P0093 engine dies and no restart!

SmokinCRD · **Joined:** Tue Dec 08, 2015 8:57 pm **Posts:** 9

I was coming up a hill on way home from work other day and I noticed check engine light and surging. I came to the stop sign and it jeep shuts down and want restart. I scanned the jeep and had a p0299 code large fuel leak. Trailered jeep home to my shop and took my cts scanner from duramax to check rail pressure and turned it over and it would only build .3k fuel rail pressure. So I'm thinking my cp3 has puked. I have a low pressure gauge on the exit of fuel filter head and it's showing 15psi from my lift pump. Any more ideas to keep an eye on before tearing it down to have the cp3 rebuilt.

Sir Sam · **Posted:** Sun Jan 22, 2017 10:54 pm

Welcome to the forum.

I suggest you read the noobguide.

This sounds like an air in fuel filter head issue. Read up on bleeding the head and take a look if the heater plug is scorching and needs replaced.

edit: missed you said you had a lift pump, still check the filter head out.

SmokinCRD · **Joined:** Tue Dec 08, 2015 8:57 pm **Posts:** 9

Thanks for the help. I have already replaced the filter head with new design a few months back when I installed lift pump. What does people see normally cranking speed rail pressure?

lacabrera · **Posted:** Mon Jan 23, 2017 9:36 am

SmokinCRD wrote:

I was coming up a hill on way home from work other day and I noticed check engine light and surging. I came to the stop sign and it jeep shuts down and want restart. I scanned the jeep and had a p0299 code large fuel leak. Trailered jeep home to my shop and took my cts scanner from duramax to check rail pressure and turned it over and it would only build .3k fuel rail pressure. So I'm thinking my cp3 has puked. I have a low pressure gauge on the exit of fuel filter head and it's showing 15psi from my lift pump. Any more ideas to keep an eye on before tearing it down to have the cp3 rebuilt.

isn't PO299 an under boost code? 3k psi? on cranking is ok for starting. It would probably start on half that pressure.

flash7210 · **Posted:** Mon Jan 23, 2017 9:51 am

lacabrera wrote:

SmokinCRD wrote:

I was coming up a hill on way home from work other day and I noticed check engine light and surging. I came to the stop sign and it jeep shuts down and want restart. I scanned the jeep and had a p0299 code large fuel leak. Trailered jeep home to my shop and took my cts scanner from duramax to check rail pressure and turned it over and it would only build .3k fuel rail pressure. So I'm thinking my cp3 has puked. I have a low pressure gauge on the exit of fuel filter head and it's showing 15psi from my lift pump. Any more ideas to keep an eye on before tearing it down to have the cp3 rebuilt.

isn't PO299 an under boost code? 3k psi? on cranking is ok for starting. It would probably start on half that pressure.

Correct.
P0299 is under boost.
Problem is either intercooler hoses, MAP sensor, vacuum solenoids, or turbo.

Fuel rail pressure is good. No issues there.

Edit:
Usually, a p0299 will only cause a low power condition and will not cause the engine to die and not restart.
If your engine dies and cannot be restarted, I would scan for codes again. If no new codes then I would suspect a bad crank sensor. Usually a bad crank sensor will keep the engine from starting but not set any codes.

Sir Sam · **Posted:** Mon Jan 23, 2017 9:37 pm

The engine will start and run without the boost hoses attached. So I don't see why that would make a difference in the starting.

Clear codes and see what comes back?

What is your map sensor reading? Maybe its failed.

If you have advanced diagnostic scanner and can read sensors, check the cam and crank sensors during crank.

joe_ · **Posted:** Mon Jan 23, 2017 11:25 pm

From what I've read on this forum, a CP3 failing is extremely rare. More often the reason for low rail pressure is one of these:

- air in fuel (almost certainly not the issue if you have 15psi from your lift pump)
- bad fuel quantity solenoid (also called MPROP, located on the back of the CP3)
- bad injector
- bad fuel pressure solenoid (located on the back of the fuel rail, up against the firewall)

If the fuel quantity solenoid has failed, it will be sending the majority of the fuel though the return line before it even reaches the high pressure part of the CP3. To test, disconnect the fuel return line from the back of the CP3 and see if an excessive amount of fuel comes out.

If an injector has failed, it can be sending an excessive amount of fuel back through its return line, preventing the rail from building up pressure. To test, remove the return line from the top of all four injectors (don't lose the metal clips!) and connect a vertical piece of clear tubing to each. Crank the engine for 15-30 seconds and compare the fuel levels in each tube. If one has substantially more fuel than the others, that injector likely has a problem.

If the fuel pressure solenoid has failed, it can be sending an excessive amount of fuel back through its return line, preventing the rail from building up pressure. To test, disconnect the return line and crank the engine. If an excessive amount of fuel comes out during cranking, it probably isn't functioning properly.

CP3s aren't cheap and I definitely suggest doing some diagnostic work before rebuilding or replacing it.

Some other threads that may be helpful:
Jeep won't start, being told it needs a new fuel pump
crank, but no start....HELP

joe_ · **Posted:** Mon Jan 23, 2017 11:28 pm

lacabrera wrote:

isn't PO299 an under boost code? 3k psi? on cranking is ok for starting. It would probably start on half that pressure.

If I'm reading it correctly, he's saying .3K which should be 300 psi

olypopper · **Posted:** Tue Jan 24, 2017 12:01 am

Yep, that's what I read Joe.....300 psi isn't enough to make the little Italian fart. Time to diagnose your high pressure side and I doubt it's the cp3.

lacabrera · **Posted:** Tue Jan 24, 2017 7:20 am

joe_ wrote:

lacabrera wrote:

isn't PO299 an under boost code? 3k psi? on cranking is ok for starting. It would probably start on half that pressure.

If I'm reading it correctly, he's saying .3K which should be 300 psi

Over here 3k means 3000? https://www.reference.com/science/lette ... 476cf09a87
Why do you associate k as 100 been looking for an answer. Does that mean if you earn 100k you only earn $10,000 per year.

joelukex4 · **Joined:** Thu Sep 29, 2011 4:54 pm **Posts:** 386

Lacabrera,

He is associating K as 1000. If you re-read the post SmokinCRD states he is only building (.3K) fuel rail pressure. This is assumed to be 0.3K which would be 300psi.

lacabrera · **Posted:** Tue Jan 24, 2017 12:13 pm

joelukex4 wrote:

Lacabrera,

He is associating K as 1000. If you re-read the post SmokinCRD states he is only building (.3K) fuel rail pressure. This is assumed to be 0.3K which would be 300psi.

I guess its time for a visit to the opticians for me lol.

flash7210 · **Posted:** Tue Jan 24, 2017 1:06 pm

joelukex4 wrote:

Lacabrera,

He is associating K as 1000. If you re-read the post SmokinCRD states he is only building (.3K) fuel rail pressure. This is assumed to be 0.3K which would be 300psi.

If it really is 300psi (0.3K) then there should be a code associated with the low fuel rail pressure. Not a P0299 code.

Before diving into the fuel system, some things to check for a cranks but no start condition:
ASD fuse and ASD relay
Is the red dot lit on the instrument cluster? Does it stay lit while cranking?

SmokinCRD · **Joined:** Tue Dec 08, 2015 8:57 pm **Posts:** 9

Guys I'm sry i told you the wrong code it was a large fuel leak code (p0093) not p0299. My duramax has the po299. Sry for the confusion I am going to be diagnosing this thing tomorrow been out of town for few weeks just now getting a chance to work on the Libby.

SmokinCRD · **Joined:** Tue Dec 08, 2015 8:57 pm **Posts:** 9

Guys I did some checks today. I unplugged the FQS on Cp3 and still had 380 Rail psi at cranking, I unplugged FPS (on back of fuel rail) and still had 380 psi at cranking. I removed the blue line on the fuel rail return in front of the FPS and it had a good bit of fuel coming out of the blue Line (not the nipple on the rail) from the CP3(while Cranking) would that indicate the FQS is bad on cp3?

flash7210 · **Posted:** Sun Mar 12, 2017 7:41 pm

SmokinCRD wrote:

Guys I did some checks today. I unplugged the FQS on Cp3 and still had 380 Rail psi at cranking, I unplugged FPS (on back of fuel rail) and still had 380 psi at cranking. I removed the blue line on the fuel rail return in front of the FPS and it had a good bit of fuel coming out of the blue Line (not the nipple on the rail) from the CP3(while Cranking) would that indicate the FQS is bad on cp3?

Assuming that the low pressure side, from tank to CP3, is all good with no leaks...

Then yes, it does seem that the FQS is bad.
Or it could be the pressure sensor.
Or both.
But start with the FQS.

SmokinCRD · **Joined:** Tue Dec 08, 2015 8:57 pm **Posts:** 9

flash7210 wrote:

SmokinCRD wrote:

Guys I did some checks today. I unplugged the FQS on Cp3 and still had 380 Rail psi at cranking, I unplugged FPS (on back of fuel rail) and still had 380 psi at cranking. I removed the blue line on the fuel rail return in front of the FPS and it had a good bit of fuel coming out of the blue Line (not the nipple on the rail) from the CP3(while Cranking) would that indicate the FQS is bad on cp3?

Assuming that the low pressure side, from tank to CP3, is all good with no leaks...

Then yes, it does seem that the FQS is bad.
Or it could be the pressure sensor.
Or both.
But start with the FQS.

Yea I checked low pressure and had 15psi from lift pump and no air bubbles in clear hose. I will order FQS tomorrow hope that fixes it. Thanks for the help

SmokinCRD · **Joined:** Tue Dec 08, 2015 8:57 pm **Posts:** 9

Replaced the FQS tonight on CP3 and still no luck had only 380 psi cranking. I disconnected blue hose again from back of rail and I am still getting little diesel from the hose itself but not the nipple. Are they away to check the FPS on back of the rail? I will check the injectors tomorrow to see if they are leaking threw the return side. Any more ideas?

flash7210 · **Posted:** Tue Mar 21, 2017 9:31 pm

Crack open the #1 fuel line.
Crank the engine till fuel drips out to bleed the rail and verify fuel is getting to the rail.
Tighten the line and try to start.

Irocelectric93 · **Joined:** Sun Jan 25, 2015 5:59 pm **Posts:** 60

I'm going through the same issue. Problem is Oregon fuel injection told me they couldn't get refurbished rails from Bosch right now.

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P0093 engine dies and no restart!

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