6.0 low power at acceleration from stop

[jbarnett31]

I've got an 04 F-350 ambulance that came in with no power. I found that tht CAC has blown out i replaced it and it felt better so i let it go. The customer came to pick it up and said it was the same as it was. I road tested it and at WOT from a dead stop it takes about 4-5 seconds to build boost and go. It runs perfect the rest of the time. I've got no codes, fuel pressure is good, no air restrictions or exhaust retrictions. HP oil is good, no exhaust leaks in y pipe or anywhere else. I removed to inspect the turbo, it was pitted up and sticking so i replaced the turbo and removed and cleaned the intake, still no power at WOT. I've drove a few amulances and they all seem alittle weak, but they say it just started this. I cant find anything wrong or out of specs. I need help PLEASE!

[mchan68]

Have you checked for an aftermarket air filter? I know I've replaced more than my fair share of BS aftermarket air filters (you know the ones with the foam lining in front of the element) with the OEM ones to repair a symptom like you describe successfully.

[jbarnett31]

Yea it's got the OEM filter and it looks close to new.

[Brad Clayton]

Quote:

I've got an 04 F-350 ambulance

Is this an early '04 (ICP in HPOP cover)? If so and it has had the PCM reflashed at anytime in it's life, then you will have to do a turbo relearn. This tsb covers it extensively: 9-15-6
6.0L - BUILT ON OR BEFORE 9/29/2003 DTCS P006A, P132B, P0401 OR P0402 - LACKS POWER, SURGE, OR FLUTTER AFTER FIELD SERVICE ACTION 06E17

IF this applies to you, then you will not have any power off the line until a relearn is performed.

[jbarnett31]

It's got the old pump but the icp is in the valve cover. It doesn't have the learn pid either.

[Brad Clayton]

disregard my post then.

[Jeff_E]

It may be worth a-b-a swapping the MAP sensor from a known good truck to see if yours is bias. On a few occasions, new MAP sensors fixed these for me after I had exhausted all of the normal causes to no avail.

 

Another thought would be to put a new fuel pressure regulator in it. It seems like the new blue spring gives them a little extra power too.

[jbarnett31]

I have replaced the map sensor with a know good one and it didn't change anything.

[Bruce Amacker]

WOT from a dead stop it takes about 4-5 seconds to build boost and go. It runs perfect the rest of the time.

This could be a bad torque convertor, too, if it's only from a dead stop. Compare stall speed with a known good unit.

 

I assume it passes the turbo and EGR tests in IDS, right? The problem is ONLY from a dead stop and runs perfect otherwise?

 

[Bruce Amacker]

Quote:

I've got an 04 F-350 ambulance

Is this an early '04 (ICP in HPOP cover)? If so and it has had the PCM reflashed at anytime in it's life, then you will have to do a turbo relearn. This TSB covers it extensively: 9-15-6

6.0L - BUILT ON OR BEFORE 9/29/2003 DTCS P006A, P132B, P0401 OR P0402 - LACKS POWER, SURGE, OR FLUTTER AFTER FIELD SERVICE ACTION 06E17

 

IF this applies to you, then you will not have any power off the line until a relearn is performed.

Brad: My experience is that the PCM does the relearn immediately after starting the engine and this can be watched in scan data as it only takes a couple of minutes at idle. It sound like you're saying that if you qucikly get in it and RT it there is a lack of power?

 

Sidebar- I still see virgin trucks that need the 06E17 and I'm afraid to flash them to that level. The (virgin) ones I've done have not resulted in happy customers- usually complain of considerably lowered fuel economy and lack of power after the reflash. (It is unknown whether exhaust leaks or other problems existed before/after the flash)

 

[Brad Clayton]

Ditto on the torque convertor, forgot all about that scenario, haven't seen one like that since my last 7.3 with no power. I take them over to this parking lot down the street that has this really steep grade, to test them from a stop.

 

Every once in a while we get a '03 that needs a relearn and yes if we get in a hurry we beat the PCM to the punch and it will exhibit no power and is very difficult to initiate a relearn once you screw it up.

[Keith Browning]

Brad: My experience is that the PCM does the relearn immediately after starting the engine and this can be watched in scan data as it only takes a couple of minutes at idle. It sound like you're saying that if you quickly get in it and RT it there is a lack of power?

I am not Brad... but I concur with his statement as I have jumped into trucks after recalibrating them and they were real sluggish off the line and at WOT. If we step into the WABAC machine we should recall that the re-learn process may not happen until EOT reaches 130'F and it may be necessary to re-clear the KAM, cycle the ignition twice and let the truck idle until VGT_LEARN reads "YES."

 

If we don't consciously perform the VGT re-learn procedure and verify that it has completed and no conditions that can affect power exist the truck may not perform properly. It may take time for the VGT learn to complete if we just back the truck out of the shop and park it.

 

I am attaching TSB 09-15-6 for your reading pleasure which addresses this concern.

[GregH]

The A/C needs to be off, too...