Ford Ranger Compressor Cutting Out

[Autosaver]

For Johnhere & tbirdtbird…

Ford parts advisor said that the TX valve has been upgraded.

My question is:
Based off the look of the new TX valve on the left & the old one on the right, what purpose does the redesign offer?
I see thinner walls which probably help with heat transfer?
Also less material used therefore reducing the price of the part?

Would like to hear your thoughts.

[tbirdtbird]

"Ford parts advisor said that the TX valve has been upgraded."

To me, that is dealerspeak for 'cheapened'
I seriously doubt there is any difference in performance. The heat transfer that we need in AC work occurs at the evap, not the TXV

The walls where the pipes engage look dangerously thin and probably could crack way more easily, especially given the temperature cycling that occurs there. If I had a choice, I would pick the old style

[JohnHere]

The bean counters have "re-engineered" that TXV, all right. The only difference that I can see comparing the new versus old part (discounting the thinner walls) is the slightly smaller HP orifice on the new TXV. What difference that makes, if any, I can't even hazard a guess.

[DetroitAC]

Agree, left valve is lower cost, less aluminum, eliminated dome insulation. These things happen over the lifespan of a vehicle model. The suppliers agree in advance to a certain level of cost reductions year over year. I doubt there is any noticeable performance difference

[Autosaver]

My last question to close off the thread is with regard to low & high side pressure readings when revving the engine.

If I increase my rpm to 1500-2000 rpm then I would expect my low side pressure to drop & my high side pressure to rise, correct?

I also have a Corolla & I revved the engine to about 2000 rpm & held it there & the high side pressure just started gradually climbing (just like the Ford). I stopped revving then engine when the high side pressure got to about 275rpm (I recently topped up the AC & it works fine both during the day & in the evening).

If I kept revving the engine at 2000 rpm would I expect the pressure to keep climbing until the HPCO turned the compressor off?
I'm thinking that when driving, the airflow & fan are sufficient enough to cool the condenser & keep the pressure rising to where the HPCO cuts in...

[JohnHere]

If I increase my rpm to 1500-2000 rpm then I would expect my low side pressure to drop & my high side pressure to rise, correct?

Yes, but within limits. The low side should stay within the normally correct range while the high side will rise (but not continue to rise) based mainly on the ambient temperature in front of the grille. So if the ambient is, say 85°F, you should expect a high-side pressure of roughly 200-225 PSI.

If I kept revving the engine at 2000 rpm would I expect the pressure to keep climbing until the HPCO turned the compressor off?

Nope. If you have a situation in which the HP continues to rise until it bumps into the HPCO (around 405 PSI), then something is wrong, like an overcharge, air and moisture in the system, etcetera.

[tbirdtbird]

As always, John has it.
On Sept 30 you posted a chart and asked if that was a good guide. On the 30th and Oct 1, John and I replied , NO.

To clarify, the pressures we spec out are always taken at 1500-1800 RPM, not idle. This is the industry standard.

You seem like you want to improve your AC diagnostic acumen.
I would suggest that you step back into the archives one page at a time and read and understand all of the posts. There are some incredible sharpshooters on this forum, the best anywhere. You will learn a lot.
Good luck

[Autosaver]

Hi John & tbird,

I'm going to take some time to read through the forum but seeing as this is Ford Ranger related, I thought I'd shoot a few questions your way first.

Another Ford Ranger came in which another technician had previously recommended a fan clutch & dryer filter.

After the repair & test drive (all okay), I started the engine up (already warm) & stuck some gauges on it, with engine idling:
1. Low side 60psi, high side 215psi (vent temp 18C)
2. After 5-10 minutes: low side 55psi, high side 300psi (vent temp 17C)
3. After about another 10 minutes: low side 50psi, high side 380psi (vent temp ?)
4. Let the engine idle for another few minutes: low side 45psi, high side 220psi (vent temp 11C)

I'm thinking that at stage 2 heat from the engine is being transferred because engine temp. is going up.

What about stage 3 & 4? The condenser pressure just plummeted as if someone had poured a bucket of water on it! Engine idle stayed the same the whole time.

I'm pretty sure this compressor doesn't have a AC control valve. I did take a temperature reading of the section of pipe going to the high side service port (post condenser) & the pipe portion entering the TX valve. There was a 5C difference. Mind you my infrared thermometer was further from the high side service port pipe & closer to the pre TX valve pipe.

[tbirdtbird]

1. To review, from before,
"To clarify, the pressures we spec out are always taken at 1500-1800 RPM, not idle. This is the industry standard."
2. All your pressures are too high
3. Another tech suggested a new fan clutch. Agree.
Use your temp gun on the pipe into and out of the condenser, as close to the actual body of the condenser as possible. You need a 30°F temp drop.
5C is 41F so something is not right there. It is not clear to me exactly where you took your readings, a pic or 2 would help
4. You will end up evacuating the system and recharging to spec. It is very likely overcharged. Remember, that is all most "techs" know how to do
5. We hope no sealer has ever been added.

[JohnHere]

I agree that the pressures are too high.

Looking at the low side, there's no way you're going to achieve acceptable vent temperatures with the LP in the 45-60 PSI range. The HP side is also too high, suggesting a condensing problem.