TBI running rich

[BobbyBigRigger]

I just got a 1990 5.7 TBI running after 10 years of sitting inside. I did a rebuild of motor, cleaned gas tank, new pump and sending unit and new filter. Also new Coolant sensors, oil pressure sending unit. I put long tube headers on it, have it timed. The issue I seem to have is its running rich, loads up with gas and stalls out. Once I do have it running and throttle to higher RPMS, it seems to mellow out. But once I shut it off it wont restart as if its flooded. Leave it sit until drys out, fires right up. Any ideas where to start?

 

[scott2093]

Any ideas where to start?

A scanner that can look at data stream might be able to point to something obviously wrong. Have you tried pulling any codes via aldl? May get lucky.
Fuel pressure test...
Did you rebuild tbi? Regulator...?

I don't see the emissions manual for your year. Maybe it's hidden somewhere in the sticky somewhere but you can probably download the 89 or 91 emissions manual and go through some of the driveabilty troubleshooting until someone else chimes in....

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[95burban]

Did you replace the o2 sensor?

 

[BobbyBigRigger]

I actually have the O2 sensor unplugged. Did not put a bung in the Header.

 

[BobbyBigRigger]

I will be putting a scanner to it. Now I'm thinking that's my issue is that the O2 sensor unplugged. I see Summit sells bung adapters for the Headman Headers

 

[termite]

My first thought would be a fuel leak if its flooding itself out (injectors leaking, perhaps incorrect injectors?).

I believe there is a clear flood mode in the FSM. Don't recall the specifics but had something to do with flooring it while cranking? Can likely be found by searching the FSM or even on here.

Without the O2 sensor feedback, it will stay in open loop and run off of the preset tables in the tune/ecm. Correct ecm and chip for the application?

Someone will be along in the next few days (or sooner) asking for the information from an actual scantool, not just code reader.