on my way to my best friends wedding my truck was sputtering a bit at about 55-60 but still ran stopped at the church and the truck would not idle assumed fuel filter. wifey got me a new one and changed after the wedding with no luck. fuel bleed out fine but would not idle or move step on the gas and sometimes it revs and sometimes it don't. I have a code 78 with the paper clip accros the a&b but nothing else. I pulled the bonehead of all boneheads and put some super in it last week pumped/siphoned out all the gas/fuel.I did not start it it was towed home and 20 gals of fresh fuel was put in fisrt. I found out at the onset of the hole pump out procedure that I had a bad lift pump and replace this. put 100 or so miles on and then this. help please I'm new to the diesel world and this is my first brakedown and I have yet to find a good manual for the 6.5td.:help:

When you say the truck wouldn't idle, did it idle too fast? erratic? stall??

When you bled the fuel filter was the truck cranking or idling? And did you do it by the bleed on top of the filter or the drain cock at the front of the engine?

You might be drawing air with fuel from the tank, find a jug or bottle or something and run some fuel from the drain cock and look for tiny air bubbles.

I idles very erraticly and stalls rpms surging up and down. I bleed it from both places and didn't notice any air but did not use a bottle the truck was running and stalled during the bleeding. I won't be able to try the bottle till tomarrow and is there anything else I should look for it has been running great since installing the new fuel pump but it has only been a short time??

Either hot wire the lift pump with an ignition controlled wire or relay a new OPS in if the LP is new. Low fuel pressure and air in the filter bowl will make it surge and stall.

Sounds like a broken armature to me.

How does it drive? Is she stuck in 'Nascar' mode? Lots of black smoke and LOTS of power?

broken armature???? it will almost run fast enough for my 99 year old grandma with puffs of smoke when it surges in rpm and no power at all. The lp seems to be working fine feul gallour out of the top for the filter after the engine dies for a few seconds.

Sounds more like fuel restriction to me. You said it didn't put out fuel at idle and then stalled. During engine operation the LP is powered by the OPS. The liftpump can work at startup and when manually powered but not during operation due to OPS in the circuit but the only time I've experience erratic idle with a surge is when the supply pressure is nill due to a particle blockage andin that case I back blow the filter by removing the ip in line and opening the drain T. put a bottle under the hose and you'll see if it's rust or whatever.

Well I broke down and hauled her to the garage the bad new is it don't appear to be a problem with feul to the pump had a quick canversation with the mechanic said I will need to take to chevy dealer cuz it has a number of codes that lead to a pump or maybe an ecm code 54,78,& I think he said 201 or 204. I was wondering if it may only need a pmd on the pump??

DTC 54 is the fuel circuit
DTC 78 is over/under boost, black smoke?

201 and 204 are OBDII codes

I have yet to see it run since he hooked up the computer but he said it now run/ idles fine and I should drive it to GM so I am assuming it is now driveable it was not when I took it there?? not sure if code were cleared then these are the new ones?? I will go get the truck tomarrow and see what I can figuire out. I am skiddish about taking to GM due to knowing most of the mechs at the 2 dealer around.

Check your fuel rate on the scanner with the engine idling in N with A/C off.
Should be 8~11mm, if its way less or way more, then you have Injection pump problems. Its not metering fuel properly, most likely fuel Solenoid problem.

I'm going to guess that when you look at it it will read really low, 1-3mm.

I will check that but in the mean time I just picked up the truck and drove haome the truck from the garage. I wouldn't say its right or anything but I cleared the codes half way home and Checked them and I have a 18 & 36. I did this a couple times and I makes me happier than the 18,35, & 54 that the mech told me I had. any more ideals would be appricated.

Well it still runs drove it a few miles checked/ cleared the codes very frequently sometimes before I even put it in gear. I know I don't know a lot about diesels but I think I'm in for a lot of money on this one!!I have a very eratic code issues 17-18-35-36-54 not in any perticular order drove for 3miles had 18-35, cleared and started and had 18-36 cleared drove .5 no ses when it started ran bueatiful for .25 m and ses came on stopped and had 18-35-36-54 cleared drove for 2.5 miles and had 17-18-35-36 cleared codes started reved to 3000rpms and had a miss at about 3050-3100 ses came on and had 17-18-35-36-54. I am lost am wishing I had bought a manual a month or 2 ago. Let me know what you think and do you if a pcm is GM only?

I'm having a similar problem with my 95 6.5, maybe you can shed some light.. I've has this truck about 4 months, replaced turbo & brakes, my first GMC Diesel. Changed fuel filter about 4000 mi ago for no reason (I drive about 250 - 300/ day) I Go on vacation and truck sits for a week. Back to work- Truck runs great til .. -Engine Just Quits, engine stops like turning off key, no sputter, no smoke, just quits - coast to stop, turn key off, try to restart cranks strong but no start. Wait a minute or two starts up like no problem. Does this about 3 times a day now. Changed fuel & Air filters, bled fuel by little valve at thermostat. Water in fuel light not on, check engine light not on... (Both are functional) - Whattya Think

your problem sounds like what I had "hoped" mine was the PMD is probably failing. everybody I talked to origanily said with no codes and stalling and no/slow start replace your PMD. I was going to buy mine from ssdieselsupply.com and still will if it turns out not to be my ECM as I fear now. good luck and get one that mount off the pump with a large amount of heat sink.

Forgot to mention - 215000 miles and leaks oil like a seive between engine & Bell housing - Like a quart per tank of fuel - Is there a seal back there behind the flywheel, or does the Engine need to come out to reseal... and quantum made reference to oil vapor at the dipstick tube... which I have - lots of... whats going on here.... Thanks

Timber, is it blowing out the oil fill? Sounds like it is. If so, that's major blowby in some form or another. The engine's CDR (Crankcase Depression Regulator) is attempting to maintain a few inches of water column vacuum on the crankcase. It won't keep up with that much blowby if that is your problem. Oil leaking is just a smyptom of your problem. I have leaking seals, but they "maintain" because of vacuum in the crankcase.

If this is your case, you'll need to find the source of that blowby - like maybe a piston?

jcbrotz, Just for kickers, check all the electrical connections on and around your IP. Check also engine ground between passenger side head and fire wall. Remove/Clean/Replace that one especially. Eliminate all possible electrical problems first, that way you are makin' sure that the pump has gone truly south.

To have aaallll those codes come up at once, it would be worth checking.

Just saw this a few months ago with another guy who pumped gas in his tank. He however drove it around for awhile and botched up the pump.