pressure spiking at startup then nomalizing

[pplusent]

I have a 93 4runner 3.0 auto 4x4. I just replaced the compressor. evaporator (134a) and matching TXV, and flushed the whole system, system was clean and was running before change with a r12 evap and TXV, but had a front seal oil leak the reason for the new comp. The system is charged with 8 oz. of ester oil, and charged the system by weight. The final pressures came out at 42 low side, 225 high side @ 85 ambient.
The system was running perfect at 40 degrees duct temp for 600 miles. Now it seems at start up the compressor comes on and runs for about 1 minute then the high and low side suddenly spike to the point the high pressure switch cuts the system off. As the pressure equalizes the clutch turns back on and the clutch squawks for a second or two and then quiets down and the system runs perfect again until the car is shut off.
I am at witts end with this. The compressor manufacture thinks it is a condenser clog, but I feel it would not cool if that were the case. I am thinking TXV malfunction or bad clutch magnet. The 93 and 95 condensers are the same units.
Any ideas on this out there?

[Dougflas]

At what RPM are you getting 42 low and 225 high? I see you stated you charged by weight but R134 needs less refrigerant than R12. Could you possibly be slightly over charged? Did I ever tell you I do not like to convert? This is coming from someone with a butt load of R12. GRINS

[pplusent]

I put in 27 oz, but the spec I was given called for 10 oz of oil. I removed 4 oz today and the spikes are way less. Once again the pressures are 45 low and 225 high at 89 degrees at the condenser, but clutch still squalling at start and chirps a bit when running. I think it was liquid locked. Now I believe the cutch is gone from all the pressure spikes, I will change it tomorrow and see what happens. I have a couple laying around. I also had to remove the ac cooling fan for now due to a short in that as well. I believe the new engine cooling fan will make up for it at 4000 cfm.
At this point I may just tear it down and start over. everything on these Toyota's are a constant aggravation.

[DarrylS]

Probably a double pass condenser which you will never fully flush. It is most likely partially stopped up and constantly feeding debris and junk through your system. Start over and replace everything including the condenser. That is why the dealerships and professional AC shops always replace the condensers as a part of compressor replacement they simply cannot be 100% flushed.