Pennock's Fiero Forum
  Technical Discussion & Questions
  AC System Troubleshooting - Fix requested

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
AC System Troubleshooting - Fix requested by altownsend
Started on: 10-17-2020 10:04 AM
Replies: 3 (64 views)
Last post by: Raydar on 10-18-2020 11:52 AM
altownsend
Member
Posts: 76
From: MISSOURI CITY
Registered: Sep 2019


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-17-2020 10:04 AM Click Here to See the Profile for altownsendClick Here to Email altownsendSend a Private Message to altownsendEdit/Delete MessageReply w/QuoteDirect Link to This Post
1986 Fiero, V6 Manual was converted to 134a, by me, in September 2020.

The system is sealed and holding a charge, however, slightly over charged.

The compressor does not activate when I turn the AC on.

New fuel pump and AC relays, fuses checked and are good

I jumped the wires at the accumulator, and the compressor did not activate. There is about 10 volts reading between the two wires (with engine running and AC on)

I tapped into the electrical line to the compressor, 12 VDC, with the engine running, AC on, the compressor activates, cold air from the AC.

Issue: Jumping the wires at the accumulator does not activate compressor, engine running, AC on
Issue: Running 12 VDC directly to compressor, engine running, AC on activates the compressor, cold air

Note: After converting to 134a, AC did not come on as expected, I had to run 12 VDC to the compressor. The engine stalled, seemingly as the drag on the engine after activating the compressor caused the engine to stall. After a few tries, the compressor seemed to suck oil through and worked just fine with the engine running, cold AC, but, again, the compressor does not perform as the AC system is designed to operate by simply turning it on, wires connected to accumulator.

No voltage reading at the compressor wire with system on, engine running.

Anyone know what my fix is?
IP: Logged
PFF
System Bot
Shho13
Member
Posts: 835
From: North Jersey
Registered: Feb 2014


Feedback score: (5)
Leave feedback

Rate this member

Report this Post10-17-2020 10:44 AM Click Here to See the Profile for Shho13Click Here to Email Shho13Send a Private Message to Shho13Edit/Delete MessageReply w/QuoteDirect Link to This Post
I've tried to jump the terminals on the low pressure switch on the accumulator and not have it work, either... Issue is that sometimes the connection when jumping is finicky and you gotta squeeze the paperclip you're using as a jumper to hit the terminals in that connector in such a way for it to make the connection.

-When you did the R132 conversion, did you change the pressure on the Low Pressure Switch by calibrating it with the screw, or did you replace it with a new one that was already set?

-Overcharged? I hope you don't mean overcharged in more than the amount the sticker says it needs in an R-12 charge... You're supposed to put about 20% less R134 in with the conversion.


------------------
"Discord"
Red 1988 GT under restoration!

Let's Go Mets!

( ͡° ͜ʖ ͡°)

IP: Logged
altownsend
Member
Posts: 76
From: MISSOURI CITY
Registered: Sep 2019


Feedback score: N/A
Leave feedback

Rate this member

Report this Post10-18-2020 10:16 AM Click Here to See the Profile for altownsendClick Here to Email altownsendSend a Private Message to altownsendEdit/Delete MessageReply w/QuoteDirect Link to This Post
I will re-test with the jumper at the accumulator.

I did not adjust the new pressure switch. Tell me more about how to do this. I do see the screw, however have never known how to adjust it. Please share.

The fill was done with instructions from the online discussions, and from the recommended instructions from EZ Chill.

Right now, today, October 18, the charge is holding, when I jump the compressor with 12 VDC, it activates, and I get cold air. Not just cool air. It feels like you open your freezer on a hot day.

So, my take-away from your response is the following:

1) Re-test the jumper at the accumulator
2) Confirm refrigerant level

If there is anything else that you know that might be a fix, please share - thanks
IP: Logged
Raydar
Member
Posts: 38514
From: Carrollton GA. Out in the... country.
Registered: Oct 1999


Feedback score:    (11)
Leave feedback





Total ratings: 451
Rate this member

Report this Post10-18-2020 11:52 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you jumper the connector at the accumulator, and nothing happens, adjusting the switch will not change anything.

There is a high pressure switch on the back of the compressor. If that switch is bad (or has a bad connection) it could cause your compressor to not kick on.
(Too much refrigerant will not cause the switch to trip. It isn't supposed to activate until it reaches several hundred lbs.)
I believe the high pressure switch is "normally closed". Too much pressure will cause it to open (switch off) and drop the signal to the compressor clutch.

...or you may just have a bad A/C relay. It's on the firewall, behind the driver, right next to the fuel pump relay. (I forget which is which.)

[This message has been edited by Raydar (edited 10-18-2020).]

IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock