Gary Lewis Posted February 11, 2023 Share Posted February 11, 2023 Ok, I need to put my EGR/vacuum stuff back on so I can start bleeding the power steering and test it. So, I checked the EVP. My Haynes manual says resistance between VREF and EVP signal pin is supposed to be "slightly less than but no greater than 5000 Ohms". Mine is around 4550. So fail, I think. Next, EVP signal pin and SIG RTN should be "slightly greater than, but no lower than 100 ohms" but it is 1200 Ohms! I think I found the problem? I will take the EVP off the EGR and make sure the pintle isn't stuck somewhere... I imagine a reading this far off could really cause the ECU to do stuff that shouldn't be happening... I think you are onto something. Good luck! Link to comment Share on other sites More sharing options...
ckuske Posted February 11, 2023 Author Share Posted February 11, 2023 I think you are onto something. Good luck! It may not be *the* thing, but it’s definitely *a* thing. I just removed the EVP from the EGR and measured again. (I noticed that when removing it, it felt “spring loaded”, meaning the pintle was depressed just be being installed.) Anyway, with it removed the measurements are now 4880 Ohms and 683 Ohms. Still out of spec, but closer. Looks like I need to hunt for a new EVP… Link to comment Share on other sites More sharing options...
ckuske Posted February 13, 2023 Author Share Posted February 13, 2023 It may not be *the* thing, but it’s definitely *a* thing. I just removed the EVP from the EGR and measured again. (I noticed that when removing it, it felt “spring loaded”, meaning the pintle was depressed just be being installed.) Anyway, with it removed the measurements are now 4880 Ohms and 683 Ohms. Still out of spec, but closer. Looks like I need to hunt for a new EVP… Got the new EVP in. The new NOS Motorcraft one registers less resistance between pins than the one that was on the truck. It still doesn't match the Haynes guidance though... Old One: 692 Ohms between SIG RTN and EVP SIG, and 4940 Ohms between VREF and SIG RTN on the old one. (the RTN/SIG was reading 1200 ohms the other day, so not sure why it is reading 692 now. I did however push the sensor rod in a few times, maybe it has a problem not returning fully out?) New One: 520 Ohms between SIG RTN and EVP SIG, and 4440 Ohms between VREF and SIG RTN on the new one. Now to try it and see if anything is different after starting... Also, the new one came with two different gaskets... I am unsure if both are needed? It seems the wider one would work. Maybe due to different vehicles? I would put both on, the smaller one sites on top of a flat region of the wider o-ring, but I since this sensor is based on depth into the EGR, I am worried it might throw it off. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 14, 2023 Share Posted February 14, 2023 Got the new EVP in. The new NOS Motorcraft one registers less resistance between pins than the one that was on the truck. It still doesn't match the Haynes guidance though... Old One: 692 Ohms between SIG RTN and EVP SIG, and 4940 Ohms between VREF and SIG RTN on the old one. (the RTN/SIG was reading 1200 ohms the other day, so not sure why it is reading 692 now. I did however push the sensor rod in a few times, maybe it has a problem not returning fully out?) New One: 520 Ohms between SIG RTN and EVP SIG, and 4440 Ohms between VREF and SIG RTN on the new one. Now to try it and see if anything is different after starting... Also, the new one came with two different gaskets... I am unsure if both are needed? It seems the wider one would work. Maybe due to different vehicles? I would put both on, the smaller one sites on top of a flat region of the wider o-ring, but I since this sensor is based on depth into the EGR, I am worried it might throw it off. I'm guessing that the different gaskets are for different vehicles. So if the wider one fits yours I'd go with it. Good luck! Link to comment Share on other sites More sharing options...
ckuske Posted February 14, 2023 Author Share Posted February 14, 2023 I'm guessing that the different gaskets are for different vehicles. So if the wider one fits yours I'd go with it. Good luck! Thanks, will try it out shortly! I realize I ask questions that are fairly obvious, but I try to not assume too much. There is a lot of tribal knowledge that you only acquire through the School of Hard Knocks, and I rely on you guys to hopefully steer me in the right direction. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 14, 2023 Share Posted February 14, 2023 Thanks, will try it out shortly! I realize I ask questions that are fairly obvious, but I try to not assume too much. There is a lot of tribal knowledge that you only acquire through the School of Hard Knocks, and I rely on you guys to hopefully steer me in the right direction. You are right to ask questions. The only dumb question is one you didn't ask. Link to comment Share on other sites More sharing options...
ckuske Posted February 14, 2023 Author Share Posted February 14, 2023 You are right to ask questions. The only dumb question is one you didn't ask. Well, not fixed. I ran the KOEO test first, it came back clean (phew). I ran the KOER test next, and got all sorts of goofy codes, some of which weren't even in the reader manual. I convinced myself last time when this happened that I didn't set the reader up correctly. (I use https://a.co/d/aW87eVS) I thought the procedure was: 1. Warm truck up, then turn ignition off 2. Connect test connector and single (ground?) wire to terminals on code reader 3. Turn code reader on 4. Turn ignition on, start engine 5. Press Test button on reader 6. See Cylinder ID code 7. Wait for 10 code 8. Press accelerator In reality, I ran the test several times - most of the time the Cylinder ID code didn't come out, the 10 code came out sometimes, and got odd codes such as 3, 4, etc. I had this happen before, but altered my steps and it was much more coherent (got Cylinder ID test, 10, and then only one code, 35). Most of the steps I find online relate to a test light, maybe I'm getting something wrong in the translation. Apart from my KOER problems here (likely my fault), the stumble is still there at fast idle. I didn't back probe the EVP connector to check the voltage differential between pins. Maybe that is next. One other note, the first time I ran KOER, the engine died during a part of the test where I assume the EGR is opened. After the engine died, there was a repetitive sound of a "click" (but deeper than that), about 8 times a second. Constant, no variability in timing etc. It sounded to be coming from the EGR, but that doens't make much sense. It was definitely from that area, I tried to stick my head close but couldn't isolate it exactly. I kind of thought maybe it would have been the thermactor solenoids, but they were silent.... I still have the truck on jack stands from bleeding the power steering, I'll lower it and take it for a quick drive in a day or so to see if the main problem is addressed. Link to comment Share on other sites More sharing options...
ckuske Posted February 14, 2023 Author Share Posted February 14, 2023 Well, not fixed. I ran the KOEO test first, it came back clean (phew). I ran the KOER test next, and got all sorts of goofy codes, some of which weren't even in the reader manual. I convinced myself last time when this happened that I didn't set the reader up correctly. (I use https://a.co/d/aW87eVS) I thought the procedure was: 1. Warm truck up, then turn ignition off 2. Connect test connector and single (ground?) wire to terminals on code reader 3. Turn code reader on 4. Turn ignition on, start engine 5. Press Test button on reader 6. See Cylinder ID code 7. Wait for 10 code 8. Press accelerator In reality, I ran the test several times - most of the time the Cylinder ID code didn't come out, the 10 code came out sometimes, and got odd codes such as 3, 4, etc. I had this happen before, but altered my steps and it was much more coherent (got Cylinder ID test, 10, and then only one code, 35). Most of the steps I find online relate to a test light, maybe I'm getting something wrong in the translation. Apart from my KOER problems here (likely my fault), the stumble is still there at fast idle. I didn't back probe the EVP connector to check the voltage differential between pins. Maybe that is next. One other note, the first time I ran KOER, the engine died during a part of the test where I assume the EGR is opened. After the engine died, there was a repetitive sound of a "click" (but deeper than that), about 8 times a second. Constant, no variability in timing etc. It sounded to be coming from the EGR, but that doens't make much sense. It was definitely from that area, I tried to stick my head close but couldn't isolate it exactly. I kind of thought maybe it would have been the thermactor solenoids, but they were silent.... I still have the truck on jack stands from bleeding the power steering, I'll lower it and take it for a quick drive in a day or so to see if the main problem is addressed. Just ran it again - maybe it's not warmed up enough? I waited until the thermostat opened etc.... about 4 to 5 minutes of running time, about 90 seconds at 2000 rpm. Choke was fully open. Anyway, the code this time (with no Cylinder ID again...): 20 47 2 5 47 3 85 2, 5, and 3 are out of bounds. 85 doesn't seem to apply to trucks at all. I am out of time today, I will drive the truck before posting again. Thanks for hanging in there. Link to comment Share on other sites More sharing options...
ckuske Posted February 17, 2023 Author Share Posted February 17, 2023 Just ran it again - maybe it's not warmed up enough? I waited until the thermostat opened etc.... about 4 to 5 minutes of running time, about 90 seconds at 2000 rpm. Choke was fully open. Anyway, the code this time (with no Cylinder ID again...): 20 47 2 5 47 3 85 2, 5, and 3 are out of bounds. 85 doesn't seem to apply to trucks at all. I am out of time today, I will drive the truck before posting again. Thanks for hanging in there. I got a smoke machine and ran a smoke test. I taped the carb up, and ran the smoke through the brake booster line. I found one 'T' vacuum fitting that had a leak. Fixed that leak. OK, I took the truck out to warm it up for a KOER test, and drove it around tried to see if the hesitation was better. At first it wasn't... same as usual. After about a minute of driving, it was essentially gone. The stumble at fast idle is still there when in park (even after pulling back in, putting it in park, then revving to 2000 rpm). It's not there when driving... Moving on to try to KOER test again: I got the cylinder code (8) just fine this time. Ok, great... maybe I didn't warm it up enough last time. A little bit went by, then got the goose code (10). Hit the gas, codes started coming out. Some puzzlers still: 31,35,82,4,41,47,92,94 I turned everything off, ran the test again. Same results up to the codes coming out. I got code 32, then 35. Another code was being read, and my scanner display went completely blank. Like dead. Batteries are fine. Disconnected it and turned it back on... lit right up. So now, I am not sure what to trust. Is my reader bad (maybe)... is my ECU bad? Maybe. KOEO still works fine every time, no issues there. So, I've fixed one vacuum leak and the hesitation in drive is better, but my KOER tests are goofy and the stumble in park is still there. I am getting a little frustrated - I feel like I am reaching my diagnosis limits. But, the one guy I've taken the truck to before hasn't been able to address the hesistation issue in drive after he's seen it three times (it was lower on the list compared to other problems). He's kind of the "go to" guy around here for this vintage of car, and I don't want to start shot gunning and trying random people. I'm not sure where to go from here to be honest. I suppose buying a new reader or just getting a test light is the next step... Link to comment Share on other sites More sharing options...
grumpin Posted February 17, 2023 Share Posted February 17, 2023 I got a smoke machine and ran a smoke test. I taped the carb up, and ran the smoke through the brake booster line. I found one 'T' vacuum fitting that had a leak. Fixed that leak. OK, I took the truck out to warm it up for a KOER test, and drove it around tried to see if the hesitation was better. At first it wasn't... same as usual. After about a minute of driving, it was essentially gone. The stumble at fast idle is still there when in park (even after pulling back in, putting it in park, then revving to 2000 rpm). It's not there when driving... Moving on to try to KOER test again: I got the cylinder code (8) just fine this time. Ok, great... maybe I didn't warm it up enough last time. A little bit went by, then got the goose code (10). Hit the gas, codes started coming out. Some puzzlers still: 31,35,82,4,41,47,92,94 I turned everything off, ran the test again. Same results up to the codes coming out. I got code 32, then 35. Another code was being read, and my scanner display went completely blank. Like dead. Batteries are fine. Disconnected it and turned it back on... lit right up. So now, I am not sure what to trust. Is my reader bad (maybe)... is my ECU bad? Maybe. KOEO still works fine every time, no issues there. So, I've fixed one vacuum leak and the hesitation in drive is better, but my KOER tests are goofy and the stumble in park is still there. I am getting a little frustrated - I feel like I am reaching my diagnosis limits. But, the one guy I've taken the truck to before hasn't been able to address the hesistation issue in drive after he's seen it three times (it was lower on the list compared to other problems). He's kind of the "go to" guy around here for this vintage of car, and I don't want to start shot gunning and trying random people. I'm not sure where to go from here to be honest. I suppose buying a new reader or just getting a test light is the next step... Which reader do you have? Link to comment Share on other sites More sharing options...
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