Need help !!!
Thread Starter
Pro
Joined: Sep 2004
Posts: 505
Likes: 1
From: Guntersville Alabama
Need help !!!
I have a 93 LT1. I have been working on this engine for the last 4 months. I have replaced a bad water pump. This soon led to a Opti replacement, plugs and wires as well. The old plugs appeared to indicate a rich combustion on all 8 cylinders. Test drove the car and it was generating code # 32. Found a vacuum leak. Fixed that and now I am getting code # 64 everytime I drive the car. The fuel economy is poor and engine performance is poor. I know code 64 indicates a lean condition. I will try dicconecting the MAP sensor per the FSM recomendation to see if it makes any difference. I do not have a tech 1 scanner. Any help toward resolving this problem is most appreciated.
Thanks,
93 cruiser
Thanks,
93 cruiser
Racer
Joined: Oct 2005
Posts: 405
Likes: 0
From: 1984 crossfire, Alhaurin de la Torre Malaga, Spain
Dunno, the opti has the sensor for the timing, so there may be a manner to do so. I am not familiar with the opti in detail because my old vette had no opti and my new vette (a 91) I just have a few days and not had the time to even open the hood (almost)
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
There is no timing to check with the opti system. The ECM figures out the ignition timing from all the Hi and Low resolution pulses from the opti and all the sensor inputs from the engine.
The only timing that could have gotten messed up would be while installing the opti and not getting the shaft correctly lined up with the notch.The opti should almost fall on the front cover with a tink and no real force. The bolts should hold it down, not pull it in for seating. I assume that since the engine is running, you probably did it right.
Check for any broken wires or disconnected plugs in places you might have been for your lean condition. A scanner would help so see the O2 readings. If the MAP was acting up it should give you a code 33 or 34. Check the temperature sensor on the water pump for bad connections & wires.
I would like to see you check the sensor also. Partial resistance chart values; 68* it is about 3250 ohms, 77* @ 2796, 86* @ 2238, 122* @ 973, 158* @ 467, and 194* is about 241 ohms. This has a hugh impact in A/F mixture.
The only timing that could have gotten messed up would be while installing the opti and not getting the shaft correctly lined up with the notch.The opti should almost fall on the front cover with a tink and no real force. The bolts should hold it down, not pull it in for seating. I assume that since the engine is running, you probably did it right.
Check for any broken wires or disconnected plugs in places you might have been for your lean condition. A scanner would help so see the O2 readings. If the MAP was acting up it should give you a code 33 or 34. Check the temperature sensor on the water pump for bad connections & wires.
I would like to see you check the sensor also. Partial resistance chart values; 68* it is about 3250 ohms, 77* @ 2796, 86* @ 2238, 122* @ 973, 158* @ 467, and 194* is about 241 ohms. This has a hugh impact in A/F mixture.
Last edited by pcolt94; Jun 13, 2006 at 06:44 AM.
Thread Starter
Pro
Joined: Sep 2004
Posts: 505
Likes: 1
From: Guntersville Alabama
Just checked the ECT at 142 degrees F. The resistance measured was 352 ohms. That is a little more than half of what the table in the FSM listed. I will check it at 90 degrees F when it cools on down. Does anyone know if this is enough of a decrepancy to cause the A/F to be off?
Thanks,
93cruiser
Thanks,
93cruiser
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I would check it first thing in the morning. Find out what the outside temp is and check the FSM for ohm's.
Thread Starter
Pro
Joined: Sep 2004
Posts: 505
Likes: 1
From: Guntersville Alabama
I checked the ECT this morning. Matched up well with the actual temperature. I believe the ECT is working to spec. I did notice something else this afternoon though. Remember, I have an intermittent code 64. The right tail pipe is leaving **** on the rear end where the right side is clean. I am thinking of pulling the exhaust down this weekend and look for problems there. Maybe I have plugged cat.
93cruiser
93cruiser
