[Idris]

1998, 6.5 turbo diesel, won't start
Daily driven truck, stalled driving highway speed once, and no previous symptoms. Now it won't start, tried the obvious and replaced PMD (it has relocation kit, under bumper), i checked grounds and have two brand new batteries (cranks over fast) lift pump is working strong, i bled the filter and the t valve multiple times (let out over 2L) but no air bubbles.

I'm also getting OBD2 code p0231. Fuel pump secondary circuit voltage low

I Already replaced the DS4 injection pump about 6 months / 10,000kms ago, as well as the lift pump.

any help is appreciated, as I'm stumped and don't know where to go from here.

 

[OkDually]

Welcome to DieselPlace

Please tell us a little bit more about the truck ( Make, Model, 2wd/4wd ) and list all mods

 

[Idris]

It's a 1998 Chevrolet k2500, 4x4.
Other then PMD extension, no mods performed.

 

[OkDually]

Install a piece of clear fuel line on the return side of the IP as shown here: Question: - 1999 GMC Bluebird 6.5L TD - PMD &amp...
This will help identify air in fuel issues

 

[Idris]

I went out and did that as shown in that post, there are no bubbles between the line. So far I'm confident there is no air in the fuel. What else can I check?

 

[blackmanta]

I would try the easy approach and rule out the connections in the relocation harness of the PMD. Just plug the PMD, or a known good one directly into the harness at the injection pump. If you don't have a good spare, I'd buy one now anyway, since you are going to need it eventually. I had an intermittent staking issue and fish biting issue with a crappy harness. New quality harness from quadstar tuning and no more issues. It's a 5 minute job to check it. If it doesn't solve your problem, you can dive deeper into the troubleshooting. Good luck.

Sent from my SM-G973U using Tapatalk

 

[Idris]

I would try the easy approach and rule out the connections in the relocation harness of the PMD. Just plug the PMD, or a known good one directly into the harness at the injection pump. If you don't have a good spare, I'd buy one now anyway, since you are going to need it eventually. I had an intermittent staking issue and fish biting issue with a crappy harness. New quality harness from quadstar tuning and no more issues. It's a 5 minute job to check it. If it doesn't solve your problem, you can dive deeper into the troubleshooting. Good luck.

Sent from my SM-G973U using Tapatalk

I've ruled out the extension harness already, I've tried two known good PMD directly to the injection pump and it made no difference.

 

[blackmanta]

Well, I'm all out of ideas..

But I'd make sure the grounds are all clean and tight. Then perhaps checking the IP harness itself. I picked UP an NOS one up for about $25. I believe you said you had a problem code referring to low voltage or continuity at the IP, right? I haven't heard of an ECU failing except from water damage/corrosion, so I wouldn't suspect that being the issue. I'm sure the gurus will be here soon to give you better answers... I'm still a bit of a rookie.

Sent from my SM-G973U using Tapatalk

 

[Glagulator]

Is the lift pump running?

 

[Tommygunner]

p0231 is low voltage to fuel pump. Usually caused by a bad fuel pump relay. Or blown LP fuse. Could also be a bad connection between the relay and LP.
As post above asks. Verify the LP is running. You should hear it when you turn the key to on position.

 

[Idris]

p0231 is low voltage to fuel pump. Usually caused by a bad fuel pump relay. Or blown LP fuse. Could also be a bad connection between the relay and LP.
As post above asks. Verify the LP is running. You should hear it when you turn the key to on position.

Yes lift pump is running properly, it makes the clicking sound when key is in and is supplying plenty fuel flow to the fuel filter. As of now I'm getting fuel to the IP and it's clean without air bubbles.
The engine code I'm getting (P0231)/ (fuel pump secondary circuit low) showed up after stalling, on our 6.5 trucks is this supposed to relate to the lift pump or the injection pump? At this stage I'm leaning towards an electrical issue, how else can I troubleshoot?
Thanks

 

[dieselolds]

You state the lift pump is working BUT is it producing enough pressure and flow if you were to direct fuel from a hose into a container?Mine was only producing a couple psi of pressure and flow was poor.On my truck the lift pump was “working “ but not enough pressure or flow.

 

[Idris]

You state the lift pump is working BUT is it producing enough pressure and flow if you were to direct fuel from a hose into a container?Mine was only producing a couple psi of pressure and flow was poor.On my truck the lift pump was “working “ but not enough pressure or flow.

Yes it's producing plenty of flow i can open the fuel filter bleed valve and fuel shoots up 6 inches high with lots of pressure. The lift pump is new and was replaced with the ACdelco injection pump 6 months ago.

Also update, the p0231 code is no longer showing up.
But still not starting.

Can a injection pump go bad without warning signs and cause no start? So far I've went over everything i could find on the forums and don't know where to go from here. This truck was starting up first crank everyday this week, it's stalled once and now it won't start.

So far:
- plenty of clean fuel with good flow, lift pump is good and no air in fuel
-good grounds and starter cranks over very quickly
-PMD has been replaced and extension harness has been ruled out
-fuses and relays are good

 

[dieselolds]

Try disconnecting the optical sensor and see if it will start.If not reconnect it back upon the injection pump and disconnect the crankshaft sensor and retry starting once more.

 

[dieselolds]

I’ve noticed cases with these trucks when the connector enters the pmd,the pins can be found pushed back some which then gives you a bad to no electrical connection.

 

[Tommygunner]

When you checked grounds. Did you check the main PCM ground on right rear intake manifold bolt. Should have 3 wires connected. If bad or wire broken PCM will have no ground. Can cause no start.
Also is the fuel shut off solenoid working? You should feel it click when key is cycled on and off.

 

[OkDually]

Lift pump should produce 1/2 pint of fuel in 15 seconds when you open the T valve and let fuel flow into a container

 

[96C3500]

I’m thinking FSS or crank position sensor

someone on here said it has to have the crank position sensor or optical sensor to run, if both are bad it will not start

 

[Redneckrailer]

I had a 2000 with similar problems for me turned out to be the anti theft system had to splice in a resistor to ignition not sure if same on 1998 though

 

[Idris]

UPDATE: Ended up being the injection pump itself, ordered a new ACDELCO reman unit (took a few weeks to get it) but truck is running now

Hope this helps anyone, as i didn't have any fault codes and no symptoms leading up to the failure.

If you checked everything it's probably your injection pump ⛽