LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

help with some DTCs and stall

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Old Mar 14, 2007 | 01:58 PM
  #16  
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Originally Posted by dfa_crunch
To see if the PCM is showing the proper reading, is that the grs im getting from my scanner? or must i check it another way.

as for 3, are you talking about disconnecting a connector to the PCM and measuring the resistance through the wire to the MAF? if so do you know which pin on which connector it is? also what measurement am i looking for?
You already have the reading which someone else stated is "open circuit" So you simply need to find it. By testing the MAF, you also prove it's working correctly.

To ohm it out, buzz from the MAF connector yellow wire to the black PCM connector pin B19 with the yellow wire with at least one end disconnected. There are no connections between those 2 connectors so if you aren't reading, either it's the splice or a break in the wire else where. You should have a reading less than 1 ohm. You should see what the meter reads with the 2 leads touching each other. Than you know the wire should read close to that.

Last edited by Guest47904; Mar 14, 2007 at 02:02 PM.
Old Mar 14, 2007 | 05:22 PM
  #17  
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first i started by checking the freq from the yellow wire on the MAF, and i was pulling .7 KHz with the throttle snapped, you said it should be 7KHz. So i plugged the MAF back in and i went into my car to shut it down so i can read the resistance between the connector and the PCM and before i did i decided to check the codes.

Cleared the codes and scanned, nothing showed. The MAF has been sitting in the history for months now and its cleared. I thought well hey maybe its working, i checked the operational data and now the MAF is reading 7 gr/s instead of 471(open circuit). MAF working? i assume so. A few minutes later my fans turned back on, i scanned the car again and now i have one code.

11 - Malf Indicator Lamp

so i guess this weekend i will have to take a look inside my instrument panel and find that stupid bulb. while im at it, is there somewhere i can get a replacement trip odometer? damn thing has never worked
Old Mar 21, 2007 | 03:01 PM
  #18  
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weird, i decided to scan for codes today to make sure nothing popped up again. well the MAP sensor to low code came back. Sort of confused i took the car for a drive with the operational data mode on my scanner running. i watched the Voltage reading on the Map sensor while i drove. At first it read 0.01 volts, then about 2-3 minutes later it was reading what it was supposed to be reading. then about 2 minutes later it went back, the entire drive it jumped from 0.01 for a few minutes back and then back to normal for a few minutes. i still havent checked on my code 11 yet inside the instrument panel. i was waiting for this weekend to do that. Any idea on why the MAP sensor readings are doing this?

*when the readings get off of 0.01 volts and back to normal the DTC goes away
Old Mar 21, 2007 | 03:44 PM
  #19  
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Either intermittent contact at the connector or a splice. I don't remember if you said the wires were spliced or not.
Old Mar 21, 2007 | 04:46 PM
  #20  
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no, they were spliced on the MAF but not the MAP. you think a new pigtail would do the trick? i guess it doesnt hurt to try. It doesnt do this in warm weather. its like the cold weather makes it intermittent.
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