Diagnosing Lower Power

[MGreer]

I'm trying to run a cp3 return test and a injector return test. On the cp3 return I got 700 mls. in one minute idling with engine at operating temps. I ran the injector test at 1200 rpm and got 70 mls. in 30 seconds. I then ran the injector test again for 30 seconds with the fca unplugged and got about 450 mls in 30 seconds.

I didn't have time to get the rpm's to 1000 so they settled at 1200 with the rail pressure at 26k. Before I ran the test I unplugged the fca at idle and the psi went to 26k. With the fca unplugged the fuel was coming out of the hose hot.


My question is should I not run the injector test with the fca unplugged.



Thanks

 

[Bob4x4]

The factory has a scan tool controlled test,running wide open pressures is a bit extreme

 

[MGreer]

BoB4x4,
After running the test at full pressure, I agree 100% with you. I ran the test that way after reading a fellow member posted it as a revised procedure. I'm just trying to wrap up the necessary tests to determine my low power problem.
I believe the problem is the cp3 with the symptoms I have.

 

[MGreer]

BoB4x4,
After running the test at full pressure, I agree 100% with you. I ran the test that way after reading a fellow member posted it as a revised procedure. I'm just trying to wrap up the necessary tests to determine my low power problem.
I believe the problem is the cp3 with the symptoms I have.

 

[cerberusiam]

Try this for the CP-3 test.


-Remove the CP3 to fuel rail line.
-Put a heater hose or any kind of hose on the CP3 outlet and secure the hose with a clamp.
-Get a bucket to collect fuel and crank the engine for 30 seconds
-Measure the CP3 flow with a conventional graduated cylinder/cup from your kitchen
-The flow must exceed 75ml (2.5floz) in case your measuring cup doesn't have ml at 125rpm or 90ml (3.0floz) at 150 rpm
-Do the test 3 times to rule out priming issues
-If it doesn't meet the specs above replace the CP3 pump.

450 ml sounds way high even with the extra pressure, more than double what would be a "good" reading for injector return flow. You did isolate the FRP from that also, right? Have you check the FRP to make sure it is not the problem.

 

[erikz]

Hi, have you tried re-torquing the fuel transfer tubes that go from the outside of the head to the injectors? I had this same problem on my 04.5 and my brother on his 05. If memory serves correct the specified torque is 37 ft/lbs but going to 43 ft/lbs is what works best.

 

[MGreer]

I ran the injector return test again according to the fsm and got 88mls in 1 minute. I also ran the cp3 test Cerb mentioned and got 100 mls at about 150 rpm. During the tests I had the miller 9013 in the prv and the 9012 in the back of the filter housing.

 

[MGreer]

The truck seems like it's not getting enough fuel. When towing and on a hill the egt's won't go over 1250. The rpm's won't go over 2300. I used to run the smarty on level 3 but now I have to run level 5 which will let me hold decent boost on hills. A few year's back the cp3 would leak fuel what looked like out of the gerator pump during the winter. The number 5 injector line would be damp on one of the fittings. Since the power issue's started the pump doesn't leak anymore and the injector line is dry. I replaced the prv with one from t&c in may 2015. I've replaced the cov, map sensor,fca and lift pump. Also, when towing up hill the last third of the go pedal does nothing. I'm having problems with this computer, hopefully this is readable. Thanks

 

[cerberusiam]

Have you logged the rail pressure when this is happening? If it is draining the rail that should be pretty obvious on RP.

 

[MGreer]

I haven't logged rail pressure while towing, just empty. I need to log some recent pressures when it stops raining here. I was watching rail pressure at idle yesterday and it was ranging from 6500 to 7600. Every few minutes or so the reading would go to 31k and stay there for about 4 seconds. The desired pressure didn't change when this happened.
I have the truck back to stock for testing.

 

[cerberusiam]

That is too wide a range at idle to bounce, and, going to 31k can't happen as the sensor won't read over 26.5k. If you reading that off the ECM something is messed up in the ECM itself, if your reading that with an analog gauge something in the gauge wiring is pooched. If you rail pressure actually jumped to 31k the engine would rattle like crazy and you would notice it.

 

[MGreer]

I ran the test on a cold start and I use the auto enginuity scanner. The reading actually read 31,033 and no engine rattle occurred.
When I ran the rpm up to about 1500 the rail pressure didn't fluctuate much. I don't believe the pressure actually went to 31k, could a flaky rail pressure sensor do that.

 

[cerberusiam]

Flaky sensor or you have ECM issues. Usually when they get those high readings like that it will set a DTC for rail pressure out of range. You need to monitor rail pressure and LP pressure when it won't accelerate to see if anything is out of range but it sounds like you may have ECM issues causing the problems.

 

[AH64ID]

Just to make sure... what is the Smarty PoD set at?

 

[MGreer]

Cerb:
When the high rail reading happens none of the other readings change and no codes are set. This power issue happens whether the truck is stock or programmed smarty. It is just more noticeable when towing.
When the truck is on smarty level 3 I used to be able to slip the clutch at will with just a small increase in pedal. Now the clutch won't slip with the smarty on level 5.
Also, with the smarty on level 3 I could lug the truck some and get a lot of smoke. Now the truck won't smoke no matter how much it's lugged.
The first time I noticed the problem I ran the truck in a bad ice storm. I had a lot of ice build up on the underneath of the truck. I wonder if I have a contaminated connection on the ecm.

 

[MGreer]

John:
I always assumed the pod is at 100 %. I've never changed it but I guess it's something I need to verify. I always run the smarty on settings 432 which is torque management, timing and pressure. I've been running with the waste gate off in order to hold good boost numbers.

 

[cerberusiam]

On TM4 you should have plenty of smoke lugging it, something is interfering with the fueling curve be it lack of fuel or programming.

 

[MGreer]

Looking over the last log recorded with the koeo the fuel pressure set point was reading 5300 psi. The fuel pressure sensor was reading from 113 to 149 psi.
Also, with the truck idling the boost reads 14 to 15 on the scanner. Getting ready for test run to log some fuel pressures.

 

[AH64ID]

Boost is in absolute pressure so 14-15 is accurate.

If there is a rail pressure fault the ECM will limit fuel to 60mm3 (around 43% load) and 2500 rpms, but IIRC it should throw a code. Maybe the Smarty disables the code. Have you tried running stock?

 

[MGreer]

The truck is back to stock when starting the thread. I haven't had any rail pressure codes. The truck doesn't run much better than stock with smarty on level 5. The main benefit is being able to hold more boost when towing.
When stock the boost will jump to about 30 then drop to about 24 and then settle on about 25 or 26. I ran the truck yesterday and on an uphill grade the truck wouldn't go over 2300 rpm, egt 1300 at 82 mph. This was in 6th gear of course.
It usually takes a while for the rail pressure to reach the desired pressure. Sometimes it doesn't reach desired pressure. Yesterday with the truck idling after the test rum the rail pressure sensor would dip to 1800.
The lift pump is flowing 550 mls in 10 seconds, the spec for the 04.5 is 590 mls in 10 seconds. Lift pump psi is 11 at idle and doesn't go below 5 under load.