I finally got my 350 crate engine installed and running, but I need some pointers to get it fine tuned as much as possible until I get my hands on a scantool. It is running pretty good and idles fine, but when I took it for some break in/ test runs it really bogged when you first got into the throttle. Once the rpms came up a little it caught on and ran like crazy. This thing isn't going to be driven for a while, so I have some time to get it right before I put it on the road and any help will be appreciated.

Here's the engine. http://www.goautocenter.com/300hp_tpi_1987-89.htm

It has a Crane 2032 cam in it. Hooker headers 2055. AFPR. Stock TPI with #24 Injectors. Heated O2 sensor. MSD coil and cap. I also added the correct knock sensor and ECM for a 91 350.

One thing I'm concerned about is that the fuel pressure stays steady and rises as it's supposed to under vaccum, but when you shut off the key the pressure drops withing 5-10 seconds to basically nothing. What would be a good pressure to set this thing at?

I have the timing set at 8 degrees. I tried it at 6 but it seems to idle a lot better at 8.

I went out and pulled the codes today and I'm getting a 42, 43, and 45. The EST code is left over from setting the timing, and I think the 45 came up when I was messing with the fuel pressure today. So that leaves the 43 to figure out. I put in a new GM knock sensor and this car has the built-in esc so I didn't change the module. Anyone know some things that will bring up a 43?

 

Code 43: Low voltage at Electronic Spark Timing circuit

 

I'm getting the codes sorted out. I remembered that it will give you a code when you set the timing because the EST is disconnected. I think that it starts running very rough when the system goes into closed loop. If you get in it, start it and then take off it will drive great for about a mile or so, then it suddenly starts to bog down low and idle like crap. When I get a chance I'm going to use the diagnostic port to figure out if the problem is starting when it goes into closed loop or not. If you just start it and let it idle it will run perfect for about five minutes and when it warms up it will start to idle badly, so whatever it is it doesn't start until the thing is warm/in closed loop.

 

To elaborate.. Poor electrical connection, open or short in circuit; defective ESC module, defective knock sensor, defective ECM.

 

I know that the EST code came up because it was disconnected when I was setting the timing. The code 45 will dissappear until I mess with the adjustable FPR and it comes back. I put a 170 thermostat in it. Could this be causing the rough idle?