6.5 will idle fine, but shuts down after driving 15 to 20 minutes, but restarts
 

Hey everyone, I have a 1994 6.5 chevy 1500, automatic, This truck has sat up for approx. 1.5 years, and now trying to get it to run again. Job I know, let me give you a little history on this, the guy I got it from was a second owner, he said he purchased the truck and installed a new pmd, let it idle until it ran out of fuel, and just never did anything else with it as he didn't know how to bleed the lines, and he had another truck, well a few months ago I end up with truck (he owed me money)thinking, a set of new batteries, added fuel, and new fuel filters, a touch of eather, and varoom, well only if I really had good luck, but here goes, new batteries, and a touch of eather, and we cranked up just fine, yippee, took it for some short trips, around property, and all seems well, decided to take it to town, on open road, and once around 60 or so, it sputters, and dies, figured trash in line from sitting up, cranks right back up and again, we try to go about our way, and a few minutes later sputters and dies, well this time looking around we find bad fuel leak, seemed to be from back of motor, so towed it home and look for issue, cannot really pinpoint leak, so we get new filter, and re do it, no go, then researching, find out there is a valley where the fuel is more than likely gathering to pour out, so off comes the intake, don't see any visible leaks, but change orings in filter canaster, and all rubber fuel lines, and intake back on, upon bleeding the air from the system, and checking, luckily no more leaks, system dry, start up with a touch of eather, and sputters a bit and dies, again sputters and dies, (expected) then she cranks with no missing, sputtering nothing, sounding like she should, let it sit in yard and idle, for a while, a pop or two initially, then smooths right out, temps look good, fuel pressure looks good, all systems go, down the road, plenty of power, but some light issues, and back, no misses skips, and no leaks, thankfully, well after idling for 5 mins or so, back down the road, not to get 2 miles from home and she shuts down, no sputtering, no spitting, just like the key was shut off, any ideas anyone, and the starter needs to be retightened, so I just came in tonight,

Please help, need a way to go, as my f150 died,

I had almost the same problem on my - 95 gmc and it was the lp that failed,well not the lp but the oilpressure switch that makes the lp work when the engine is running.If your truck is build the same way as mine you can check the lp by get shifter in Drive and try to crank it,in crank position you hear the lp ticking to give fuel in starting moment and then when it has started the oilpressure switch is supposed to give power to the lp.

thanks, will check this when the sun rises and rain goes away, will let you know,

if your dash go's dead but blower motor and radio work when the truck dies, you need a new ignition switch:c:

You can jump the lp and bleed the fuelsystem.If it starts the injection pump is supposed to hold the engine running by it self,if it's in pretty good condition.I guess the lp works,if not you haven't notised the leaks at the filter.Maybe it suck's air somewhere,check fuellines under pressure.

---AutoMerged DoublePost---

By the way,Check racer55's answer in this question. https://www.dieselbombers.com/chevy-...y-running.html He has a lot of smart solutions

Keep spraying a 6.5 with starting fluid and you will have 2 dead trucks use non-stick cooking spray instead or WD-40

thanks,
 

only needed the ether for initial start, it starts and runs fine at an idle, but put it in gear take it down the road, and in about 15 to 20 mins, it just dies, like someone turned off the switch, but lights remain working, no smoke, no missing, just dies, but however it cranks up just fine, after it dies, the oil is really really dark, and did lp tests seems to be working fine, but havn't done one with the truck in drive yet as the weather decided not to cooperate today, plan on doing it first thing tomorrow, and will let you know, thanks everyone for your input it is greatly appreciated :tu:

It might be the pmd that cause this problem,they can behave strange before they shut of compleatly.Is the pmd moved from ip to a heatsink? In that case check the conections,there's a lot of bad cables in market.If it's not moved,move it to somewear there it get's cooling.Heat diesel for example can help you with parts.

Similar cutoff problem - fuel tank delaminated
 

I must be the only GM owner to have the Ford fuel tank problem. I have read many posts but do not recall reading anything about BioDiesel causing fuel tank problems on the 6.5's.
I used to buy fuel at the same station all the time. The station switched to BioDiesel. After about 6 months my 96 GMC K3500 6.5L began to shut down on me. I eventually found that the inside of the tank had "delaminated". There were silver flakes floating in the fuel. Looked like silver paint. The chips would clog the strainer and my fuel supply would be cutoff. Refilling the tank washed the flakes from the strainer and fuel would flow freely for awhile. I had to replace tank, pickup and sending unit, lift pump, etc. I now look for fuel that is not marked BioDiesel, but am experiencing similar problems again. I have a remote mounted pump driver, but after having replaced the lift pump and filter, thought I would try a new PMD instead of dropping the tank.

finally right bolts for starter, yippee, don't go to parts store, they will send you home with the wrong ones, lesssons learned, going to get oil pressure switch, filter, and oil, will let ya know outcome

Try running with the fuel cap loose as well.

If the vent is plugged in the cap it can cause high enough vacuum in the tank that fuel stops flowing.

---AutoMerged DoublePost---

Thanx for the nod but that info originally came from another poster nammed knkreb.

just an update
 

got correct starter bolts in, oil sensor on, everything hooked back up, fired her up she purrs, went to turn truck off, and guess she decided she sat around so much she didn't want to stop, new ignition switch now, wow, what did they do to this poor truck....., one piece at a time, will keep ya updated

---AutoMerged DoublePost---

Installed new ignition switch, bolted up steering column, and started her up, seemed good, the first time shutting down, cranked her back up, and wowow, was like someone had full throttle, and would not shut off, pulled pmd to kill, looking for bad wires now, as this was not an issue till replaced ops,,

---AutoMerged DoublePost---

still trying to keep truck running, upon searching for the (new wont shut down issue, after ops sensor replaced), found a wire that runs out of cab, goes under truck and is attached to pump (Not factory), could this had been a bypass because the previous owner didn't want to replace ops, and if so, do you think we could had damaged the new ops by not disconnecting it? and still have issues with fueling when truck is on open road, seems it will idle and put put around here all day. but on open road dies after a few miles. can bleed the canasters (fill them up) and go again with no problem at an idle, lp tests show it is ok, but again on open road will die. and did remove the fuel cap, filter in canister is new, new fuel lines just because, new o rings on canister to resolve leak, no difference, im thinking I need to remove tank and check sock filter, but going to check pump under cab first. Oh yea, service engine light is coming on, and oil pressure is reading around 50lbs or so, any other ideas other than parking it in the river if I can make it that far....lol

CPS AC/Delco only BWD=crap had same issue with my 1994 that I had put new CPS it was a new truck after that you may have trouble getting old one out but we will cross that bridge later if needed

The situation you now have is power to the key at all times because of that wire being spliced in that way.

The OPS/lift pump circuit has power at all times an is supposed to.

To solve your no shut down issue remove the added wire.

As for the lift pump not supplying enough fuel the reasons could be many:
air leak between the fuel level in the tank and LP
dirt in the tank clogging the sending unit fuel sock
aftermarket sending-they are sent with the wrong sock/strainer that limits fuel flow
plugged vent in the filler cap-try running with the cap loose and if that solves the problem replace with a diesel cap

took a day off from truck,,
 

thanks, for info, just to be on safe side, ordered pmd, and relocation kit, removed rogue wire, and replacing again ops, will check fuel flow, once new items are in will update you when i get all parts delivered and instaalled, :)

I think the OPS is just fine but you can change it if you want to.

a feed the beast upgrade and a new lift pump that will give at least 10 psi of fuel would take the heat off your new pmd and save your injection pump from working so hard.
easy and cheap thing to do to make a bullet proof truck.:c:

In truth,neither of those things aid in PMD life.
They do help with performance and IP life though.

The stock system works just fine at cooling the PMD with the engine running.

Where improvement needs to happen is after engine shutdown,heatsoak that happens at that time when fuel is no longer circulating is when the compenents inside the PMD get shocked/stressed.

The best PMD life improver there is,is to remote mount it to a location outside the engine bay wher e it can spend it's life in ambient temps with no sudden extreme heating or cooling cycles.

just running on the thought that a ip working harder than it should would have its fuel solenoid driver(pmd) working harder to. saving pmd or not its still 1 of the best things of done to my truck.
buying your ip some time in life at 1800$ to replace makes a 150$ mod worth it alone. anyhoo:c:

well the day turned into a couple weeks, but finally have new pmd, and relocation kit, installed to front bumper, and new ops (once again) installed all, removed rogue wire, had lines blown out, and bled, fuel filter in canister good, try to start and do not hear lift pump running, seems as if it is not getting power, can however plug in the rogue wire, and lift pump begins working but with rogue wire attached, truck will not power down. seems as if there maybe a broken wire or short somewhere, to the lift pump, but not sure where to begin looking at this point, any ideas, or any other sensors that may control the lift pump? Lift pump is working with being straight wired, and with ops disconnected, will shut down with straight wire, but without the straight wire lift pump will not work.:argh::argh:

ops mod
 

if u look up "ops relay mod" you will see that 1 of the 3 wires coming out of your ops go's to power your lift pump. find out which color it is and do a power test (close to ops) if u have power run a new power lead right to your lp. ive done the mod but cant remember the color code. hope this helps. ps the truck has to crank over i believe to send power.

---AutoMerged DoublePost---

grey wire should be live when turning or running. it can run right to your red lp wire under your drivers side frame.

With a 94 you won't hear the LP run when you turn the key to run,the LP relay is only active during cranking and once running the OPS takes over control of powering the LP.

The condition you have is normal without the extra wire hooked up-check to see if the LP is working when the engine is running by putting your hand on it with the truck safely parked.(or jumer the orange and grey wires at the OPS harness connector)
If you can feel it working then open the water in fuel drain Tee-valve with the engine also running to con firm that it is pumping.
If the engine continues to run all is well,might want to put a catch can under the general area of the drain hose to catch fuel.

if the engine stalls out then the LP is shot since they can run but not pump any fuel.

if after feeling the LP with the engine running and it doesn't act like it's doing anything you need to verify that power is getting to it via the OPS circuit.
using a test light check for power at the LP harness with the engine running or by jumping the orange and grey wires at the OPS harness.
If no power is getting to the LP run a new wire from the OPS harness grey wire to the LP harness,cut close enough to each harness end to still make a good connection.

hey! I know this is an old thread. I’m having same issue! Wondering if this would cause the dash to read low oil pressure as well!

would this cause the oil pressure on the dash to drop low and show the “check gauges” light?

My fix when this happened was to loosen ,clean, and tighten All GROUNDS, add a new ground from BTY#1 to the block, and a ground wire to the big pump from the battery.,
Days of hair pulling was fixed for free, .