changes. I've had about five different "master" mechanics check it out, to no avail. the last one supposedly checked all the wiring, (the rebuilt pump had only about 2500 miles on it at this point), also this mechanic cranked on the starter so long that he burned out the end bushing, stripping the flywheel, so I doubt his qualifications now) Now, with the flywheel replaced, it sounds like crap, like a dodge. Anyway, he gave up on it, said it was only the second time in his life he couldn't figure out one. (I doubt that). anyway, I always thought it was something in the wiring, but, changed the injector pumps anyway. (I have changed about everything else too) Now, get this, both the second (used) and the third (rebuilt) pumps worked fine for a short time, then it started dying when going down the road. I could just put it in neutral and kill it, it would start right back. At first, that is, then it got worse, and finally it wouldn't start at all. But, now back to my "now get this", I got sidetracked. both of the pumps I put on, after they started dying, I had up to five (spares) of the black boxes that are mounted on the side of the injector pump. (I mounted them on a bracket on the intake) When it would die, i would change the black box, and the motor would crank right back, even though it wouldn't before I changed the box. I did this a million times. finally that quit working, but many times it would quit working on a box, but several changes later, it would work on that same black box again. Over and over and over I did this. finally it quit working on all the boxes, and I took one off my brothers truck (which was running fine) and it wouldn't crank mine anymore. thats when I bowed down and went to a "mechanic". actually a "shade-tree" mechanic, I'm sure. but, now for my question that I asked for an answer. If, when I took my intake off, and sprayed 2 cans of WD-40, one in each side of the motor, and it wouldn't crank, or even try to crank, did this mean that something else is wrong, like the timing chain or something? OR, since it is an electronic injector pump,(stanadyne) would it have not cranked anyway if simply the injector pump was bad??? the last mechanic that looked at it, said that it might be a timing chain, because it MUST crank when he sprayed the WD-40 in the motor. I just want to know if this is true, or can it just be the injector pump. I just thought that since it has electronics controlling the fuel to the cylinders, that it might not crank even with the help of the WD-40. Now I don't know if I'm dealing with an internal problem or just an injector pump, or wiring, or WHAT the heck is wrong. I'm ready to pull my hair out, I've had a lot of trouble with this motor, I've changed everything you can imagine, except the wiring harness. Even had the computer checked out, it was fine. It has about 250,000 on it, but don't smoke, or use hardly any oil, which I change every 3500 miles. I loved the motor, the power, the smootheness of the running, the quickness of the starting, everything about it, except the NOT RUNNING!!!!sorry this is so long, thanks for reading it. Good Day!!!!!!!! (anybody want to buy a good 6.5?http://www.dieselplace.com/forum/smileys/HiHi.gif http://www.dieselplace.com/forum/smileys/Evil%20Smile.gif http://www.dieselplace.com/forum/smileys/Cry.gif <IMG id='chkImg1' name='chkImg2' onclick="AddSmileyIc

Billy,

The black box you referred to is the PMD - Pump Mounted Driver. It's also known as the FSD - Fuel Solenoid Driver. The problems you describe are common for a bad FSD. The FSD contains transistor drivers for the fuel solenoid in the pump. These FSD transistors generate a lot of heat and it relies on the pump housing and the fuel flowing through the pump to act as a heat sink - keeping the FSD cool. To make them more reliable many people remote mount the FSD on an external heat sink called an FSD Cooler (http://www.thedieselpage.com/reviews/FSDCooler.htm) (I had one on my 98 6.5). It's heat that kills FSD's - especially if the screws holding the FSD to pump loosen up and diminish the heat transfer. When and FSD is on the way out they are often intermittent when hot and cause stalls and no-starts. A bad wiring harness that connects the FSD to the injection pump and/or an inoperative lift pump (on the frame rail) can also cause similar problems.

Rregarding WD-40, it's my understanding that it used to contain a propane propellant, which is why it was a good starting fluid. However, the current formulation no longer contains propane so it won't work as well if at all..

Also try reading/searching the 6.5 forum for more info. Hope this helps. ..

http://www.dieselplace.com/forum/smileys/Geek.gif Edited by: jbplock

Hey, thanks for the info, I wonder if you think the PMD would stay cooler by leaving it mounted on the injector pump, or, if like I did, mounted on the manifold, up high getting better air flow. I have been told by several mechanics, that this is a better option. I even mounted mine on the cold line of the air conditoning system. surely that will help. I have changed the wiring harness from the PMD to the back of the pump too. Also, as I mentioned, the motor will not run on a "definately good" PMD now. By the way, the last mechanic looked at it friday, and thinks it may be the injector pump as well as maybe something to do with the factory alarm system. Man, that's what i'm hoping for, the alarm system. I don't know. He's looking again Monday. But, still I don't know the answer to my main question "If I spray "starting fluid" in the open intake, will it try to run, or do the "electronics" on the injector pump prevent this." If it SHOULD attempt to run, reguardless of the electronics, then maybe I do have an internal problem. That is what I need to know. Thanks for your time!~http://www.dieselplace.com/forum/smileys/Big Smile.gif

Billy,


I'ts been a while since I worked on my 6.5 (sold it in 02) so I can't remember all the details, but if you truck won't start at all with a good PMD, it could be either an electrical problem preventing the pump from working or just a bad pump. There is also an optical sensor in the pump that goes bad. Also you said it wont' crank over at all ?? Have you checked the starter and batteries?


Regarding the PMD, moving it off the injection pump can help keep it cooler but you need a good heat sink. The FSD Cooler referenced in my previous post has precision machined surface to get good heat transfer.


Also using starting fluid - especially ether - in a diesel is dangerous and can cause damage.. I personally woudn't do it... I know some folks do this with older diesels, but I'm not sure it's the best way to trouble shoot a diesel with the DS4 electronically controlled injection pump. Good luck..


http://www.dieselplace.com/forum/smileys/Geek.gifEdited by: jbplock

Hey, thanks for the info. I haven't used "starting fluid", only WD-40. and it didn't work. so, still I don't know, "if the injector pump is dead, will the motor try to start if I spray "flamable liquid" in the intake?" This is what I've been told: "It WILL try to crank, even if the pump is bad"....This is what I need to know. See, if this is true, then, since it DOES NOT try to crank, with "flamable liquid" then, maybe I DO have an internal problem. And, I still don't understand about what you say about "a good heat sink"....I just figured that if the PMD is just "floating in the air" cool air, that it would be cooler. It seems to me that you are saying that it needs to be mounted "tightly" to something to provide a "heat sink"....I just don't understand. THANKS!!


billyh

Billy,


I don’t have any experience using starting fluid with a 6.5 so I can’t help you with your first question…


Regarding the heat sink for the PMD, yes it needs a good physical contact to transfer the heat away. When mounted to the pump the pump is the heat sink – heat is transferred to the pump and engine. If you move the PMD it has to mount to some thing that can transfer the heat away form it. Air-cooling the PMD by itself is not enough. In the case of the FSD Cooler the excess heat is transferred to the air via the finned metal on the cooler. Same idea as the fins on the back of a audio power amp that are used to keep the power transistors cool.


http://www.dieselplace.com/forum/smileys/Geek.gif

Billy, do a compression test. If the compression is good, it should run, if you had fuel. I think the problem you're having with the injector pumps going out, is not the PMD. Have you checked your lift pump pressure with the engine running? Without enough lift pump pressure, the injection pump will run out of fuel and engine will die, also the inj pump will be running with no lubrication(diesel fuel) and it will be getting ruined from no lubrication. If the oil pressure switch is no good it could also cause what you're talking about. See, the lift pump will work when you're cranking the engine but after you're done cranking the signal goes through the oil pressure switch to the fuel pump relay and to the lift pump.


Here's what I think you should do.


Remove the fuel line going to the inj pump from the fuel filter. Crank the engine and see if fuel comes out. If ok, reattach the line and remove the fuel return line from the pump and crank and see if fuel comes out. If ok, then crack open a fuel line at an injector and see if fuel squirts out. If you have fuel to the pump, and it comes out of the return while cranking but none at the injector line, then you need to further diagnose your pump. If that is the case you probably need a pump since you already tried a PMD. I'd bet your lift pump or something to do with the fuel supply is no good. If you run those pumps dry and have them pull vacuum to get fuel , they wear themselves out real quick. Hope this helps.