Hey guys,

I spent all last night and most of today changing the water pump and smog pump on my 84 Trans Am. However, once the car gets up to operating temp, the check engine light comes on. If I let it cool down, the light goes out...until it warms back up. I can't figure out why. I've checked all my wiring...I had to replace a plug on the Smog pump diverter (Thing that all the A.I.R. hoses run to off the headers and cat), but that was a simple two-wire affair (I broke the plastic around the leads). The only things that are different now, than when I took it apart, are the new smog pump, new water pump, and I switched the vaccum port and thermostat sensor oin my intake manifold around so the vaccum lines wouldn't hit the air cleaner. I put all new check-valves on the A.I.R. tubes coming from my headers and cat, and new hoses also. What am I missing? All the Vac-lines have a place to be plugged in (Except for one which went down to a valve on my old original exhaust manifold that I blocked off--would I be better off not blocking it off?), all the heater hoses, exhaust hoses and all that are hooked up... two hours so far checking something, running the car up, shutting it down...rinse and repeat. I'm getting very fed up with it.

Just a note, I did have the headers installed prior to replacing the smog pump and everything was working fine. Maybe by putting an actual working smog pump on(?) or the new (working) check-valves freaked the computer out a bit? Thanks for any imput you can provide.

 

The first thing that I'd suggest is getting the code that being thrown. Most likely it'll be related to the egr / exhaust system. I had this same condition in my RS. After you know the code, go from there.

 

Ok, but I don't even know where to get this code from. I"ve never had to deal with this type of thing before. My only other car was a 67 Camaro that well, I'm lucky it had lights on it. :P

 

Where do I look to find the error code on this problem?

 

You will need to get the computer scanned for codes. I have heard that a parts store like O`Reilly`s or Autozone can do this.

 

Alright, I'll check with Autozone and Advanced Auto Parts.

 

You don't need a scanner. Do a search for the ALDL paperclip trick.

 

you can do it yourself too, with a paperclip.
Q: How can I display the error codes from a Service Engine Light?
A: If your car does not have the 12 pin DLC connector, you may not be able to manually "flash" your trouble codes. The language "may be possible" appears to suggest that this method should work with most, if not all, 12 pin DLC equipped cars.
THE CONNECTOR
----------------------- | 1 2 3 4 5 6 | | 7 8 9 10 11 12 | -----------------------
DISPLAYING THE TROUBLE CODES
Run a wire/hairpin from Pin 6 to Pin 12 with the ignition off (although on later cars it should be from Pin 5 to Pin 6), then turning the ignition to the on position without starting the engine will flash the "Service Engine Soon" light in the following sequence: flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause Following this "12" code repeating three times will come any trouble codes stored, flashing each of them three times. If you do not see the "12" flash three times, your diagnostic circuit is defective. Some vehicles will display stored trouble codes, then "12" again, followed by energizing "most system controlled relays." The fuel pump relay will not energize. The idle air control valve will fully extend to enable checking minimum idle speed.
CLEARING THE TROUBLE CODES
Turn the keyswitch to the off position. To clear any trouble codes, disconnect the power feed for 30 seconds. If this is done at the battery, and your car stereo is equipped and programmed with a four digit pin code, you may have to re-enter that as well to use your stereo again. A better place to remove power is at the fuse.
TROUBLE CODES

12.No reference pulses to Electronic Control Module (ECM).
13.Oxygen sensor signal stays lean during warm engine cruise
14.High temperature indicated at engine coolant temp sensor
15.Low temperature indicated at engine coolant temp sensor
16.High battery voltage OR Direct inition system open or shorted to ground
17.RPM signal problem
18-20.N/A
21.High voltage at throttle positon sensor
22.Low voltage at throttle positon sensor OR Fuel cutoff relay circuit open or shorted to ground
23.Low temperature at manifold air temperature sensor OR Throttle position sensor error
24.Circuit fault in vehicle speed sensor
25.High temperature at manifold air temperature sensor OR Vacuum switching valve circuit open or shorted to ground OR High voltage at ATS sensor
26.Fault in quad driver module
27.Fault in 2nd gear switch
28.Fault in 3rd gear switch
29.Fault in 4th gear switch
30.N/A
31.Low voltage at manifold absolute pressure sensor OR Fuel injector OR Park or neutral switch OR CAM diagnostic OR Governor malfunction OR Wastegate overboost OR Wastegate eletrical signal open or shorted to ground
32.Fault in barometric pressure sensor circuit OR Fault in exhaust gas recirculation valve diagnostic switch OR Fault in electronic vacuum regulator valve
33.High voltage (low vacuum) at mass air flow sensor (or MAP sensor)
34.Low voltage (high vacuum) at mass air flow sensor (or MAP sensor)
35.Idle speed can not be set to desired RPM
36.Burn off at mass air flow sensor OR Problem in transmission shift OR Fault in direct ignition system OR Missing pulses in electronic spark timing signal
37.N/A
38.Fault in torque converter clutch brake switch
39.Fault in torque converter clutch circuit
40.N/A
41.Fault at cam sensor OR Cylinder select error OR Tach input error
42.Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit
43.Low voltage at electronic spark timing circuit
44.Oxygen sensor lean
45.Oxygen sensor rich
46.Fault at vehicle anti-theft sytem OR Fault at power steering switch
47.Problem at Electronic Control Module (ECM)
48.Misfire
49.Vacuum leak
50.N/A
51.PROM error
52.Problem at Electronic Control Module (ECM) - Missing fuel calpac missing OR Analog to digital converter error OR Fault at quad driver module OR Low voltage at oil temperature sensor
53.High voltage at battery OR High voltage at exhaust gas recirculation valve OR Voltage reference error OR Problem at vehicle anti-theft system
54.Low voltage at fuel pump OR Low voltage at Fuel pump relay OR Output failure at quad driver module
55.Problem at Electronic Control Module (ECM) - ECM failure OR Serial bus error OR Fuel lean malfunction
56.Low coolant or corrosivity OR Fault in port throttle system vacuum sensor
57.N/A
58.Problem at vehicle anti-theft system
59-60.N/A
61.Oxygen sensor degraded OR Port throttle system error OR Cruise control problems
62.Gear switch input diagnostics OR High voltage at oil temperature sensor OR Fault in cruise control- vacuum solenoid circuit
63.High voltage at manifold absolute pressure sensor OR Fault in exhaust gas recirculation valve OR Fault at right oxygen sensor
64.Low voltage at manifold absolute pressure sensor OR Fault in exhaust gas recirculation valve OR Right oxygen sensor lean
65.Failure at exhaust gas recirculation valve OR Faulure at injector peak/hold diagnostic OR Right oxygen sensor rich OR Fault at cruise control position sensor
66.Internal reset of Electronic Control Module (ECM)
67.Fault at cruise control switch
68.Fault at cruise control switch
69.Fault at air conditioner pressure switch
70-87.N/A
88.Internal reset of Electronic Control Module (ECM)
| 1 2 3 4 5 6 |
| 7 8 9 10 11 12 |

 

Thanks for the info guys, I really appreciate it. This is a carbureted car and I'm almost positive there wasn't an O2 sensor on it when I pulled the original manifolds (Could be mistaken, I've been wrong before) I'll try this and see what happens. It runs, and on the upside the Waterpump doesn't leak, just a stupid check engine light once it warms up. /sigh Why can't things just go on and work like they're supposed to? lol

 

Alright, this is a code "44" which means according to the people at Autozone who looked it up on their computer, that they car is trying to find a reading from the oxygen sensor but it either isn't getting a reading, or the reading isn't coming in time for the computer to sense it. Or, their guy said, I might just have a vacumm leak that's causing it to freak out as the light only comes on once the temp gets up around the normal driving temp (185*+).

Now, when I installed my headers, I don't ever recall seeing an O2 sensor anywhere on the original exhaust manifolds...where else could it be? ANyone out there with knowledge of where an O2 sensor on an 84 Pontiac Trans Am might be located?

 

Probably (was) near the exhaust junction area of the drivers side exhaust manifold. If the OE exhaust manifolds have been removed then the 02 sensor went with it... There should still be a single wire connector for it located along the bottom side of the drivers side of the motor. It's probably dangling loose down there... If you can locate it, you may need to have an 02 bung added to your exhaust system if the headers didnt have it already welded in place.

 

The headers don't and I'll check for the O2 sensor. Was there only one or should I be looking for one along the passenger side as well? Still, I swear I didn't see one when I removed the original manifolds. Hmm...

 

yeah there is only one on the drivers side. Black wire IIRC .

 

Alright, I found it, and yes, it's installed. It's on the driver's side section of the Y-Pipe just under where the header bolts to the Y-pipe. Everything there seems to be in order. I double checked all my vacuum lines and they are all in order.

Tonight I took the car on a 40-mile round trip jaunt on some back roads and I can surely say the water pump doesn't leak. Also, the check engine light never came on (now I'm really confused). I let it idle for about 20 min after I got home and still no check engine light. However, the idle does seem a bit rough and I can't seem to smooth it out any. But otherwise, I'd consider this a success! for the most part. lol