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Satan's Truck: Almost no fuel from CP3, none in return, good pressure from AirDog,

10K views 13 replies 5 participants last post by  nskyline34 
#1 ·
ok, I've had my share of projects but this truck has been months of pushing a rock up hill basically - almost feels like its cursed! lol

The truck:
Ok, so got this truck to fix and flip - had a blown engine, so got a 'new' engine from a local pull-a-part that was guaranteed to run, even came with a 30 day warranty. Got it in an long story short I basically have the truck at the BARE MINIMUM stage to start. Basically the intake is on, and everything is installed that has any kind of sensor, but the cooling system is completely empty (no hoses even) and none of the accessories are hooked up. I had a cam sensor code, had to replace the reluctor wheel, now all I have is a #2 glow plug code which I'm not worried about right now. Otherwise no codes at this point. Turns over great. I have no flue what’s done to the truck tune wise since I’ve never even driven it (bought it blown up). Has an Airdog on it, have it drawing from a 5 gal bucket and returning to said bucket right now so I could verify that it actually moves fuel. All I have is a normal scanner that pulls codes and does some really basic high level live data reading. Problem is it wont read fuel pressure. However, for my track car I have HPTuners which will read live data on a chevy for all kinds of stuff, problem is that when you turn the key to start the truck kills power to everything to give max cranking juice. So not sure how to read the ACTUAL rail pressure just yet.

What I've done:
Got engine in as said, cranked over, sounded just like a dmax with no prime basically. Everything sounds good except for the main part…it starting. Again, no codes to go off of, so I went to the basic – fuel and air.

Air:
No air obstructions going into the intake manifold, not even a filter, just wide open. (Air filter is in the truck so I can hook up the MAF, just don’t have the intercooler stuff all hooked up).

Fuel:
Have the Airdog pushing fuel, got truck primed, little plunger gets damn near rock hard like it should. Bled the air out of the little bleeder screw on top of the OE filter housing. (new filter on the OE housing too). Have a lot of fuel from the check port too. You can leave the truck for a day or two, primer goes soft, turn the key to kick on the Airdog and within 1 second primer goes firm again and you crack the bleeder and no air comes out. So it is maintain a prime from what I can tell.

What I have tried:
I tried having a buddy crank it and crack a couple injector lines because I figured there was still a little air in it somewhere. (I’m a Cummins guy and this was the ticket 90% of the time, but my other LBZ, and LLY have NEVER needed that, but figured it was worth a shot). No fuel came out at all. So I back tracked and cracked the line on the forward side of the driver side fuel rail, again, had a buddy crank it, there was BARELY any bubbles. For a system that should have about 5,000psi on start up, there wasn’t anywhere NEAR that amount.
I then replaced the line into, and out of the CP3 with a section of clear hose to see what’s happening. When cranking or turning the key on (the primer is still very firm) the fuel in the line feeding the CP3 has a couple big bubbles in it that are NOT being pushed to the CP3? When I first hooked it up (clear lines empty) it shoved fuel through it right away, then basically compressed the air and stopped it seemed like? The return line from the CP3 had NO fuel in it. I haven’t had a chance to do the bottle test, but hopefully will tonight.

What I need help with:
I feel like the lift pump should be shoving fuel ALL THE WAY into the CP3 pump, not having ANY air bubbles in the clear line. So why do I have NO air from the filter housing bleed screw, but have a couple inches worth of air bubble in my clear plastic line? And why wont it push the fuel into the CP3? Could this be the FPR not allowing it? I was going to disconnect the FPR to make it go to 100% to see what happens next time I’m out there. Otherwise, I’m just about stumped… any ideas fellas? Also might try to start it on ether tonight - (I know there are mixed reviews on this approach, but its never had a negative affect for me.)

Sorry for the novel
 
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#2 ·
Might try this-- Here's how you "teach" the truck your new ECM:

Turn ignition on
Try to start (it won't)
Leave ignition on.
In 10 minutes exactly the SECURITY (lock) light will turn off.
Try to start (it won't)
Leave ignition on.
In 10 minutes exactly the SECURITY (lock) light will turn off.
Try to start (it won't)
Leave ignition on.

In 10 minutes, the light will go out, and it will start up, and will "marry" the ECM to the BCM permanently.

This will even work with locked "pre-programmed" ECM's so you can test them on other trucks
 
#3 · (Edited)
OK, dumb question: Do I need to 'teach' the truck anything? I didnt change any electronic anything. Even used the wiring harness from the old engine and swapped sensors until I had no CEL's.

Just making sure I'm not missing something obvious. But hell, I'll still give it a try at this point. Just assumed I wouldnt have to since ALL the computers and xCM's are all the same (OE I'd assume)

After my clear hose test, I'm really thinking this is a fuel problem, not a computer problem really.

Thanks jc!
 
#4 ·
Really? No one has any idea what I can check?

Spent days searching on several forums and google in general...
 
#5 ·
UPDATE:

Still no luck.

Desired rail pressure is about 7,xxx psi or so, only gets about 320 psi. This happened with the FPR unplugged as well. there was no difference.

Have 12psi of fuel pressure from lift pump before I even start cranking.

Failed bottle test - not even a drop came out.

Still not getting fuel/air through the CP3 pump. Have clear lines on the feed going into it and there are still some air bubbles in there, and even under the 10+ psi pressure from the lift pump, cranking it, the air doesnt move - nor does the fuel.

Going to try and pull off the fuel lines from the CP3 and see if I can use some air to blow backwards through it and maybe reverse flush it out or something - wondering if there is a blockage.

Going to try checking the fuel pressure right AT the CP3 (low pressure feeding into it) and if that still says its about 10+ psi, I will try and 'flush' out the CP# however I can... Also going to pull the fuse for the lift pump so there will be no fuel pressure going to the CP3, crank it over, and see if it pulls vac or not.

Anything else I should check?
 
#6 ·
Update: New CP3, still wont start, but now I have 6000-9000 psi rail pressure when cranking. Cracked a couple injector lines and got fuel out this time, so making progress.

Not sure if the injectors are firing though, is there a way to test this mechanically? I had my laptop hooked up and it didnt seem like they were firing, just curious if I can verify this physically or not.

Also what if you do the bottle test and nothing comes out?
 
#7 ·
update:

did a return rate test last night, just pulled the return line off, put a hose on it, and cranked it for 10 and 15 seconds. 10 seconds yielded 83cc and 15 seconds yielded 130cc - so its DEFINITELY returning too much fuel, and considering that the CP3 is known to be good, I'm going to assume its the injectors (one or more or all) returning far too much fuel. I recall reading somewhere that the overall total was like 56cc after 10 seconds or maybe 15 seconds? can anyone confirm what the number is for TOTAL return? (CP3 return + injector return). Also does anyone know what the return rate should be for each bank? I am trying to really narrow it down before ordering those injector block off caps to test it...

also tried starting on ether - wanted to start, spun over faster, but no dice - didnt want to try it too much though. Oh, and its a good idea to kill the glowplugs BEFORE trying the starter fluid... lol oops

Am I on the right track?

Thanks fellas!
 
#8 ·
UPDATE: SUCCESS!!!

Truck runs - and apparently there is a tune in this thing that is f***in' nuts... pavement was a little damp, its a dually, stock everything that I put on it, and apparently a built trans. Jumped on it a little last night, thing cooked the duals without any problem all the way well into 4th upto about 60... there was no bed on it, so I'm sure that helped. What surprised me is the SOB was banging gears hard (but perfectly) and shifting about 3800... I've never felt anything like that before! Was so sick!

So, the big question everyone has: "what was the problem" - Well I'm sure someone in the future will wonder - and please email me if you have questions in case this thread goes away: nskyline34@hotmail.com

There were a LOT of very small problems that added up. There were several injector return lines leaking, a fuel line going to an injector was plugged, 3 injector elec connector pins werent making contact so it was trying to start on 5 cylinders, but 1 of the lines was plugged so it was trying actually start on 4 cylinders. That's why with the ether it wanted to start a little more because it was making it spin faster. and a big thing that I found out from on here that was the last thing - the truck wont start if the glowplug control module box (on driverside of the turbo by the firewall) is unplugged. I pulled power to it (the main wire not the big multi-pin connector) to kill the glowplugs when using the starter fluid. Also I had to crank it for about 15 sec and it caughed, another 5 sec and it caughed again a few more times, another 10 sec and it started to stumble to life, and then finally caught, running on 6 cyl (#3 and #8 werent firing). So I fixed the pins again in the inj connectors and #3 started working, #8 was still not, so I just decided to let it warm up and see if maybe it would magically work, pulled the connector on and off a few times to try and clean the contact points and it began to work.

All balance races are between 2.6 and 4.1 - close enough for this guy!

What a project. Few more things to wrap up on it, but they are the easy things.

Hope this helps someone in the future.

....now, to get my hands on a version of this tune somehow...
 
#12 ·
UPDATE: SUCCESS!!!



Truck runs - and apparently there is a tune in this thing that is f***in' nuts... pavement was a little damp, its a dually, stock everything that I put on it, and apparently a built trans. Jumped on it a little last night, thing cooked the duals without any problem all the way well into 4th upto about 60... there was no bed on it, so I'm sure that helped. What surprised me is the SOB was banging gears hard (but perfectly) and shifting about 3800... I've never felt anything like that before! Was so sick!



So, the big question everyone has: "what was the problem" - Well I'm sure someone in the future will wonder - and please email me if you have questions in case this thread goes away: nskyline34@hotmail.com



There were a LOT of very small problems that added up. There were several injector return lines leaking, a fuel line going to an injector was plugged, 3 injector elec connector pins werent making contact so it was trying to start on 5 cylinders, but 1 of the lines was plugged so it was trying actually start on 4 cylinders. That's why with the ether it wanted to start a little more because it was making it spin faster. and a big thing that I found out from on here that was the last thing - the truck wont start if the glowplug control module box (on driverside of the turbo by the firewall) is unplugged. I pulled power to it (the main wire not the big multi-pin connector) to kill the glowplugs when using the starter fluid. Also I had to crank it for about 15 sec and it caughed, another 5 sec and it caughed again a few more times, another 10 sec and it started to stumble to life, and then finally caught, running on 6 cyl (#3 and #8 werent firing). So I fixed the pins again in the inj connectors and #3 started working, #8 was still not, so I just decided to let it warm up and see if maybe it would magically work, pulled the connector on and off a few times to try and clean the contact points and it began to work.



All balance races are between 2.6 and 4.1 - close enough for this guy!



What a project. Few more things to wrap up on it, but they are the easy things.



Hope this helps someone in the future.



....now, to get my hands on a version of this tune somehow...


Im in the same kind of area, trying to sort out the air leak first. I do really appreciate the updates, not many out there like you!


Sent from my iPhone using Tapatalk
 
#9 ·
Wow, glad you got it going and thanks for the update.
 
#11 ·
I figured I would record it all for people. We all know how it is when you get on a thread that's your exact problem, and then it all the sudden stops... WTF??? lol

Unfortunately not keeping it, it will go down the road. Just going to detail it really well, take it on a road trip to make sure it's perfect and then sell it. Saved if from the junk-yard, so I'm happy. Body and interior was really nice, even has some nice 18's on it, so figured why not, I could use a challenging project... lol well I got one!

Anyone on here use HPTuners to tune? I want to copy the tune from it and put it in my other LBZ to keep, but it wont allow me to read it. Almost wonder if its a PPE tune or something and its locked? All I know is I need whatever tune is in there! haha Its a damn missile!
 
#14 ·
dang, well, I wish I could download a copy of a PPE 225 tune from someones truck now just to try it. lol
 
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