TPI help before I LS swap

[85 Jimmy]

Need some help with my TPI. After sitting for about 2 years it was hard to start and would backfire out the exhaust under acceleration and while just idling in gear. I pulled the injectors and ultrasonic cleaned them in seafoam while pulsing them, and that fixed the hard cold start, but it still backfires under acceleration. Put in a new O2 sensor and it does the same thing. It doesn't have any codes. Checked timing and it's at 0* at idle. I've had the TPI in and running for years, but it has sat due to an overheating issue that I fixed.

 

[eodcoduto]

I would check your fuel pressure and intake gasket leaks. It sounds like its going lean under load.

 

[85 Jimmy]

Just replaced the runner and plenum gaskets when I did the injectors. I'll check fuel pressure

 

[Blue85]

How old is the gas? Fuel pressure should always be checked for fuel injection issues. Shouldn't you have some timing advance at idle? Did you check this with a timing light or a scan tool? I'm not sure because I have a TPI setup on the K5, but not using the TPI ECU. Mine definitely idles better with some advance. What else has been touched lately? Could some plug wires have been crossed? I think you should look through the distributor for worn or corroded stuff and look at the plug wires in the dark for arcing. Visual inspection of the spark plugs never hurts.

 

[85 Jimmy]

Gas is fresh, just put 20 gallons in it last week.
Pretty sure it's supposed to be at 0* at idle. But I haven't touched the distributor since I installed the TPI. haven't touched the poug wires either.
Installed a 203/205 doubler and went single exhaust and started having over heating issues. Just went back to dual exhaust