OK guys, now I could use some help. 1998 Astro Van 4.3. Cranks over, wants to start but won't. I checked fuel pressure at the port in the engine bay on the fuel supply. When turning key on, pressure builds to 60ish and holds at 55psi when turning key off. Put a new distributor rotor and cap on as ol...

Did you add the R134a with a scale to insure the proper amount? What is the high side PSI? A multiflow condenser is better than single flow.

If you can the cost, I would not use a 50 year old evaporator.

The new one is working fine. The other may be sticking. Sometimes they can be brought back to life by pouring oil in them and letting them sit.

It appears your problem is the condenser is not rejecting enough heat from the refrigerant. Look at missing shields/baffles, fan clutch, fan motor if electric, blocked fins on condenser, plugged condenser passages. You may need a more efficient condenser for this conversion.

You mentioned using hard lines. There is a lot of vibration in the engine compartment nd if it were me, I would use new custom made rubber hoses.

Did you mist the condenser with a water hose? If you did, did the high side drop like a rock? Some of the conversions from R12 to R134 require a large capacity condenser.

Mist the condenser with a water hose. If pressures drop radically, you have an airflow across the condenser or a condenser that is not rejecting heat from the refrigerant. Engine rpm 1500, system on max, high speed blower, doors/windows open. You may also have a hose that is collapsing.

The standard for testing: RPM's at 1500, windows/doors open, max blower speed, recir mode (max air cooling) If you added 4 oz of oil, you may have over done it because 2 items can not occupy the same space (oil and refrigerant). If the high side went to 400 PSi, there is your problem. You are not re...

Did you check a blend door between driver and passenger?