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'04 6 liter in a '70 k5 swap

P0101Mass Air Flow System Performance
P0315Crankshaft Position System Variation Not Learned
P0507Idle Control System RPM Higher Than Expected

I couldn't find a match for P2761 are you sure you've got that one right?
 
billyjo said:
P0101Mass Air Flow System Performance
P0315Crankshaft Position System Variation Not Learned
P0507Idle Control System RPM Higher Than Expected

I couldn't find a match for P2761 are you sure you've got that one right?
Click to expand...

P2761 is correct according to the Predator. Took it for a ride today gave it some gas and it wasn't very impressive. The old 350 would have left it sitting at the light. I have to figure out why it runs so poorly, misses and idles so fast. I'm sure one thing will fix it all but what is the one thing? Maybe LS1edit is in my future.

did the AC picture help you at all?
 
Keep in mind that I'm no expert and take this with a grain of salt, but from what I've read most of the time they won't start without the crankshaft relearn done. I'd definately start with that one, I'd call who you got your programer from.

Then the MAF, are you running O2 sensors in your exhaust and are they where they are or close to where they put them in from the factory? The computer uses readings from the MAF and O2 sensors to control fueling and the timing so if you're not using them that could be another problem.
 
I originally installed two new o2 sensors that were from the same vehicle. They are installed right next to the exhast manifold within 2" of the original placement. My next step is to call the computer guy and clean the MAF. Someone suggested to check the fuses also. I'll keep you updated.
 
P2761: TCC circuit failure.

The MAF and idle codes could be caused by a vacuum leak. Idle code can also be caused by a throttle plate no closing all the way, bad IAC etc. With your rough idle Id bet you have a vacuum leak somewhere. If you don't see anything unhooked from the intake then check the intake seals to the head, the gaskets leak fairly often on the 4.8/5.3/6.0s and cause the symptoms you describe.

You'll need to have a good scanner to enable the CKP relearn procedure.
 
Got the computer back for the third time. It now does everything that it is supposed to idles at 650rpm, doesn't miss, has one code for low signal to the MAF which might be my fault. After a long discussion with the computer guy he figured out the problem and shipped me a completely different computer. Significant power increase from the first time I drove it. It has at least as much power as the old 350 which ran really, really well.
 
Had some minor transmisison trouble with low shift points. Talked with the rebuilder, Bowtie Overdrive, and they sent out a new govenor. It now shifts at 5500 RPM from 1st to 2nd. Checked the mileage for the first time and got 8.5 MPG. Not bad since most of the time the truck was either floored or idling in the driveway. I'm still praying for the 15MPG that I thought I could get with the new motor.

I would recommend that if anyone does the engine swap that they buy the software, HPTuner, EFILive or such to prevent some of the problems that I had with the computer.
 
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