I think I did a bad thing. I swapped the TPI runners on my 89 firebird for 88 hiflow runners. In doing so I plugged the injector hole but didn't plug the air hole at the top. The resulting vaccuum leak meant that the car wouldn't run at anything below 3000rpm. While at 3000RPM there was a loud back fire and big flame that came out from under the plenum. I think might have been the EGR. I plugged the air leak and now the car starts & runs. It will surge at idle after driving and being stopped for about 15-20 seconds. The idle is also a little lumpier than before. Could I have hurt the EGR or can there still be a vaccuum leak? All the hoses are back where they belong. None of the switches were modified. I did try disconnecting (& plugging) the egr vaccuum line but ther was no change. Also no codes so far. Any ideas?

 

I don't have TPI so take this with a grain of salt. Perhaps you may need to change your prom setup in the computer. This has programmed information for the fuel injectors and this may need to be altered for the new setup. Just a thought. I don't think you have an EGR problem. To check for proper EGR function, rev the engine to about 3000 rpm. Check the diaphram underneath on the EGR valve for movement. If it moves during revving then it is ok.

 

You have to be a magician to check the egr on a tpi motor. Its burried under the plenum. According to the manufacturers of the hiflow runners there is no need to reprogram. The 89 I have is MAF based and a little friendlier to small changes like runner diameter