ckuske Posted November 5, 2023 Share Posted November 5, 2023 Hi Guys, I'm still not driving my truck as much as I'd like, but every couple weeks I'll drive it 10 or 15 miles. I noticed last time I drove it that the "hesitation off a stop" was worse, so I broke out my code reader. I replaced the original computer with a Cardone reman, and the codes went away. Now, code 31 is back (grr) Code 31 is the only KOEO code, but there is Code 31 and 33 in continuous memory. There used to be a lot more codes before replacing sensors, wiring, and the computer, but still, some aren't good... I ran the following wiring tests, and the DD6 test is failing. I also checked resistance of Pins 27 to 40 and 40 to 46 at the EEC connector, and both pairs are reading infinity (so no shorts, unless that is intermittent). I also just for fun (and to double check that I could accurately probe other pins at the EEC connector, I checked continuity between Pins 40 and 60, and that was very close to zero resistance) I am kind of worried that there is an intermittent short that is killing the computer, since DD6 is telling me to replace it?? Link to comment Share on other sites More sharing options...
ckuske Posted November 5, 2023 Author Share Posted November 5, 2023 I also jumpered Pins 27 and 46 (Sig and Sig Rtn) at the EVP connector, and buzzed out the same pins at the EEC connector. .36 ohms resistance - so looks like the wiring is OK? Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 5, 2023 Share Posted November 5, 2023 I also jumpered Pins 27 and 46 (Sig and Sig Rtn) at the EVP connector, and buzzed out the same pins at the EEC connector. .36 ohms resistance - so looks like the wiring is OK? It does look like the wiring is ok. But I'm not sure what that means. Link to comment Share on other sites More sharing options...
ckuske Posted November 7, 2023 Author Share Posted November 7, 2023 It does look like the wiring is ok. But I'm not sure what that means. I’m not either. Either my reconditioned ECU has gone bad with one of the same codes the original ECU had, I have an intermittent short that is damaging ECUs at those input pins. I am going to try and do the jiggle test tomorrow with a test light to see if I can get something to happen. I’ve also ordered another ECU from eBay to compare and contrast but that just adds variables. It seems like an EEC-IV could be done pretty easily these days on a Raspberry Pi or Arduino, if we had access to the data tables etc. I know it’s not THAT easy, but relying on second hand 40 year old hardware with each example having different potential unknown issues isnt fun, either! Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 7, 2023 Share Posted November 7, 2023 I’m not either. Either my reconditioned ECU has gone bad with one of the same codes the original ECU had, I have an intermittent short that is damaging ECUs at those input pins. I am going to try and do the jiggle test tomorrow with a test light to see if I can get something to happen. I’ve also ordered another ECU from eBay to compare and contrast but that just adds variables. It seems like an EEC-IV could be done pretty easily these days on a Raspberry Pi or Arduino, if we had access to the data tables etc. I know it’s not THAT easy, but relying on second hand 40 year old hardware with each example having different potential unknown issues isnt fun, either! Maybe time to go EEC-V? Would be a lot of work, but... Link to comment Share on other sites More sharing options...
85lebaront2 Posted November 7, 2023 Share Posted November 7, 2023 I’m not either. Either my reconditioned ECU has gone bad with one of the same codes the original ECU had, I have an intermittent short that is damaging ECUs at those input pins. I am going to try and do the jiggle test tomorrow with a test light to see if I can get something to happen. I’ve also ordered another ECU from eBay to compare and contrast but that just adds variables. It seems like an EEC-IV could be done pretty easily these days on a Raspberry Pi or Arduino, if we had access to the data tables etc. I know it’s not THAT easy, but relying on second hand 40 year old hardware with each example having different potential unknown issues isnt fun, either! I am not sure if this will help, but, a friend and I ran into EGR position sensor codes with replacement sensors. They would show a small open position reading with the valve verified closed. If you loosened the sensor to where there was a slight gap, then the closed position value would be in spec. Our solution was to shorten the plunger on the sensor enough that it came in spec. I seem to recall it was about 1/8" we took off. Link to comment Share on other sites More sharing options...
ckuske Posted November 7, 2023 Author Share Posted November 7, 2023 I am not sure if this will help, but, a friend and I ran into EGR position sensor codes with replacement sensors. They would show a small open position reading with the valve verified closed. If you loosened the sensor to where there was a slight gap, then the closed position value would be in spec. Our solution was to shorten the plunger on the sensor enough that it came in spec. I seem to recall it was about 1/8" we took off. Thanks Bill! I've seen that post as well. That is on the list of things to try, but the resistance between pins at the EEC is what has me worried (DD6 on the image I posted above). With that resistance, I'm thinking a trace on the board is partially blown, a new bad cap on the processor board, etc. I don't think the two would be correlated, but I'm not assuming anything at this point! I'm not sure if a BOB is really needed, but since we are geeking out on EEC-IV, this seems like a good deal, doesn't it? https://www.ebay.com/itm/296017000421 I think everything is there as far as cables/adapters... Link to comment Share on other sites More sharing options...
ckuske Posted November 7, 2023 Author Share Posted November 7, 2023 Maybe time to go EEC-V? Would be a lot of work, but... Gary, yes, that is a thought too. I mean... I only have ONE code. But this one code is a bugger. I found a few more pinpoint tests to run, I think I will try them right at the EEC instead of the harness (measuring resistance between pins) and see if anything is different (it shouldn't be, but you never know...) Link to comment Share on other sites More sharing options...
ckuske Posted November 9, 2023 Author Share Posted November 9, 2023 Thanks Bill! I've seen that post as well. That is on the list of things to try, but the resistance between pins at the EEC is what has me worried (DD6 on the image I posted above). With that resistance, I'm thinking a trace on the board is partially blown, a new bad cap on the processor board, etc. I don't think the two would be correlated, but I'm not assuming anything at this point! I'm not sure if a BOB is really needed, but since we are geeking out on EEC-IV, this seems like a good deal, doesn't it? https://www.ebay.com/itm/296017000421 I think everything is there as far as cables/adapters... I posted the link here for the breakout box to ask about it, and someone scooped it up. That kinda stinks but I guess that was the risk I took I have another EEC coming in tomorrow, I will let everyone know how it goes after plugging it in (just trying a KOEO test to start!) Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 9, 2023 Share Posted November 9, 2023 I posted the link here for the breakout box to ask about it, and someone scooped it up. That kinda stinks but I guess that was the risk I took I have another EEC coming in tomorrow, I will let everyone know how it goes after plugging it in (just trying a KOEO test to start!) Good luck! Link to comment Share on other sites More sharing options...
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