Engine/Transmission (1998.5 - 2002) 02 Dead Throttle

[WVilla]

02 throttle sometimes is non responsive when cold. Starts fine but will only idle. throttle is dead, black smoke, no increase in rpm. will usually snap out of it (after going 10 mph max) after driving a mile or two. It has not done it with a warm engine, only in am when cold. Replaced the water pump awhile back, so my mechanic thought that water temp sensor was bad, so replaced but problem is still there. Any Ideas?
W.Villa

 

[SAndreasen]

check for codes and see if any come up
cycle key on till gauges move then off do it 3 times and codes wil come in odometer display

 

[WVilla]

OK thanks...........was not quite sure how to do that

 

[MLee]

OK thanks...........was not quite sure how to do that

Did you get it figured out yet?

Turn key to on/ run three times, on third time leave on and watch for the CEL to flash, count flashes, there will be a pause between the numbers, wright them down and then come back here with the numbers.

 

[WVilla]

I am not able to do that yet, as the truck is in the shop for a different issue (Pinion seal bearing). I will get it back today, so will try to pull up the codes this pm. Thanks

 

[WVilla]

OK.........the codes I got were P PCU and P ECU

 

[SAndreasen]

Might need to take it somewhere and have it hooked. To a scan tool

 

[WVilla]

Sounds good. I will do that. Thanks for the help

 

[WVilla]

Mechanic said that the circuitry of the throttle position sensor was not right. We replaced the throttle position sensor. So far so good.

 

[SAndreasen]

Good deal .

 

[bromano676]

FYI. I replaced the factory APPS when it went bad with a $500 factory only part. A year later it went bad again. I ordered the retrofit one from a guy on the forum. Now geno's garage sells it for about $160. Close to 5 years no problems.

 

[WVilla]

Well......the Dead Throttle is back. It does it now cold or warm, idling or high speed. When it locks up in idle, throttle pressure will not get it much over 1000 rpm and 10 mph. If it is at high speed, truck decelerates to less than 1000 rpm and 10 mph. Throttle pressure results in only black smoke. It will usually unlock in 2-5 minutes and when it does (at idle) you can hear and see a slight increase in rpm (50-60). Toggling ignition only results in P PCU and P DONE. We have replaced a Water Temp Sensor and a Throttle Position Sensor. Any Thoughts?

 

[SnoKing]

Try this:

http://www.bluechipdiesel.com/vp44_diagnostics.html

SNOKING

 

[WVilla]

OK......Thanks.

 

[klcammie]

Just a thought if throttling down sounds like engine derate, with the black smoke over fuel. Check MAP sensor maybe it's going bad and showing overboost. Maybe a good cleaning of MAP ia worth trying.

 

[WVilla]

OK. Thanks. Will keep the MAP as something to consider. Here is the latest: My mechanic has the truck and he believes that the problem is that the Pacbrake is sticking closed. He said that when it went dead for him he removed one of the vacuum (?) lines on the brake and it immediately unlocked. He checked the canister and said it was good, the filter was very dirty. Cleaned the filter but still have the issue. He still believes that it is the Pacbrake and is going to work on it for a few days. Looking at what the truck does when it goes "dead throttle", seems like it would be consistent with an exhaust blockage with back pressure to the engine and black smoke? I know a lot of you have Pacbrakes out there.............ever have this problem??

 

[SnoKing]

If the exhaust brake is stuck on you will hear a hiss at the tail pipe. Just disable it for a while and drive it to see if problem goes away. Snoking

 

[klcammie]

Never had the problem, but PacBrake recommends using the brake all the time plus regular PM on the valve to keep it from sticking.

 

[WVilla]

Familiar with the hiss and do have it on most of the time. Had it put on the truck when new in 02. 220,000 miles now. Really apprecciate the help and will keep those interested informed.

 

[WVilla]

Apparently the issue was the Pacbrake. Vacuum canister just wore out. The way the people at Packbrake explained it was that the seals in the canister were probably leaking, but when the canister warmed up. the seals would seal and the brake would operate as it should. I turned off the brake and no problems for over a month. Just got the new canister and lubricating oil in the mail. So hopefully that is the only culprit. Thanks for all the help!!