Big_Mark Posted January 19, 2021 Share Posted January 19, 2021 On 11/21/2020 at 8:47 PM, Big_Mark said: Not yet, I guess I'll give it a go and see what happens. Will post up here and in my thread with results. thanks man I feel you pain. SO yes I tried this and there was zero change in behavior. I've also thrown some parts at it (from a junk yard truck) to no avail, including the ignitor and coil. Tested all plug wires, they are good, I'll wait until spring to work on this, hopefully I'll have had my vaccines and my mechanic buddy can help me out. When it's warm again I plan to take off the hood and do the Cruiser54 sensor ground hack to see if that makes any difference for this issue. I'll post up later! Link to comment Share on other sites More sharing options...
Dammerung Posted January 20, 2021 Author Share Posted January 20, 2021 SO yes I tried this and there was zero change in behavior. I've also thrown some parts at it (from a junk yard truck) to no avail, including the ignitor and coil. Tested all plug wires, they are good, I'll wait until spring to work on this, hopefully I'll have had my vaccines and my mechanic buddy can help me out. When it's warm again I plan to take off the hood and do the Cruiser54 sensor ground hack to see if that makes any difference for this issue. I'll post up later!Have you done the injector swap with the 746s? It hasn’t fully solved the problem for me, but it made it more tolerable. All those errors (except the lean loop fault) have gone away naturally, which I think is due to the computer resetting. To be honest, I think I might have an issue with the IAC because unplugging it does nothing or the MAP as my truck will get the “lean loop” fault when it’s in open loop (at least I think it’s open loop. It’s on start up, which is when open loop is used)Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Dammerung Posted February 1, 2021 Author Share Posted February 1, 2021 Question for the people who have engine monitors - how does your O2 sensor perform when you start up? Mine stays near 4.98 volts and drops slowly while in Open loop before swapping into closed and running terribly because of the lean value. Then it swaps back into open loop. I personally don’t think this is how the sensor should be working, but I want to see if other people see the same thing.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
JMO413 Posted February 1, 2021 Share Posted February 1, 2021 9 hours ago, Dammerung said: Question for the people who have engine monitors - how does your O2 sensor perform when you start up? Mine stays near 4.98 volts and drops slowly while in Open loop before swapping into closed and running terribly because of the lean value. Then it swaps back into open loop. I personally don’t think this is how the sensor should be working, but I want to see if other people see the same thing. Sent from my iPhone using Tapatalk Mine stays rich for a little bit then goes into closed and jumps back and forth between rich and lean constantly. Link to comment Share on other sites More sharing options...
fiatslug87 Posted February 1, 2021 Share Posted February 1, 2021 As JM0413 says, jumps between Rich/Lean and O2 reading jumps from low value (~0.2) to high value (~4.8). What you're describing is what I saw in the post I linked on page 2. Link to comment Share on other sites More sharing options...
Ωhm Posted February 1, 2021 Share Posted February 1, 2021 10 hours ago, Dammerung said: I personally don’t think this is how the sensor should be working 02S could be telling you the truth. What's your STFT/LTFT values? Link to comment Share on other sites More sharing options...
JMO413 Posted February 1, 2021 Share Posted February 1, 2021 This is mine today. Is currently 28° in beautiful Iowa. It was warmer up earlier today that's why the coolant temp is slightly warmer. Link to comment Share on other sites More sharing options...
BeatCJ Posted February 2, 2021 Share Posted February 2, 2021 I think what you are seeing is a symptom, not the cause. Sounds like your O2 sensor is working, something else is driving you into Open loop. Link to comment Share on other sites More sharing options...
Dammerung Posted February 2, 2021 Author Share Posted February 2, 2021 02S could be telling you the truth. What's your STFT/LTFT values?When it starts up, both are at 128, which is what I assume to be normal in an open loop startup. When it kicks into closed loop for the first time, LT stays at 128 and ST climbs from 128 up to around 250 before going back into open loop and resetting back to 128. Once it finally works as close to correctly as it can, the STFT bounces between 57-80 if I remember correctly. LTFT is constantly at 128, and I’ve seen no change.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Ωhm Posted February 2, 2021 Share Posted February 2, 2021 13 hours ago, Dammerung said: When it starts up, both are at 128, which is what I assume to be normal in an open loop startup. 128=Normal or Fuel Trim centering point. 13 hours ago, Dammerung said: When it kicks into closed loop for the first time, LT stays at 128 and ST climbs from 128 up to around 250 before going back into open loop and resetting back to 128. ECU is adding fuel (increasing INJ PW time) while attempting to enter CL (ST≈250). This matches what your 02 is seeing (LEAN). 13 hours ago, Dammerung said: Once it finally works as close to correctly as it can, the STFT bounces between 57-80 if I remember correctly Don't know why STFT levels out at 57-80. 02 must be seeing RICH. Does 02S rapidly switch between RICH & LEAN when in CL mode? Link to comment Share on other sites More sharing options...
Ωhm Posted February 2, 2021 Share Posted February 2, 2021 @JMO413 Seems odd you showing KNOCK (KNO) units during (2:33-2:35) IDLE. Not sure if it means anything. Link to comment Share on other sites More sharing options...
Dammerung Posted February 2, 2021 Author Share Posted February 2, 2021 Don't know why STFT levels out at 57-80. 02 must be seeing RICH. Does 02S rapidly switch between RICH & LEAN when in CL mode?O2 does move between Rich and lean with the values being between 1.8 and 4.9 volts.Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Ωhm Posted February 2, 2021 Share Posted February 2, 2021 Only suggestion is check 02 heater circuit for continuity. Disconnect 02S and measure resistance (component) side between C229_A and C229_B. Looking for ≈6Ω. This connector view is harness side. Link to comment Share on other sites More sharing options...
JMO413 Posted February 2, 2021 Share Posted February 2, 2021 4 hours ago, Ωhm said: @JMO413 Seems odd you showing KNOCK (KNO) units during (2:33-2:35) IDLE. Not sure if it means anything. I'm guessing that would be piston slap. She's a little rattaly. Link to comment Share on other sites More sharing options...
Dammerung Posted February 3, 2021 Author Share Posted February 3, 2021 Only suggestion is check 02 heater circuit for continuity. Disconnect 02S and measure resistance (component) side between C229_A and C229_B. Looking for ≈6Ω. This connector view is harness side.I was reading 4.5 ohmsSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Ωhm Posted February 3, 2021 Share Posted February 3, 2021 O2S heater element looks good. Link to comment Share on other sites More sharing options...
fiatslug87 Posted February 3, 2021 Share Posted February 3, 2021 That's the exact reading I was getting on all my non-functional O2 sensors, specification is 5-7. Read the post I linked on page 2. Link to comment Share on other sites More sharing options...
Ωhm Posted February 3, 2021 Share Posted February 3, 2021 May or may not solve your problem but O2 Sensor is a vehicle maintenance item. Replace every 82,500 miles. Link to comment Share on other sites More sharing options...
Big_Mark Posted February 13, 2021 Share Posted February 13, 2021 Since it snowed today I decided to give the old Jeep a hammerdown through the yard, I started it and it was responsive and worked well, but by the 3rd pass across the snow covered field it started stumbling off idle. I noticed the engine had come up to temp. Research on Cherocar forums indicate O2 sensor, when the sun comes out I'll try that since as it has been mentioned here, O2 Sensors are replacement parts and I haven't replaced mine yet. It was fun to drive hard again, even if it was just for 10-15 minutes :-) Link to comment Share on other sites More sharing options...
Big_Mark Posted July 11, 2021 Share Posted July 11, 2021 @Dammerung any progress here? I'm still having the same issues so today I am going to go over all the vacuum lines. Will start by blocking off the accessory line that comes off the manifold, then will spray some carb cleaner around the seals and hose ends. Thing's I've done since Feb: Swapped in new Alternator, replaced fuel pressure regulator, re-wired battery grounds and starter cable. I pulled open my wiring harness under the hood on the firewall to work on Cruiser54s ground hack, only to find it had been fixed already. I plan to solder a wire directly to the ground bundle to see if that makes any improvements. Before I had this issue I had been working on the heater controls, and vacuum reservoir. It's entirely possible one of the one-way vacuum valve has just given out. Fingers crossed that's the issue here, I really want to drive this thing! Link to comment Share on other sites More sharing options...
Dammerung Posted July 11, 2021 Author Share Posted July 11, 2021 @Dammerung any progress here? I'm still having the same issues so today I am going to go over all the vacuum lines. Will start by blocking off the accessory line that comes off the manifold, then will spray some carb cleaner around the seals and hose ends. Thing's I've done since Feb: Swapped in new Alternator, replaced fuel pressure regulator, re-wired battery grounds and starter cable. I pulled open my wiring harness under the hood on the firewall to work on Cruiser54s ground hack, only to find it had been fixed already. I plan to solder a wire directly to the ground bundle to see if that makes any improvements. Before I had this issue I had been working on the heater controls, and vacuum reservoir. It's entirely possible one of the one-way vacuum valve has just given out. Fingers crossed that's the issue here, I really want to drive this thing!Nope. Never figured it out. It just decided to come and go and hasn’t done it since. My fuel trim is still absolutely screwed, but I haven’t been able to figure that out. It runs well enough that I’ve decided to not look the gift horse in the mouth. 1988 Jeep Comanche Pioneer4.0 Liter w/ AW4 2WD Link to comment Share on other sites More sharing options...
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