Limp mode still 5 months on [Archive] - Diesel Place : Chevrolet and GMC Diesel Truck Forums

: Limp mode still 5 months on


brad carlin
05-12-2005, 07:24 PM
Hello:
I have a 2004 January plated 6.6 lly started going into limp mode (2000 rpm only) at less than 5000km, the truck was imported from Canada to Australia and converted left to right hand drive from new.
We changed the fuel filter several times, throttle position sensor, turbocontrol valve and map sensor with no change. Sent truck to a diesel dyno shop which have no lly or lb7 background at all, this is the test description, road test truck and fault diagnosis, carry out 4wd dyno tests and diagnostics, supply and fit boost test point reassemble and record 22lbs boost and p0239, p0102, p1093 fault codes. Test ALDL wiring and connection. Circuit test engine control module, fuel control module, transmission control module, body harness, instrument and dash harnesses. Test serial port wiring and verify that no wiring faults can be located. Verify engine MIL operation. ALL OK
Carry out fuel return flow and volume tests on standard Australian equipment and could not relate to known figures.
Download GM information and test procedures. Carrry out fuel system test. Procedures as recognised by the manufacturere and could not fault. Reassemble intake, turbo, FCM, PCV and fuel return systems to standard and retest.
Carry out scan tool command test procedures and confirm system functions to standard override ECM and command fuel system operations to test real time fuel pump operation and return line flow, verify that electro mechanical systems do function as required if requested to do so.
Call up vehicle history information, make necessary calls to Canada and USA dealer, distribution networks to verify diagnostic opinion and report. Software faults pre-existing from factory appears to cause the ECM to direct the FCM to reduce main rail pressure from 23200PSI to 15950PSI which in turn induces a limp home mode.
I believe that the ECM program is at fault and requires reprogramming. The ECM has been reprogrammed twice now, now waiting for new ECM to arrive from the US.
The truck has been in the shop for 12 weeks.
Also is it normal to have full power with accelorator pedal only half to the floor.
Any help is greatly appreciated.

email address: lavenco@albury.net.au

05 D/A 2500
05-13-2005, 01:40 AM
Good luck with that, i wish I could be of some help. I am sure some techs will chime in soon this is a great place to get info!


:grd:

shelden27
05-13-2005, 08:46 AM
Check Mass Air Flow Sensor You Have Set A Code For It If You Have A K&n Air Filter It Is Probably Contaminated Replace It It Will Cause This Problem Possible Faulty Fuel Pressure Regulator Have Seen It Also You Should Check The Injector Return Rates Due To Pump Can Not Make Full Pressure If The Injectors Are Returning To Much Fuel Due To Internal Seat Being Cracked

shelden27
05-14-2005, 09:13 AM
no it is not normal to have full power with pedal have way to the floor. bad reading from the mass air flow sensor could cause that or the app sensor could cause that. let me know what you find

brad carlin
05-15-2005, 09:36 PM
what fuel return rates should we have from the injectors and what the procedure for this test

baumbanshee380
06-02-2005, 05:58 PM
Sounds like there might be some emmisions issue. I got the same codes when I ditched the cat. Installed a finger stick and all is well. Don't know just thought I would throw it in