Alrighty fellas, here is one to wrap your brains around... Ive got a '92 RS that came with the 305 that we all know and hate. sadly(happily) It finally died and forced me(allowed me) to replace it. due to budget constraints I couldnt go with a full on LS swap, all though I would have liked to. so I bought one of these:

http://www.jegs.com/p/Chevrolet-Perf...32025/10002/-1

seemed to be the best bang for my buck...

after getting all the appropriate parts, intake manifold, larger throttle body, bigger injectors, bigger fuel pump, 350 knock sensor and ESC module; I went ahead and also got a few "go faster" parts like aluminum pulleys and water pump, 1.6 ratio full roller rockers and MSD distributor and 6AL-2 box.

obviously all of this was going to need a custom Prom made for it to behave so I found a place, Sinister Performance LLC to make the new chip for me.
they have been really helpful and happy to give advice and suggestions as well as instructions as to what they need from YOU to make a new PROM chip.

now here comes the issues, first off, the ECU insists on running like 30* timing advance at idle (I have already gone throught the appropriate procedure for setting the base timing). which brings up another issue, when I have the base timing set to TDC like its supposed to be, the thing runs like a pig, spits sputters and shoots flames out the intake, not exactly desirable. So to get the thing to run decent the Base timing has to be set to around 10* advance, but no matter what, In park, at idle, it runs it forward to 30+* advance. Furthermore, the thing wont idle at less that 1100 RPM. According to the guys at Sinister, they programed a 750 rpm idle speed.

Occasionally the Rpms will drop that low briefly but when they are down there, it misfires like crazy, shaking the whole car. Ive got a feeling that because I have to have the base timing set so advanced it wont allow the engine to run properly at that low of RPMs.


So, any and all Ideas will be appreciated as to what to check into or what you think might be the cause for my symptoms I will try and provide any further information if you have any questions. And again, in summary my issues are these:

High Idle, wont run smoothly at less than 1100 rpms
Very advanced Idle timing, the ECU commands the timing to run 30* at idle
Advanced Base timing, The base timing must be set to around 10* advance for the engine to operate in a useable fashion

sinister performance claims that it isnt their tune that is making the timing be so advanced. I have no way to check this claim so I have to trust that they are correct.

 

You should make more threads to get your answer.

 

This has been asked elsewhere, and isn't really an engine swap issue.