2002 rcsb 4.3 to 4.8 swap issues.

I just got drug into trying to fix a 02 Silveraldo 4.3 to 4.8 swap and have ideas but don't really know where to start. Here's a little background on whats going on. A coworker of mine had his truck swapped over for a 4.3 to a 4.8 by a local shop (that didn't have a clue on how to do it) well when he bought the engine he got everything with it, engine harness, engine computer, instrument cluster, new fuel pump, he's spent so much money on this truck he could've bought a v8 truck but it's too late for that. The shops had it for 6 mo's and still havn't gotten it to run. So he ended up taking it to the dealership to have a new computer installed well now it starts (when sprayed with starting fluid) but will not run can someone give me some ideas on what to start checking? I know the first thing to check is fuel press. Is there a way to check the cam and crank sensor to see if they're bad? I havn't had too much dealings with trucks this new but I have done alot of work on the older trucks.

Any help or suggestions would be greatly appreciated to help get this truck back on the road.

Thank's

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Originally Posted by chevyracer8262

I just got drug into trying to fix a 02 Silveraldo 4.3 to 4.8 swap and have ideas but don't really know where to start. Here's a little background on whats going on. A coworker of mine had his truck swapped over for a 4.3 to a 4.8 by a local shop (that didn't have a clue on how to do it) well when he bought the engine he got everything with it, engine harness, engine computer, instrument cluster, new fuel pump, he's spent so much money on this truck he could've bought a v8 truck but it's too late for that. The shops had it for 6 mo's and still havn't gotten it to run. So he ended up taking it to the dealership to have a new computer installed well now it starts (when sprayed with starting fluid) but will not run can someone give me some ideas on what to start checking? I know the first thing to check is fuel press. Is there a way to check the cam and crank sensor to see if they're bad? I havn't had too much dealings with trucks this new but I have done alot of work on the older trucks.

Any help or suggestions would be greatly appreciated to help get this truck back on the road.

Thank's

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VATS most likely is causing it not to start.

that's why he took it to the dealership and supposidly they made sure all that was correct, cause they installed a new computer and reprogramed it to match the body computer. But i'll check into that as well. thx

Well I found a little more info on this problem turns out he bought the BCM and had it programed to match the v8 pcm he bought so those two match. But he also informed me that he bought a column to convert his truck from manual to auto from the salvage yard but are unsure if they came from the same vehicle or not. So if the case is that he has the wrong ing switch or instrument cluster for the vats sys what would be the easiest fix for that?

Well I got a chance to look over the truck today and it's got 55lb at the fuel rail, plenty of fire and tries to start but will not. Does anyone know what could be the cause of this?

how long was the motor sitting up? pull the injectors and see if there clogged, flip them ovber on a 2x4 and gentley tap them make sure they are clean

well i checked out the injectors and their not dirty, i even borrowed my buddies snapon scan tool and there's no dtc's, does anyonw have anything else to checkout so we can get his truck running. It starts for about 3 seconds then dies after that it tries to start but wont. We did notice that the security light folases when the door is opened would that have anything to do with it?

Still sounds like VATS. Know anyone with HPTuners or EFI Live?

like he said above, it's definitely vats. there is also security in the ignition switch.

you can try this
http://www.nelsonperformance.com/passkey.htm

and if that don't work, you need to get the pcm to someone who can disable vats.
Even in the future, I bet he will always have an issue with vats, it's a very picky system, so just get vats disabled in the pcm.

send me the pcm, i'll do it for $25.


later,
allen

Thanks's alot everybody after he finally showed me the reciepts for everything that he bought I realized that everyone was correct about the VATS system it is the issue. Turns out that all the parts he bought, engine, transmission, wiring harness, Pcm, steering column, instrument cluster all came from different vehicles cause the reciepts had the vin no's for all the trucks they came from. So the ignition switch is the wrong switch for the vats system. So Mr farmtruc that pcm will be on it's way to you Monday with a note and mine and the truck owners contact information.

Thank's again everyone.

Ok just to add my two cents also. The vats system is fairly simple to relearn no matter what module you replace and equally as easy if you replace every module. I find it difficult to believe that dealership would not do a complete relearn on the security using the techII. If in fact you were in a security fault situation the security light in the ipc will be flashing, and yes you will have a PCM DTC which is described as VTD fuel disable. Granted Snap-On may not have the ability to see all of the factory DTC's, I really can't say I have zero experience with there scan tools. I also want to remind everyone that there isn't actually a chip in the key on these systems, as stated above the ignition switch is the component for providing the IPC with the security signal although this is not application specific it is a generated signal based on time of pulse as the ignition is cycled from off to on. If you were to perform the security relearn properly the signal sent will be the only signal recognised from then on. I hope this may clear up some confusion on the VATS which is Vehicle Anti-theft System and has seen many different methods of providing vehicle theft protection including keys with chips which were very problematic and not very secure.

Shane

Well we got the pcm back from Nelson perf after getting the vats system disabled and we finally got it to run, but it won't idle. What could be some common causes for this engine not to start when the throttle blades closed? It'll start with the throttle partly open but if you let off for it to idle it dies.

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Originally Posted by chevyracer8262

Well we got the pcm back from Nelson perf after getting the vats system disabled and we finally got it to run, but it won't idle. What could be some common causes for this engine not to start when the throttle blades closed? It'll start with the throttle partly open but if you let off for it to idle it dies.

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Relearn TPS?

yes it turned out to be a relearn situation, he's started it several times since we got it running and now it's idles fine, just had to relearn the sensors. thanks again, now i can move on to my 94 s10 383 project finally