1992 lumina dies when engine goes into open loop

[st.pierre]

1992 lumina 3.1 Automatic will start and run great till it warms up and goes into closed loop. then it just wont accept any throttle or it dies. will start back up but you cant touch the accelerator or she just quits. no check engine light and no codes set. new fuel pump. any ideas. thanks!!! Thinking it could be a vacuum leak?.I checked all injectors and replaced plenum gasket.

[Schurkey]

Connect a real scan tool, look at the data stream. What is the O2 sensor volts, and crosscounts? What is the short- and long-term fuel trim? What is the coolant temperature? MAP sensor output?

What is the fuel pressure?

What is the cranking compression psi?

[st.pierre]

I have an old odb1 scan tool that I will have time to look again at the live data stream this weekend but I'm not sure if it has short and long fuel trim and cranking com psi, can I read those on a tool I can get at o'riley...but I will get the other info from the scan tool I have.Car has 129000 miles. Thanks for the reply Schurkey!

[st.pierre]

Well the car took about 7 cranks to start up and then ran well, this time when it hit closed loop it ran fine and I warmed it up for about 10 min and drove it around my property up and down hills and a-lot of start stops. seemed to run pretty well but did sputter every once and a while just for a second and smelled rich. I also noticed the ac or heat will only blow out the defrost, cant get heat or ac to switch to the vents so I still think I have a vacuum issue.Some numbers off my scan tool are Battery 13.8, o2s 3-7 hundred mv, o2 crosscnts 0-250 ?, integrator 128, loop closed, maf 12 gr/sec, map 145 v, inj pw ms 2, engine rpm 825, est bypass on, exhaust o2 switching fron lean to rich , fuel pump 13.8, iac position 8, idle req rpm 700, prom id 1051, spark advance 19, tcc solenoid off , throttle percent 0, tps sensor .64, dont think I have cranking pressure psi? data. thanks for any input I will look over the vacuum lines sometime this week after work. Gas in car is old so that may have some bearing. thanks again

[Schurkey]

There is a vacuum tube that powers the cruise control and the HVAC system, it wraps around the rear of the engine and down the driver's side of the engine compartment, ending in a vacuum reservoir "ball" ahead of the LF tire.

This vacuum hose is often cracked or perforated where it goes under the battery to the vacuum "ball". Another common problem area is directly under the cruise control module.

A perforation anywhere in the hose can affect the cruise control and/or the HVAC air-handling system. On my vehicles, I would have "weak" cruise control that would hold speed on flat ground, but lose speed on uphill sections. Any acceleration or uphill requiring additional throttle opening would result in the air handling switching to "defrost" vents.

Repairing that hose (multiple times!) always fixed the problem. The plastic tubing used became brittle and cracked. I'd splice in a short section of vacuum hose and it would be fine for another year or two.

[st.pierre]

Thank you again for the reply, I will have time this weekend to trace that vacuum line and see what I can find. I will check back with the news. Have a good weekend.