Notices
1999 - 2003 7.3L Power Stroke Diesel  
Sponsored by:
Sponsored by: DP Tuner

interesting AC issue

Thread Tools
 
Search this Thread
 
Old Aug 22, 2017 | 03:04 PM
  #1  
carl2591's Avatar
carl2591
Thread Starter
|
Fleet Mechanic
20 Year Member
Liked
Loved
Community Favorite
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
interesting AC issue

SO after reading about the air gap on AC compressor i checked mine and it was large so I removed the shim and the gap was almost like new..

Now when i first switch on AC the compressor will click on and off several times especially at any RPM above 1000.

I hooked up hoses and tried it again with wife holding RPM at 1200. The high side would bounce from 100 to 400, compressor would cycle off and then back on in quick secession with high side bouncing back and forth for 10 seconds or if she let off pedal back to idle RPM.. low side was not moving a lot at this point but not bouncing like the high side

any idea what can be causing the pressure issue.. when it stabilizes the pressures are right on for OD temp accoding to charging chart for R-134a.
 
Reply
Old Aug 22, 2017 | 03:19 PM
  #2  
Colorado350's Avatar
Colorado350
Postmaster
Joined: Nov 2015
Posts: 4,807
Likes: 125
From: Colorado Springs
You are seeing the clutch actually turning? Are you using an AC charger that connects to BOTH sides of the system? If you are, make sure both valves are on, turn AC on Max Cold, then let compressor cycle a few times. I've seen it take 5 minutes or better for the pressures to equalize and get a good reading.
 
Reply
Old Aug 22, 2017 | 04:30 PM
  #3  
carl2591's Avatar
carl2591
Thread Starter
|
Fleet Mechanic
20 Year Member
Liked
Loved
Community Favorite
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
Originally Posted by Colorado350
You are seeing the clutch actually turning?

Are you using an AC charger that connects to BOTH sides of the system? If you are, make sure both valves are on, turn AC on Max Cold, then let compressor cycle a few times. I've seen it take 5 minutes or better for the pressures to equalize and get a good reading.
yes clutch is turning then as the pressure goes above 400 to shuts off and then back on and then off..

Yes using hvac hoses with r-134a adapters.. and yes both handles are closed.. (hvac service background 5 yrs)

I have service cars ac's before and have not seen one with so much pressure fluctuations.

wondering if the filter thing in return line is some what clogged? not sure why the high pressure but it will smooth out in 15 to 20 seconds.
 
Reply
Old Aug 22, 2017 | 06:05 PM
  #4  
shortblockchevy's Avatar
shortblockchevy
Junior User
Joined: Jul 2015
Posts: 90
Likes: 0
Sounds like the orifice tube may be blocked. Do you have a way to recover and vacuum the system down?
 
Reply
Old Aug 22, 2017 | 06:21 PM
  #5  
Colorado350's Avatar
Colorado350
Postmaster
Joined: Nov 2015
Posts: 4,807
Likes: 125
From: Colorado Springs
Originally Posted by carl2591
yes clutch is turning then as the pressure goes above 400 to shuts off and then back on and then off..

Yes using hvac hoses with r-134a adapters.. and yes both handles are closed.. (hvac service background 5 yrs)

I have service cars ac's before and have not seen one with so much pressure fluctuations.

wondering if the filter thing in return line is some what clogged? not sure why the high pressure but it will smooth out in 15 to 20 seconds.
I wasn't implying that you don't know what you're doing just offering suggestions.

You meant both handles are open right? I replaced my compressor, accumulator dryer and the orifice tube (filter) last summer. The orifice tube had to be the original, there was even several pieces of leaves on it, yes leaves! The system seemed to work alright with it being as full as it was... The OT is only a couple of dollars but you'll have to recharge your system.

What happens if you leave the gauges hooked up, and just let the compressor cycle for 10 minutes?
 
Reply
Old Aug 22, 2017 | 06:25 PM
  #6  
timmyboy76's Avatar
timmyboy76
Lead Driver
Joined: Sep 2010
Posts: 7,793
Likes: 50
Mine was doing that at the start of summer. Installed a new ac clutch assy, set gap at .030, and alls good
 
Reply
Old Aug 22, 2017 | 06:52 PM
  #7  
carl2591's Avatar
carl2591
Thread Starter
|
Fleet Mechanic
20 Year Member
Liked
Loved
Community Favorite
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
Originally Posted by Colorado350
I wasn't implying that you don't know what you're doing just offering suggestions.

You meant both handles are open right? I replaced my compressor, accumulator dryer and the orifice tube (filter) last summer. The orifice tube had to be the original, there was even several pieces of leaves on it, yes leaves! The system seemed to work alright with it being as full as it was... The OT is only a couple of dollars but you'll have to recharge your system.

What happens if you leave the gauges hooked up, and just let the compressor cycle for 10 minutes?
no worries.. why accumulator replace? they are just a liquid container for the system to prevent it flooding the compressor?

no the gauges ports/handles are closed during this time.. only time the gauges ports are open is to vacuum out system, or to add freon on the low side.

When the system quite cycling the pressures then started to look more normal. The high side would then drop down to 150ish psi and then start to raise to normal pressure for the temp which was around 85 deg

yes I do have a way to evacuate the system and vacuum pump. Guess i need to watch video on how to remove the strainer in the suction line and give that a try.. if the suction was restricted that would prevent the high side from increasing in pressure it would seem not the other way around?
 
Reply
Old Aug 22, 2017 | 07:22 PM
  #8  
Colorado350's Avatar
Colorado350
Postmaster
Joined: Nov 2015
Posts: 4,807
Likes: 125
From: Colorado Springs
Originally Posted by carl2591
no worries.. why accumulator replace? they are just a liquid container for the system to prevent it flooding the compressor?

no the gauges ports/handles are closed during this time.. only time the gauges ports are open is to vacuum out system, or to add freon on the low side.

When the system quite cycling the pressures then started to look more normal. The high side would then drop down to 150ish psi and then start to raise to normal pressure for the temp which was around 85 deg

yes I do have a way to evacuate the system and vacuum pump. Guess i need to watch video on how to remove the strainer in the suction line and give that a try.. if the suction was restricted that would prevent the high side from increasing in pressure it would seem not the other way around?
I bought the kit off eBay for $170ish for everything, truck has 350K so I just replaced everything except the condenser.
https://www.ebay.com/itm/120622861252

New AC Compressor & Clutch W/ Complete A/C Repair Kit For Ford Powerstroke 7.3L
-----------

Ok, maybe we're talking about two different handles? On your gauge You use the quick release Fittings to clamp onto the high and low pressure side, and then there's two handles that allow the pressure from the system to reach the gauges. I'm referring to those two handles. They need to be open So you're actually getting the pressure from both sides as it cycles . Hopefully I'm being clear?

Another thought, do you have enough oil in your compressor?
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-1

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-2

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-3

Every 2026 Ford Engine Explained

 Brett Foote
story-4

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-5

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-6

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-7

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-8

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-9

Top 10 Ford Truck Tragedies

 Joe Kucinski
Old Aug 22, 2017 | 07:38 PM
  #9  
The Brad's Avatar
The Brad
Laughing Gas
10 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Nov 2013
Posts: 868
Likes: 1
From: SoCal
Originally Posted by Colorado350
I bought the kit off eBay for $170ish for everything, truck has 350K so I just replaced everything except the condenser.
https://www.ebay.com/itm/120622861252


Another thought, do you have enough oil in your compressor?
I replaced everything but the condenser, and the orifice clogged again after a year. It's not easy to get the condenser completely flushed out. If the problem is a clogged orifice, then its best to replace the condenser too.

I'm not sure about an auto application, but in a building AC, short cycling the can migrate the oil away from the compressor.
 
Reply
Old Aug 22, 2017 | 07:48 PM
  #10  
carl2591's Avatar
carl2591
Thread Starter
|
Fleet Mechanic
20 Year Member
Liked
Loved
Community Favorite
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
is there not a filter you can install to catch the material like on home AC system we install a filter on the liquid line to filter the freon after replacing something like a compressor or in a heat pump the reversing valve. seem like
it might be a good idea like show the issues can return.
 
Reply
Old Aug 22, 2017 | 07:55 PM
  #11  
carl2591's Avatar
carl2591
Thread Starter
|
Fleet Mechanic
20 Year Member
Liked
Loved
Community Favorite
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
Originally Posted by Colorado350
I bought the kit off eBay for $170ish for everything, truck has 350K so I just replaced everything except the condenser.
https://www.ebay.com/itm/120622861252

New AC Compressor & Clutch W/ Complete A/C Repair Kit For Ford Powerstroke 7.3L
-----------

Ok, maybe we're talking about two different handles? On your gauge You use the quick release Fittings to clamp onto the high and low pressure side, and then there's two handles that allow the pressure from the system to reach the gauges. I'm referring to those two handles. They need to be open So you're actually getting the pressure from both sides as it cycles . Hopefully I'm being clear?

Another thought, do you have enough oil in your compressor?
on my set there is no handle to turn on or off the fittings.. they are just screwed on the end of my regular hose fittings but i do know what you are referring to now that you mention it.

I would guess the oil level is fine as there has not been a leak.

once it settles down and pressure get stable it does cool but not all that well, getting something like 20ish degrees over the coil... I have tried to remove gas and add gas and checking the temp pressure chart.

is there a kit that does not include the compressor.. mine seem good,, it pumps and all.. just need accumulator, orings and some oil.
 
Reply
Old Aug 22, 2017 | 08:27 PM
  #12  
Colorado350's Avatar
Colorado350
Postmaster
Joined: Nov 2015
Posts: 4,807
Likes: 125
From: Colorado Springs
Originally Posted by carl2591
on my set there is no handle to turn on or off the fittings.. they are just screwed on the end of my regular hose fittings but i do know what you are referring to now that you mention it.

I would guess the oil level is fine as there has not been a leak.

once it settles down and pressure get stable it does cool but not all that well, getting something like 20ish degrees over the coil... I have tried to remove gas and add gas and checking the temp pressure chart.

is there a kit that does not include the compressor.. mine seem good,, it pumps and all.. just need accumulator, orings and some oil.
At least we're on the same page, LOL
How's this look?


Look at this on eBay:

https://www.ebay.com/itm/162640693676

AC Accumulator Kit 1999-2003 F250 F350 F450 F550 V8 7.3L Powerstroke Diesel
 
Reply
Old Aug 22, 2017 | 08:32 PM
  #13  
carl2591's Avatar
carl2591
Thread Starter
|
Fleet Mechanic
20 Year Member
Liked
Loved
Community Favorite
Joined: Nov 2005
Posts: 1,508
Likes: 87
From: North Carolina, Raleigh
Originally Posted by Colorado350
At least we're on the same page, LOL
How's this look?


Look at this on eBay:

https://www.ebay.com/itm/162640693676

AC Accumulator Kit 1999-2003 F250 F350 F450 F550 V8 7.3L Powerstroke Diesel
bingo... that looks like the deal.. how long ago did you do yours. any issues or problems. do they have instruction or is there a video on this process?

looks like a lot of oring to replace.

thanks man
 
Reply
Old Aug 22, 2017 | 08:40 PM
  #14  
The Brad's Avatar
The Brad
Laughing Gas
10 Year Member
Photogenic
Photoriffic
Shutterbug
Joined: Nov 2013
Posts: 868
Likes: 1
From: SoCal
Originally Posted by carl2591
is there not a filter you can install to catch the material like on home AC system we install a filter on the liquid line to filter the freon after replacing something like a compressor or in a heat pump the reversing valve. seem like
it might be a good idea like show the issues can return.
The orifice has a screen on it. I'm not sure if there's any media in the accumulator.


 
Reply
Old Aug 22, 2017 | 08:56 PM
  #15  
Colorado350's Avatar
Colorado350
Postmaster
Joined: Nov 2015
Posts: 4,807
Likes: 125
From: Colorado Springs
Originally Posted by carl2591
bingo... that looks like the deal.. how long ago did you do yours. any issues or problems. do they have instruction or is there a video on this process?

looks like a lot of oring to replace.

thanks man

Last summer, depressurize the system, unbolt, vaseline on new orings, recharge it. Be very careful with the low pressure sensor, which screws in the accumulator. I cracked the sensor, ford has a replacement that requires a new pigtail...this sensor IMO doesn't work with the 7.3L...I've tried 2! My compressor turns on even when the switch in the cab is not on AC or AC max, been trying to find a 7.3 with the original sensor and pigtail that I can salvage. But overall the job is very easy.
 
Reply



All times are GMT -5. The time now is 02:13 AM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE