6.5 turbo diesel not starting!!!

[94redrebuild]

i am having an issue with my 1994 6.5 td not starting. i have just rebuilt the motor and had it running, it got hot and i had to have it towed home because of air in the cooling system i later figured out bc it was never bled while running just poured in. once i got it back i tried restarting it to bleed the system and it won't start. it cranks just fine, rolls over fast on 2 brand new batteries. i get fuel at my injectors, glow plugs are all brand new, crank sensor brand new, replaced again to make sure wasn't crank sensor, timing has been adjusted to see if it had gotten off, replaced pmd, loft pump and fuel pump work, just super stumped bc it won't start. i am getting codes dtc 17 & 18 but it should still start in limp mode even if cam sensor is down? extended cranking may be an effect of that but it won't start. have spent weeks trying to chase this problem and cannot seem to get it.

[Yukon6.2]

With fuel at the injectors...
You should do a compression test to find out the health of your engine.

[Dvldog8793]

compression test....

[94redrebuild]

okay will check compression again. checked before and was fine, not to say something couldn't have changed bc it's possible. puzzles me because it was starting on it's own and it got harder and harder to start over about 10-15 starts until this point where it won't. it was running and driving good then went back to square one

[arveetek]

Cranking speed? The 6.5L is really sensitive to cranking RPM. Fresh, healthy, fully-charged batteries, good battery cables, and a good starter are essential to 6.5L starting.

Casey

[94redrebuild]

my cranking speed does not seem to register anything at all, although it does seem to be cranking well over what should be required. idk if it makes a difference or not but it is a manual transmission.

[94redrebuild]

update// i checked fuel pressure. i have roughly 8 psi at fuel filter housing. i have no air in system, check with clear line on return fuel and on hose going into injection pump, solid fuel, 0 bubbles. fuel shutoff solenoid is working, took it out and checked it, when i crank engine with an injector line off injector i get merely a drip but only when cranking, if you hold your finger over it builds up pressure. tried cranking with injector out and connected to IP line, was getting a very weak almost stream when it was supposed to fire that injector, would squirt the fuel almost rather than mist it and even then, the squirt was not very powerful, is my IP going out? PMD is good, replaced and checked that.

[Robyn]

Seems to be a very strange series of events.

The engine is rebuilt... You get it going and it overheats due to an air lock...

Now there is a NO START ??????

Do you have a spare PMD ???

If so get it installed and see what happens.

The PMD is always suspect on these engines.

How hot did the engine get ??

Just getting it a bit warm should not cause a no restart.


My first suggestion is to try a different (known good) PMD

I have seen new ones die in real short order...


With no fuel at the injectors there are few causes.

BAD PMD
AIR LOCKED IP
BAD FSO SOLENOID

[94redrebuild]

i had a spare pmd that i checked it with, same result. i took FSO out and turned key on and off, full range of motion, no goop on it, worked flawlessly. how would you know if i had air locked IP and if so how would you clear it? i've cranked it with an injector line loose. oh and it didn't get past the red mark on my gauge for the temp, which i believe is 260 it got around 30 degrees over normal. and i have replaced thermostat also to check if it was that. pmd also has relocate kit on it

[DmaxMaverick]

Keep it simple!

Back to basics....
Only 3 (three) things are needed to run an internal combustion engine. Fuel (gasoline or Diesel), O2 (ambient air), and heat (spark or compression). A cold start Diesel may require supplemental heat, if fuel and air are present. If compression is sufficient to forcefully blow air out the GP holes, then there's enough for a cold start with sufficient supplemental heat. If it was running before, then suddenly not, something broke or changed. Unless you have some indication of a failure, of some sort, assume compression is sufficient. They generally run poorly for a long period before refusing to start, while something wears out. If you are getting fuel at the cylinders, that leaves air and heat. If the airway isn't blocked, it is getting air (an assumption, easily verified). That leaves only heat. GP's, new or not, fail for a variety of reasons. Check them all. (assuming all good) Now, check that they are all getting full Batt+ power when the key is cycled to "ON". Also, if the "Wait to Start" lamp is on, they are getting Batt+ power, at least minimally, as the lamp is powered by the same circuit that powers the individual GP's. Make sure the GP cycle is long enough for the plugs you have installed. Too short = not enough heat. AC60G plugs often require nearly twice the glow cycle of other common plugs to heat enough. Good plugs, just sloooow.

You should test fuel to the injectors with the injectors and lines fully installed and tight. Remove the GP's and crank the starter. Fuel should mist from the GP holes. Fuel weeping from open lines, but none under pressure of the connected injectors indicates low fuel pressure or air in the system. The fuel supply is restricted or leaking, or the IP is in need of repair. Air in the system is unlikely if the engine started and ran fine before, unless something changed (empty fuel tank), or broke (fuel supply line leak).

Fuel + Air + Heat = Start. If not, you missed something, or the planets are out of alignment, or something. It's only that simple.

[Julius]

Keep it simple!

Back to basics....
Only 3 (three) things are needed to run an internal combustion engine. Fuel (gasoline or Diesel), O2 (ambient air), and heat (spark or compression). A cold start Diesel may require supplemental heat, if fuel and air are present. If compression is sufficient to forcefully blow air out the GP holes, then there's enough for a cold start with sufficient supplemental heat. If it was running before, then suddenly not, something broke or changed. Unless you have some indication of a failure, of some sort, assume compression is sufficient. They generally run poorly for a long period before refusing to start, while something wears out. If you are getting fuel at the cylinders, that leaves air and heat. If the airway isn't blocked, it is getting air (an assumption, easily verified). That leaves only heat. GP's, new or not, fail for a variety of reasons. Check them all. (assuming all good) Now, check that they are all getting full Batt+ power when the key is cycled to "ON". Also, if the "Wait to Start" lamp is on, they are getting Batt+ power, at least minimally, as the lamp is powered by the same circuit that powers the individual GP's. Make sure the GP cycle is long enough for the plugs you have installed. Too short = not enough heat. AC60G plugs often require nearly twice the glow cycle of other common plugs to heat enough. Good plugs, just sloooow.

You should test fuel to the injectors with the injectors and lines fully installed and tight. Remove the GP's and crank the starter. Fuel should mist from the GP holes. Fuel weeping from open lines, but none under pressure of the connected injectors indicates low fuel pressure or air in the system. The fuel supply is restricted or leaking, or the IP is in need of repair. Air in the system is unlikely if the engine started and ran fine before, unless something changed (empty fuel tank), or broke (fuel supply line leak).

Fuel + Air + Heat = Start. If not, you missed something, or the planets are out of alignment, or something. It's only that simple.


Hello, new here.

I just recently replaced a IP on a 2000 6.5 3500 GMC. prior to this, truck had been sitting for 6 months due to white smoke and no start. After IP replacement, Truck fired right up and would start/drive all week. During this week I was attempting to perform the TDC offset learn & adjusting the pump position ALL WEEK. Trying to get it within spec per repair manual -.25 -.75. Well after the second week, I cam to the shop and went to start it to pull it outside, crank - no start. I thought maybe I adjusted the pump too far to the point it went out of spec. Nope. Made sure I'm getting fuel at the IP and lines. Made sure in tank pump was working, made sure glow plugs were operating, made sure there was no air in the system etc... at a full stop with tis project. I tried 3 different known good PMD's. I'm stuck because the truck ran perfectly fine and then all of the sudden nothing. I didn't change anything, nobody even touched the truck. So I'm not entirely sure what changed. The only thing that I noticed was, on my Tech2; the last time i tried to re learn the TDC offset. The engine load was reading 99% with key on ENG off. This was something new. as it would read 15-18% at idle. So, I thought maybe the pedal position sensor or ASSY was the cause, unplugging it changed nothing. Please, I'd like to get rid of this dang thing haha. Thank you in advance and I'm sorry this is so long.


2000 6.5 3500

[Yukon6.2]

Electrical gremlins...
I drove a 2000 Suburban into my shop last year to work on it,the next day it would not start.
Turned out the security feature wasn't getting clean power. Turned out to be a bad fuse after i changed ignition switches,security modal.

[More Power]

Hello, new here.

I just recently replaced a IP on a 2000 6.5 3500 GMC. prior to this, truck had been sitting for 6 months due to white smoke and no start. After IP replacement, ...
2000 6.5 3500

Spend some time looking at every electrical connector on the engine that had been disconnected during the IP change, looking for a loose connector or damaged wiring.