85: what do these codes indicate?
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by Pete K
33-mass air power
34-mass air burnoff
43-knock sensor
45-I forget
34-mass air burnoff
43-knock sensor
45-I forget
33 is MAF Sensor Signal Voltage High
34 is MAF Sensor Signal Voltage Low
43 is Electronic Spark Control
45 is Rich Exhaust Indication
These are out of the 86 Shop Manual. I don't try to memorize the code meanings, old age gives bad memory. LOL
Jake
Last edited by JAKE; Mar 12, 2005 at 08:47 PM.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by jerander
thank you for your help. Now I need to try and figgure out what I need to fix.
Well, looks like you definitely need a MAF.
I'd first make sure the MAF is plugged in.
Then try borrowing one from a friend with the same MAF. Many 'F' body cars use the same MAF, Firebirds/Trans Ams and Camaros.
Then install the new/borrowed MAF, clear the codes by disconnecting the battery for about 30 seconds, and see if any code returns when you start the engine.
Your MAF codes should be gone, but you may still have the other two.
The 43 code could be the knock sensor itself, or the ESC module mounted on the passenger side of the car outboard of the A/C box. It's flat, about half the size of a pack of cigarettes.
The knock sensor is screwed into the block on the passenger side, too, back between about #6 and #8 cylinders. It'll be in the block, not the head. See if it's plugged in.
There's a step by step procedure for sorting out which one it is. I can walk you through it if the time comes you need it.
The rich exhaust indication code is a result of the other sensors not working properly.
You never know, maybe a working MAF will solve all those issues.
Jake
Last edited by JAKE; Mar 12, 2005 at 08:59 PM.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
A disconnected knock sensor won't cause a code on an '85. Mine on my '84 has been disconnected for years...on purpose. It's time for the commercial. You really need a Factory Service Manual to decipher the codes, trace them down, and trouble shoot the questionable components, to prevent replacing good parts.
RACE ON!!!
RACE ON!!!
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
[SNIP=CFI-EFI]A disconnected knock sensor won't cause a code on an '85. Mine on my '84 has been disconnected for years...on purpose. It's time for the commercial. RACE ON!!![/SNIP]
Okay, if the 85 won't set a code with the KS disconnected, what if it's connected but malfunctioning or not functioning at all. Will that set a code?
If not, will a bad ESC module set a code?
What if both are bad, will that set a code?
If not, are we talking ECM problems?
Jake
Okay, if the 85 won't set a code with the KS disconnected, what if it's connected but malfunctioning or not functioning at all. Will that set a code?
If not, will a bad ESC module set a code?
What if both are bad, will that set a code?
If not, are we talking ECM problems?
Jake
Last edited by JAKE; Mar 13, 2005 at 02:25 AM.
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Team Owner
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From: Athens AL
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#1 fix is the MAF relay, on 85 the burnoff module is rather expensive and is buried within the dash unit.
Its not behind the battery on the firewall like later years, 85 is different.
Then clear and see what comes back, if MAF comes back then replace the MAF sensor. Theres a good chance that fixing one thing will kill the rest of the codes. For example, the faulty MAF system would cause the Code 45 to set because of the MAF bad Air input to the computer.
Its not behind the battery on the firewall like later years, 85 is different.
Then clear and see what comes back, if MAF comes back then replace the MAF sensor. Theres a good chance that fixing one thing will kill the rest of the codes. For example, the faulty MAF system would cause the Code 45 to set because of the MAF bad Air input to the computer.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
I too own an 85. My suggestion is to sell the car and buy a 67 427/435. It just so happens the 85's are worth the most of all the C4's, by far. I read this out of the famed book, "I had a Dream", so it must be true.
Team Owner
Joined: Aug 1999
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St. Jude Donor '10
Originally Posted by CFI-EFI
A disconnected knock sensor won't cause a code on an '85. Mine on my '84 has been disconnected for years...on purpose. It's time for the commercial. You really need a Factory Service Manual to decipher the codes, trace them down, and trouble shoot the questionable components, to prevent replacing good parts.
RACE ON!!!
RACE ON!!!
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by SurfnSun
My 85 threw a code when the knock sensor was disconnected.
I'll have to take the word of those more familar than I am with the 85.
Jake
Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 3,003
Likes: 0
thank you all for the help.
here is what my car is doing.
It only run right if there is fuel injector cleaner (techron) in the tank. Other wise it will not idle right(unless been on for a while), no power before 2000rpms(lots of pops, and very jerky). runs fine if the rpms are over 2000(or I have been driving for a while then it will come and go). will not start sometimes unless i'm giving it gas. One time it started misbehaving(jerky, loosing power) when i was doing a constant 65 mph(raining hard at the time). Every time this happens the check engine light comes on. there is a very strong fuel smell whenever problem is accuring
here is what my car is doing.
It only run right if there is fuel injector cleaner (techron) in the tank. Other wise it will not idle right(unless been on for a while), no power before 2000rpms(lots of pops, and very jerky). runs fine if the rpms are over 2000(or I have been driving for a while then it will come and go). will not start sometimes unless i'm giving it gas. One time it started misbehaving(jerky, loosing power) when i was doing a constant 65 mph(raining hard at the time). Every time this happens the check engine light comes on. there is a very strong fuel smell whenever problem is accuring
Instructor
Joined: Jan 2005
Posts: 141
Likes: 0
From: Tucson AZ
I have an '85 also
On mine, the MAF power relay and the burnoff relay are both by the battery. They are about $25 for the pair. You should replace them if you replace the MAF. You may need to replace them anyway. I replaced my MAF with a rebuilt from Autozone. It was $150. The first one threw codes and acted funny. They warranteed it and the replacement runs perfect.
Maybe you should look around at a few other things while you're at it. Maybe see if there is any indication of vacuum or induction leaks, primary ignition wires worn and leaking electricity, etc.....,
Maybe you should look around at a few other things while you're at it. Maybe see if there is any indication of vacuum or induction leaks, primary ignition wires worn and leaking electricity, etc.....,
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by JAKE
[SNIP=CFI-EFI]A disconnected knock sensor won't cause a code on an '85. Mine on my '84 has been disconnected for years...on purpose. It's time for the commercial. RACE ON!!![/SNIP]
Okay, if the 85 won't set a code with the KS disconnected, what if it's connected but malfunctioning or not functioning at all. Will that set a code?
If not, will a bad ESC module set a code?
What if both are bad, will that set a code?
If not, are we talking ECM problems?
Jake
Okay, if the 85 won't set a code with the KS disconnected, what if it's connected but malfunctioning or not functioning at all. Will that set a code?
If not, will a bad ESC module set a code?
What if both are bad, will that set a code?
If not, are we talking ECM problems?
Jake
"Code 43 means the ECM has seen low voltage at CKT, terminal "4" in the white ECM connector, for longer than 4 seconds with the engine running.
This voltage drops when the ESC module shuts off because it receives a knock signal.
1. The ESC module supplies voltage to the ECM. It should always over 6 volts unless the system is sensing engine detonation.
2. Checks (the test in the trouble shooting chart on the following page) for intermittent ESC operation. If the voltage is now over 6 volts, it is faulty ESC terminal C connection or ESC module." The non-italicized, parenthetical statement, is my own insertion.
When the knock sensor is activated (by a knock), circuit 496 from terminal E of the ESC is grounded, through the knock sensor to the block. That causes the ESC to drop the voltage on circuit 485 from the ESC terminal C, to ECM terminal 4, to below 6 volts. As the manual states, if this lasts for more than 4 seconds, code 43 is set.This voltage drops when the ESC module shuts off because it receives a knock signal.
1. The ESC module supplies voltage to the ECM. It should always over 6 volts unless the system is sensing engine detonation.
2. Checks (the test in the trouble shooting chart on the following page) for intermittent ESC operation. If the voltage is now over 6 volts, it is faulty ESC terminal C connection or ESC module." The non-italicized, parenthetical statement, is my own insertion.
With the knock sensor disconnected, circuit 496 cannot become grounded by a knock signal, and the 6 volt signal on circuit 485 will remain uninterrupted. And therefore, no code set.
Make sense?
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Jan 2005
Posts: 3,003
Likes: 0
Originally Posted by flylowguy
On mine, the MAF power relay and the burnoff relay are both by the battery. They are about $25 for the pair. You should replace them if you replace the MAF. You may need to replace them anyway. I replaced my MAF with a rebuilt from Autozone. It was $150. The first one threw codes and acted funny. They warranteed it and the replacement runs perfect.
Maybe you should look around at a few other things while you're at it. Maybe see if there is any indication of vacuum or induction leaks, primary ignition wires worn and leaking electricity, etc.....,
Maybe you should look around at a few other things while you're at it. Maybe see if there is any indication of vacuum or induction leaks, primary ignition wires worn and leaking electricity, etc.....,
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by jerander
how hard is it to change the relays and the MAF?
I'm told that one of the MAF relays on the 85 is behind the dash, so you're looking at maybe an hour for that one. The other one inside the engine compartment, maybe 20 minutes or so.
This is all ball-park based on the times I've had to tear into my dash and relay locations.
Jake