K2500 6.5 TurboDiesel with troubles.
Hello to all.
I own a 1996 K2500 Silverado with a 6.5 TurboDiesel engine. My father purchased the truck new in 1996. The reason he bought this pick-up was that he needed something big and strong to haul trailers. It has done great and it proved to be a very though truck.
The problem of owning an American pick-up in Belgium (Europe) is that almost nobody knows what the weak points are on these diesels. We have found out the hard way that the PMD is weak point.
When the truck had about 60.000km (37.000 miles) it had became unreliable. Problem was that it would stall when driving. We contacted the importer and official Chevrolet dealers. They said the fuel pump needed to be changed along with the electronics. We had this done and it was llike new again.
Untill around 3 years ago. We had occasional troubles with it. Usually it would start again when you waited 5 minutes. This went from bad to worse to completly broken. Again the fuel pump and electronics were changed. My father had searched the internet to find out what was causing the problems. He found out that heat was the enemy. The solutions was to relocate the PMD as away from the valley of the engine as the original wiring would allow. The PMD was mounted on flat solid block of aluminium.
It again ran fine. My father was very happy to apparently have found the solution. Unfortunatly he passed away in 2007. Because the truck has lots of emotional value to me and my mother we have kept the truck. From then on I have been the driver of the pick-up.
About 2 months ago the troubles started again. It would sometimes stall about 30 seconds after the engine fired up. Again I began searching for answers. Recently I have found a dealer who claims to know what the trouble is with the PMD. He told me that heat indeed is the enemy. He also to me to see if there was a calibration resistor inside the PMD. There isn't one. This lack of resistor causes the engine to go in emergency procedure resulting in higher engine bay temperatures. The lift pump that is mounted in the chassis is good.
Now, to fix the problem I think I need:
1) a new PMD. I have searched the net and have found that Stanadyne makes a new PMD. The new and improved one is grey instead of black like our old one. Problem is that it has a new connector.
2) a calibration resistor.
3) a kind of cool fin to keep the PMD as cool as possible.
I have also read some about the oil pressure switch. But I do not understand how this is related to the fuel pump. Could somebody tell me if this is part of the trouble?
When it comes to getting the new parts I have a couple of options:
- by a PMD form Stanadyne and a calibration resistor from GM here in Belgium. But then I have to make some kind of cooling device. I have understood that the aluminium block we have now isn't good as it holds heath to long. If it is a grey PMD I have the trouble that the old wiring won't fit with the new connector.
- by a kit from accuratediesel (http://www.accuratediesel.com/shop/8.html) or by a kit from ********* (http://www.*********.com/pdc_pmd_fsd...ver_cooler.htm)
Now my questions are:
- have I got it wright this time? Or are there others ting that need to be done first?
- where should I get my parts from? Are there places besides accurate or a1 where I can get my parts?
this is how my engine bay looks currently:
http://i68.photobucket.com/albums/i5...5/PICT0811.jpg
http://i68.photobucket.com/albums/i5...5/PICT0812.jpg
and here is a picture of the pick-up:
http://i68.photobucket.com/albums/i5...5/PICT0318.jpg
Thank you all.
Re: K2500 6.5 turbo Diesel w/troubles !
While I'm fairly new here, and only been aware of 6.5 turbo diesel Injector pump & PMD problems since obtaining my '94 Chevy Suburban, this past August. I made the effort, like every 6.5 turbo engine owner, to understand the workings of their trucks. I did so the first night after driving it home, and getting on the computer to learn as much as I could, even before the PMD started acting up, and I had stalling problems weeks later too.
First let me say, that's a pretty nice Chevy you have there. I'm glad you held on to it, I would of done like wise if it had been my Dad's also.
From your pictures, of the remotely mounted PMD, I would suggest, taking the Aluminum block (heatsink) off, and take it to a local Machine Shop, and have the mill, in 1/4" wide slots, 1-1/8" deep, on the top side between the PMD bolt holes, cut from front to rear, leaving .125" thick fins for cooling, I'm basing that from the picture, and guess of an 1-1/2" thick aluminum block used, would leave a thickness of 3/8" to bolt the PMD to.
From what I've learned about the PMD's online, all the after market producers of relocation kits, say to use grade 5 bolts, torqued to 23 in. lbs, this leads me to the fact that a #10-32 requires 23 in. lbs. and is not a grade 5 machine screw.
I also learned that the owner of SSDiesel, was first to produce a relocation heatsink for the PMD/FSD's and all the others followed suite.
Some diesel machanics, even produced kits to mount the PMD's behind the front bumper, using a 65" to 76" long wiring harness, which adds to the resistance of the current from the ECM, which affects the transistors in the PMD even more, the two 500 watt transistors in the PMD, were by design of Stanadyne's Engineers, choosen for two functions, one to increase the weak signal from the ECM, to a voltage the solenoid needed to actuate the plunger in three positions within the function of the Injector pump. and secondly to heat the side (heavy boss/wall [heatsink] on the side of the pump, to pre-heat the diesel fuel for cold starts. ( One of the threads in this forum, someone found a web site that offered an Army Tech manual, on the 6.5 turbo diesel engins, that had complete tear down and rebuid of the IP, plus Testing and Calibration of same.) I down loaded it, it's a good read! And I learned a little more, than I knew two months ago. One thing was, during calibration after a rebuild, a pump being bolted to the test stand, and all fuel lines bled and connected, the pump was run at 2200 rpms for twenty minutes to warm the fuel, before any adjustments were made. The heat being provided only from the PMD's transistors.
Well son of a gun! Maybe the Engineers at Stanadyne designed it that way, only half the power of the PMD's transistors are required to boost the current for the solenoid to work. Let's think about this for a moment, when the trucks were new in 1994, there were no PMD problems at first, maybe around 50,000 miles, one would go bad!
Or did it? How many times when a truck is serviced, are the four screws to the PMD checked for tightness? Once loosened from 2500 rpms of engine vibrations, will the thermal compound grease be displaced? And not replaced by the service mechanic, because he just did the normal checks, or was hunting down a rattle you heard, after he changed the oil. ??
What about them GM quick-disconnects electrical plugs? How many times have you seen a mechanic, plug and un-plug one to brighten up the connections. ( Stanadyne's new Bullet Proof one has gold pins!) Even they may need to be checked now and again!
I remember a time before the quick-disconnects, when I was about 16 years old, my Dad a master mechanic at the time, was working on our car, checking wires to find a problem, when he pulled a connection full of corrosion and had me run into the house for three or four books of matches, I could not figure out why he wanted them, only to see him tear off the striker strip, and use them to brighten up the brass connectors, attach them and the car started right up, he then wrapped the connection in friction tape ! Who sells that any more?
Whats the Oil pressure switch got to do with the IP or PMD? Well it's in the electrical circuit with the frame fuel lift pump, connected to the lift pump relay, so when and if the engine lost or was low on oil, it would shut off the lift pump, stopping the flow of cooling fuel in the Injector pump that cools the PMD, whereby the PMD overheats and shuts off the IP solenoid, which informs the ECM of low fuel pressure, and the ECM, sends a signal to the Fuel Shut Off solenoid and the engine stalls to prevent a high RPM hunting condition.
One other thing to consider, is since 1997 the U.S. EPA, had determined that we are polluting the atmosphere, and ordered all sulfer be removed from Diesel Fuel, that same Sulfer kept the Optical sensor and internals of the Injector pump working better by the lubrication factor of sulfer, so use a fuel additive with every top off of the fuel tank. Why wait to an eighth of a tank to top off, when under the right climate conditions, water droplets form inside the fuel tank, just waiting to be sucked up and stop a Diesel in it's tracks.
When Stanadyne first produced the DB-4 (DS-4) IP, they told GM's engineers, the IP would work better if not in the engine valley, but a little higher up on the engine, GM needed the service work then, how they needed a bail-out is beyond my understanding, my Grandkids and their children will be paying for that for a long time, after I'm gone.
Which reminds me, my Suburban must be done at the Chevy Dealer, I gotta give them a call to see how much it's going to cost me now!
See Ya All later!
Semper Fi !
Ski
;)