1985, no close loop
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From: Crestwood Mo
1985, no close loop
Does not pass emissions because it will not go into close loop. Replaced o2 sensor. O2 wire from ECM is good.Continue to get a .39 volts from ECM so it was replaced, same reading. Have checked all grounds,checked and or replaced fuses. Continue to get trouble code 52 calibration pack missing. Also, 54 fuel pump failure even though the relay was replaced.. Major dilemma here...anyone?????????
Drifting
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From: Latham NY
Re: 1985, no close loop (62k)
I would drop the ecm and open the access cover. There are two chips there. Disconnect the battery cable. Remove and reinsert the two chips. Reconnect battery and see if all is well. If not, could be bad chip or more likely you're ecm is dead.
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From: SE NY
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Re: 1985, no close loop (62k)
It sounds like a problem with the ECM or chip.
Also the coolant temp sensor in the front of the block under the TB could be bad.
Four things are required for closed loop:
-time from startup
-coolant temp over about 145 deg F.
-O2 sensor at operating temp
-ECM & chip functioning correctly
Also the coolant temp sensor in the front of the block under the TB could be bad.
Four things are required for closed loop:
-time from startup
-coolant temp over about 145 deg F.
-O2 sensor at operating temp
-ECM & chip functioning correctly
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From: Crestwood Mo
Re: 1985, no close loop (montie98)
You're correct, there are two chips. The large one is the prom and the other is the calpak. Has anyone ever had the calpak malfunction? My prom was burned by TPS. The things we go threw day by day.....
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From: Farmington NY
Re: 1985, no close loop (62k)
I've encountered the same problem with the missing CalPac Code 52. I don't believe I'm going into open loop either (85 also) I only went to a 185 thermostat so it should get up to temp. My gauges say coolant gets up to temp also. I'm checking with an Auto xray which I've read is not very accurate with an 85. The other problem I encounter is that I have not cross counts from the O2 sensor. I've replaced it once but think I may have to try again. Any other suggestions?? Keep us up to date on your progress, thanks.
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From: Crestwood Mo
Re: 1985, no close loop (Gregory VanLare)
Greg:
Thanks for the reply. There has to be an answer for the problem. I've purchased a calpak prom from a Chev. dealer. Will let you know what I find.
I too changed to a higher thermo with no results. Iv'e also talked with two mechanic shops and one dealer shop. After explaining what I have done to resolve the problem they either scratch their heads or make it clear they are not interested in working on the Vet. Lastly, I have also checked or replaced the ground straps - nothing....
Thanks for the reply. There has to be an answer for the problem. I've purchased a calpak prom from a Chev. dealer. Will let you know what I find.
I too changed to a higher thermo with no results. Iv'e also talked with two mechanic shops and one dealer shop. After explaining what I have done to resolve the problem they either scratch their heads or make it clear they are not interested in working on the Vet. Lastly, I have also checked or replaced the ground straps - nothing....
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From: St Louis MO
Re: 1985, no close loop (62k)
Greg:
I've purchased a calpak prom from a Chev. dealer.
I've purchased a calpak prom from a Chev. dealer.
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From: St Louis MO
Re: 1985, no close loop (MrNuke)
What and where is the calpack on the '85?
I only see one chip in the ECM.
I only see one chip in the ECM.
memcal:
http://www.thirdgen.org/newdesign/te...om/1138118.jpg
with cover removed, the prom is the chip on the left:
http://www.thirdgen.org/newdesign/te...om/1138119.jpg
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From: SE NY
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Re: 1985, no close loop (62k)
OK, lets start with an easy one...that code 54, fuel pump circuit.
Connect a DMM between ALDL pin "G" and ground and turn the ignition on; you should see about +12Vdc for 2sec.
If so start the engine and repeat the check at pin "G"; if not service the oil pressure switch.
If so repeat the ignition on check at pin B2 of the ECM connector; if not repeat the test at pin "A" of the fuel pump relay.
Now to the code 52, Calpack Error issue.
Use a small flat blade screw driver to carefully remove the EPROM from it's socket. Straighten any bent pins and carefully install it back into it's socket.
Clear all codes and use the method on my site to put the ECM into diagnostic mode and check for closed loop operation at idle and say at a steady 2,000rpm.
For the O2 sensor issue; it provides between .1-1.0Vdc to the ECM when above operating temp. The voltage should switch between high & low values in closed loop. The low value indicates lean, so the ECM adds fuel; the high value indicates rich so the ECM subtracts fuel. Typically the O2 sensor will switch between about .3Vdc and .9Vdc.
Connect a DMM between ALDL pin "G" and ground and turn the ignition on; you should see about +12Vdc for 2sec.
If so start the engine and repeat the check at pin "G"; if not service the oil pressure switch.
If so repeat the ignition on check at pin B2 of the ECM connector; if not repeat the test at pin "A" of the fuel pump relay.
Now to the code 52, Calpack Error issue.
Use a small flat blade screw driver to carefully remove the EPROM from it's socket. Straighten any bent pins and carefully install it back into it's socket.
Clear all codes and use the method on my site to put the ECM into diagnostic mode and check for closed loop operation at idle and say at a steady 2,000rpm.
For the O2 sensor issue; it provides between .1-1.0Vdc to the ECM when above operating temp. The voltage should switch between high & low values in closed loop. The low value indicates lean, so the ECM adds fuel; the high value indicates rich so the ECM subtracts fuel. Typically the O2 sensor will switch between about .3Vdc and .9Vdc.
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From: Crestwood Mo
Re: 1985, no close loop (65Z01)
Thank you. I'll work first with code 51 as per your suggestion. The second problem is different. Regardless of how long I run the engine or at what rpm it will not go into close loop. This makes it impossible to scan the o2 sensor.
I'm definitely open and welcome suggestions. Shops in the St. Louis area are less than helpful especially if you explain what you have experienced and tried to date......
[Modified by 62k, 10:37 PM 5/31/2003]
I'm definitely open and welcome suggestions. Shops in the St. Louis area are less than helpful especially if you explain what you have experienced and tried to date......
[Modified by 62k, 10:37 PM 5/31/2003]
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From: Farmington NY
Re: 1985, no close loop (62k)
I went to my local Chevy dealer, trying to find a CalPac and they told me they were no longer available and I wouldn't be able to replace it! I'm now going to pull my ECM and make sure each of the proms are properly seated. I did replace my chip with one I had burned by a forum member a couple of years ago to go with my 185 thermostat. I had never checked for closed loop after that so don't know if when i put it in something happened. I'll let you know.
greg
greg
