87 Intake air Temp Sensor
06-08-2014, 01:40 PM
#31
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The gm sensor arrived yesterday, more issues. The gm is 3/8 npt my Cherokee uses 1/4 npt threads. I did more research and a dodge neon sensor is 1/4 npt don't know if specs are the same. Heading to parts store will let you know.
06-08-2014, 02:39 PM
#32
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Put the GM one in the air cleaner lid.......
06-09-2014, 01:33 AM
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Cruiser, its obvious that you know way more than I do, here is my thinking. If I put the 200 ohm resistor in my backfire (lean?) goes away, I think it tells the ecu engine is up to temp. The neon iat I bought caused my backfire to come back, (it must have different values than the stock iat) I put the resistor back in and it goes away. ohm meter reading the neon iat is too high at operating temp. I think if I put the gm iat in the air cleaner it won't get hot enough to get the resistance to 200 ohms. I connected the resistor in during the same test run. Thank you for your help
06-09-2014, 02:55 AM
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Know what? that GM guy may well have an excellent point. I'm working now but later I'll take a peek in the Renix fuel injection manual. In "open loop" it only uses a few crucial sensors, then the manual tells you which are added in "closed loop" after it warms a bit. 
06-09-2014, 03:17 AM
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Cruiser, its obvious that you know way more than I do, here is my thinking. If I put the 200 ohm resistor in my backfire (lean?) goes away, I think it tells the ecu engine is up to temp. The neon iat I bought caused my backfire to come back, (it must have different values than the stock iat) I put the resistor back in and it goes away. ohm meter reading the neon iat is too high at operating temp. I think if I put the gm iat in the air cleaner it won't get hot enough to get the resistance to 200 ohms. I connected the resistor in during the same test run. Thank you for your help
Ain't that something Pete? lerob 225, ohms is what I'm using. Around 500 ohms seems normal, which translates to the sensor reading around 160* there in the manifold. Cruiser is maybe.... mildly..... interested in my experiment. "So Lerob, does the backfire go away if you just leave it unplugged?" , I asked back in post #22.
Do you have an exhaust leak? Like at the header pipe? Backfiring might be rich, with 02 there to "participate" in the bang. If your 02 sensor is getting air it will increase the fuel, (pulse width) to the injectors. Then the gas and air go down the pipe. (A bang might be expected there)
Last edited by DFlintstone; 06-09-2014 at 03:29 AM.
06-09-2014, 06:31 AM
#36
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Could it be the EGR operation? I must be losing it - I thought Cruiser had suggested possible EGR issue on this thread but looking through I can't find his comment. The stuff below is from another source on the web:
EMISSION CONTROL
ECU controls EGR valve and fuel evaporative operation. By energizing the EGR/EVAP solenoid, vacuum is shut off, making this system non-operative. When engine reaches normal operating temperatures, ECU de-energizes solenoid. When de-energized, solenoid allows vacuum to flow to EGR valve. ECU will energize solenoid whenever EGR action is undesirable, during idle, cold engine
operation, wide open throttle and rapid acceleration or deceleration
I guess a test would be to disconnect the EGR solenoid and see if acts differently.
Maybe not the right issue.
Grasping at straws.
EMISSION CONTROL
ECU controls EGR valve and fuel evaporative operation. By energizing the EGR/EVAP solenoid, vacuum is shut off, making this system non-operative. When engine reaches normal operating temperatures, ECU de-energizes solenoid. When de-energized, solenoid allows vacuum to flow to EGR valve. ECU will energize solenoid whenever EGR action is undesirable, during idle, cold engine
operation, wide open throttle and rapid acceleration or deceleration
I guess a test would be to disconnect the EGR solenoid and see if acts differently.
Maybe not the right issue.
Grasping at straws.
Last edited by 67 GMC; 06-09-2014 at 06:33 AM. Reason: formatting
06-09-2014, 07:11 AM
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Cruiser, its obvious that you know way more than I do, here is my thinking. If I put the 200 ohm resistor in my backfire (lean?) goes away, I think it tells the ecu engine is up to temp. The neon iat I bought caused my backfire to come back, (it must have different values than the stock iat) I put the resistor back in and it goes away. ohm meter reading the neon iat is too high at operating temp. I think if I put the gm iat in the air cleaner it won't get hot enough to get the resistance to 200 ohms. I connected the resistor in during the same test run. Thank you for your help
06-09-2014, 07:14 AM
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Guess what the first 4 sensors in that scan of the manual share?
06-09-2014, 03:31 PM
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67 gmc, egr is stuck closed, I hooked up hand held vacuum pump and egr shaft didn't move and it held vacuum. I assumed stuck closed and no vacuum leak was good for this trouble shooting, but we know what happens with assumptions. I'm going camping for the week when I get back I'll continue on with the quest. Thanks for all the help everyone
06-09-2014, 06:32 PM
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06-10-2014, 06:46 AM
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06-10-2014, 08:06 AM
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06-10-2014, 06:23 PM
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Btw, Ed says in post #5 he "applied" Cruiser's tips... Maybe re-checking the sensor ground with a bettter handle on the meter would make sense though.