1985 L98,No clossed loop.
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Instructor
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From: Crestwood Mo
1985 L98,No clossed loop.
1985 TPI,383, previously passed inspection but did not this year. Scanning found trouble code 52 - calpak missing. Replaced calpak, no help. Secondly in checking o2 sensor I'm getting a .425 voltage from ecm to o2 sensor. According to Motorbook's Chev fuel injection between .3 to .6 volts indicate a bad ecm.....Replaced the ecm with a Mid America rebuilt . Slightly different reading but still between .3 and .6. O2 ground wire is good, ground straps replaced, fuses replaced, pins on prom and calpak are good, o2 is new. I mean what else is there?????????????Who knows how to check ecm's? As you can see, I could use some help......
Team Owner
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From: Boston, MA
Re: 1985 L98,No clossed loop. (MrNuke)
calpack is the little board with the chip piggy backed on it..
Le Mans Master
Joined: Apr 2000
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From: Shelton CT
Re: 1985 L98,No clossed loop. (scorp508)
calpack is the little board with the chip piggy backed on it..
I know that, but the calpack also has the "other" chip in it with the limp home information. Thats why you still attach your original calpack to 1/2 of those EPROM adapters like Craig Moates makes. Was the 2nd chip in there too? They soldered on?
I know that, but the calpack also has the "other" chip in it with the limp home information. Thats why you still attach your original calpack to 1/2 of those EPROM adapters like Craig Moates makes. Was the 2nd chip in there too? They soldered on?
To replace chips on an '85 is just a cheesy chip. Gotta be real carefull not to screw the contacts/legs up when you put it in or pull it out..
[Modified by MrNuke, 7:50 PM 8/13/2003]
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From: Crestwood Mo
Re: 1985 L98,No clossed loop. (MrNuke)
The larger chip in the ecm is the prom. The second chip is smaller and is designated as the calpak serial number 16042437. Of main concern however is why is it not going into closed loop???????
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Racer
Joined: Mar 2001
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From: woodstock, Ga
Re: 1985 L98,No clossed loop. (62k)
what kind of scanner are you using, auto xray will give you that cal pac message and it is not the problem, any other codes, check eng light on????that ecm has a prom in it
Racer
Joined: Mar 2001
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From: woodstock, Ga
Re: 1985 L98,No clossed loop. (62k)
ps, one other thing, that 85 has a burn off module behind the bread box, be sure it is going through the burn off cycle when you shut it down, see if the wires light up in the MAF sensor??? mine ran very rich, heavy fuel smell, burn off was not working ........
Pro
Joined: Jul 2002
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From: Yukon OK
Re: 1985 L98,No clossed loop. (62k)
I use an AutoXray on my 85 and have also had the Calpak code show up. A good Vette mechanic here checked it out with his professional equipment and found no problem, so I just ignore it.
Also, on my 85 the AC/Requested, Park/Neutral detected, Block Learn, Cross Count and MAT do not read correctly. If I configure the scanner to VIN code L instead of 8 then I get correct readings on AC/Requested, Park/Neutral detected, Block Learn, and Cross Count. But still no MAT. Also, with it set for VIN code L it does not read all of the original information. So I go back and forth.
Been exchanging messages with the tech department at AutoXray and so far they have not resolved the issue.
One issue with Closed loop is the temperature of the engine. How warm is your engine when you are testing it?
Also, on my 85 the AC/Requested, Park/Neutral detected, Block Learn, Cross Count and MAT do not read correctly. If I configure the scanner to VIN code L instead of 8 then I get correct readings on AC/Requested, Park/Neutral detected, Block Learn, and Cross Count. But still no MAT. Also, with it set for VIN code L it does not read all of the original information. So I go back and forth.
Been exchanging messages with the tech department at AutoXray and so far they have not resolved the issue.
One issue with Closed loop is the temperature of the engine. How warm is your engine when you are testing it?
Pro
Joined: Jun 2003
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From: OKC OK
Re: 1985 L98,No clossed loop. (frank moran)
ps, one other thing, that 85 has a burn off module behind the bread box, be sure it is going through the burn off cycle when you shut it down, see if the wires light up in the MAF sensor??? mine ran very rich, heavy fuel smell, burn off was not working ........
Update...the MAF burnoff is working...how cool is that?! I used a mirror and while it was running gently disconnected the maf from the air cleaner ducting and put a mirror at an angle so I could see the front of the MAF from the driver seat and turned off the ignition...seconds later...light show!
When I was in the dash I thought I found the burnoff module...another black box about the size of a pack of cigarettes with a wiring harness attached. It wasn't mounted to anything (previous owners handy work) and I couldn't see where it might belong so it's snugged in there loosely. It still works!
[Modified by MtlSphere, 6:04 AM 8/14/2003]
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Instructor
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From: Crestwood Mo
Re: 1985 L98,No clossed loop. (LaVidaLoca)
Temperature. I had a 175 degree thermo to accomodate my TPS prom so I changed to a 185 - no help. The engine need only to be 140 to go into closed loop. Again, I'm getting a .425 volt reading with the ignition FROM THE ECM TO THE o2 sensor instead of the other way around. There should be no voltage coming from the ecm. This is a Mid America rebuilt could it be defunct as well????? Anyone out there know of someone or company that works on ecm's Appreciate the info thus far...thanks.
Drifting
Joined: Nov 2001
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From: Latham NY
Re: 1985 L98,No clossed loop. (62k)
another black box about the size of a pack of cigarettes with a wiring harness attached
Going into closed loop is a function of several parameters. Time and temp are two of them. There are two temperature sensors. The sensor between cylinders 1+3 is for the dash display only. The sensor the ecm uses is in front of the intake manifold next to the cold start injector switch. Your scan tool reads the Intake manifold sensor. I have the parameters for going into closed loop read from the stock chip at home and I will post them tonight.
Pro
Joined: Dec 2000
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From: Farmington NY
Re: 1985 L98,No clossed loop. (62k)
I had the same problem and couldn't figure it out. It was pinging horribly under hard load but ran well otherwise. The timing was way off and since then has been pretty good. I've encountered some other issues in the last week with an ESC error which is odd, I drive 15K every summer and have had to replace one twice, once last year and once the year before!! Something else must be going on to cause that! Good luck I know I need it!
