Need help with a diagnosis

[Mister Furious]

Hi all, I could use some help diagnosing what’s going on with my 05 ISX; it’s in an 05 T600. Full rebuild 570k ago; was de-mandated and the VGT replaced with a regular turbo at that time. ECM tune was done by {Horrible delete tuning shop name deleted by Rawze} and set at 600hp. This is info from the previous owner. I’ve owned it for 3 months and put 30k on it.

A few weeks ago it started to surge at idle, for a few seconds. Gradually it increased over the next few weeks until now it is constant. When I start the truck it will idle perfectly for about 30 seconds, then it’s like a switch gets flipped and the surging starts. Doesn’t matter, hot or cold or anywhere in between. I can turn it off, restart it and the cycle repeats. I swapped the timing and metering actuators off of a perfectly running truck with no change. It sounds like it’s got a hot cam in it. Apply the throttle and it runs perfectly. Mileage has remained the same; 6.1.

Yesterday it suddenly would not build rpm’s past 1650, in or out of gear. At the same time engaging the cruise would cause the throttle pedal to go dead. Turn the cruise off and instantly the throttle returns. Is my ECM on its way out?

[tree98]

You have a bad demandate program from piss poor power that is your first problem. Your second problem is a fixed vane turbo that has your air fuel mix totally out of whack. Pull that program out and send it to Rawze so he can tell you everything that's wrong with it and trust me it will be a LOT!! Now you need to find a VG turbo to put back on it so you can put a proper program in it.

[Bengy88]

I’ve personally done one vgt delete on a cm2250 and 2 years later with the truck running from South Carolina to Pennsylvania twice a week I have had to replace all 6 injectors twice, a camshaft, a cylinder head, and 2 fuel pumps. I will never do another. There are two people on this planet I would trust performing this programming and I still wouldn’t do it. (The guy that did mine had no clue what he was doing, just like most others)

With that being said the delete is most likely not your issue, it probably has contributed to it but not the actual issue. It does sound like you may be having an ecm issue though. As the head honcho says “smack it with a rubber hammer” that will usually tell you. Also if you have a truck that you can pull the metering and timing actuators from then I’m assuming you have one you can pull an ecm from. It never hurts to try. One more thing. If you are having cruise control, throttle, and idling issues then the throttle position sensor would be another smart place to start. Monitor your throttle position with Insite and you may find your problem

[Rawze]

you have a long journey ahead of you.

like others have already said... start gathering all the parts necessary to put the VG turbo back onto it properly. It is not going to be cheap to straighten out that hot mess of a red-neck garbage crap someone did to that $40,000 commercial engine you have there.

That place you mention is ONE OF THE WORST PLACES IN THE USA TO TAKE A TRUCK TO.. . THAT NON-VG TURBO MODS AND HORRIBLE PROGRAMMING IS WHAT YOU HAVE HANDS DOWN!!!. BOTH WILL SHORTEN ENGINE LIFE WITH NO GAINS WHATSOEVER EXCEPT TO MAKE YOU REBUILD IT 2X MORE OFTEN THAN IT SHOULD AND HAVE A TERRIBLE POWER CURVE AND UNSTABLE IDEL, SURGING, ETC!.!.

Non-vg turbo makes the engine completely loose it ability to have proper fuel-air mix any more.. and that is bad all in itself.. now pile on top of that, a wonky as h#ell bad program.. and you have exactly what that shop offers people for big $$$ and rips them off.. all in the name of big-boy pants, bragging rights, and nothing but engine destruction in the end.

WELCOME TO THE BAD DELETE CLUB. YOU ARE THIS WEEKS WINNER.!!!
REF: http://rawze.com/forums/showthread.php?t...5#pid13255