SteveOh,
as far as the Throttle body there is no setting for that, it gets it's signals from the coorelation between the pedal position sensor and the ECU.
Now as for the Pedal position
If you happen to have the software to hook up the pedal position readings should be:
idle: 35-45 units (700 rpms)
full pedal: 195-205 units (2700 rpms)

If you are setting using a VOM
idle: +.7 volts and up
full pedal: 3.8 volts

Jumping in here only because this seems to be the closest CAT model discussion thread to the CG30K troubling me. Suspect (and ordered) the Throttle Positioning Sensor, engine runs at idle but will not accept any throttle input. I don't have the "setup data" to insure the replacement TPS is properly adjusted once it arrives and I install it. Hope someone has the resistance readings needed to get the replacement TPS properly installed.

Sorry guys,
i did get it going finally, it was the pick up for the crank, the wire was pinched and not getting a good circuit, replaced it and tried it again and we were off. sorry i was on vacation right after and forgot to reply. thanks to everyone who gave us help on this one.

Well Pat_r from the rain capital of Canada, did you get this truck going? Lots of really good info was shared, we're dying to find out what the solution was....

oh yeah, edward did ask didnt he lol
whoops.....

Sorry for the confusion on this thread but Edward T did ask me to post the info although it did not pertain to the truck in question. If ever you have this problem with the "TB45", it will blow the clip on cap off the air filter housing. This provides plenty of oxygen for the filter to continue to burn. The plastic housing may also melt and burn if not extinguished. It may get a bit messy. Worse than the mess, until I discovered the service bulletin, this backfire was really kicking my butt. If you go to Service publication there are photos.

Well I think he ruled out the distributor when he swapped it out. He could try the MAF sensor cleaning or even swap that out too. It's the only thing he didn't mention. But then again i dont remember these machines having one of those.

That document is for GP40,45 and 50K trucks.

ehhhh :o/

MCFA document: 000098-08C Sept. 22 2008

GP40K GP45K GP50K

Subject: TB45 engine backfiring- The engine backfiring may also burn the air filter.

Cause: Dust could enter the distributor cap. Check the mass air flow sensor. Dust can fill the cam sensor photo slots causing the engine to miss and backfire. Check the air filter for burned spots

Resolution: Remove the distributor cap and three screws holding the cover. Blow out the distributor assembly. Seal the three vent holes on the base with sensor safe silicone sealant. Remove the Mass Air Flow sensor and clean only with MAF sensor cleaner. Do not use brake or carb cleaner. They both leave a residue and will affect plastics and rubber O-rings.

Check ignition and fuel first. You must eliminate one or the other. Main fuel pressure should be checked 3+ psi out from convertor.

wekcome Whitebuzzbait.
can you tell us more about the TB45 lighting up air filters?

Yes, I'm pretty sure I stated I didn't know what model truck he had. Guess I being new to this forum did not see above that he had a GC25. I will read more carefully next time.

hehe yeah edward i'd like to see that trick with the TB45 in a GC/GP25k , Might need a frame stretcher for that one ;o)

I would have expected most all of the trucks with the "MTRTWR8" connection concern to have been fixed long ago, this PSB came out in 2004 or 2005 and only was concerned with 4g64 and 4g63 motors produced in the 1st 1/2 of 2004, and really did keep the motor from charging properly, so much so that correction was done asap.
Since we still don't have a serial number series to be sure,,,
Some other things his symptoms call to mind would be not enough fuel getting to or through the LPG regulator (dirty filter, or bad "rego" quick disconnect) or possibly an "almost will fit" rotor button or bad distributor shaft bearing that has a little play that shows up at higher rpm.
Whitebuzzbait, I am pretty sure that no tb45 (a straight 6 cylinder) ever got stuffed into a GC25k or GP25k (they all used the 4g6* series motors).

More info i came across about the alternator not charging
Now if its not charging at all and will not initiate even at high rpm's then of course it will have to come out and be rebuilt or replaced with a new one.
BUT....
If you can rev up the engine and it does start charging there is a fix for this from CAT, they released a service document on this problem that requires moving a wire in the wire harness under the floor plate on the RH side.

Located on the right hand side of the truck, underneath the floor panel, is the 8-pin connector "MTRTWR8". This will be on the main chassis harness "B". It is located just to the right of the transmission. Do not confuse this with the engine harness side of the connection.
On this connector you will see the letter "G". The White 14ga.wire with Red Brown rings in "G" terminal socket will be removed and then reinserted into the empty terminal socket "F". You will then start the engine and idle it only.
Connect a suitable volt meter between the battery terminals Positive (+) and Negative ( -) and check for charging DC voltage. Voltage should be at 14.5 VDC and continue to charge at this rate when accelerating through the high rpm range of the engine.

Something else i learned the other day is that most all charging circuits go through the charge indicator light on the dash believe it or not and if that bulb burns out the truck will not charge, check the bulb and see if it is burned out and replace it if it is.

Don't know what model Cat you have. If by some chance you are looking at a TB45 engine you should definitely let me know because I had the same problem and there is a PSB publication about this. In fact it will actually backfire and set the air filter a blaze as in " HELP FIRE get the fire extinguisher!!!"

my bet is he has an a 4g64 motor that is tier 2, his actual problem is either "wobble" in the crank sensor wheel (mounted external to the crankshaft pulley) or has the distance from the wheel to the sensor pick up just a -little- out of round (only 2 thousandths of an inch). you MUST use a non magnetic (brass) feeler gauge to measure, and you MUST mark the wheel at 12, 3, 6, &9 o'clock, and check the gap each place [remove all spark plugs and turn the engine by hand, check spark plug gap before re-installing the spark plugs]. Cat has/had a special "cross" that will hold the wheel in place as you tighten up the 4 bolts that hold it in place [if you work for an MCFA dealer the Service engineering department will loan your dealer the cross, I think]. There is not a lot of adjustment you can do to the pickup sensor, but the wheel itself can get out of exact position when it gets hit, (and on the 15s the wheel was so close to the frame, that hitting a pole would cause the wheel to hit the frame when the motor rocked, but even if it was not hard enough to damage anything else [other than paint], the scrape on the wheel was enough to cause the symptoms you describe.
These trucks would have mitsu 4g motors and the Impco spectrum LPG system, and were sold only in the 1st half of 2004.

these trucks had problems with the coil harness wires breaking

if you have a faulty coil harness it can cause misfiring, stalls or failure to start conditions.

try changing out the coil and harness

also, when you changed out the sensor on the crank timing wheel did you inspect the timing wheel itself? any visible damage? if any of those teeth get damaged it can cause problems like this.

I would take a look at the valve springs.

i have a new battery in it. i wasn't told that they changed it yesterday, as far as alt output goes i have nill. Why is this causing the issue if it is the problem? ordering an alternator right now will keep you posted

Put in a new battery & then check alt output.