I just finished putting a 2004 LQ4 into my 1972 k20 with an nv4500 transmission. I am using the stock PCM with a BP automotive speed density only harness (no MAF) as well as the DBW pedal and the TAC Module from the same wrecked pickup. I used the built in HP tuners software upgrade to run a 1 bar MAP in speed density mode. I did install a sloppy mechanics stage 2 cam with the following specs: 228/230 .585"/.585" 112 LSA. Everything else about the engine is stock. The pickup starts, idles, and runs good and I have put around 100 miles on it so far. I could use some advice on how to make it more drivable.
The issues:
1. At low rpm and low speed just off idle (driving through a parking lot) the engine will surge and get the whole pickup "bucking" until you shove in the clutch slip the clutch a bit to keep the engine closer to 1200 rpm.
2. At any rpm above around 2000 when shifting, the rpms are slow to fall even when not touching the throttle making it slow to shift into the next gear.
3. The last and probably most significant issue is that when coming to a stop light when you push in the clutch to coast the last 10 feet or so, if you do not give it any throttle the engine will drop rpm and most of the time it dies.
Attached are the most recent tune from the computer and a datalog of the last trip I made with the pickup. Any advice on what tables or values need to be changed to make this pickup more drivable would be greatly appreciated.
- Brett
Attachment 145890
Attachment 145891